def supernova_rate(self):
"""
Calculates the SN rate at time t by integrating over mass m
"""
# initialize
sn_rate_list = []
dm = 0.01
prev_t = 1e-3
# define time array
time = self.sfh[:, 0]
time = time[time < self.tend]
for t in time:
# need to clear the sn_rates as we don't want them adding up
sn_rate = 0.0
dsn_rate = 0.0
if t < 0.049:
m = lookup_fn(t_lifetime, "lifetime_high_metals", t)[0]
else:
m = 9.0
while m < 40.0:
if m > 10.0:
dm = 0.5
sn_rate += f.initial_mass_function(m, self.imf_type) * dm
m += dm
r_sn = self.sfr(t) * sn_rate # units in N per Gyr
dt = t - prev_t
prev_t = t
sn_rate_list.append(r_sn)
return np.array(sn_rate_list)
def test_minimum_mass_lookup_highZ(self):
t_lifetime = Table(rows=lifetime,
names=('mass', 'lifetime_low_metals',
'lifetime_high_metals'),
meta={'name': 'Lifetime'})
minimum_mass = lookup_fn(t_lifetime, 'lifetime_high_metals',
1.75)['mass']
assert minimum_mass == 2.0
def mass_integral(choice, reduce_sn, t, metallicity, sfr_lookup, z_lookup, imf):
'''
This function does the mass integral for:
- e(t): ejected gas mass em
- ez(t): ejected metal mass ezm
- ed(t): ejected dust mass edm
- Zdiff and SFR diff are also calculated ie at t-taum
In:
-- choice: array of dust source choices
-- t: time in Gyrs
-- metallicity: metal mass fraction Mz/Mg
-- sfr_lookup: SFR array (time, SFR) based on previous time steps
-- z_lookup: metallicity array (time, Z) based on previous time steps
-- imf: choice of IMF
'''
mu = t_lifetime[-1]['mass']
dm = 0.01
t_0 = 1e-3
ezm = 0.
edm = 0.
em = 0.
# we pull out mass corresponding to age of system
# to get lower limit of integral
# to make taum lookup faster
m = lookup_fn(t_lifetime,'lifetime_low_metals',t)['mass']
lifetime_cols = {'low_metals':1, 'high_metals':2}
if metallicity < 0.019:
col_choice = lifetime_cols['low_metals']
else:
col_choice = lifetime_cols['high_metals']
while m <= mu:
if m > 10.:
dm = 0.5
# pull out lifetime of star of mass m so we can
# calculate SFR when star was born which is t-lifetime
taum = lookup_taum(m,col_choice)
tdiff = t - taum
# only release material after stars die
if tdiff <= 0:
ezm = 0
edm = 0
em = 0
else:
# get nearest Z which corresponds to Z at time=t-taum
zdiff = find_nearest(z_lookup,tdiff)[1]
sfrdiff = find_nearest(sfr_lookup,tdiff)[1]
ezm += ejected_metal_mass(m, sfrdiff, zdiff, metallicity, imf) * dm
em += ejected_gas_mass(m, sfrdiff, imf) * dm
edm += ejected_dust_mass(choice, reduce_sn, m, sfrdiff, zdiff, metallicity, imf) * dm
m += dm
return em, ezm, edm
def mass_integral(choice, delta_lims, reduce_sn, t, metallicity, sfr_lookup,
z_lookup, oxy_lookup, imf):
'''
This function does the mass integral for:
- e(t): ejected gas mass em
- ez(t): ejected metal mass ezm
- ed(t): ejected dust mass edm
- Zdiff and SFR diff are also calculated ie at t-taum (when stars that are dying now were born)
In:
-- choice: array of dust source choices
-- delta_lims: efficiency of fresh metals condensing into dust, set by user
-- t: time in Gyrs
-- metallicity: metal mass fraction Mz/Mg
-- sfr_lookup: SFR array (time, SFR) based on previous time steps
-- z_lookup: metallicity array (time, Z) based on previous time steps
-- imf: choice of IMF
'''
mu = t_lifetime[-1]['mass']
t_0 = 1e-3
ezm = 0.
eom = 0.
edm = 0.
em = 0.
