def generate_energies(self, t_exp, area, prng=None, quiet=False):
"""
Generate photon energies from this spectrum
given an exposure time and effective area.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The effective area in cm**2. If one is creating
events for a SIMPUT file, a constant should be
used and it must be large enough so that a
sufficiently large sample is drawn for the ARF.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
quiet : boolean, optional
If True, log messages will not be displayed when
creating energies. Useful if you have to loop over
a lot of spectra. Default: False
"""
t_exp = parse_value(t_exp, "s")
area = parse_value(area, "cm**2")
prng = parse_prng(prng)
rate = area*self.total_flux.value
energy = _generate_energies(self, t_exp, rate, prng, quiet=quiet)
flux = np.sum(energy)*erg_per_keV/t_exp/area
energies = Energies(energy, flux)
return energies
def from_models(cls, name, spectral_model, spatial_model,
t_exp, area, prng=None):
"""
Generate a single photon list from a spectral and a spatial
model.
Parameters
----------
name : string
The name of the photon list. This will also be the prefix
of any photon list file that is written from this photon list.
spectral_model : :class:`~soxs.spectra.Spectrum`
The spectral model to use to generate the event energies.
spatial_model : :class:`~soxs.spatial.SpatialModel`
The spatial model to use to generate the event coordinates.
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The effective area in cm**2. If one is creating
events for a SIMPUT file, a constant should be
used and it must be large enough so that a
sufficiently large sample is drawn for the ARF.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
t_exp = parse_value(t_exp, "s")
area = parse_value(area, "cm**2")
e = spectral_model.generate_energies(t_exp, area, prng=prng)
ra, dec = spatial_model.generate_coords(e.size, prng=prng)
return cls(name, ra, dec, e, e.flux)
def generate_fluxes(fov, prng):
from soxs.data import cdf_fluxes, cdf_gal, cdf_agn
prng = parse_prng(prng)
fov = parse_value(fov, "arcmin")
logf = np.log10(cdf_fluxes)
n_gal = np.rint(cdf_gal[-1])
n_agn = np.rint(cdf_agn[-1])
F_gal = cdf_gal / cdf_gal[-1]
F_agn = cdf_agn / cdf_agn[-1]
f_gal = InterpolatedUnivariateSpline(F_gal, logf)
f_agn = InterpolatedUnivariateSpline(F_agn, logf)
fov_area = fov**2
n_gal = int(n_gal * fov_area / 3600.0)
n_agn = int(n_agn * fov_area / 3600.0)
mylog.debug(f"{n_agn} AGN, {n_gal} galaxies in the FOV.")
randvec1 = prng.uniform(size=n_agn)
agn_fluxes = 10**f_agn(randvec1)
randvec2 = prng.uniform(size=n_gal)
gal_fluxes = 10**f_gal(randvec2)
return agn_fluxes, gal_fluxes
def make_instrument_background(bkgnd_name,
event_params,
focal_length,
rmf,
prng=None):
prng = parse_prng(prng)
bkgnd_spec = instrument_backgrounds[bkgnd_name]
# Generate background events
energy = bkgnd_spec.generate_energies(event_params["exposure_time"],
event_params["fov"],
focal_length=focal_length,
prng=prng,
quiet=True).value
if energy.size == 0:
raise RuntimeError(
"No instrumental background events were detected!!!")
else:
mylog.info("Making %d events from the instrumental background." %
energy.size)
return make_uniform_background(energy, event_params, rmf, prng=prng)
def absorb_photons(self, eobs, prng=None):
r"""
Determine which photons will be absorbed by foreground
galactic absorption.
Parameters
----------
eobs : array_like
The energies of the photons in keV.
prng : integer, :class:`~numpy.random.RandomState` object or :mod:`~numpy.random`, optional
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
n_events = eobs.size
if n_events == 0:
return np.array([], dtype='bool')
detected = np.zeros(n_events, dtype='bool')
nchunk = n_events // 100
if nchunk == 0:
nchunk = n_events
k = 0
pbar = get_pbar("Absorbing photons", n_events)
while k < n_events:
absorb = self.get_absorb(eobs[k:k+nchunk])
nabs = absorb.size
randvec = prng.uniform(size=nabs)
detected[k:k+nabs] = randvec < absorb
k += nabs
pbar.update(k)
pbar.finish()
return detected
def generate_energies(self, t_exp, area, prng=None, quiet=False):
"""
Generate photon energies from this spectrum
given an exposure time and effective area.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The effective area in cm**2. If one is creating
events for a SIMPUT file, a constant should be
used and it must be large enough so that a
sufficiently large sample is drawn for the ARF.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
quiet : boolean, optional
If True, log messages will not be displayed when
creating energies. Useful if you have to loop over
a lot of spectra. Default: False
"""
t_exp = parse_value(t_exp, "s")
area = parse_value(area, "cm**2")
prng = parse_prng(prng)
rate = area*self.total_flux.value
energy = _generate_energies(self, t_exp, rate, prng, quiet=quiet)
flux = np.sum(energy)*erg_per_keV/t_exp/area
energies = Energies(energy, flux)
return energies
def absorb_photons(self, eobs, prng=None):
r"""
Determine which photons will be absorbed by foreground
galactic absorption.
Parameters
----------
eobs : array_like
The energies of the photons in keV.
prng : integer, :class:`~numpy.random.RandomState` object or :mod:`~numpy.random`, optional
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
n_events = eobs.size
if n_events == 0:
return np.array([], dtype='bool')
detected = np.zeros(n_events, dtype='bool')
nchunk = n_events // 100
if nchunk == 0:
nchunk = n_events
k = 0
pbar = get_pbar("Absorbing photons", n_events)
while k < n_events:
absorb = self.get_absorb(eobs[k:k + nchunk])
nabs = absorb.size
randvec = prng.uniform(size=nabs)
detected[k:k + nabs] = randvec < absorb
k += nabs
pbar.update(k)
pbar.finish()
return detected
def convolve_spectrum(self, cspec, exp_time, noisy=True, prng=None):
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
counts = cspec.flux.value * exp_time * cspec.de.value
spec = np.histogram(cspec.emid.value, self.ebins, weights=counts)[0]
conv_spec = np.zeros(self.n_ch)
pbar = tqdm(leave=True, total=self.n_e, desc="Convolving spectrum ")
if np.all(self.data["N_GRP"] == 1):
# We can do things a bit faster if there is only one group each
f_chan = ensure_numpy_array(np.nan_to_num(self.data["F_CHAN"]))
n_chan = ensure_numpy_array(np.nan_to_num(self.data["N_CHAN"]))
mat = np.nan_to_num(np.float64(self.data["MATRIX"]))
mat_size = np.minimum(n_chan, self.n_ch-f_chan)
for k in range(self.n_e):
conv_spec[f_chan[k]:f_chan[k]+n_chan[k]] += spec[k]*mat[k,:mat_size[k]]
pbar.update()
else:
# Otherwise, we have to go step-by-step
for k in range(self.n_e):
f_chan = ensure_numpy_array(np.nan_to_num(self.data["F_CHAN"][k]))
n_chan = ensure_numpy_array(np.nan_to_num(self.data["N_CHAN"][k]))
mat = np.nan_to_num(np.float64(self.data["MATRIX"][k]))
mat_size = np.minimum(n_chan, self.n_ch-f_chan)
for i, f in enumerate(f_chan):
conv_spec[f:f+n_chan[i]] += spec[k]*mat[:mat_size[i]]
pbar.update()
pbar.close()
if noisy:
return prng.poisson(lam=conv_spec)
else:
return conv_spec
def generate_energies(self, t_exp, prng=None, quiet=False):
"""
Generate photon energies from this convolved spectrum given an
exposure time.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
quiet : boolean, optional
If True, log messages will not be displayed when
creating energies. Useful if you have to loop over
a lot of spectra. Default: False
"""
t_exp = parse_value(t_exp, "s")
prng = parse_prng(prng)
rate = self.total_flux.value
energy = _generate_energies(self, t_exp, rate, prng, quiet=quiet)
earea = self.arf.interpolate_area(energy).value
flux = np.sum(energy)*erg_per_keV/t_exp/earea.sum()
energies = Energies(energy, flux)
return energies
def generate_energies(self, t_exp, prng=None, quiet=False):
"""
Generate photon energies from this convolved spectrum given an
exposure time.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
quiet : boolean, optional
If True, log messages will not be displayed when
creating energies. Useful if you have to loop over
a lot of spectra. Default: False
"""
t_exp = parse_value(t_exp, "s")
prng = parse_prng(prng)
rate = self.total_flux.value
energy = _generate_energies(self, t_exp, rate, prng, quiet=quiet)
earea = self.arf.interpolate_area(energy).value
flux = np.sum(energy)*erg_per_keV/t_exp/earea.sum()
energies = Energies(energy, flux)
return energies
def generate_sources(fov, sky_center, prng=None):
r"""
Make a catalog of point sources.
Parameters
----------
fov : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The field of view in arcminutes.
sky_center : array-like
The center RA, Dec of the field of view in degrees.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
fov = parse_value(fov, "arcmin")
agn_fluxes, gal_fluxes = generate_fluxes(fov, prng)
fluxes = np.concatenate([agn_fluxes, gal_fluxes])
ind = np.concatenate([
get_agn_index(np.log10(agn_fluxes)),
gal_index * np.ones(gal_fluxes.size)
])
ra0, dec0 = generate_positions(fluxes.size, fov, sky_center, prng)
return ra0, dec0, fluxes, ind
def ch_to_eb(self, channels, prng=None):
prng = parse_prng(prng)
emin = self.ebounds_data["E_MIN"]
emax = self.ebounds_data["E_MAX"]
de = emax-emin
ch = channels - self.cmin
e = emin[ch] + prng.uniform(size=channels.size)*de[ch]
return e
def make_foreground(event_params, arf, rmf, prng=None):
import pyregion._region_filter as rfilter
prng = parse_prng(prng)
conv_frgnd_spec = ConvolvedBackgroundSpectrum(hm_astro_bkgnd, arf)
energy = conv_frgnd_spec.generate_energies(event_params["exposure_time"],
event_params["fov"], prng=prng,
quiet=True).value
prng = parse_prng(prng)
bkg_events = {}
n_events = energy.size
nx = event_params["num_pixels"]
bkg_events["detx"] = prng.uniform(low=-0.5*nx, high=0.5*nx, size=n_events)
bkg_events["dety"] = prng.uniform(low=-0.5*nx, high=0.5*nx, size=n_events)
bkg_events["energy"] = energy
if event_params["chips"] is None:
bkg_events["chip_id"] = np.zeros(n_events, dtype='int')
else:
bkg_events["chip_id"] = -np.ones(n_events, dtype='int')
for i, chip in enumerate(event_params["chips"]):
thisc = np.ones(n_events, dtype='bool')
rtype = chip[0]
args = chip[1:]
r = getattr(rfilter, rtype)(*args)
inside = r.inside(bkg_events["detx"], bkg_events["dety"])
thisc = np.logical_and(thisc, inside)
bkg_events["chip_id"][thisc] = i
keep = bkg_events["chip_id"] > -1
if keep.sum() == 0:
raise RuntimeError("No astrophysical foreground events were detected!!!")
else:
mylog.info("Making %d events from the astrophysical foreground." % keep.sum())
for key in bkg_events:
bkg_events[key] = bkg_events[key][keep]
return make_diffuse_background(bkg_events, event_params, rmf, prng=prng)
def make_foreground(event_params, arf, rmf, prng=None):
import pyregion._region_filter as rfilter
prng = parse_prng(prng)
conv_frgnd_spec = ConvolvedBackgroundSpectrum(hm_astro_bkgnd, arf)
energy = conv_frgnd_spec.generate_energies(event_params["exposure_time"],
event_params["fov"], prng=prng,
quiet=True).value
prng = parse_prng(prng)
bkg_events = {}
n_events = energy.size
nx = event_params["num_pixels"]
bkg_events["detx"] = prng.uniform(low=-0.5*nx, high=0.5*nx, size=n_events)
bkg_events["dety"] = prng.uniform(low=-0.5*nx, high=0.5*nx, size=n_events)
bkg_events["energy"] = energy
if event_params["chips"] is None:
bkg_events["chip_id"] = np.zeros(n_events, dtype='int')
else:
bkg_events["chip_id"] = -np.ones(n_events, dtype='int')
for i, chip in enumerate(event_params["chips"]):
thisc = np.ones(n_events, dtype='bool')
rtype = chip[0]
args = chip[1:]
r = getattr(rfilter, rtype)(*args)
inside = r.inside(bkg_events["detx"], bkg_events["dety"])
thisc = np.logical_and(thisc, inside)
bkg_events["chip_id"][thisc] = i
keep = bkg_events["chip_id"] > -1
if keep.sum() == 0:
raise RuntimeError("No astrophysical foreground events were detected!!!")
else:
mylog.info("Making %d events from the astrophysical foreground." % keep.sum())
for key in bkg_events:
bkg_events[key] = bkg_events[key][keep]
return make_diffuse_background(bkg_events, event_params, rmf, prng=prng)
def make_point_sources(area, exp_time, positions, sky_center,
spectra, prng=None):
r"""
Create a new :class:`~pyxsim.event_list.EventList` which contains
point sources.
