def main():
potential = AxisymmetricLogPotential(units=usys,
s=1/0.9,
a=0.5*(u.kpc/u.Myr)**2,
b=0.*u.kpc)
x0 = np.array([10.0, 0.0, 2.]) # kpc
v0 = (np.array([0., 220., 20.])*u.km/u.s)\
.to(u.kpc/u.Myr).value # kpc/Myr
integrator = LeapfrogIntegrator(potential._acceleration_at,
x0.T, v0.T)
ts, xs, vs = integrator.run(dt=0.1, Nsteps=10000)
fig,axes = plt.subplots(2,2,sharex=True,sharey=True,figsize=(10,10))
axes[0,0].plot(xs[:,0,0], xs[:,0,1])
axes[0,0].set_xlim(-12,12)
axes[0,0].set_ylim(-12,12)
axes[1,0].plot(xs[:,0,0], xs[:,0,2])
axes[1,1].plot(xs[:,0,1], xs[:,0,2])
axes[0,1].set_visible(False)
fig.subplots_adjust(hspace=0.05, wspace=0.05)
plt.show()
.to_frame(heliocentric)
p_hel = particles._X.copy()
s_hel = satellite._X.copy()
p_gc = _hel_to_gc(p_hel)
s_gc = _hel_to_gc(s_hel)
gc = np.vstack((s_gc,p_gc)).copy()
acc = np.zeros_like(gc[:,:3])
times = []
for ii in range(10):
a = time.time()
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(gc[:,:3]), np.array(gc[:,3:]),
args=(gc.shape[0], acc))
t, rs, vs = integrator.run(t1=6200, t2=0, dt=-1)
times.append(time.time()-a)
print(np.min(times), "seconds per integration")
times = []
for ii in range(10):
a = time.time()
back_integration_likelihood(6200, 0, -1, potential, p_gc, s_gc,
2.5e8, 0.01, particles.tub, 1.5,
np.array([-1]*nparticles))
times.append(time.time()-a)
def q_p(**kwargs):
filename = os.path.join(plot_path, "q_p.pdf")
fig,axes = plt.subplots(2,4,figsize=(14,7.5),
sharex=True, sharey=True)
bins = np.linspace(0.,10,40)
nparticles = 5000
for kk,_m in enumerate(range(6,9+1)):
mass = "2.5e{}".format(_m)
m = float(mass)
print(mass)
sgr = SgrSimulation(sgr_path.format(_m), snapfile)
p = sgr.particles(n=nparticles, expr="(tub!=0)")#" & (tub<400)")
tub = p.tub
s = sgr.satellite()
potential = LawMajewski2010()
X = np.vstack((s._X[...,:3], p._X[...,:3].copy()))
V = np.vstack((s._X[...,3:], p._X[...,3:].copy()))
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(X), np.array(V),
args=(X.shape[0], np.zeros_like(X)))
ts, rs, vs = integrator.run(t1=sgr.t1, t2=sgr.t2, dt=-1.)
