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 fresh_metals(m, metallicity):
'''
Function to return the fresh new elements made by stars
These are metallicity dependent and calls mass_yields table
in lookups.py
metals for LIMS are from van Hoek
Massive stars are from Maeder 1992
For m > 40, then only winds contribute to ejected metals
For m <= 40, winds + SNe contribute
'''
massyields = find_nearest(mass_yields, m)
if metallicity <= 0.0025:
if m <= 40:
sum_yields = massyields[yn.index('yields_sn_001')]+massyields[yn.index('yields_winds_001')]
else:
sum_yields = massyields[yn.index('yields_winds_001')]
elif metallicity <= 0.006:
if m <= 40:
sum_yields = massyields[yn.index('yields_sn_004')]+massyields[yn.index('yields_winds_004')]
else:
sum_yields = massyields[yn.index('yields_winds_004')]
elif metallicity <= 0.01:
if m <= 40:
sum_yields = massyields[yn.index('yields_sn_008')]+massyields[yn.index('yields_winds_008')]
else:
sum_yields = massyields[yn.index('yields_winds_008')]
else:
if m <= 40:
sum_yields = massyields[yn.index('yields_sn_02')]+massyields[yn.index('yields_winds_02')]
else:
sum_yields = massyields[yn.index('yields_winds_02')]
return sum_yields
def sfr(self, t):
try:
vals = find_nearest(self.sfh, t)
return vals[1]
except:
logger.error("No SFH yet")
def sfr(self, t):
'''
define sfr as function to look up nearest sfr value at any specified time
'''
try:
vals = find_nearest(self.sfh, t)
return vals[1]
except:
logger.error("No SFH yet")
def sfr(self, t):
'''
define sfr as function to look up nearest sfr value at any specified time
'''
try:
vals = find_nearest(self.sfh,t)
return vals[1]
except:
logger.error("No SFH yet")
def dust_masses_fresh(choice, reduce_sn, m, metallicity):
'''
This function returns the dust mass ejected by a star
of initial mass m made from freshly synthesised elements
For dust formed from newly processed metals we split into
two categories: winds from LIMS and SN.
LIMS: we multiply the metal yields by a dust condensation
efficiency parameter assumed to be 0.45
For high mass stars we use the SN yields of
Todini & Ferrara 2001 (MNRAS 325 276)
In:
-- choice: array of dust source choices, set by user in inits
0th element = sn value 1 or 0
1st element = lims value 1 or 0
2nd element = grain growth value 1 or 0
-- reduce_sn: factor to reduce SN dust contribution, set by user in inits
-- m: mass of star
-- metallicity: metal mass fraction Mz/Mg
delta_new_LIMS - dust condensation efficiency for new metals in LIMS
yields - metal yields by mass
See Figure 3 in Rowlands et al 2014 (MNRAS 441, 1040)
'''
# Which dust sources are turned on or off?
choice_sn = choice[0]
choice_lims = choice[1]
delta_new_LIMS = 0.45
if (m <= 8.0):
dustmass = choice_lims*delta_new_LIMS * fresh_metals(m, metallicity)
elif (m > 8.0) & (m <= 40.0):
# find dust mass from TF01 in dust_mass_sn table
# assume massive star winds don't form dust
dustmass = choice_sn*(reduce_sn)**-1*find_nearest(np.array(dust_mass_sn),m)[1]
else:
dustmass = 0.
return dustmass
def dust_masses_fresh(choice, reduce_sn, m, metallicity):
'''
This function returns the dust mass ejected by a star
of initial mass m made from freshly synthesised elements
For dust formed from newly processed metals we split into
two categories: winds from LIMS and SN.
LIMS: we multiply the metal yields by a dust condensation
efficiency parameter assumed to be 0.45
For high mass stars we use the SN yields of
Todini & Ferrara 2001 (MNRAS 325 276)
In:
-- choice: array of dust source choices, set by user in inits
0th element = sn value 1 or 0
1st element = lims value 1 or 0
2nd element = grain growth value 1 or 0
-- reduce_sn: factor to reduce SN dust contribution, set by user in inits
-- m: mass of star
-- metallicity: metal mass fraction Mz/Mg
delta_new_LIMS - dust condensation efficiency for new metals in LIMS
yields - metal yields by mass
See Figure 3 in Rowlands et al 2014 (MNRAS 441, 1040)
'''
delta_new_LIMS = 0.45
if (m <= 8.0) and choice['lims']:
dustmass = delta_new_LIMS * fresh_metals(m, metallicity)
elif (m > 8.0) and (m <= 40.0) and choice['sn']:
# find dust mass from TF01 in dust_mass_sn table
# assume massive star winds don't form dust
dustmass = reduce_sn**-1 * find_nearest(np.array(dust_mass_sn), m)[1]
else:
dustmass = 0.
return dustmass
def fresh_oxygen(m, metallicity):
'''
Function to return the fresh oxygen made by stars
These are metallicity dependent and calls oxymass_yields table
in lookups.py
metals for LIMS are from van Hoek
Massive stars are from Maeder 1992
For m > 40, then only winds contribute to ejected metals
For m <= 40, winds + SNe contribute
'''
oxymassyields = find_nearest(oxymass_yields, m)
if metallicity <= 0.0025:
if m <= 40:
sum_yields = oxymassyields[yn.index(
'yields_sn_001')] + oxymassyields[yn.index('yields_winds_001')]
else:
sum_yields = oxymassyields[yn.index('yields_winds_001')]
elif metallicity <= 0.006:
if m <= 40:
sum_yields = oxymassyields[yn.index(
'yields_sn_004')] + oxymassyields[yn.index('yields_winds_004')]
else:
sum_yields = oxymassyields[yn.index('yields_winds_004')]
elif metallicity <= 0.01:
if m <= 40:
sum_yields = oxymassyields[yn.index(
'yields_sn_008')] + oxymassyields[yn.index('yields_winds_008')]
else:
sum_yields = oxymassyields[yn.index('yields_winds_008')]
else:
if m <= 40:
sum_yields = oxymassyields[yn.index(
'yields_sn_02')] + oxymassyields[yn.index('yields_winds_02')]
else:
sum_yields = oxymassyields[yn.index('yields_winds_02')]
return sum_yields
def final_sfr(self, t):
try:
vals = find_nearest(self.extra_sfr, t)
return vals[1]
except:
logger.error("No SFH yet")
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.
# we pull out mass corresponding to age of system
# to get lower limit of integral
# to make taum lookup faster
m_min = lookup_fn(t_lifetime,'lifetime_low_metals',t)['mass']
# 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
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
col_choice = lifetime_cols['low_metals']
else:
col_choice = lifetime_cols['high_metals']
# 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 = find_nearest(z_lookup,tdiff)[1]
sfrdiff = 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