Parameters
----------
area : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The collecting area to determine the number of events. If units are
not specified, it is assumed to be in cm^2.
exp_time : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The exposure time to determine the number of events. If units are
not specified, it is assumed to be in seconds.
positions : array of source positions, shape 2xN
The positions of the point sources in RA, Dec, where N is the
number of point sources. Coordinates should be in degrees.
sky_center : array-like
Center RA, Dec of the events in degrees.
spectra : list (size N) of :class:`~soxs.spectra.Spectrum` objects
The spectra for the point sources, where N is the number
of point sources. Assumed to be in the observer frame.
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
spectra = ensure_list(spectra)
positions = ensure_list(positions)
area = parse_value(area, "cm**2")
exp_time = parse_value(exp_time, "s")
t_exp = exp_time.value/comm.size
x = []
y = []
e = []
for pos, spectrum in zip(positions, spectra):
eobs = spectrum.generate_energies(t_exp, area.value, prng=prng)
ne = eobs.size
x.append(YTArray([pos[0]] * ne, "deg"))
y.append(YTArray([pos[1]] * ne, "deg"))
e.append(YTArray.from_astropy(eobs))
parameters = {"sky_center": YTArray(sky_center, "degree"),
"exp_time": exp_time,
"area": area}
events = {}
events["xsky"] = uconcatenate(x)
events["ysky"] = uconcatenate(y)
events["eobs"] = uconcatenate(e)
return EventList(events, parameters)
def make_point_sources(area, exp_time, positions, sky_center,
spectra, prng=None):
r"""
Create a new :class:`~pyxsim.event_list.EventList` which contains
point sources.
Parameters
----------
area : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The collecting area to determine the number of events. If units are
not specified, it is assumed to be in cm^2.
exp_time : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The exposure time to determine the number of events. If units are
not specified, it is assumed to be in seconds.
positions : array of source positions, shape 2xN
The positions of the point sources in RA, Dec, where N is the
number of point sources. Coordinates should be in degrees.
sky_center : array-like
Center RA, Dec of the events in degrees.
spectra : list (size N) of :class:`~soxs.spectra.Spectrum` objects
The spectra for the point sources, where N is the number
of point sources. Assumed to be in the observer frame.
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
spectra = ensure_list(spectra)
positions = ensure_list(positions)
area = parse_value(area, "cm**2")
exp_time = parse_value(exp_time, "s")
t_exp = exp_time.value/comm.size
x = []
y = []
e = []
for pos, spectrum in zip(positions, spectra):
eobs = spectrum.generate_energies(t_exp, area.value, prng=prng)
ne = eobs.size
x.append(YTArray([pos[0]] * ne, "degree"))
y.append(YTArray([pos[1]] * ne, "degree"))
e.append(YTArray.from_astropy(eobs))
parameters = {"sky_center": YTArray(sky_center, "degree"),
"exp_time": exp_time,
"area": area}
events = {}
events["eobs"] = uconcatenate(e)
events["xsky"] = uconcatenate(x)
events["ysky"] = uconcatenate(y)
return EventList(events, parameters)
def __init__(self, e0, emin, emax, emission_field, alpha, prng=None):
self.e0 = parse_value(e0, "keV")
self.emin = parse_value(emin, "keV")
self.emax = parse_value(emax, "keV")
self.emission_field = emission_field
self.alpha = alpha
self.prng = parse_prng(prng)
self.spectral_norm = None
self.redshift = None
def __init__(self, e0, emin, emax, emission_field, alpha, prng=None):
self.e0 = parse_value(e0, "keV")
self.emin = parse_value(emin, "keV")
self.emax = parse_value(emax, "keV")
self.emission_field = emission_field
self.alpha = alpha
self.prng = parse_prng(prng)
self.spectral_norm = None
self.redshift = None
def scatter_energies(self, events, prng=None):
"""
Scatter photon energies with the RMF and produce the
corresponding channel values.
Parameters
----------
events : dict of np.ndarrays
The energies and positions of the photons.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
eidxs = np.argsort(events["energy"])
sorted_e = events["energy"][eidxs]
detectedChannels = []
# run through all photon energies and find which bin they go in
fcurr = 0
last = sorted_e.shape[0]
emin = sorted_e[0]
emax = sorted_e[-1]
pbar = tqdm(leave=True, total=last, desc="Scattering energies ")
for (k, low), high in zip(enumerate(self.elo), self.ehi):
if high < emin or low > emax:
continue
e = sorted_e[fcurr:last]
nn = np.logical_and(low <= e, e < high).sum()
if nn == 0:
continue
# weight function for probabilities from RMF
weights = np.nan_to_num(np.float64(self.data["MATRIX"][k]))
weights /= weights.sum()
trueChannel = self._make_channels(k)
if len(trueChannel) > 0:
channelInd = prng.choice(len(weights), size=nn, p=weights)
detectedChannels.append(trueChannel[channelInd])
fcurr += nn
pbar.update(nn)
pbar.close()
for key in events:
events[key] = events[key][eidxs]
events[self.header["CHANTYPE"]] = np.concatenate(detectedChannels)
return events
def make_instrument_background(inst_spec, event_params, rmf, prng=None):
from collections import defaultdict
prng = parse_prng(prng)
bkgnd_spec = inst_spec["bkgnd"]
if isinstance(bkgnd_spec[0], str):
nchips = len(event_params["chips"])
bkgnd_spec = [bkgnd_spec] * nchips
bkg_events = defaultdict(list)
pixel_area = (event_params["plate_scale"] * 60.0)**2
for i, chip in enumerate(event_params["chips"]):
rtype = chip[0]
args = chip[1:]
r, bounds = create_region(rtype, args, 0.0, 0.0)
sa = (bounds[1] - bounds[0]) * (bounds[3] - bounds[2]) * pixel_area
bspec = InstrumentalBackground.from_filename(bkgnd_spec[i][0],
bkgnd_spec[i][1],
inst_spec['focal_length'])
chan = bspec.generate_channels(event_params["exposure_time"],
sa,
prng=prng)
n_events = chan.size
detx = prng.uniform(low=bounds[0], high=bounds[1], size=n_events)
dety = prng.uniform(low=bounds[2], high=bounds[3], size=n_events)
if rtype in ["Box", "Rectangle"]:
thisc = slice(None, None, None)
n_det = n_events
else:
thisc = r.contains(PixCoord(detx, dety))
n_det = thisc.sum()
ch = chan[thisc].astype('int')
e = rmf.ch_to_eb(ch, prng=prng)
bkg_events["energy"].append(e)
bkg_events[rmf.chan_type].append(ch)
bkg_events["detx"].append(detx[thisc])
bkg_events["dety"].append(dety[thisc])
bkg_events["chip_id"].append(i * np.ones(n_det))
for key in bkg_events:
bkg_events[key] = np.concatenate(bkg_events[key])
if bkg_events["energy"].size == 0:
raise RuntimeError(
"No instrumental background events were detected!!!")
else:
mylog.info(f"Making {bkg_events['energy'].size} events "
f"from the instrumental background.")
return make_diffuse_background(bkg_events, event_params, rmf, prng=prng)
def detect_events(self, events, exp_time, flux, refband, prng=None):
"""
Use the ARF to determine a subset of photons which
will be detected. Returns a boolean NumPy array
which is the same is the same size as the number
of photons, wherever it is "true" means those photons
have been detected.
Parameters
----------
events : dict of np.ndarrays
The energies and positions of the photons.
exp_time : float
The exposure time in seconds.
flux : float
The total flux of the photons in erg/s/cm^2.
refband : array_like
A two-element array or list containing the limits
of the energy band which the flux was computed in.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
energy = events["energy"]
if energy.size == 0:
return events
earea = self.interpolate_area(energy).value
idxs = np.logical_and(energy >= refband[0], energy <= refband[1])
rate = flux / (energy[idxs].sum() * erg_per_keV) * earea[idxs].sum()
n_ph = prng.poisson(lam=rate * exp_time)
fak = float(n_ph) / energy.size
if fak > 1.0:
mylog.error(
"Number of events in sample: %d, Number of events wanted: %d" %
(energy.size, n_ph))
raise ValueError(
"This combination of exposure time and effective area "
"will result in more photons being drawn than are available "
"in the sample!!!")
w = earea / self.max_area
randvec = prng.uniform(size=energy.size)
eidxs = prng.permutation(
np.where(randvec < w)[0])[:n_ph].astype("int64")
mylog.info("%s events detected." % n_ph)
for key in events:
events[key] = events[key][eidxs]
return events
def make_background(area, exp_time, fov, sky_center, spectrum, prng=None):
r"""
Create a new :class:`~pyxsim.event_list.EventList` which is filled
uniformly with background events.
Parameters
----------
area : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The collecting area to determine the number of events. If units are
not specified, it is assumed to be in cm^2.
exp_time : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The exposure time to determine the number of events. If units are
not specified, it is assumed to be in seconds.
fov : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The field of view of the event file. If units are not
provided, they are assumed to be in arcminutes.
sky_center : array-like
Center RA, Dec of the events in degrees.
spectrum : :class:`~soxs.spectra.Spectrum`
The spectrum for the background.
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
fov = parse_value(fov, "arcmin")
exp_time = parse_value(exp_time, "s")
area = parse_value(area, "cm**2")
t_exp = exp_time.value / comm.size
e = spectrum.generate_energies(t_exp, area.value, prng=prng)
fov_model = FillFOVModel(sky_center[0], sky_center[1], fov.value)
ra, dec = fov_model.generate_coords(e.size, prng=prng)
parameters = {
"sky_center": YTArray(sky_center, "degree"),
"exp_time": exp_time,
"area": area
}
events = {}
events["xsky"] = YTArray(ra.value, "degree")
events["ysky"] = YTArray(dec.value, "degree")
events["eobs"] = YTArray(e.value, "keV")
return EventList(events, parameters)
def make_xrb_photons(ds, redshift, area, exp_time, emin, emax,
center="c", cosmology=None, prng=None):
r"""
Take a dataset produced by
:func:`~pyxsim.source_generators.xray_binaries.make_xrb_particles`
and produce a :class:`~pyxsim.photon_list.PhotonList`.
Parameters
----------
ds : :class:`~yt.data_objects.static_output.Dataset`
The dataset of XRB particles to use to make the photons.
redshift : float
The cosmological redshift for the photons.
area : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The collecting area to determine the number of photons. If units are
not specified, it is assumed to be in cm^2.
exp_time : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The exposure time to determine the number of photons. If units are
not specified, it is assumed to be in seconds.
emin : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The minimum energy of the photons to be generated, in the rest frame of
the source. If units are not given, they are assumed to be in keV.
emax : float, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The maximum energy of the photons to be generated, in the rest frame of
the source. If units are not given, they are assumed to be in keV.
center : string or array_like, optional
The origin of the photon spatial coordinates. Accepts "c", "max", or a coordinate.
If not specified, pyxsim attempts to use the "center" field parameter of the data_source.
cosmology : :class:`~yt.utilities.cosmology.Cosmology`, optional
Cosmological information. If not supplied, we try to get
the cosmology from the dataset. Otherwise, LCDM with
the default yt parameters is assumed.
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
dd = ds.all_data()
e0 = (1.0, "keV")
prng = parse_prng(prng)
xrb_model = PowerLawSourceModel(e0, emin, emax,
"particle_count_rate",
"particle_spectral_index", prng=prng)
photons = PhotonList.from_data_source(dd, redshift, area, exp_time,
xrb_model, center=center,
point_sources=True,
cosmology=cosmology)
return photons
def __init__(self, spectral_model, emin, emax, nchan,
temperature_field=None, emission_measure_field=None,
kT_min=0.008, kT_max=64.0, n_kT=10000,
kT_scale="linear", Zmet=0.3, var_elem=None,
method="invert_cdf", thermal_broad=True,
model_root=None, model_vers=None, nei=False,
nolines=False, abund_table="angr", prng=None):
if isinstance(spectral_model, string_types):
if spectral_model not in thermal_models:
raise KeyError("%s is not a known thermal spectral model!" % spectral_model)
spectral_model = thermal_models[spectral_model]
self.temperature_field = temperature_field
self.Zmet = Zmet
self.nei = nei
if var_elem is None:
var_elem = {}
var_elem_keys = None
self.num_var_elem = 0
else:
var_elem_keys = list(var_elem.keys())
self.num_var_elem = len(var_elem_keys)
self.var_elem = var_elem
self.spectral_model = spectral_model(emin, emax, nchan,
var_elem=var_elem_keys,
thermal_broad=thermal_broad,
model_root=model_root,
model_vers=model_vers,
nolines=nolines, nei=nei,
abund_table=abund_table)
self.var_elem_keys = self.spectral_model.var_elem_names
self.var_ion_keys = self.spectral_model.var_ion_names
self.method = method
self.prng = parse_prng(prng)
self.kT_min = kT_min
self.kT_max = kT_max
self.kT_scale = kT_scale
self.n_kT = n_kT
self.spectral_norm = None
self.redshift = None
self.pbar = None
self.kT_bins = None
self.dkT = None
self.emission_measure_field = emission_measure_field
self.Zconvert = 1.0
self.abund_table = abund_table
self.atable = self.spectral_model.atable
self.mconvert = {}
def detect_events(self, events, exp_time, flux, refband, prng=None):
"""
Use the ARF to determine a subset of photons which
will be detected. Returns a boolean NumPy array
which is the same is the same size as the number
of photons, wherever it is "true" means those photons
have been detected.
