/
galpy_potential.py
82 lines (58 loc) · 3.32 KB
/
galpy_potential.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
from galpy import potential
from galpy.util import bovy_conversion
class galpy_profile(LiteratureReferencesMixIn):
"""
User-defined potential from GALPY
.. [#] Bovy, J; ApJSS, Volume 216, Issue 2, article id. 29, 27 pp. (2015)
"""
def __init__(self,pot, t = 0. | units.Gyr, tgalpy = 0. | units.Gyr, ro=8, vo=220.):
LiteratureReferencesMixIn.__init__(self)
#Galpy scaling parameters
self.ro=ro
self.vo=vo
#Galpy potential
self.pot = pot
#Initialize model time
self.model_time=t
#Initialize galpy time
#Depending on how the galpy potential is setup, one may want to define a different initial galpy time
#from which to evolve the potential (e.g. negative times)
self.tgalpy=tgalpy.value_in(units.Gyr)/bovy_conversion.time_in_Gyr(ro=self.ro,vo=self.vo)
def evolve_model(self,t_end):
print('EVOLVE: ',self.model_time.value_in(units.Gyr),self.tgalpy,t_end.value_in(units.Gyr))
dt=t_end-self.model_time
self .model_time=t_end
self.tgalpy+=dt.value_in(units.Gyr)/bovy_conversion.time_in_Gyr(ro=self.ro,vo=self.vo)
def get_potential_at_point(self,eps,x,y,z):
R=np.sqrt(x.value_in(units.kpc)**2.+y.value_in(units.kpc)**2.)
zed=z.value_in(units.kpc)
phi=np.arctan2(y.value_in(units.kpc),x.value_in(units.kpc))
pot=potential.evaluatePotentials(self.pot,R/self.ro,zed/self.ro,phi=phi,t=self.tgalpy,ro=self.ro,vo=self.vo) | units.km**2*units.s**-2
return pot
def get_gravity_at_point(self,eps,x,y,z):
R=np.sqrt(x.value_in(units.kpc)**2.+y.value_in(units.kpc)**2.)
zed=z.value_in(units.kpc)
phi=np.arctan2(y.value_in(units.kpc),x.value_in(units.kpc))
Rforce=potential.evaluateRforces(self.pot,R/self.ro,zed/self.ro,phi=phi,t=self.tgalpy)
phiforce=potential.evaluatephiforces(self.pot,R/self.ro,zed/self.ro,phi=phi,t=self.tgalpy)/(R/self.ro)
zforce=potential.evaluatezforces(self.pot,R/self.ro,zed/self.ro,phi=phi,t=self.tgalpy)
ax=(Rforce*np.cos(phi)-phiforce*np.sin(phi))*bovy_conversion.force_in_kmsMyr(ro=self.ro,vo=self.vo) | units.kms * units.myr**-1
ay=(Rforce*np.sin(phi)+phiforce*np.cos(phi))*bovy_conversion.force_in_kmsMyr(ro=self.ro,vo=self.vo) | units.kms * units.myr**-1
az=zforce*bovy_conversion.force_in_kmsMyr(ro=self.ro,vo=self.vo) | units.kms * units.myr**-1
return ax,ay,az
def mass_density(self,x,y,z):
R=np.sqrt(x.value_in(units.kpc)**2.+y.value_in(units.kpc)**2.)
zed=z.value_in(units.kpc)
phi=np.arctan2(y.value_in(units.kpc),x.value_in(units.kpc))
dens=potential.evaluateDensities(self.pot,R/self.ro,zed/self.ro,phi=phi,t=self.tgalpy,ro=self.ro,vo=self.vo) | units.MSun/(units.parsec**3.)
return dens
def circular_velocity(self,r):
vcirc=potential.vcirc(self.pot,r.value_in(units.kpc)/self.ro,phi=0,ro=self.ro,vo=self.vo) | units.kms
return vcirc
def enclosed_mass(self,r):
grav=4.302e-6 #kpc (km/s)^2/Msun
vc2=potential.vcirc(self.pot,r.value_in(units.kpc)/self.ro,phi=0,t=self.tgalpy,ro=self.ro,vo=self.vo)**2.
menc= vc2*r.value_in(units.kpc)/grav | units.MSun
return menc
def stop(self):
pass