s_orbit = np.vstack((rs[:,0][:,np.newaxis].T, vs[:,0][:,np.newaxis].T)).T
p_orbits = np.vstack((rs[:,1:].T, vs[:,1:].T)).T
t_idx = np.array([np.argmin(np.fabs(ts - t)) for t in p.tub])
p_x = np.array([p_orbits[jj,ii] for ii,jj in enumerate(t_idx)])
s_x = np.array([s_orbit[jj,0] for jj in t_idx])
#############################################
# determine tail_bit
diff = p_x-s_x
norm_r = s_x[:,:3] / np.sqrt(np.sum(s_x[:,:3]**2, axis=-1))[:,np.newaxis]
norm_diff_r = diff[:,:3] / np.sqrt(np.sum(diff[:,:3]**2, axis=-1))[:,np.newaxis]
dot_prod_r = np.sum(norm_diff_r*norm_r, axis=-1)
tail_bit = (dot_prod_r > 0.).astype(int)*2 - 1
#############################################
r_tide = potential._tidal_radius(m, s_orbit[...,:3])#*0.69336
s_R_orbit = np.sqrt(np.sum(s_orbit[...,:3]**2, axis=-1))
a_pm = (s_R_orbit + r_tide*tail_bit) / s_R_orbit
q = np.sqrt(np.sum((p_x[:,:3] - s_x[:,:3])**2,axis=-1))
f = r_tide / s_R_orbit
s_V = np.sqrt(np.sum(s_orbit[...,3:]**2, axis=-1))
vdisp = s_V * f / 1.4
p = np.sqrt(np.sum((p_x[:,3:] - s_x[...,3:])**2,axis=-1))
fig,axes = plt.subplots(2,1,figsize=(10,6),sharex=True)
axes[0].plot(tub, q, marker='.', alpha=0.5, color='#666666')
axes[0].plot(ts, r_tide*1.4, linewidth=2., alpha=0.8, color='k',
linestyle='-', marker=None)
axes[0].set_ylim(0., max(r_tide)*4)
axes[1].plot(tub, (p*u.kpc/u.Myr).to(u.km/u.s).value,
marker='.', alpha=0.5, color='#666666')
axes[1].plot(ts, (vdisp*u.kpc/u.Myr).to(u.km/u.s).value, color='k',
linewidth=2., alpha=0.75, linestyle='-', marker=None)
M_enc = potential._enclosed_mass(s_R_orbit)
#delta_E = 4/3.*G.decompose(usys).value**2*m*(M_enc / s_V)**2*r_tide**2/s_R_orbit**4
delta_v2 = 4/3.*G.decompose(usys).value**2*(M_enc / s_V)**2*\
np.mean(r_tide**2)/s_R_orbit**4
delta_v = (np.sqrt(2*delta_v2)*u.kpc/u.Myr).to(u.km/u.s).value
axes[1].plot(ts, delta_v, linewidth=2., color='#2166AC',
alpha=0.75, linestyle='--', marker=None)
axes[1].set_ylim(0., max((vdisp*u.kpc/u.Myr).to(u.km/u.s).value)*4)
axes[0].set_xlim(min(ts), max(ts))
fig.savefig(os.path.join(plot_path, "q_p_{}.png".format(mass)),
transparent=True)
.to_frame(heliocentric)
p_hel = particles._X.copy()
s_hel = satellite._X.copy()
p_gc = _hel_to_gc(p_hel)
s_gc = _hel_to_gc(s_hel)
gc = np.vstack((s_gc, p_gc)).copy()
acc = np.zeros_like(gc[:, :3])
times = []
for ii in range(10):
a = time.time()
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(gc[:, :3]),
np.array(gc[:, 3:]),
args=(gc.shape[0], acc))
t, rs, vs = integrator.run(t1=6200, t2=0, dt=-1)
times.append(time.time() - a)
print(np.min(times), "seconds per integration")
times = []
for ii in range(10):
a = time.time()
back_integration_likelihood(6200, 0, -1, potential, p_gc, s_gc, 2.5e8,
0.01, particles.tub, 1.5,
np.array([-1] * nparticles))
times.append(time.time() - a)
def total_rv():
filenamer = os.path.join(plot_path, "rel_r.png")
filenamev = os.path.join(plot_path, "rel_v.png")
figr,axesr = plt.subplots(4,1,figsize=(10,14),
sharex=True)
figv,axesv = plt.subplots(4,1,figsize=(10,14),
sharex=True)
nparticles = 2000
for k,_m in enumerate(range(6,9+1)):
mass = "2.5e{}".format(_m)
m = float(mass)
print(mass)
sgr = SgrSimulation(sgr_path.format(_m),snapfile)
p = sgr.particles(n=nparticles, expr=expr)
s = sgr.satellite()
X = np.vstack((s._X[...,:3], p._X[...,:3].copy()))
V = np.vstack((s._X[...,3:], p._X[...,3:].copy()))
integrator = LeapfrogIntegrator(sgr.potential._acceleration_at,
np.array(X), np.array(V),
args=(X.shape[0], np.zeros_like(X)))
ts, rs, vs = integrator.run(t1=sgr.t1, t2=sgr.t2, dt=-1.)