Parameters
----------
events : dict of np.ndarrays
The energies and positions of the photons.
exp_time : float
The exposure time in seconds.
flux : float
The total flux of the photons in erg/s/cm^2.
refband : array_like
A two-element array or list containing the limits
of the energy band which the flux was computed in.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
energy = events["energy"]
if energy.size == 0:
return events
earea = self.interpolate_area(energy).value
idxs = np.logical_and(energy >= refband[0], energy <= refband[1])
rate = flux/(energy[idxs].sum()*erg_per_keV)*earea[idxs].sum()
n_ph = prng.poisson(lam=rate*exp_time)
fak = float(n_ph)/energy.size
if fak > 1.0:
mylog.error("Number of events in sample: %d, Number of events wanted: %d" % (energy.size, n_ph))
raise ValueError("This combination of exposure time and effective area "
"will result in more photons being drawn than are available "
"in the sample!!!")
w = earea / self.max_area
randvec = prng.uniform(size=energy.size)
eidxs = prng.permutation(np.where(randvec < w)[0])[:n_ph].astype("int64")
mylog.info("%s events detected." % n_ph)
for key in events:
events[key] = events[key][eidxs]
return events
def convolve_spectrum(self, cspec, exp_time, prng=None):
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
counts = cspec.flux.value * exp_time * cspec.de.value
spec = np.histogram(cspec.emid.value, self.ebins, weights=counts)[0]
conv_spec = np.zeros(self.n_ch)
pbar = tqdm(leave=True, total=self.n_e, desc="Convolving spectrum ")
for k in range(self.n_e):
f_chan = ensure_numpy_array(np.nan_to_num(self.data["F_CHAN"][k]))
n_chan = ensure_numpy_array(np.nan_to_num(self.data["N_CHAN"][k]))
mat = np.nan_to_num(np.float64(self.data["MATRIX"][k]))
for f, n in zip(f_chan, n_chan):
mat_size = min(n, self.n_ch-f)
conv_spec[f:f+n] += spec[k]*mat[:mat_size]
pbar.update()
pbar.close()
return prng.poisson(lam=conv_spec)
def detect_events_spec(self, src, exp_time, refband, prng=None):
from soxs.spectra import ConvolvedSpectrum
prng = parse_prng(prng)
cspec = ConvolvedSpectrum.convolve(
src.spec, self).new_spec_from_band(refband[0], refband[1])
energy = cspec.generate_energies(exp_time, quiet=True, prng=prng).value
if getattr(src, "imhdu", None):
x, y = image_pos(src.imhdu.data, energy.size, prng)
w = pywcs.WCS(header=src.imhdu.header)
w.wcs.crval = [src.ra, src.dec]
ra, dec = w.wcs_pix2world(x, y, 1)
else:
pones = np.ones_like(energy)
ra = src.ra*pones
dec = src.dec*pones
mylog.info(f"{energy.size} events detected.")
return {"energy": energy, "ra": ra, "dec": dec}
def scatter_energies(self, events, prng=None):
"""
Scatter photon energies with the RMF and produce the
corresponding channel values.
Parameters
----------
events : dict of np.ndarrays
The energies and positions of the photons.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
eidxs = np.argsort(events["energy"])
sorted_e = events["energy"][eidxs]
detectedChannels = []
# run through all photon energies and find which bin they go in
fcurr = 0
last = sorted_e.shape[0]
pbar = tqdm(leave=True, total=last, desc="Scattering energies ")
for (k, low), high in zip(enumerate(self.elo), self.ehi):
# weight function for probabilities from RMF
weights = np.nan_to_num(np.float64(self.data["MATRIX"][k]))
weights /= weights.sum()
trueChannel = self._make_channels(k)
if len(trueChannel) > 0:
e = sorted_e[fcurr:last]
nn = np.logical_and(low <= e, e < high).sum()
channelInd = prng.choice(len(weights), size=nn, p=weights)
detectedChannels.append(trueChannel[channelInd])
fcurr += nn
pbar.update(nn)
pbar.close()
for key in events:
events[key] = events[key][eidxs]
events[self.header["CHANTYPE"]] = np.concatenate(detectedChannels)
return events
def generate_energies(self,
t_exp,
fov,
focal_length=None,
prng=None,
quiet=False):
"""
Generate photon energies from this instrumental
background spectrum given an exposure time,
effective area, and field of view.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
fov : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The width of the field of view on a side in
arcminutes.
focal_length : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The focal length in meters. Default is to use
the default focal length of the instrument
configuration.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
quiet : boolean, optional
If True, log messages will not be displayed when
creating energies. Useful if you have to loop over
a lot of spectra. Default: False
"""
t_exp = parse_value(t_exp, "s")
fov = parse_value(fov, "arcmin")
prng = parse_prng(prng)
if focal_length is None:
focal_length = self.default_focal_length
else:
focal_length = parse_value(focal_length, "m")
rate = fov * fov * self.total_flux.value
rate *= (focal_length / self.default_focal_length)**2
energy = _generate_energies(self, t_exp, rate, prng, quiet=quiet)
flux = np.sum(energy) * erg_per_keV / t_exp
energies = Energies(energy, flux)
return energies
def make_foreground(event_params, arf, rmf, prng=None):
prng = parse_prng(prng)
conv_frgnd_spec = ConvolvedBackgroundSpectrum.convolve(hm_astro_bkgnd, arf)
bkg_events = {"energy": [], "detx": [], "dety": [], "chip_id": []}
pixel_area = (event_params["plate_scale"]*60.0)**2
for i, chip in enumerate(event_params["chips"]):
rtype = chip[0]
args = chip[1:]
r, bounds = create_region(rtype, args, 0.0, 0.0)
fov = np.sqrt((bounds[1]-bounds[0])*(bounds[3]-bounds[2])*pixel_area)
e = conv_frgnd_spec.generate_energies(event_params["exposure_time"],
fov, prng=prng, quiet=True).value
n_events = e.size
detx = prng.uniform(low=bounds[0], high=bounds[1], size=n_events)
dety = prng.uniform(low=bounds[2], high=bounds[3], size=n_events)
if rtype in ["Box", "Rectangle"]:
thisc = slice(None, None, None)
n_det = n_events
else:
thisc = r.contains(PixCoord(detx, dety))
n_det = thisc.sum()
bkg_events["energy"].append(e[thisc])
bkg_events["detx"].append(detx[thisc])
bkg_events["dety"].append(dety[thisc])
bkg_events["chip_id"].append(i*np.ones(n_det))
for key in bkg_events:
bkg_events[key] = np.concatenate(bkg_events[key])
if bkg_events["energy"].size == 0:
raise RuntimeError("No astrophysical foreground events "
"were detected!!!")
else:
mylog.info(f"Making {bkg_events['energy'].size} events from the "
f"astrophysical foreground.")
bkg_events = make_diffuse_background(bkg_events,
event_params, rmf, prng=prng)
mylog.info(f"Scattering energies with "
f"RMF {os.path.split(rmf.filename)[-1]}.")
return rmf.scatter_energies(bkg_events, prng=prng)
def __call__(self, events, prng=None):
"""
Calling method for :class:`~pyxsim.instruments.InstrumentSimulator`.
Parameters
----------
events : :class:`~pyxsim.events.EventList`
An EventList instance of unconvolved events.
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
issue_deprecation_warning("The pyXSIM built-in instrument simulators "
"have been deprecated and will be removed "
"in a future release!")
if "pi" in events or "pha" in events:
raise RuntimeError(
"These events have already been convolved with a response!!")
prng = parse_prng(prng)
flux = np.sum(events["eobs"]).to("erg") / \
events.parameters["exp_time"]/events.parameters["area"]
exp_time = events.parameters["exp_time"]
emin = events["eobs"].min().value
emax = events["eobs"].max().value
new_events = {}
new_events.update(events.events)
new_events["energy"] = new_events.pop("eobs")
new_events = self.arf.detect_events(new_events,
exp_time,
flux, [emin, emax],
prng=prng)
new_events = self.rmf.scatter_energies(new_events, prng=prng)
new_events["eobs"] = new_events.pop("energy")
chantype = self.rmf.header["CHANTYPE"].lower()
new_events[chantype] = new_events.pop(self.rmf.header["CHANTYPE"])
parameters = {}
parameters.update(events.parameters)
parameters["channel_type"] = chantype
parameters["mission"] = self.rmf.header.get("MISSION", "")
parameters["instrument"] = self.rmf.header["INSTRUME"]
parameters["telescope"] = self.rmf.header["TELESCOP"]
parameters["arf"] = self.arf.filename
parameters["rmf"] = self.rmf.filename
return ConvolvedEventList(new_events, parameters)
def make_foreground(event_params, arf, rmf, prng=None):
prng = parse_prng(prng)
conv_bkgnd_spec = ConvolvedBackgroundSpectrum(hm_astro_bkgnd, arf)
energy = conv_bkgnd_spec.generate_energies(event_params["exposure_time"],
event_params["fov"],
prng=prng,
quiet=True).value
if energy.size == 0:
raise RuntimeError(
"No astrophysical foreground events were detected!!!")
else:
mylog.info("Making %d events from the astrophysical foreground." %
energy.size)
return make_uniform_background(energy, event_params, rmf, prng=prng)
def generate_sources(exp_time, fov, sky_center, area=40000.0, prng=None):
r"""
Make a catalog of point sources.
Parameters
----------
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time of the observation in seconds.
fov : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The field of view in arcminutes.
sky_center : array-like
The center RA, Dec of the field of view in degrees.
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The effective area in cm**2. It must be large enough
so that a sufficiently large sample is drawn for the
ARF. Default: 40000.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
fov = parse_value(fov, "arcmin")
area = parse_value(area, "cm**2")
agn_fluxes, gal_fluxes = generate_fluxes(exp_time, area, fov, prng)
fluxes = np.concatenate([agn_fluxes, gal_fluxes])
ind = np.concatenate([get_agn_index(np.log10(agn_fluxes)),
gal_index * np.ones(gal_fluxes.size)])
dec_scal = np.fabs(np.cos(sky_center[1] * np.pi / 180))
ra_min = sky_center[0] - fov / (2.0 * 60.0 * dec_scal)
dec_min = sky_center[1] - fov / (2.0 * 60.0)
ra0 = prng.uniform(size=fluxes.size) * fov / (60.0 * dec_scal) + ra_min
dec0 = prng.uniform(size=fluxes.size) * fov / 60.0 + dec_min
return ra0, dec0, fluxes, ind
def generate_coords(self, num_events, prng=None):
"""
Generate a sample of photon positions from this
spatial model.
Parameters
----------
num_events : integer
The number of events to generate.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
x, y = self._generate_coords(num_events, prng)
ra, dec = self.w.wcs_pix2world(x, y, 1)
return u.Quantity(ra, "deg"), u.Quantity(dec, "deg")
def generate_coords(self, num_events, prng=None):
"""
Generate a sample of photon positions from this
spatial model.
Parameters
----------
num_events : integer
The number of events to generate.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
x, y = self._generate_coords(num_events, prng)
ra, dec = self.w.wcs_pix2world(x, y, 1)
return u.Quantity(ra, "deg"), u.Quantity(dec, "deg")
def __call__(self, events, prng=None):
"""
Calling method for :class:`~pyxsim.instruments.InstrumentSimulator`.
Parameters
----------
events : :class:`~pyxsim.events.EventList`
An EventList instance of unconvolved events.
