v = v * u.Unit('km/s')
# b
bval = (v/const.c.to('km/s'))
# R
R = np.sqrt((1-bval)/(1+bval))
# Finally
znew = (1+z)/R - 1
return znew.value
# ###################
# TESTING
if __name__ == '__main__':
from astropy.relativity import velocities as arv
# v_from_z
z1=2.0
z2=2.01
v = arv.v_from_z(z1,z2)
print('v_from_z: v = {:g}, for (z1,z2) = ({:g},{:g})'.format(v,z1,z2))
# z_from_v
z1 = arv.z_from_v(z2,v)
print('z_from_v: v = {:g}, for (z1,z2) = ({:g},{:g})'.format(v,z1,z2))
twov = np.array([-300., -3000.])
z2 = arv.z_from_v(z1,twov)
print(z2)
def get_zpeak(self):
''' Measure zpeak from an ionic transition
'''
if self.ions is None:
print('get_zpeak: Need to fill ions with get_ions first.')
return
# Ions for analysis
low_ions = [ (14,2), (6,2), (13,2), (26,2), (13,3)]
high_ions= [(14,4), (6,4)]
for tt in range(4):
if tt == 0:
ions = low_ions
iflg = 1 # Standard
elif tt == 1:
ions = low_ions
iflg = 2 # Saturated
elif tt == 2:
ions = high_ions
iflg = 1 # Standard
elif tt == 3:
ions = high_ions
iflg = 2 # Standard
else:
raise ValueError('Bad value')
# Search
for ion in ions:
try:
t = self.ions[ion]
except KeyError:
continue
# Measurement?
if t['flg_clm'] == iflg:
# Identify the transition
gdi = np.where( (self.ions.trans['Z'] == ion[0]) &
(self.ions.trans['ion'] == ion[1]) &
(self.ions.trans['flg_clm'] <= iflg) )[0]
# Take the first one
gdt = self.ions.trans[gdi[0]]
wrest = gdt['wrest']
flgs = self.clm_analy.clm_lines[wrest].analy['FLAGS']
spec_file = self.clm_analy.fits_files[flgs[1] % 64]
# Generate an Abs_Line with spectrum
line = abs_line.Abs_Line(wrest, z=self.clm_analy.zsys, spec_file=spec_file)
# vpeak
from astropy.relativity import velocities as arv
vpeak = line.vpeak()
self.zpeak = arv.z_from_v(self.clm_analy.zsys, vpeak)
if tt == 3:
print('zpeak WARNING: Using saturated high-ions!!')
break
else:
continue
# get out
break
# Error catching
if self.zpeak is None:
# Skip primordial LLS
print('lls_utils.zpeak: No transition in {:s}'.format(self.clm_analy.clm_fil))
xdb.set_trace()
return (0,0), 0.
# Return
return ion, vpeak
v = v * u.Unit('km/s')
# b
bval = (v / const.c.to('km/s'))
# R
R = np.sqrt((1 - bval) / (1 + bval))
# Finally
znew = (1 + z) / R - 1
return znew.value
# ###################
# TESTING
if __name__ == '__main__':
from astropy.relativity import velocities as arv
# v_from_z
z1 = 2.0
z2 = 2.01
v = arv.v_from_z(z1, z2)
print('v_from_z: v = {:g}, for (z1,z2) = ({:g},{:g})'.format(v, z1, z2))
# z_from_v
z1 = arv.z_from_v(z2, v)
print('z_from_v: v = {:g}, for (z1,z2) = ({:g},{:g})'.format(v, z1, z2))
twov = np.array([-300., -3000.])
z2 = arv.z_from_v(z1, twov)
print(z2)