s_orbit = np.vstack((rs[:,0][:,np.newaxis].T, vs[:,0][:,np.newaxis].T)).T
p_orbits = np.vstack((rs[:,1:].T, vs[:,1:].T)).T
t_idx = np.array([np.argmin(np.fabs(ts - t)) for t in p.tub])
m_t = (-s.mdot*ts + s.m0)[:,np.newaxis]
s_R = np.sqrt(np.sum(s_orbit[...,:3]**2, axis=-1))
s_V = np.sqrt(np.sum(s_orbit[...,3:]**2, axis=-1))
r_tide = sgr.potential._tidal_radius(m_t, s_orbit[...,:3])
v_disp = s_V * r_tide / s_R
# cartesian basis to project into
x_hat = s_orbit[...,:3] / np.sqrt(np.sum(s_orbit[...,:3]**2, axis=-1))[...,np.newaxis]
_y_hat = s_orbit[...,3:] / np.sqrt(np.sum(s_orbit[...,3:]**2, axis=-1))[...,np.newaxis]
z_hat = np.cross(x_hat, _y_hat)
y_hat = -np.cross(x_hat, z_hat)
# translate to satellite position
rel_orbits = p_orbits - s_orbit
rel_pos = rel_orbits[...,:3]
rel_vel = rel_orbits[...,3:]
# project onto each
X = np.sum(rel_pos * x_hat, axis=-1)
Y = np.sum(rel_pos * y_hat, axis=-1)
Z = np.sum(rel_pos * z_hat, axis=-1)
RR = np.sqrt(X**2 + Y**2 + Z**2)
VX = np.sum(rel_vel * x_hat, axis=-1)
VY = np.sum(rel_vel * y_hat, axis=-1)
VZ = np.sum(rel_vel * z_hat, axis=-1)
VV = (np.sqrt(VX**2 + VY**2 + VZ**2)*u.kpc/u.Myr).to(u.km/u.s).value
v_disp = (v_disp*u.kpc/u.Myr).to(u.km/u.s).value
_tcross = r_tide / np.sqrt(G.decompose(usys).value*m/r_tide)
for ii,jj in enumerate(t_idx):
#tcross = r_tide[jj,0] / _v[jj,ii]
tcross = _tcross[jj]
bnd = int(tcross / 2)
ix1,ix2 = jj-bnd, jj+bnd
if ix1 < 0: ix1 = 0
if ix2 > max(sgr.t1,sgr.t2): ix2 = -1
axesr[k].plot(ts[ix1:ix2],
RR[ix1:ix2,ii],
linestyle='-', alpha=0.1, marker=None, color='#555555', zorder=-1)
axesv[k].plot(ts[ix1:ix2],
VV[ix1:ix2,ii],
linestyle='-', alpha=0.1, marker=None, color='#555555', zorder=-1)
axesr[k].plot(ts, r_tide*2., marker=None)
axesr[k].set_xlim(ts.min(), ts.max())
axesv[k].set_xlim(ts.min(), ts.max())
axesr[k].set_ylim(0,max(r_tide)*7)
axesv[k].set_ylim(0,max(v_disp)*7)
# axes[1,k].set_xlabel(r"$x_1$")
# if k == 0:
# axes[0,k].set_ylabel(r"$x_2$")
# axes[1,k].set_ylabel(r"$x_3$")
axesr[k].text(3000, max(r_tide)*5, r"$2.5\times10^{}M_\odot$".format(_m))
axesv[k].text(3000, max(v_disp)*5, r"$2.5\times10^{}M_\odot$".format(_m))
axesr[-1].set_xlabel("time [Myr]")
axesv[-1].set_xlabel("time [Myr]")
figr.suptitle("Relative distance", fontsize=26)
figr.tight_layout()
figr.subplots_adjust(top=0.92, hspace=0.025, wspace=0.1)
figr.savefig(filenamer)
figv.suptitle("Relative velocity", fontsize=26)
figv.tight_layout()
figv.subplots_adjust(top=0.92, hspace=0.025, wspace=0.1)
figv.savefig(filenamev)
mass = float(_m)