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
issue_deprecation_warning("The pyXSIM built-in instrument simulators "
"have been deprecated and will be removed "
"in a future release!")
if "pi" in events or "pha" in events:
raise RuntimeError("These events have already been convolved with a response!!")
prng = parse_prng(prng)
flux = np.sum(events["eobs"]).to("erg") / \
events.parameters["exp_time"]/events.parameters["area"]
exp_time = events.parameters["exp_time"]
emin = events["eobs"].min().value
emax = events["eobs"].max().value
new_events = {}
new_events.update(events.events)
new_events["energy"] = new_events.pop("eobs")
new_events = self.arf.detect_events(new_events, exp_time, flux,
[emin, emax], prng=prng)
new_events = self.rmf.scatter_energies(new_events, prng=prng)
new_events["eobs"] = new_events.pop("energy")
chantype = self.rmf.header["CHANTYPE"].lower()
new_events[chantype] = new_events.pop(self.rmf.header["CHANTYPE"])
parameters = {}
parameters.update(events.parameters)
parameters["channel_type"] = chantype
parameters["mission"] = self.rmf.header.get("MISSION", "")
parameters["instrument"] = self.rmf.header["INSTRUME"]
parameters["telescope"] = self.rmf.header["TELESCOP"]
parameters["arf"] = self.arf.filename
parameters["rmf"] = self.rmf.filename
return ConvolvedEventList(new_events, parameters)
def __init__(self,
ra0,
dec0,
width,
height,
num_events,
theta=0.0,
prng=None):
prng = parse_prng(prng)
ra0 = parse_value(ra0, "deg")
dec0 = parse_value(dec0, "deg")
width = parse_value(width, "arcsec")
height = parse_value(height, "arcsec")
w = construct_wcs(ra0, dec0)
x = prng.uniform(low=-0.5 * width, high=0.5 * width, size=num_events)
y = prng.uniform(low=-0.5 * height, high=0.5 * height, size=num_events)
coords = rotate_xy(theta, x, y)
ra, dec = w.wcs_pix2world(coords[0, :], coords[1, :], 1)
super(RectangleModel, self).__init__(ra, dec, coords[0, :],
coords[1, :], w)
def generate_energies(self, t_exp, fov, focal_length=None,
prng=None, quiet=False):
"""
Generate photon energies from this instrumental
background spectrum given an exposure time,
effective area, and field of view.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
fov : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The width of the field of view on a side in
arcminutes.
focal_length : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The focal length in meters. Default is to use
the default focal length of the instrument
configuration.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
quiet : boolean, optional
If True, log messages will not be displayed when
creating energies. Useful if you have to loop over
a lot of spectra. Default: False
"""
t_exp = parse_value(t_exp, "s")
fov = parse_value(fov, "arcmin")
prng = parse_prng(prng)
if focal_length is None:
focal_length = self.default_focal_length
else:
focal_length = parse_value(focal_length, "m")
rate = fov*fov*self.total_flux.value
rate *= (focal_length/self.default_focal_length)**2
energy = _generate_energies(self, t_exp, rate, prng, quiet=quiet)
flux = np.sum(energy)*erg_per_keV/t_exp
energies = Energies(energy, flux)
return energies
def __init__(self, e0, emission_field, sigma=None, prng=None):
self.e0 = parse_value(e0, "keV")
if isinstance(sigma, (float, YTQuantity)) or (isinstance(sigma, tuple) and isinstance(sigma[0], float)):
# The broadening is constant
try:
self.sigma = parse_value(sigma, "keV")
except YTUnitConversionError:
try:
self.sigma = parse_value(sigma, "km/s")
self.sigma *= self.e0/clight
self.sigma.convert_to_units("keV")
except YTUnitConversionError:
raise RuntimeError("Units for sigma must either be in dimensions of "
"energy or velocity! sigma = %s" % sigma)
else:
# Either no broadening or a field name
self.sigma = sigma
self.emission_field = emission_field
self.prng = parse_prng(prng)
self.spectral_norm = None
self.redshift = None
def __init__(self,
ra0,
dec0,
func,
num_events,
theta=0.0,
ellipticity=1.0,
prng=None):
prng = parse_prng(prng)
ra0 = parse_value(ra0, "deg")
dec0 = parse_value(dec0, "deg")
theta = parse_value(theta, "deg")
x, y = generate_radial_events(num_events,
func,
prng,
ellipticity=ellipticity)
w = construct_wcs(ra0, dec0)
coords = rotate_xy(theta, x, y)
ra, dec = w.wcs_pix2world(coords[0, :], coords[1, :], 1)
super(RadialFunctionModel, self).__init__(ra, dec, coords[0, :],
coords[1, :], w)
def from_models(cls,
name,
spectral_model,
spatial_model,
t_exp,
area,
prng=None):
"""
Generate a single photon list from a spectral and a spatial
model.
Parameters
----------
name : string
The name of the photon list. This will also be the prefix
of any photon list file that is written from this photon list.
spectral_model : :class:`~soxs.spectra.Spectrum`
The spectral model to use to generate the event energies.
spatial_model : :class:`~soxs.spatial.SpatialModel`
The spatial model to use to generate the event coordinates.
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The effective area in cm**2. If one is creating
events for a SIMPUT file, a constant should be
used and it must be large enough so that a
sufficiently large sample is drawn for the ARF.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
t_exp = parse_value(t_exp, "s")
area = parse_value(area, "cm**2")
e = spectral_model.generate_energies(t_exp, area, prng=prng)
ra, dec = spatial_model.generate_coords(e.size, prng=prng)
return cls(name, ra, dec, e, e.flux)
def __init__(self, e0, emission_field, sigma=None, prng=None):
self.e0 = parse_value(e0, "keV")
if isinstance(sigma, (float, YTQuantity)) or (isinstance(
sigma, tuple) and isinstance(sigma[0], float)):
# The broadening is constant
try:
self.sigma = parse_value(sigma, "keV")
except YTUnitConversionError:
try:
self.sigma = parse_value(sigma, "km/s")
self.sigma *= self.e0 / clight
self.sigma.convert_to_units("keV")
except YTUnitConversionError:
raise RuntimeError(
"Units for sigma must either be in dimensions of "
"energy or velocity! sigma = %s" % sigma)
else:
# Either no broadening or a field name
self.sigma = sigma
self.emission_field = emission_field
self.prng = parse_prng(prng)
self.spectral_norm = None
self.redshift = None
def generate_channel_spectrum(self,
t_exp,
solid_angle,
focal_length=None,
prng=None):
"""
Generate photon energy channels from this instrumental
background spectrum given an exposure time,
effective area, and solid angle.
Parameters
----------
t_exp : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
solid_angle : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The solid angle in arcmin**2.
focal_length : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The focal length in meters. Default is to use
the default focal length of the instrument
configuration.
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
t_exp = parse_value(t_exp, "s")
solid_angle = parse_value(solid_angle, "arcmin**2")
prng = parse_prng(prng)
if focal_length is None:
focal_length = self.default_focal_length
else:
focal_length = parse_value(focal_length, "m")
fac = t_exp * solid_angle # Backgrounds are normalized to 1 arcmin**2
fac *= (focal_length / self.default_focal_length)**2
return prng.poisson(lam=self.count_rate * fac)
def make_cosmological_sources(exp_time, fov, sky_center, cat_center=None,
absorb_model="wabs", nH=0.05, area=40000.0,
output_sources=None, prng=None):
r"""
Make an X-ray source made up of contributions from
galaxy clusters, galaxy groups, and galaxies.
Parameters
----------
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time of the observation in seconds.
fov : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The field of view in arcminutes.
sky_center : array-like
The center RA, Dec of the field of view in degrees.
cat_center : array-like
The center of the field in the coordinates of the
halo catalog, which range from -5.0 to 5.0 in
degrees in both directions. If None is given, a
center will be randomly chosen.
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The effective area in cm**2. It must be large enough
so that a sufficiently large sample is drawn for the
ARF. Default: 40000.
output_sources : string, optional
If set to a filename, output the properties of the sources
within the field of view to a file. Default: None
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
exp_time = parse_value(exp_time, "s")
fov = parse_value(fov, "arcmin")
if nH is not None:
nH = parse_value(nH, "1.0e22*cm**-2")
area = parse_value(area, "cm**2")
prng = parse_prng(prng)
cosmo = FlatLambdaCDM(H0=100.0*h0, Om0=omega_m)
agen = ApecGenerator(0.1, 10.0, 10000, broadening=False)
mylog.info("Creating photons from cosmological sources.")
mylog.info("Loading halo data from catalog: %s" % halos_cat_file)
halo_data = h5py.File(halos_cat_file, "r")
scale = cosmo.kpc_proper_per_arcmin(halo_data["redshift"]).to("Mpc/arcmin")
# 600. arcmin = 10 degrees (total FOV of catalog = 100 deg^2)
fov_cat = 10.0*60.0
w = construct_wcs(*sky_center)
cat_min = -0.5*fov_cat
cat_max = 0.5*fov_cat
if cat_center is None:
xc, yc = prng.uniform(low=cat_min+0.5*fov, high=cat_max-0.5*fov, size=2)
else:
xc, yc = cat_center
xc *= 60.0
yc *= 60.0
xc, yc = np.clip([xc, yc], cat_min+0.5*fov, cat_max-0.5*fov)
mylog.info("Coordinates of the FOV within the catalog are (%g, %g) deg." %
(xc/60.0, yc/60.0))
xlo = (xc-1.1*0.5*fov)*scale.value*h0
xhi = (xc+1.1*0.5*fov)*scale.value*h0
ylo = (yc-1.1*0.5*fov)*scale.value*h0
yhi = (yc+1.1*0.5*fov)*scale.value*h0
mylog.info("Selecting halos in the FOV.")
fov_idxs = (halo_data["x"] >= xlo) & (halo_data["x"] <= xhi)
fov_idxs = (halo_data["y"] >= ylo) & (halo_data["y"] <= yhi) & fov_idxs
n_halos = fov_idxs.sum()
mylog.info("Number of halos in the field of view: %d" % n_halos)
# Now select the specific halos which are in the FOV
z = halo_data["redshift"][fov_idxs].astype("float64")
m = halo_data["M500c"][fov_idxs].astype("float64")/h0
s = scale[fov_idxs].to("Mpc/arcsec").value
ra0, dec0 = w.wcs_pix2world(halo_data["x"][fov_idxs]/(h0*s)-xc*60.0,
halo_data["y"][fov_idxs]/(h0*s)-yc*60.0, 1)
# Close the halo catalog file
halo_data.close()
# Some cosmological stuff
rho_crit = cosmo.critical_density(z).to("Msun/Mpc**3").value
# halo temperature and k-corrected flux
kT = Tx(m, z)
flux_kcorr = 1.0e-14*lum(m, z)/flux2lum(kT, z)
# halo scale radius
r500 = (3.0*m/(4.0*np.pi*500*rho_crit))**(1.0/3.0)
r500_kpc = r500 * 1000.0
rc_kpc = r500/conc * 1000.0
rc = r500/conc/s
# Halo slope parameter
beta = prng.normal(loc=0.666, scale=0.05, size=n_halos)
beta[beta < 0.5] = 0.5
# Halo ellipticity
ellip = prng.normal(loc=0.85, scale=0.15, size=n_halos)
ellip[ellip < 0.0] = 1.0e-3
# Halo orientation
theta = 360.0*prng.uniform(size=n_halos)
# If requested, output the source properties to a file
if output_sources is not None:
t = Table([ra0, dec0, rc_kpc, beta, ellip, theta, m, r500_kpc, kT, z, flux_kcorr],
names=('RA', 'Dec', 'r_c', 'beta', 'ellipticity',
'theta', 'M500c', 'r500', 'kT', 'redshift', 'flux_0.5_2.0_keV'))
t["RA"].unit = "deg"
t["Dec"].unit = "deg"
t["flux_0.5_2.0_keV"].unit = "erg/(cm**2*s)"
t["r_c"].unit = "kpc"
t["theta"].unit = "deg"
t["M500c"].unit = "solMass"
t["r500"].unit = "kpc"
t["kT"].unit = "kT"
t.write(output_sources, format='ascii.ecsv', overwrite=True)
tot_flux = 0.0
ee = []
ra = []
dec = []
pbar = tqdm(leave=True, total=n_halos, desc="Generating photons from halos ")
for halo in range(n_halos):
spec = agen.get_spectrum(kT[halo], abund, z[halo], 1.0)
spec.rescale_flux(flux_kcorr[halo], emin=emin, emax=emax, flux_type="energy")
if nH is not None:
spec.apply_foreground_absorption(nH, model=absorb_model)
e = spec.generate_energies(exp_time, area, prng=prng, quiet=True)
beta_model = BetaModel(ra0[halo], dec0[halo], rc[halo], beta[halo],
ellipticity=ellip[halo], theta=theta[halo])
xsky, ysky = beta_model.generate_coords(e.size, prng=prng)
tot_flux += e.flux
ee.append(e.value)
ra.append(xsky.value)
dec.append(ysky.value)
pbar.update()
pbar.close()
ra = np.concatenate(ra)
dec = np.concatenate(dec)
ee = np.concatenate(ee)
mylog.info("Created %d photons from cosmological sources." % ee.size)
output_events = {"ra": ra, "dec": dec, "energy": ee,
"flux": tot_flux.value}
return output_events
def generate_events(input_events, exp_time, instrument, sky_center,
no_dither=False, dither_params=None,
roll_angle=0.0, subpixel_res=False, prng=None):
"""
Take unconvolved events and convolve them with instrumental responses. This
function does the following:
1. Determines which events are observed using the ARF
2. Pixelizes the events, applying PSF effects and dithering
3. Determines energy channels using the RMF
This function is not meant to be called by the end-user but is used by
the :func:`~soxs.instrument.instrument_simulator` function.
Parameters
----------
input_events : string, dict, or None
The unconvolved events to be used as input. Can be one of the
following:
1. The name of a SIMPUT catalog file.
2. A Python dictionary containing the following items:
"ra": A NumPy array of right ascension values in degrees.
"dec": A NumPy array of declination values in degrees.
"energy": A NumPy array of energy values in keV.
"flux": The flux of the entire source, in units of erg/cm**2/s.
out_file : string
The name of the event file to be written.
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time to use, in seconds.
instrument : string
The name of the instrument to use, which picks an instrument
specification from the instrument registry.
sky_center : array, tuple, or list
The center RA, Dec coordinates of the observation, in degrees.
no_dither : boolean, optional
If True, turn off dithering entirely. Default: False
dither_params : array-like of floats, optional
The parameters to use to control the size and period of the dither
pattern. The first two numbers are the dither amplitude in x and y
detector coordinates in arcseconds, and the second two numbers are
the dither period in x and y detector coordinates in seconds.