lifetime_cols = {'low_metals': 1, 'high_metals': 2}
if metallicity <= 0.008: # in between Z=0.001 and Z=0.02 files from Schaller et al 1992
# get the correct lower mass of integral based on age of system
m_min = lookup_fn(t_lifetime, 'lifetime_low_metals', t)['mass']
# define column choice to speed up taum fn below
col_choice = lifetime_cols['low_metals']
else:
m_min = lookup_fn(t_lifetime, 'lifetime_high_metals', t)['mass']
# define column choice to speed up taum fn below
col_choice = lifetime_cols['high_metals']
# checks that m_min does not exceed mu
if (m_min >= mu):
m_min = mu
# increasing the number of steps increases the
# resolution in the mass integral
steps = 500
m = m_min
dlogm = 0
logmnew = np.log10(m) + dlogm
dm = 10**(logmnew) - m
dlogm = (np.log10(mu) - np.log10(m_min)) / steps
count = 0
z_near = lambda td: z_lookup[(abs(z_lookup[:, 0] - td)).argmin()]
oxy_near = lambda td: oxy_lookup[(abs(oxy_lookup[:, 0] - td)).argmin()]
sfr_near = lambda td: sfr_lookup[(abs(sfr_lookup[:, 0] - td)).argmin()]
# loop over the full mass range
while count < steps:
count += 1
logmnew = np.log10(m) + dlogm
dm = 10.0**(logmnew) - m
mmid = 10.0**((logmnew + np.log10(m)) / 2.0)
# pull out lifetime of star of mass m so we can
# calculate SFR when star was born which is t-lifetime
taum = lookup_taum(mmid, col_choice)
tdiff = t - taum
# only release material after stars die
if tdiff <= 0:
ezm = 0
eom = 0
edm = 0
em = 0
else:
# get nearest Z and SFR which corresponds to Z and SFR at time=t-taum
zdiff = z_near(tdiff)[1] # find_nearest(z_lookup,tdiff)[1]
oxydiff = oxy_near(tdiff)[1] # find_nearest(oxy_lookup,tdiff)[1]
sfrdiff = sfr_near(tdiff)[1] # find_nearest(sfr_lookup,tdiff)[1]
ezm += ejected_metal_mass(mmid, sfrdiff, zdiff, metallicity,
imf) * dm
eom += ejected_oxygen_mass(mmid, sfrdiff, oxydiff, metallicity,
imf) * dm
em += ejected_gas_mass(mmid, sfrdiff, imf) * dm
edm += ejected_dust_mass(choice, delta_lims, reduce_sn, mmid,
sfrdiff, zdiff, metallicity, imf) * dm
#Calculate the next mass value
mnew = 10**(logmnew)
m = mnew
return em, ezm, eom, edm
def mass_integral(choice, reduce_sn, t, metallicity, sfr_lookup, z_lookup, imf):
'''
This function does the mass integral for:
- e(t): ejected gas mass em
- ez(t): ejected metal mass ezm
- ed(t): ejected dust mass edm
- Zdiff and SFR diff are also calculated ie at t-taum (when stars that are dying now were born)
In:
-- choice: array of dust source choices
-- t: time in Gyrs
-- metallicity: metal mass fraction Mz/Mg
-- sfr_lookup: SFR array (time, SFR) based on previous time steps
-- z_lookup: metallicity array (time, Z) based on previous time steps
-- imf: choice of IMF
'''
mu = t_lifetime[-1]['mass']
t_0 = 1e-3
ezm = 0.
edm = 0.
em = 0.
lifetime_cols = {'low_metals':1, 'high_metals':2}
if metallicity <= 0.008: # in between Z=0.001 and Z=0.02 files from Schaller et al 1992
# get the correct lower mass of integral based on age of system
m_min = lookup_fn(t_lifetime,'lifetime_low_metals',t)['mass']
# define column choice to speed up taum fn below
col_choice = lifetime_cols['low_metals']
else:
m_min = lookup_fn(t_lifetime,'lifetime_high_metals',t)['mass']
# define column choice to speed up taum fn below
col_choice = lifetime_cols['high_metals']
# checks that m_min does not exceed mu
if(m_min >= mu):
m_min = mu
# increasing the number of steps increases the
# resolution in the mass integral
steps = 500
m = m_min
dlogm = 0
logmnew = np.log10(m) + dlogm
dm = 10**(logmnew)- m
dlogm = (np.log10(mu)-np.log10(m_min))/steps
count = 0
z_near = lambda td : z_lookup[(abs(z_lookup[:,0]-td)).argmin()]
sfr_near = lambda td : sfr_lookup[(abs(sfr_lookup[:,0]-td)).argmin()]
# loop over the full mass range
while count < steps:
count += 1
logmnew = np.log10(m) + dlogm
dm = 10.0**(logmnew) - m
mmid = 10.0**((logmnew+np.log10(m))/2.0)
# pull out lifetime of star of mass m so we can
# calculate SFR when star was born which is t-lifetime
taum = lookup_taum(mmid,col_choice)
tdiff = t - taum
# only release material after stars die
if tdiff <= 0:
ezm = 0
edm = 0
em = 0
else:
# get nearest Z and SFR which corresponds to Z and SFR at time=t-taum
zdiff = z_near(tdiff)[1] # find_nearest(z_lookup,tdiff)[1]
sfrdiff = sfr_near(tdiff)[1] # find_nearest(sfr_lookup,tdiff)[1]
ezm += ejected_metal_mass(mmid, sfrdiff, zdiff, metallicity, imf) * dm
em += ejected_gas_mass(mmid, sfrdiff, imf) * dm
edm += ejected_dust_mass(choice, reduce_sn, mmid, sfrdiff, zdiff, metallicity, imf) * dm
#Calculate the next mass value
mnew = 10**(logmnew)
m = mnew
return em, ezm, edm
def test_minimum_mass_lookup_highZ(self):
t_lifetime = Table(rows=lifetime, names=('mass','lifetime_low_metals','lifetime_high_metals'),meta={'name': 'Lifetime'})
minimum_mass = lookup_fn(t_lifetime,'lifetime_high_metals',1.75)['mass']
assert minimum_mass == 2.0