# simulation = io.SgrSimulation(mass=_m)
# particles = simulation.particles(N=1000, expr="tub!=0")
# satellite = simulation.satellite()\
# .to_frame(heliocentric)
# s_hel = satellite._X.copy()
# s_gc = _hel_to_gc(s_hel)
s_gc = np.array([[8.363919011, 0.243352771, 16.864546659,
-0.04468993, -0.12392801, -0.01664498]]) # Pal5
s_hel = _gc_to_hel(s_gc)
# First integrate the orbit of the satellite back to get initial conditions
acc = np.zeros_like(s_gc[:,:3])
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(s_gc[:,:3]), np.array(s_gc[:,3:]),
args=(s_gc.shape[0], acc))
t, rs, vs = integrator.run(t1=T, t2=0, dt=-dt)
init_r,init_v = rs[-1], vs[-1]
# integrate the orbit of the satellite
acc = np.zeros_like(s_gc[:,:3])
integrator = LeapfrogIntegrator(potential._acceleration_at,
init_r, init_v,
args=(1, acc))
t, rs, vs = integrator.run(t1=0, t2=T, dt=dt)
satellite_orbit = np.vstack((rs.T,vs.T)).T
def fig3(**kwargs):
""" Plot the PSD for 10 stars vs. back-integration time. """
seed = int(kwargs.get("seed", 999))
nPlot= 10
nIntegrate = 1000
dt = -1.
# Read in the LM10 data
np.random.seed(seed)
lm10 = io.LM10Simulation()
particles = lm10.particles(N=nIntegrate,
expr="(Pcol>-1) & (abs(Lmflag)==1) & (Pcol < 8)")
satellite = lm10.satellite()
# array of starting 6d positions
gc = np.vstack((satellite._X,particles._X)).copy()
acc = np.zeros_like(gc[:,:3])
true_potential = LawMajewski2010()
true_params = dict([(k,v.truth) for k,v in true_potential.parameters.items()])
wrong_params = true_params.copy()
wrong_params['v_halo'] = 1.25*wrong_params['v_halo']
wrong_potential = LawMajewski2010(**wrong_params)
sat_R = list()
D_pses = list()
ts = list()
for potential in [true_potential, wrong_potential]:
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(gc[:,:3]), np.array(gc[:,3:]),
args=(gc.shape[0], acc))
times, rs, vs = integrator.run(t1=lm10.t1, t2=lm10.t2, dt=dt)
s_orbit = np.vstack((rs[:,0][:,np.newaxis].T, vs[:,0][:,np.newaxis].T)).T
p_orbits = np.vstack((rs[:,1:].T, vs[:,1:].T)).T
sat_var = np.zeros((len(times),6))
sat_var[:,:3] = potential._tidal_radius(2.5e8, s_orbit[...,:3])*1.26
sat_var[:,3:] += 0.02179966
cov = (sat_var**2)[:,np.newaxis]
D_ps = np.sqrt(np.sum((p_orbits - s_orbit)**2 / cov, axis=-1))
D_pses.append(D_ps)
sat_R.append(np.sqrt(np.sum(s_orbit[:,0,:3]**2, axis=-1)))
ts.append(times)
rcparams = {'xtick.major.size' : 16,
'xtick.major.width' : 1.5}
with rc_context(rc=rcparams):
fig = plt.figure(figsize=(12.5,7))
gs = GridSpec(2,4)
axes = [plt.subplot(gs[0,:3]), plt.subplot(gs[1,:3]),
plt.subplot(gs[0,3]), plt.subplot(gs[1,3])]
axes[0].axhline(1.4, linestyle='--', color='#444444', linewidth=2.)