Default: [8.0, 8.0, 1000.0, 707.0].
roll_angle : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The roll angle of the observation in degrees. Default: 0.0
subpixel_res: boolean, optional
If True, event positions are not randomized within the pixels
within which they are detected. Default: False
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
import pyregion._region_filter as rfilter
exp_time = parse_value(exp_time, "s")
roll_angle = parse_value(roll_angle, "deg")
prng = parse_prng(prng)
if isinstance(input_events, dict):
parameters = {}
for key in ["flux", "emin", "emax", "sources"]:
parameters[key] = input_events[key]
event_list = []
for i in range(len(parameters["flux"])):
edict = {}
for key in ["ra", "dec", "energy"]:
edict[key] = input_events[key][i]
event_list.append(edict)
elif isinstance(input_events, string_types):
# Assume this is a SIMPUT catalog
event_list, parameters = read_simput_catalog(input_events)
try:
instrument_spec = instrument_registry[instrument]
except KeyError:
raise KeyError("Instrument %s is not in the instrument registry!" % instrument)
if not instrument_spec["imaging"]:
raise RuntimeError("Instrument '%s' is not " % instrument_spec["name"] +
"designed for imaging observations!")
arf_file = get_response_path(instrument_spec["arf"])
rmf_file = get_response_path(instrument_spec["rmf"])
arf = AuxiliaryResponseFile(arf_file)
rmf = RedistributionMatrixFile(rmf_file)
nx = instrument_spec["num_pixels"]
plate_scale = instrument_spec["fov"]/nx/60. # arcmin to deg
plate_scale_arcsec = plate_scale * 3600.0
if not instrument_spec["dither"]:
dither_on = False
else:
dither_on = not no_dither
if dither_params is None:
dither_params = [8.0, 8.0, 1000.0, 707.0]
dither_dict = {"x_amp": dither_params[0],
"y_amp": dither_params[1],
"x_period": dither_params[2],
"y_period": dither_params[3],
"dither_on": dither_on,
"plate_scale": plate_scale_arcsec}
event_params = {}
event_params["exposure_time"] = exp_time
event_params["arf"] = arf.filename
event_params["sky_center"] = sky_center
event_params["pix_center"] = np.array([0.5*(2*nx+1)]*2)
event_params["num_pixels"] = nx
event_params["plate_scale"] = plate_scale
event_params["rmf"] = rmf.filename
event_params["channel_type"] = rmf.header["CHANTYPE"]
event_params["telescope"] = rmf.header["TELESCOP"]
event_params["instrument"] = instrument_spec['name']
event_params["mission"] = rmf.header.get("MISSION", "")
event_params["nchan"] = rmf.n_ch
event_params["roll_angle"] = roll_angle
event_params["fov"] = instrument_spec["fov"]
event_params["chan_lim"] = [rmf.cmin, rmf.cmax]
event_params["chips"] = instrument_spec["chips"]
event_params["dither_params"] = dither_dict
event_params["aimpt_coords"] = instrument_spec["aimpt_coords"]
w = pywcs.WCS(naxis=2)
w.wcs.crval = event_params["sky_center"]
w.wcs.crpix = event_params["pix_center"]
w.wcs.cdelt = [-plate_scale, plate_scale]
w.wcs.ctype = ["RA---TAN","DEC--TAN"]
w.wcs.cunit = ["deg"]*2
rot_mat = get_rot_mat(roll_angle)
all_events = defaultdict(list)
for i, evts in enumerate(event_list):
mylog.info("Detecting events from source %s." % parameters["sources"][i])
# Step 1: Use ARF to determine which photons are observed
mylog.info("Applying energy-dependent effective area from %s." % os.path.split(arf.filename)[-1])
refband = [parameters["emin"][i], parameters["emax"][i]]
events = arf.detect_events(evts, exp_time, parameters["flux"][i], refband, prng=prng)
n_evt = events["energy"].size
if n_evt == 0:
mylog.warning("No events were observed for this source!!!")
else:
# Step 2: Assign pixel coordinates to events. Apply dithering and
# PSF. Clip events that don't fall within the detection region.
mylog.info("Pixeling events.")
# Convert RA, Dec to pixel coordinates
xpix, ypix = w.wcs_world2pix(events["ra"], events["dec"], 1)
xpix -= event_params["pix_center"][0]
ypix -= event_params["pix_center"][1]
events.pop("ra")
events.pop("dec")
n_evt = xpix.size
# Rotate physical coordinates to detector coordinates
det = np.dot(rot_mat, np.array([xpix, ypix]))
detx = det[0,:] + event_params["aimpt_coords"][0]
dety = det[1,:] + event_params["aimpt_coords"][1]
# Add times to events
events['time'] = prng.uniform(size=n_evt, low=0.0,
high=event_params["exposure_time"])
# Apply dithering
x_offset, y_offset = perform_dither(events["time"], dither_dict)
detx -= x_offset
dety -= y_offset
# PSF scattering of detector coordinates
if instrument_spec["psf"] is not None:
psf_type, psf_spec = instrument_spec["psf"]
if psf_type == "gaussian":
sigma = psf_spec/sigma_to_fwhm/plate_scale_arcsec
detx += prng.normal(loc=0.0, scale=sigma, size=n_evt)
dety += prng.normal(loc=0.0, scale=sigma, size=n_evt)
else:
raise NotImplementedError("PSF type %s not implemented!" % psf_type)
# Convert detector coordinates to chip coordinates.
# Throw out events that don't fall on any chip.
cx = np.trunc(detx)+0.5*np.sign(detx)
cy = np.trunc(dety)+0.5*np.sign(dety)
if event_params["chips"] is None:
events["chip_id"] = np.zeros(n_evt, dtype='int')
keepx = np.logical_and(cx >= -0.5*nx, cx <= 0.5*nx)
keepy = np.logical_and(cy >= -0.5*nx, cy <= 0.5*nx)
keep = np.logical_and(keepx, keepy)
else:
events["chip_id"] = -np.ones(n_evt, dtype='int')
for i, chip in enumerate(event_params["chips"]):
thisc = np.ones(n_evt, dtype='bool')
rtype = chip[0]
args = chip[1:]
r = getattr(rfilter, rtype)(*args)
inside = r.inside(cx, cy)
thisc = np.logical_and(thisc, inside)
events["chip_id"][thisc] = i
keep = events["chip_id"] > -1
mylog.info("%d events were rejected because " % (n_evt-keep.sum()) +
"they do not fall on any CCD.")
n_evt = keep.sum()
if n_evt == 0:
mylog.warning("No events are within the field of view for this source!!!")
else:
# Keep only those events which fall on a chip
for key in events:
events[key] = events[key][keep]
# Convert chip coordinates back to detector coordinates, unless the
# user has specified that they want subpixel resolution
if subpixel_res:
events["detx"] = detx[keep]
events["dety"] = dety[keep]
else:
events["detx"] = cx[keep] + prng.uniform(low=-0.5, high=0.5, size=n_evt)
events["dety"] = cy[keep] + prng.uniform(low=-0.5, high=0.5, size=n_evt)
# Convert detector coordinates back to pixel coordinates by
# adding the dither offsets back in and applying the rotation
# matrix again
det = np.array([events["detx"] + x_offset[keep] - event_params["aimpt_coords"][0],
events["dety"] + y_offset[keep] - event_params["aimpt_coords"][1]])
pix = np.dot(rot_mat.T, det)
events["xpix"] = pix[0,:] + event_params['pix_center'][0]
events["ypix"] = pix[1,:] + event_params['pix_center'][1]
if n_evt > 0:
for key in events:
all_events[key] = np.concatenate([all_events[key], events[key]])
if len(all_events["energy"]) == 0:
mylog.warning("No events from any of the sources in the catalog were detected!")
for key in ["xpix", "ypix", "detx", "dety", "time", "chip_id", event_params["channel_type"]]:
all_events[key] = np.array([])
else:
# Step 4: Scatter energies with RMF
mylog.info("Scattering energies with RMF %s." % os.path.split(rmf.filename)[-1])
all_events = rmf.scatter_energies(all_events, prng=prng)
return all_events, event_params
def make_background_file(out_file,
exp_time,
instrument,
sky_center,
overwrite=False,
foreground=True,
instr_bkgnd=True,
ptsrc_bkgnd=True,
no_dither=False,
dither_params=None,
subpixel_res=False,
input_sources=None,
absorb_model="wabs",
nH=0.05,
prng=None):
"""
Make an event file consisting entirely of background events. This will be
useful for creating backgrounds that can be added to simulations of sources.
Parameters
----------
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time to use, in seconds.
instrument : string
The name of the instrument to use, which picks an instrument
specification from the instrument registry.
sky_center : array, tuple, or list
The center RA, Dec coordinates of the observation, in degrees.
overwrite : boolean, optional
Whether or not to overwrite an existing file with the same name.
Default: False
foreground : boolean, optional
Whether or not to include the Galactic foreground. Default: True
instr_bkgnd : boolean, optional
Whether or not to include the instrumental background. Default: True
ptsrc_bkgnd : boolean, optional
Whether or not to include the point-source background. Default: True
no_dither : boolean, optional
If True, turn off dithering entirely. Default: False
dither_params : array-like of floats, optional
The parameters to use to control the size and period of the dither
pattern. The first two numbers are the dither amplitude in x and y
detector coordinates in arcseconds, and the second two numbers are
the dither period in x and y detector coordinates in seconds.
Default: [8.0, 8.0, 1000.0, 707.0].
subpixel_res: boolean, optional
If True, event positions are not randomized within the pixels
within which they are detected. Default: False
input_sources : string, optional
If set to a filename, input the point source positions, fluxes,
and spectral indices from an ASCII table instead of generating
them. Default: None
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
events, event_params = make_background(exp_time,
instrument,
sky_center,
ptsrc_bkgnd=ptsrc_bkgnd,
foreground=foreground,
instr_bkgnd=instr_bkgnd,
no_dither=no_dither,
dither_params=dither_params,
subpixel_res=subpixel_res,
input_sources=input_sources,
absorb_model=absorb_model,
nH=nH,
prng=prng)
write_event_file(events, event_params, out_file, overwrite=overwrite)
def project_photons(self, normal, sky_center, absorb_model=None,
nH=None, no_shifting=False, north_vector=None,
sigma_pos=None, kernel="top_hat", prng=None,
**kwargs):
r"""
Projects photons onto an image plane given a line of sight.
Returns a new :class:`~pyxsim.event_list.EventList`.
Parameters
----------
normal : character or array-like
Normal vector to the plane of projection. If "x", "y", or "z", will
assume to be along that axis (and will probably be faster). Otherwise,
should be an off-axis normal vector, e.g [1.0, 2.0, -3.0]
sky_center : array-like
Center RA, Dec of the events in degrees.
absorb_model : string or :class:`~pyxsim.spectral_models.AbsorptionModel`
A model for foreground galactic absorption, to simulate the
absorption of events before being detected. This cannot be applied
here if you already did this step previously in the creation of the
:class:`~pyxsim.photon_list.PhotonList` instance. Known options for
strings are "wabs" and "tbabs".
nH : float, optional
The foreground column density in units of 10^22 cm^{-2}. Only used
if absorption is applied.
no_shifting : boolean, optional
If set, the photon energies will not be Doppler shifted.
north_vector : a sequence of floats
A vector defining the "up" direction. This option sets the
orientation of the plane of projection. If not set, an arbitrary
grid-aligned north_vector is chosen. Ignored in the case where a
particular axis (e.g., "x", "y", or "z") is explicitly specified.
sigma_pos : float, optional
Apply a gaussian smoothing operation to the sky positions of the
events. This may be useful when the binned events appear blocky due
to their uniform distribution within simulation cells. However, this
will move the events away from their originating position on the
sky, and so may distort surface brightness profiles and/or spectra.
Should probably only be used for visualization purposes. Supply a
float here to smooth with a standard deviation with this fraction
of the cell size. Default: None
kernel : string, optional
The kernel used when smoothing positions of X-rays originating from
SPH particles, "gaussian" or "top_hat". Default: "top_hat".
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers,
such as for a test. Default is to use the :mod:`numpy.random`
module.
Examples
--------
>>> L = np.array([0.1,-0.2,0.3])
>>> events = my_photons.project_photons(L, [30., 45.])
"""
prng = parse_prng(prng)
scale_shift = -1.0/clight.to("km/s")
if "smooth_positions" in kwargs:
issue_deprecation_warning("'smooth_positions' has been renamed to "
"'sigma_pos' and the former is deprecated!")
sigma_pos = kwargs["smooth_positions"]
if "redshift_new" in kwargs or "area_new" in kwargs or \
"exp_time_new" in kwargs or "dist_new" in kwargs:
issue_deprecation_warning("Changing the redshift, distance, area, or "
"exposure time has been deprecated in "
"project_photons!")
if sigma_pos is not None and self.parameters["data_type"] == "particles":
raise RuntimeError("The 'smooth_positions' argument should not be used with "
"particle-based datasets!")
if isinstance(absorb_model, string_types):
if absorb_model not in absorb_models:
raise KeyError("%s is not a known absorption model!" % absorb_model)
absorb_model = absorb_models[absorb_model]
if absorb_model is not None:
if nH is None:
raise RuntimeError("You specified an absorption model, but didn't "
"specify a value for nH!")
absorb_model = absorb_model(nH)
sky_center = YTArray(sky_center, "degree")
n_ph = self.photons["num_photons"]
if not isinstance(normal, string_types):
L = np.array(normal)
orient = Orientation(L, north_vector=north_vector)
x_hat = orient.unit_vectors[0]
y_hat = orient.unit_vectors[1]
z_hat = orient.unit_vectors[2]
else:
x_hat = np.zeros(3)
y_hat = np.zeros(3)
z_hat = np.zeros(3)
parameters = {}
D_A = self.parameters["fid_d_a"]
events = {}
eobs = self.photons["energy"].v
if not no_shifting:
if comm.rank == 0:
mylog.info("Doppler-shifting photon energies.")
if isinstance(normal, string_types):
shift = self.photons["vel"][:,"xyz".index(normal)]*scale_shift
else:
shift = np.dot(self.photons["vel"], z_hat)*scale_shift
doppler_shift(shift, n_ph, eobs)
if absorb_model is None:
det = np.ones(eobs.size, dtype='bool')
num_det = eobs.size
else:
if comm.rank == 0:
mylog.info("Foreground galactic absorption: using "
"the %s model and nH = %g." % (absorb_model._name, nH))
det = absorb_model.absorb_photons(eobs, prng=prng)
num_det = det.sum()
events["eobs"] = YTArray(eobs[det], "keV")
num_events = comm.mpi_allreduce(num_det)
if comm.rank == 0:
mylog.info("%d events have been detected." % num_events)
if num_det > 0:
if comm.rank == 0:
mylog.info("Assigning positions to events.")
if isinstance(normal, string_types):
norm = "xyz".index(normal)
else:
norm = normal
xsky, ysky = scatter_events(norm, prng, kernel,
self.parameters["data_type"],
num_det, det, self.photons["num_photons"],
self.photons["pos"].d, self.photons["dx"].d,
x_hat, y_hat)
if self.parameters["data_type"] == "cells" and sigma_pos is not None:
if comm.rank == 0:
mylog.info("Optionally smoothing sky positions.")
sigma = sigma_pos*np.repeat(self.photons["dx"].d, n_ph)[det]
xsky += sigma * prng.normal(loc=0.0, scale=1.0, size=num_det)
ysky += sigma * prng.normal(loc=0.0, scale=1.0, size=num_det)
d_a = D_A.to("kpc").v
xsky /= d_a
ysky /= d_a
if comm.rank == 0:
mylog.info("Converting pixel to sky coordinates.")
pixel_to_cel(xsky, ysky, sky_center)
else:
xsky = []
ysky = []
events["xsky"] = YTArray(xsky, "degree")
events["ysky"] = YTArray(ysky, "degree")
parameters["exp_time"] = self.parameters["fid_exp_time"]
parameters["area"] = self.parameters["fid_area"]
parameters["sky_center"] = sky_center
return EventList(events, parameters)
def simulate_spectrum(spec, instrument, exp_time, out_file,
instr_bkgnd=False, foreground=False,
ptsrc_bkgnd=False, bkgnd_area=None,
absorb_model="wabs", nH=0.05,
overwrite=False, prng=None):
"""
Generate a PI or PHA spectrum from a :class:`~soxs.spectra.Spectrum`
by convolving it with responses. To be used if one wants to
create a spectrum without worrying about spatial response. Similar
to XSPEC's "fakeit".
Parameters
----------
spec : :class:`~soxs.spectra.Spectrum`
The spectrum to be convolved. If None is supplied, only backgrounds
will be simulated (if they are turned on).
instrument : string
The name of the instrument to use, which picks an instrument
specification from the instrument registry.
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
out_file : string
The file to write the spectrum to.
instr_bkgnd : boolean, optional
Whether or not to include the instrumental/particle background.
Default: False
foreground : boolean, optional
Whether or not to include the local foreground.
Default: False
ptsrc_bkgnd : boolean, optional
Whether or not to include the unresolved point-source background.
Default: False
bkgnd_area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The area on the sky for the background components, in square arcminutes.
Default: None, necessary to specify if any of the background components
are turned on.
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
overwrite : boolean, optional
Whether or not to overwrite an existing file. Default: False
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
Examples
--------
>>> spec = soxs.Spectrum.from_file("my_spectrum.txt")
>>> soxs.simulate_spectrum(spec, "lynx_lxm", 100000.0,
... "my_spec.pi", overwrite=True)
"""
from soxs.events import _write_spectrum
from soxs.instrument import RedistributionMatrixFile, \
AuxiliaryResponseFile
from soxs.spectra import ConvolvedSpectrum
from soxs.background.foreground import hm_astro_bkgnd
from soxs.background.instrument import instrument_backgrounds
from soxs.background.spectra import BackgroundSpectrum, \
ConvolvedBackgroundSpectrum
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
try:
instrument_spec = instrument_registry[instrument]
except KeyError:
raise KeyError("Instrument %s is not in the instrument registry!" % instrument)
if foreground or instr_bkgnd or ptsrc_bkgnd:
if instrument_spec["grating"]:
raise NotImplementedError("Backgrounds cannot be included in simulations "
"of gratings spectra at this time!")
if bkgnd_area is None:
raise RuntimeError("The 'bkgnd_area' argument must be set if one wants "
"to simulate backgrounds! Specify a value in square "
"arcminutes.")
bkgnd_area = np.sqrt(parse_value(bkgnd_area, "arcmin**2"))
elif spec is None:
raise RuntimeError("You have specified no source spectrum and no backgrounds!")
arf_file = get_response_path(instrument_spec["arf"])
rmf_file = get_response_path(instrument_spec["rmf"])
arf = AuxiliaryResponseFile(arf_file)
rmf = RedistributionMatrixFile(rmf_file)
event_params = {}
event_params["RESPFILE"] = os.path.split(rmf.filename)[-1]
event_params["ANCRFILE"] = os.path.split(arf.filename)[-1]
event_params["TELESCOP"] = rmf.header["TELESCOP"]
event_params["INSTRUME"] = rmf.header["INSTRUME"]
event_params["MISSION"] = rmf.header.get("MISSION", "")
out_spec = np.zeros(rmf.n_ch)
if spec is not None:
cspec = ConvolvedSpectrum(spec, arf)
out_spec += rmf.convolve_spectrum(cspec, exp_time, prng=prng)
fov = None if bkgnd_area is None else np.sqrt(bkgnd_area)
if foreground:
mylog.info("Adding in astrophysical foreground.")
cspec_frgnd = ConvolvedSpectrum(hm_astro_bkgnd.to_spectrum(fov), arf)
out_spec += rmf.convolve_spectrum(cspec_frgnd, exp_time, prng=prng)
if instr_bkgnd and instrument_spec["bkgnd"] is not None:
mylog.info("Adding in instrumental background.")
instr_spec = instrument_backgrounds[instrument_spec["bkgnd"]]
cspec_instr = instr_spec.to_scaled_spectrum(fov,
instrument_spec["focal_length"])
out_spec += rmf.convolve_spectrum(cspec_instr, exp_time, prng=prng)
if ptsrc_bkgnd:
mylog.info("Adding in background from unresolved point-sources.")
spec_plaw = BackgroundSpectrum.from_powerlaw(1.45, 0.0, 2.0e-7, emin=0.01,
emax=10.0, nbins=300000)
spec_plaw.apply_foreground_absorption(nH, model=absorb_model)
cspec_plaw = ConvolvedBackgroundSpectrum(spec_plaw.to_spectrum(fov), arf)
out_spec += rmf.convolve_spectrum(cspec_plaw, exp_time, prng=prng)
bins = (np.arange(rmf.n_ch)+rmf.cmin).astype("int32")
_write_spectrum(bins, out_spec, exp_time, rmf.header["CHANTYPE"],
event_params, out_file, overwrite=overwrite)
def __init__(self, prng=None):
self.spectral_norm = None
self.redshift = None
self.prng = parse_prng(prng)
def make_background_file(out_file, exp_time, instrument, sky_center,
overwrite=False, foreground=True, instr_bkgnd=True,
ptsrc_bkgnd=True, no_dither=False, dither_params=None,
subpixel_res=False, input_sources=None,
absorb_model="wabs", nH=0.05, prng=None):
"""
Make an event file consisting entirely of background events. This will be
useful for creating backgrounds that can be added to simulations of sources.
Parameters
----------
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time to use, in seconds.
instrument : string
The name of the instrument to use, which picks an instrument
specification from the instrument registry.
sky_center : array, tuple, or list
The center RA, Dec coordinates of the observation, in degrees.
overwrite : boolean, optional
Whether or not to overwrite an existing file with the same name.
Default: False
foreground : boolean, optional
Whether or not to include the Galactic foreground. Default: True
instr_bkgnd : boolean, optional
Whether or not to include the instrumental background. Default: True
ptsrc_bkgnd : boolean, optional
Whether or not to include the point-source background. Default: True
no_dither : boolean, optional
If True, turn off dithering entirely. Default: False
dither_params : array-like of floats, optional
The parameters to use to control the size and period of the dither
pattern. The first two numbers are the dither amplitude in x and y
detector coordinates in arcseconds, and the second two numbers are
the dither period in x and y detector coordinates in seconds.
Default: [8.0, 8.0, 1000.0, 707.0].
subpixel_res: boolean, optional
If True, event positions are not randomized within the pixels
within which they are detected. Default: False
input_sources : string, optional
If set to a filename, input the point source positions, fluxes,
and spectral indices from an ASCII table instead of generating
them. Default: None
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
events, event_params = make_background(exp_time, instrument, sky_center,
ptsrc_bkgnd=ptsrc_bkgnd,
foreground=foreground,
instr_bkgnd=instr_bkgnd,
no_dither=no_dither,
dither_params=dither_params,
subpixel_res=subpixel_res,
input_sources=input_sources,
absorb_model=absorb_model,
nH=nH, prng=prng)
write_event_file(events, event_params, out_file, overwrite=overwrite)
def make_background(exp_time, instrument, sky_center, foreground=True,
ptsrc_bkgnd=True, instr_bkgnd=True, no_dither=False,
dither_params=None, roll_angle=0.0, subpixel_res=False,
input_sources=None, absorb_model="wabs", nH=0.05, prng=None):
"""
Make background events.
Parameters
----------
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time to use, in seconds.
instrument : string
The name of the instrument to use, which picks an instrument
specification from the instrument registry.
sky_center : array, tuple, or list
The center RA, Dec coordinates of the observation, in degrees.
foreground : boolean, optional
Whether or not to include the Galactic foreground. Default: True
instr_bkgnd : boolean, optional
Whether or not to include the instrumental background. Default: True
no_dither : boolean, optional
If True, turn off dithering entirely. Default: False
dither_params : array-like of floats, optional
The parameters to use to control the size and period of the dither
pattern. The first two numbers are the dither amplitude in x and y
detector coordinates in arcseconds, and the second two numbers are
the dither period in x and y detector coordinates in seconds.
Default: [8.0, 8.0, 1000.0, 707.0].
ptsrc_bkgnd : boolean, optional
Whether or not to include the point-source background. Default: True
Default: 0.05
roll_angle : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The roll angle of the observation in degrees. Default: 0.0
subpixel_res: boolean, optional
If True, event positions are not randomized within the pixels
within which they are detected. Default: False
input_sources : string, optional
If set to a filename, input the point source positions, fluxes,
and spectral indices from an ASCII table instead of generating
them. Default: None
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
from soxs.background import make_instrument_background, \
make_foreground, make_ptsrc_background
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
roll_angle = parse_value(roll_angle, "deg")
try:
instrument_spec = instrument_registry[instrument]
except KeyError:
raise KeyError("Instrument %s is not in the instrument registry!" % instrument)
if not instrument_spec["imaging"]:
raise RuntimeError("Instrument '%s' is not " % instrument_spec["name"] +
"designed for imaging observations!")
fov = instrument_spec["fov"]
input_events = defaultdict(list)
arf_file = get_response_path(instrument_spec["arf"])
arf = AuxiliaryResponseFile(arf_file)
rmf_file = get_response_path(instrument_spec["rmf"])
rmf = RedistributionMatrixFile(rmf_file)
if ptsrc_bkgnd:
mylog.info("Adding in point-source background.")
ptsrc_events = make_ptsrc_background(exp_time, fov, sky_center,
area=1.2*arf.max_area,
input_sources=input_sources,
absorb_model=absorb_model,
nH=nH, prng=prng)
for key in ["ra", "dec", "energy"]:
input_events[key].append(ptsrc_events[key])
input_events["flux"].append(ptsrc_events["flux"])
input_events["emin"].append(ptsrc_events["energy"].min())
input_events["emax"].append(ptsrc_events["energy"].max())
input_events["sources"].append("ptsrc_bkgnd")
events, event_params = generate_events(input_events, exp_time,
instrument, sky_center,
no_dither=no_dither,
dither_params=dither_params,
roll_angle=roll_angle,
subpixel_res=subpixel_res,
prng=prng)
mylog.info("Generated %d photons from the point-source background." % len(events["energy"]))
else:
nx = instrument_spec["num_pixels"]
events = defaultdict(list)
if not instrument_spec["dither"]:
dither_on = False
else:
dither_on = not no_dither
if dither_params is None:
dither_params = [8.0, 8.0, 1000.0, 707.0]
dither_dict = {"x_amp": dither_params[0],
"y_amp": dither_params[1],
"x_period": dither_params[2],
"y_period": dither_params[3],
"dither_on": dither_on,
"plate_scale": instrument_spec["fov"]/nx*60.0}
event_params = {"exposure_time": exp_time,
"fov": instrument_spec["fov"],
"num_pixels": nx,
"pix_center": np.array([0.5*(2*nx+1)]*2),
"channel_type": rmf.header["CHANTYPE"],
"sky_center": sky_center,
"dither_params": dither_dict,
"plate_scale": instrument_spec["fov"]/nx/60.0,
"chan_lim": [rmf.cmin, rmf.cmax],
"rmf": rmf_file, "arf": arf_file,
"telescope": rmf.header["TELESCOP"],
"instrument": instrument_spec['name'],
"mission": rmf.header.get("MISSION", ""),
"nchan": rmf.n_ch,
"roll_angle": roll_angle,
"aimpt_coords": instrument_spec["aimpt_coords"]}
if "chips" not in event_params:
event_params["chips"] = instrument_spec["chips"]
if foreground:
mylog.info("Adding in astrophysical foreground.")
bkg_events = make_foreground(event_params, arf, rmf, prng=prng)
for key in bkg_events:
events[key] = np.concatenate([events[key], bkg_events[key]])
if instr_bkgnd and instrument_spec["bkgnd"] is not None:
mylog.info("Adding in instrumental background.")
bkg_events = make_instrument_background(instrument_spec["bkgnd"],
event_params, rmf, prng=prng)
for key in bkg_events:
events[key] = np.concatenate([events[key], bkg_events[key]])
return events, event_params
def make_xrb_particles(data_source, age_field, scale_length,
sfr_time_range=(1.0, "Gyr"), prng=None):
r"""
This routine generates an in-memory dataset composed of X-ray binary particles
from an input data source containing star particles.