axes[1].axhline(1.4, linestyle='--', color='#444444', linewidth=2.)
for ii in range(nPlot):
for jj in range(2):
d = D_pses[jj][:,ii]
sR = sat_R[jj]
axes[jj].semilogy(ts[jj]/1000, d, alpha=0.4, color=sgr_color, linewidth=2.)
axes[jj].semilogy(ts[jj][np.argmin(d)]/1000, np.min(d), marker='|',
markeredgewidth=4, markeredgecolor='k', color='k',
alpha=0.9, markersize=25)
axes[0].set_ylim(0.6,20)
axes[0].set_xlim(-6.1, 0.)
axes[1].set_ylim(axes[0].get_ylim())
axes[1].set_xlim(axes[0].get_xlim())
axes[0].tick_params(axis='y', which='both', length=0., labelleft='off')
axes[1].tick_params(axis='y', which='both', length=0., labelleft='off')
# vertical histograms of D_ps values
ylim = axes[0].get_ylim()
bins = np.logspace(np.log10(ylim[0]), np.log10(ylim[1]), 50)
n,xx,patches = axes[2].hist(np.min(D_pses[0], axis=0), bins=bins,
orientation='horizontal', histtype='step',
linewidth=2., fill=True, facecolor='w', edgecolor='k')
n,xx,patches = axes[3].hist(np.min(D_pses[1], axis=0), bins=bins,
orientation='horizontal', histtype='step',
linewidth=2., fill=True, facecolor='w', edgecolor='k')
axes[2].set_yscale('log')
axes[3].set_yscale('log')
axes[2].axis('off')
axes[3].axis('off')
axes[2].set_ylim(axes[0].get_ylim())
axes[3].set_ylim(axes[1].get_ylim())
axes[3].set_ylim(top=axes[1].get_ylim()[1]*1.02)
axes[2].set_xlim(right=1.05*axes[2].get_xlim()[1])
axes[3].set_xlim(right=1.05*axes[3].get_xlim()[1])
axes[1].xaxis.tick_bottom()
axes[1].set_xticklabels([])
axes[0].xaxis.set_visible(False)
fig.subplots_adjust(hspace=0.02, wspace=0., top=0.98, bottom=0.02, left=0.02, right=0.98)
fig.savefig(os.path.join(plot_path, "fig3.pdf"))
def q_p(**kwargs):
filename = os.path.join(plot_path, "q_p.pdf")
fig, axes = plt.subplots(2, 4, figsize=(14, 7.5), sharex=True, sharey=True)
bins = np.linspace(0., 10, 40)
nparticles = 5000
for kk, _m in enumerate(range(6, 9 + 1)):
mass = "2.5e{}".format(_m)
m = float(mass)
print(mass)
sgr = SgrSimulation(sgr_path.format(_m), snapfile)
p = sgr.particles(n=nparticles, expr="(tub!=0)") #" & (tub<400)")
tub = p.tub
s = sgr.satellite()
potential = LawMajewski2010()
X = np.vstack((s._X[..., :3], p._X[..., :3].copy()))
V = np.vstack((s._X[..., 3:], p._X[..., 3:].copy()))
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(X),
np.array(V),
args=(X.shape[0], np.zeros_like(X)))
ts, rs, vs = integrator.run(t1=sgr.t1, t2=sgr.t2, dt=-1.)