Parameters
----------
data_source : :class:`~yt.data_objects.data_containers.YTSelectionContainer`
The yt data source to obtain the data from, such as a sphere, box, disk,
etc.
age_field : string or (type, name) field tuple
The stellar age field. Must be in some kind of time units.
scale_length : string, (ftype, fname) tuple, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`
The radial length scale over which to scatter the XRB particles
from their parent star particle. Can be the name of a smoothing
length field for the stars, a (value, unit) tuple, or a YTQuantity.
sfr_time_range : string, (ftype, fname) tuple, (value, unit) tuple, :class:`~yt.units.yt_array.YTQuantity`, or :class:`~astropy.units.Quantity`, optional
The recent time range over which to calculate the star formation rate from
the current time in the dataset. Default: 1.0 Gyr
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
ds = data_source.ds
ptype = data_source._determine_fields(age_field)[0][0]
t = data_source[age_field].to("Gyr")
m = data_source[(ptype, "particle_mass")].to("Msun")
sfr_time_range = parse_value(sfr_time_range, "Gyr")
recent = t < sfr_time_range
n_recent = recent.sum()
if n_recent == 0:
sfr = 0.0
else:
sfr = (m[recent].sum()/sfr_time_range).to("Msun/yr").v
mylog.info("%d star particles were formed in the last " % n_recent +
"%s for a SFR of %4.1f Msun/yr." % (sfr_time_range, sfr))
mtot = m.sum()
npart = m.size
scale_field = None
if isinstance(scale_length, tuple):
if isinstance(scale_length[0], string_types):
scale_field = scale_length
elif isinstance(scale_length, string_types):
scale_field = (ptype, scale_length)
if scale_field is None:
if isinstance(scale_length, tuple):
scale = YTArray([scale_length[0]]*npart, scale_length[1])
elif isinstance(scale_length, YTQuantity):
scale = YTArray([scale_length]*npart)
else:
scale = YTArray([scale_length[0]]*npart, "kpc")
else:
scale = data_source[scale_length]
scale = scale.to('kpc').d
N_l = lmxb_cdf(Lcut)*mtot.v*1.0e-11
N_h = hmxb_cdf(Lcut)*sfr
N_all = N_l+N_h
if N_all == 0.0:
raise RuntimeError("There are no X-ray binaries to generate!")
# Compute conversion factors from luminosity to count rate
lmxb_factor = get_scale_factor(alpha_lmxb, emin_lmxb, emax_lmxb)
hmxb_factor = get_scale_factor(alpha_hmxb, emin_hmxb, emax_hmxb)
xp = []
yp = []
zp = []
vxp = []
vyp = []
vzp = []
lp = []
rp = []
ap = []
if N_l > 0.0:
F_l = np.zeros(nbins+1)
for i in range(1, nbins+1):
F_l[i] = lmxb_cdf(Lbins[i])
F_l /= F_l[-1]
invcdf_l = InterpolatedUnivariateSpline(F_l, logLbins)
n_l = prng.poisson(lam=N_l*m/mtot)
mylog.info("Number of low-mass X-ray binaries: %s" % n_l.sum())
for i, n in enumerate(n_l):
if n > 0:
randvec = prng.uniform(size=n)
l = YTArray(10**invcdf_l(randvec)*1.0e38, "erg/s")
r = YTArray(l.v*lmxb_factor, "photons/s/keV")
# Now convert output luminosities to bolometric
l *= bc_lmxb
x = YTArray(prng.normal(scale=scale[i], size=n), "kpc")
y = YTArray(prng.normal(scale=scale[i], size=n), "kpc")
z = YTArray(prng.normal(scale=scale[i], size=n), "kpc")
x += data_source[ptype, "particle_position_x"][i].to("kpc")
y += data_source[ptype, "particle_position_y"][i].to("kpc")
z += data_source[ptype, "particle_position_z"][i].to("kpc")
vx = YTArray([data_source[ptype, "particle_velocity_x"][i]]*n).to('km/s')
vy = YTArray([data_source[ptype, "particle_velocity_y"][i]]*n).to('km/s')
vz = YTArray([data_source[ptype, "particle_velocity_z"][i]]*n).to('km/s')
xp.append(x)
yp.append(y)
zp.append(z)
vxp.append(vx)
vyp.append(vy)
vzp.append(vz)
lp.append(l)
rp.append(r)
ap.append(np.array([alpha_lmxb]*n))
if N_h > 0.0:
F_h = np.zeros(nbins+1)
for i in range(1, nbins+1):
F_h[i] = hmxb_cdf(Lbins[i])
F_h /= F_h[-1]
invcdf_h = InterpolatedUnivariateSpline(F_h, logLbins)
n_h = prng.poisson(lam=N_h*m/mtot)
mylog.info("Number of high-mass X-ray binaries: %s" % n_h.sum())
for i, n in enumerate(n_h):
if n > 0:
randvec = prng.uniform(size=n)
l = YTArray(10**invcdf_h(randvec)*1.0e38, "erg/s")
r = YTArray(l.v*hmxb_factor, "photons/s/keV")
# Now convert output luminosities to bolometric
l *= bc_hmxb
x = YTArray(prng.normal(scale=scale[i], size=n), "kpc")
y = YTArray(prng.normal(scale=scale[i], size=n), "kpc")
z = YTArray(prng.normal(scale=scale[i], size=n), "kpc")
x += data_source[ptype, "particle_position_x"][i].to("kpc")
y += data_source[ptype, "particle_position_y"][i].to("kpc")
z += data_source[ptype, "particle_position_z"][i].to("kpc")
vx = YTArray([data_source[ptype, "particle_velocity_x"][i]]*n).to('km/s')
vy = YTArray([data_source[ptype, "particle_velocity_y"][i]]*n).to('km/s')
vz = YTArray([data_source[ptype, "particle_velocity_z"][i]]*n).to('km/s')
xp.append(x)
yp.append(y)
zp.append(z)
vxp.append(vx)
vyp.append(vy)
vzp.append(vz)
lp.append(l)
rp.append(r)
ap.append(np.array([alpha_hmxb]*n))
xp = uconcatenate(xp)
yp = uconcatenate(yp)
zp = uconcatenate(zp)
vxp = uconcatenate(vxp)
vyp = uconcatenate(vyp)
vzp = uconcatenate(vzp)
lp = uconcatenate(lp)
rp = uconcatenate(rp)
ap = uconcatenate(ap)
data = {"particle_position_x": (xp.d, str(xp.units)),
"particle_position_y": (yp.d, str(yp.units)),
"particle_position_z": (zp.d, str(zp.units)),
"particle_velocity_x": (vxp.d, str(vxp.units)),
"particle_velocity_y": (vyp.d, str(vyp.units)),
"particle_velocity_z": (vzp.d, str(vzp.units)),
"particle_luminosity": (lp.d, str(lp.units)),
"particle_count_rate": (rp.d, str(rp.units)),
"particle_spectral_index": ap}
dle = ds.domain_left_edge.to("kpc").v
dre = ds.domain_right_edge.to("kpc").v
bbox = np.array([[dle[i], dre[i]] for i in range(3)])
new_ds = load_particles(data, bbox=bbox, length_unit="kpc",
time_unit="Myr", mass_unit="Msun",
velocity_unit="km/s")
return new_ds
def simulate_spectrum(spec,
instrument,
exp_time,
out_file,
instr_bkgnd=False,
foreground=False,
ptsrc_bkgnd=False,
bkgnd_area=None,
absorb_model="wabs",
nH=0.05,
overwrite=False,
prng=None):
"""
Generate a PI or PHA spectrum from a :class:`~soxs.spectra.Spectrum`
by convolving it with responses. To be used if one wants to
create a spectrum without worrying about spatial response. Similar
to XSPEC's "fakeit".
Parameters
----------
spec : :class:`~soxs.spectra.Spectrum`
The spectrum to be convolved. If None is supplied, only backgrounds
will be simulated (if they are turned on).
instrument : string
The name of the instrument to use, which picks an instrument
specification from the instrument registry.
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time in seconds.
out_file : string
The file to write the spectrum to.
instr_bkgnd : boolean, optional
Whether or not to include the instrumental/particle background.
Default: False
foreground : boolean, optional
Whether or not to include the local foreground.
Default: False
ptsrc_bkgnd : boolean, optional
Whether or not to include the unresolved point-source background.
Default: False
bkgnd_area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The area on the sky for the background components, in square arcminutes.
Default: None, necessary to specify if any of the background components
are turned on.
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
overwrite : boolean, optional
Whether or not to overwrite an existing file. Default: False
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
Examples
--------
>>> spec = soxs.Spectrum.from_file("my_spectrum.txt")
>>> soxs.simulate_spectrum(spec, "lynx_lxm", 100000.0,
... "my_spec.pi", overwrite=True)
"""
from soxs.events import _write_spectrum
from soxs.response import RedistributionMatrixFile, \
AuxiliaryResponseFile
from soxs.spectra import ConvolvedSpectrum
from soxs.background.foreground import hm_astro_bkgnd
from soxs.background.spectra import BackgroundSpectrum
from soxs.background.instrument import InstrumentalBackground
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
try:
instrument_spec = instrument_registry[instrument]
except KeyError:
raise KeyError(
f"Instrument {instrument} is not in the instrument registry!")
if foreground or instr_bkgnd or ptsrc_bkgnd:
if instrument_spec["grating"]:
raise NotImplementedError(
"Backgrounds cannot be included in simulations "
"of gratings spectra at this time!")
if bkgnd_area is None:
raise RuntimeError(
"The 'bkgnd_area' argument must be set if one wants "
"to simulate backgrounds! Specify a value in square "
"arcminutes.")
bkgnd_area = np.sqrt(parse_value(bkgnd_area, "arcmin**2"))
elif spec is None:
raise RuntimeError(
"You have specified no source spectrum and no backgrounds!")
arf_file = get_data_file(instrument_spec["arf"])
rmf_file = get_data_file(instrument_spec["rmf"])
arf = AuxiliaryResponseFile(arf_file)
rmf = RedistributionMatrixFile(rmf_file)
event_params = {
"RESPFILE": os.path.split(rmf.filename)[-1],
"ANCRFILE": os.path.split(arf.filename)[-1],
"TELESCOP": rmf.header["TELESCOP"],
"INSTRUME": rmf.header["INSTRUME"],
"MISSION": rmf.header.get("MISSION", "")
}
out_spec = np.zeros(rmf.n_ch)
if spec is not None:
cspec = ConvolvedSpectrum.convolve(spec, arf)
out_spec += rmf.convolve_spectrum(cspec, exp_time, prng=prng)
fov = None if bkgnd_area is None else np.sqrt(bkgnd_area)
if foreground:
mylog.info("Adding in astrophysical foreground.")
cspec_frgnd = ConvolvedSpectrum.convolve(
hm_astro_bkgnd.to_spectrum(fov), arf)
out_spec += rmf.convolve_spectrum(cspec_frgnd, exp_time, prng=prng)
if instr_bkgnd and instrument_spec["bkgnd"] is not None:
mylog.info("Adding in instrumental background.")
bkgnd_spec = instrument_spec["bkgnd"]
# Temporary hack for ACIS-S
if "aciss" in instrument_spec["name"]:
bkgnd_spec = bkgnd_spec[1]
bkgnd_spec = InstrumentalBackground.from_filename(
bkgnd_spec[0], bkgnd_spec[1], instrument_spec['focal_length'])
out_spec += bkgnd_spec.generate_channel_spectrum(exp_time,
bkgnd_area,
prng=prng)
if ptsrc_bkgnd:
mylog.info("Adding in background from unresolved point-sources.")
spec_plaw = BackgroundSpectrum.from_powerlaw(1.45,
0.0,
2.0e-7,
emin=0.01,
emax=10.0,
nbins=300000)
spec_plaw.apply_foreground_absorption(nH, model=absorb_model)
cspec_plaw = ConvolvedSpectrum.convolve(spec_plaw.to_spectrum(fov),
arf)
out_spec += rmf.convolve_spectrum(cspec_plaw, exp_time, prng=prng)
bins = (np.arange(rmf.n_ch) + rmf.cmin).astype("int32")
_write_spectrum(bins,
out_spec,
exp_time,
rmf.header["CHANTYPE"],
event_params,
out_file,
overwrite=overwrite)
def generate_events(self, area, exp_time, angular_width,
source_model, sky_center, parameters=None,
velocity_fields=None, absorb_model=None,
nH=None, no_shifting=False, sigma_pos=None,
prng=None):
"""
Generate projected events from a light cone simulation.
Parameters
----------
area : float, (value, unit) tuple, or :class:`~yt.units.yt_array.YTQuantity`
The collecting area to determine the number of events. If units are
not specified, it is assumed to be in cm^2.
exp_time : float, (value, unit) tuple, or :class:`~yt.units.yt_array.YTQuantity`
The exposure time to determine the number of events. If units are
not specified, it is assumed to be in seconds.
angular_width : float, (value, unit) tuple, or :class:`~yt.units.yt_array.YTQuantity`
The angular width of the light cone simulation. If units are not
specified, it is assumed to be in degrees.
source_model : :class:`~pyxsim.source_models.SourceModel`
A source model used to generate the events.
sky_center : array-like
Center RA, Dec of the events in degrees.
parameters : dict, optional
A dictionary of parameters to be passed for the source model to use,
if necessary.
velocity_fields : list of fields
The yt fields to use for the velocity. If not specified, the following will
be assumed:
['velocity_x', 'velocity_y', 'velocity_z'] for grid datasets
['particle_velocity_x', 'particle_velocity_y', 'particle_velocity_z'] for particle datasets
absorb_model : string or :class:`~pyxsim.spectral_models.AbsorptionModel`
A model for foreground galactic absorption, to simulate the absorption
of events before being detected. This cannot be applied here if you
already did this step previously in the creation of the
:class:`~pyxsim.photon_list.PhotonList` instance. Known options for
strings are "wabs" and "tbabs".
nH : float, optional
The foreground column density in units of 10^22 cm^{-2}. Only used if
absorption is applied.
no_shifting : boolean, optional
If set, the photon energies will not be Doppler shifted.
sigma_pos : float, optional
Apply a gaussian smoothing operation to the sky positions of the
events. This may be useful when the binned events appear blocky due
to their uniform distribution within simulation cells. However, this
will move the events away from their originating position on the
sky, and so may distort surface brightness profiles and/or spectra.
Should probably only be used for visualization purposes. Supply a
float here to smooth with a standard deviation with this fraction
of the cell size. Default: None
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
area = parse_value(area, "cm**2")
exp_time = parse_value(exp_time, "s")
aw = parse_value(angular_width, "deg")
tot_events = defaultdict(list)
for output in self.light_cone_solution:
ds = load(output["filename"])
ax = output["projection_axis"]
c = output["projection_center"]*ds.domain_width + ds.domain_left_edge
le = c.copy()
re = c.copy()
width = ds.quan(aw*output["box_width_per_angle"], "unitary").to("code_length")
depth = ds.domain_width[ax].in_units("code_length")*output["box_depth_fraction"]
le[ax] -= 0.5*depth
re[ax] += 0.5*depth
for off_ax in axes_lookup[ax]:
le[off_ax] -= 0.5*width
re[off_ax] += 0.5*width
reg = ds.box(le, re)
photons = PhotonList.from_data_source(reg, output['redshift'], area,
exp_time, source_model,
parameters=parameters,
center=c,
velocity_fields=velocity_fields,
cosmology=ds.cosmology)
if sum(photons["num_photons"]) > 0:
events = photons.project_photons("xyz"[ax], sky_center,
absorb_model=absorb_model, nH=nH,
no_shifting=no_shifting,
sigma_pos=sigma_pos,
prng=prng)
if events.num_events > 0:
tot_events["xsky"].append(events["xsky"])
tot_events["ysky"].append(events["ysky"])
tot_events["eobs"].append(events["eobs"])
del events
del photons
parameters = {"exp_time": exp_time,
"area": area,
"sky_center": YTArray(sky_center, "deg")}
for key in tot_events:
tot_events[key] = uconcatenate(tot_events[key])
return EventList(tot_events, parameters)
def generate_events(self,
area,
exp_time,
angular_width,
source_model,
sky_center,
parameters=None,
velocity_fields=None,
absorb_model=None,
nH=None,
no_shifting=False,
sigma_pos=None,
prng=None):
"""
Generate projected events from a light cone simulation.
Parameters
----------
area : float, (value, unit) tuple, or :class:`~yt.units.yt_array.YTQuantity`
The collecting area to determine the number of events. If units are
not specified, it is assumed to be in cm^2.
exp_time : float, (value, unit) tuple, or :class:`~yt.units.yt_array.YTQuantity`
The exposure time to determine the number of events. If units are
not specified, it is assumed to be in seconds.
angular_width : float, (value, unit) tuple, or :class:`~yt.units.yt_array.YTQuantity`
The angular width of the light cone simulation. If units are not
specified, it is assumed to be in degrees.
source_model : :class:`~pyxsim.source_models.SourceModel`
A source model used to generate the events.
sky_center : array-like
Center RA, Dec of the events in degrees.
parameters : dict, optional
A dictionary of parameters to be passed for the source model to use,
if necessary.
velocity_fields : list of fields
The yt fields to use for the velocity. If not specified, the following will
be assumed:
['velocity_x', 'velocity_y', 'velocity_z'] for grid datasets
['particle_velocity_x', 'particle_velocity_y', 'particle_velocity_z'] for particle datasets
absorb_model : string or :class:`~pyxsim.spectral_models.AbsorptionModel`
A model for foreground galactic absorption, to simulate the absorption
of events before being detected. This cannot be applied here if you
already did this step previously in the creation of the
:class:`~pyxsim.photon_list.PhotonList` instance. Known options for
strings are "wabs" and "tbabs".
nH : float, optional
The foreground column density in units of 10^22 cm^{-2}. Only used if
absorption is applied.
no_shifting : boolean, optional
If set, the photon energies will not be Doppler shifted.
sigma_pos : float, optional
Apply a gaussian smoothing operation to the sky positions of the
events. This may be useful when the binned events appear blocky due
to their uniform distribution within simulation cells. However, this
will move the events away from their originating position on the
sky, and so may distort surface brightness profiles and/or spectra.
Should probably only be used for visualization purposes. Supply a
float here to smooth with a standard deviation with this fraction
of the cell size. Default: None
prng : integer or :class:`~numpy.random.RandomState` object
A pseudo-random number generator. Typically will only be specified
if you have a reason to generate the same set of random numbers, such as for a
test. Default is to use the :mod:`numpy.random` module.
"""
prng = parse_prng(prng)
area = parse_value(area, "cm**2")
exp_time = parse_value(exp_time, "s")
aw = parse_value(angular_width, "deg")
tot_events = defaultdict(list)
for output in self.light_cone_solution:
ds = load(output["filename"])
ax = output["projection_axis"]
c = output[
"projection_center"] * ds.domain_width + ds.domain_left_edge
le = c.copy()
re = c.copy()
width = ds.quan(aw * output["box_width_per_angle"],
"unitary").to("code_length")
depth = ds.domain_width[ax].in_units(
"code_length") * output["box_depth_fraction"]
le[ax] -= 0.5 * depth
re[ax] += 0.5 * depth
for off_ax in axes_lookup[ax]:
le[off_ax] -= 0.5 * width
re[off_ax] += 0.5 * width
reg = ds.box(le, re)
photons = PhotonList.from_data_source(
reg,
output['redshift'],
area,
exp_time,
source_model,
parameters=parameters,
center=c,
velocity_fields=velocity_fields,
cosmology=ds.cosmology)
if sum(photons["num_photons"]) > 0:
events = photons.project_photons("xyz"[ax],
sky_center,
absorb_model=absorb_model,
nH=nH,
no_shifting=no_shifting,
sigma_pos=sigma_pos,
prng=prng)
if events.num_events > 0:
tot_events["xsky"].append(events["xsky"])
tot_events["ysky"].append(events["ysky"])
tot_events["eobs"].append(events["eobs"])
del events
del photons
parameters = {
"exp_time": exp_time,
"area": area,
"sky_center": YTArray(sky_center, "deg")
}
for key in tot_events:
tot_events[key] = uconcatenate(tot_events[key])
return EventList(tot_events, parameters)
def make_ptsrc_background(exp_time, fov, sky_center, absorb_model="wabs",
nH=0.05, area=40000.0, input_sources=None,
output_sources=None, prng=None):
r"""
Make a point-source background.
Parameters
----------
exp_time : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The exposure time of the observation in seconds.
fov : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`
The field of view in arcminutes.
sky_center : array-like
The center RA, Dec of the field of view in degrees.
absorb_model : string, optional
The absorption model to use, "wabs" or "tbabs". Default: "wabs"
nH : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The hydrogen column in units of 10**22 atoms/cm**2.
Default: 0.05
area : float, (value, unit) tuple, or :class:`~astropy.units.Quantity`, optional
The effective area in cm**2. It must be large enough
so that a sufficiently large sample is drawn for the
ARF. Default: 40000.
input_sources : string, optional
If set to a filename, input the source positions, fluxes,
and spectral indices from an ASCII table instead of generating
them. Default: None
output_sources : string, optional
If set to a filename, output the properties of the sources
within the field of view to a file. Default: None
prng : :class:`~numpy.random.RandomState` object, integer, or None
A pseudo-random number generator. Typically will only
be specified if you have a reason to generate the same
set of random numbers, such as for a test. Default is None,
which sets the seed based on the system time.
"""
prng = parse_prng(prng)
exp_time = parse_value(exp_time, "s")
fov = parse_value(fov, "arcmin")
if nH is not None:
nH = parse_value(nH, "1.0e22*cm**-2")
area = parse_value(area, "cm**2")
if input_sources is None:
ra0, dec0, fluxes, ind = generate_sources(exp_time, fov, sky_center,
area=area, prng=prng)
num_sources = fluxes.size
else:
mylog.info("Reading in point-source properties from %s." % input_sources)
t = ascii.read(input_sources)
ra0 = t["RA"].data
dec0 = t["Dec"].data
fluxes = t["flux_0.5_2.0_keV"].data
ind = t["index"].data
num_sources = fluxes.size
mylog.debug("Generating spectra from %d sources." % num_sources)
# If requested, output the source properties to a file
if output_sources is not None:
t = Table([ra0, dec0, fluxes, ind],
names=('RA', 'Dec', 'flux_0.5_2.0_keV', 'index'))
t["RA"].unit = "deg"
t["Dec"].unit = "deg"
t["flux_0.5_2.0_keV"].unit = "erg/(cm**2*s)"
t["index"].unit = ""
t.write(output_sources, format='ascii.ecsv', overwrite=True)
# Pre-calculate for optimization
eratio = spec_emax/spec_emin
oma = 1.0-ind
invoma = 1.0/oma
invoma[oma == 0.0] = 1.0
fac1 = spec_emin**oma
fac2 = spec_emax**oma-fac1
fluxscale = get_flux_scale(ind, fb_emin, fb_emax, spec_emin, spec_emax)
# Using the energy flux, determine the photon flux by simple scaling
ref_ph_flux = fluxes*fluxscale*keV_per_erg
# Now determine the number of photons we will generate
n_photons = prng.poisson(ref_ph_flux*exp_time*area)
all_energies = []
all_ra = []
all_dec = []
for i, nph in enumerate(n_photons):
if nph > 0:
# Generate the energies in the source frame
u = prng.uniform(size=nph)
if ind[i] == 1.0:
energies = spec_emin*(eratio**u)
else:
energies = fac1[i] + u*fac2[i]
energies **= invoma[i]
# Assign positions for this source
ra = ra0[i]*np.ones(nph)
dec = dec0[i]*np.ones(nph)
all_energies.append(energies)
all_ra.append(ra)
all_dec.append(dec)
mylog.debug("Finished generating spectra.")
all_energies = np.concatenate(all_energies)
all_ra = np.concatenate(all_ra)
all_dec = np.concatenate(all_dec)
all_nph = all_energies.size
# Remove some of the photons due to Galactic foreground absorption.
# We will throw a lot of stuff away, but this is more general and still
# faster.
if nH is not None:
if absorb_model == "wabs":
absorb = get_wabs_absorb(all_energies, nH)
elif absorb_model == "tbabs":
absorb = get_tbabs_absorb(all_energies, nH)
randvec = prng.uniform(size=all_energies.size)
all_energies = all_energies[randvec < absorb]
all_ra = all_ra[randvec < absorb]
all_dec = all_dec[randvec < absorb]
all_nph = all_energies.size
mylog.debug("%d photons remain after foreground galactic absorption." % all_nph)
all_flux = np.sum(all_energies)*erg_per_keV/(exp_time*area)
output_events = {"ra": all_ra, "dec": all_dec,
"energy": all_energies, "flux": all_flux}
return output_events