s_orbit = np.vstack(
(rs[:, 0][:, np.newaxis].T, vs[:, 0][:, np.newaxis].T)).T
p_orbits = np.vstack((rs[:, 1:].T, vs[:, 1:].T)).T
t_idx = np.array([np.argmin(np.fabs(ts - t)) for t in p.tub])
p_x = np.array([p_orbits[jj, ii] for ii, jj in enumerate(t_idx)])
s_x = np.array([s_orbit[jj, 0] for jj in t_idx])
#############################################
# determine tail_bit
diff = p_x - s_x
norm_r = s_x[:, :3] / np.sqrt(np.sum(s_x[:, :3]**2,
axis=-1))[:, np.newaxis]
norm_diff_r = diff[:, :3] / np.sqrt(np.sum(diff[:, :3]**2,
axis=-1))[:, np.newaxis]
dot_prod_r = np.sum(norm_diff_r * norm_r, axis=-1)
tail_bit = (dot_prod_r > 0.).astype(int) * 2 - 1
#############################################
r_tide = potential._tidal_radius(m, s_orbit[..., :3]) #*0.69336
s_R_orbit = np.sqrt(np.sum(s_orbit[..., :3]**2, axis=-1))
a_pm = (s_R_orbit + r_tide * tail_bit) / s_R_orbit
q = np.sqrt(np.sum((p_x[:, :3] - s_x[:, :3])**2, axis=-1))
f = r_tide / s_R_orbit
s_V = np.sqrt(np.sum(s_orbit[..., 3:]**2, axis=-1))
vdisp = s_V * f / 1.4
p = np.sqrt(np.sum((p_x[:, 3:] - s_x[..., 3:])**2, axis=-1))
fig, axes = plt.subplots(2, 1, figsize=(10, 6), sharex=True)
axes[0].plot(tub, q, marker='.', alpha=0.5, color='#666666')
axes[0].plot(ts,
r_tide * 1.4,
linewidth=2.,
alpha=0.8,
color='k',
linestyle='-',
marker=None)
axes[0].set_ylim(0., max(r_tide) * 4)
axes[1].plot(tub, (p * u.kpc / u.Myr).to(u.km / u.s).value,
marker='.',
alpha=0.5,
color='#666666')
axes[1].plot(ts, (vdisp * u.kpc / u.Myr).to(u.km / u.s).value,
color='k',
linewidth=2.,
alpha=0.75,
linestyle='-',
marker=None)
M_enc = potential._enclosed_mass(s_R_orbit)
#delta_E = 4/3.*G.decompose(usys).value**2*m*(M_enc / s_V)**2*r_tide**2/s_R_orbit**4
delta_v2 = 4/3.*G.decompose(usys).value**2*(M_enc / s_V)**2*\
np.mean(r_tide**2)/s_R_orbit**4
delta_v = (np.sqrt(2 * delta_v2) * u.kpc / u.Myr).to(u.km / u.s).value
axes[1].plot(ts,
delta_v,
linewidth=2.,
color='#2166AC',
alpha=0.75,
linestyle='--',
marker=None)
axes[1].set_ylim(0.,
max((vdisp * u.kpc / u.Myr).to(u.km / u.s).value) * 4)
axes[0].set_xlim(min(ts), max(ts))
fig.savefig(os.path.join(plot_path, "q_p_{}.png".format(mass)),
transparent=True)
# particles = simulation.particles(N=1000, expr="tub!=0")
# satellite = simulation.satellite()\
# .to_frame(heliocentric)
# s_hel = satellite._X.copy()
# s_gc = _hel_to_gc(s_hel)
s_gc = np.array([[
8.363919011, 0.243352771, 16.864546659, -0.04468993, -0.12392801,
-0.01664498
]]) # Pal5
s_hel = _gc_to_hel(s_gc)
# First integrate the orbit of the satellite back to get initial conditions
acc = np.zeros_like(s_gc[:, :3])
integrator = LeapfrogIntegrator(potential._acceleration_at,
np.array(s_gc[:, :3]),
np.array(s_gc[:, 3:]),
args=(s_gc.shape[0], acc))
t, rs, vs = integrator.run(t1=T, t2=0, dt=-dt)
init_r, init_v = rs[-1], vs[-1]
# integrate the orbit of the satellite
acc = np.zeros_like(s_gc[:, :3])
integrator = LeapfrogIntegrator(potential._acceleration_at,
init_r,
init_v,
args=(1, acc))
t, rs, vs = integrator.run(t1=0, t2=T, dt=dt)
satellite_orbit = np.vstack((rs.T, vs.T)).T