independent
- class cosmic.sample.sampler.independent.InitialBinaryTable
Bases:
object- classmethod InitialBinaries(m1, m2, porb, ecc, tphysf, kstar1, kstar2, metallicity, **kwargs)
Create single binary
- Parameters:
- m1float
Primary mass [Msun]
- m2float
Secondary mass [Msun]
- porbfloat
Orbital period [days]
- eccfloat
Eccentricity
- tphysffloat
Time to evolve the binary [Myr]
- kstar1array
0-14 Initial stellar type of the larger object; main sequence stars are 0 if m < 0.7 Msun and 1 otherwise
- kstar2array
0-14 Initial stellar type of the smaller object; main sequence stars are 0 if m < 0.7 Msun and 1 otherwise
- metallicityfloat
Metallicity of the binaries; Z_sun = 0.02
- **kwargs
- binfracfloat
System-specific probability of the primary star being in a binary
mass0_1,mass0_2,rad1,rad2,lumin1,lumin2, massc1,massc2,radc1,radc2,menv1,menv2,renv1,renv2, ospin1,ospin2,b_0_1,b_0_2,bacc1,bacc2, tacc1,tacc2,epoch1,epoch2,tms1,tms2 bhspin1,bhspin2
- Returns:
- InitialBinariesDataFrame
Single binary initial conditions
- __annotations__ = {}
- __dict__ = mappingproxy({'__module__': 'cosmic.sample.initialbinarytable', 'InitialBinaries': <classmethod(<function InitialBinaryTable.InitialBinaries>)>, 'sampler': <classmethod(<function InitialBinaryTable.sampler>)>, '__dict__': <attribute '__dict__' of 'InitialBinaryTable' objects>, '__weakref__': <attribute '__weakref__' of 'InitialBinaryTable' objects>, '__doc__': None, '__annotations__': {}})
- __doc__ = None
- __module__ = 'cosmic.sample.initialbinarytable'
- __weakref__
list of weak references to the object (if defined)
- classmethod sampler(format_, *args, **kwargs)
Fetch a method to generate an initial binary sample
- Parameters:
- formatstr
the method name; Choose from ‘independent’ or ‘multidim’
- *args
the arguments necessary for the registered sample method; see help(InitialBinaryTable.sampler(‘independent’) to see the arguments necessary for the independent sample
- The available named formats are:
- =========== …
Format …
- =========== …
- independent …
multidim …
- =========== …
- class cosmic.sample.sampler.independent.Sample
Bases:
object- __annotations__ = {}
- __dict__ = mappingproxy({'__module__': 'cosmic.sample.sampler.independent', 'sample_primary': <function Sample.sample_primary>, 'sample_secondary': <function Sample.sample_secondary>, 'binary_select': <function Sample.binary_select>, 'sample_porb': <function Sample.sample_porb>, 'sample_ecc': <function Sample.sample_ecc>, 'sample_SFH': <function Sample.sample_SFH>, 'set_kstar': <function Sample.set_kstar>, 'set_reff': <function Sample.set_reff>, '__dict__': <attribute '__dict__' of 'Sample' objects>, '__weakref__': <attribute '__weakref__' of 'Sample' objects>, '__doc__': None, '__annotations__': {}})
- __doc__ = None
- __module__ = 'cosmic.sample.sampler.independent'
- __weakref__
list of weak references to the object (if defined)
- binary_select(primary_mass, binfrac_model=0.5, **kwargs)
Select which primary masses will have a companion using either a binary fraction specified by a float or a primary-mass dependent binary fraction following van Haaften et al.(2009) in appdx or Offner et al.(2022) in fig 1
- Parameters:
- primary_massarray
Mass that determines the binary fraction
- binfrac_modelstr or float
vanHaaften - primary mass dependent and ONLY VALID up to 100 Msun
offner22 - primary mass dependent
float - fraction of binaries; 0.5 means 2 in 3 stars are a binary pair while 1 means every star is in a binary pair
- Optional kwargs are defined in `get_independent_sampler`
- Returns:
- stars_in_binaryarray
primary masses that will have a binary companion
- stars_in_singlearray
primary masses that will be single stars
- binary_fractionarray
system-specific probability of being in a binary
- binaryIdxarray
Idx of stars in binary
- sample_SFH(SF_start=13700.0, SF_duration=0.0, met=0.02, size=None)
Sample an evolution time for each binary based on a user-specified time at the start of star formation and the duration of star formation. The default is a burst of star formation 13,700 Myr in the past.
- Parameters:
- SF_startfloat
Time in the past when star formation initiates in Myr
- SF_durationfloat
Duration of constant star formation beginning from SF_Start in Myr
- metfloat
metallicity of the population [Z_sun = 0.02] Default: 0.02
- sizeint, optional
number of evolution times to sample NOTE: this is set in cosmic-pop call as Nstep
- Returns:
- tphysarray
array of evolution times of size=size
- metallicityarray
array of metallicities
- sample_ecc(aRL_over_a, ecc_model='sana12', size=None)
Sample the eccentricity according to a user specified model
- Parameters:
- ecc_modelstring
‘thermal’ samples from a thermal eccentricity distribution following Heggie (1975) ‘uniform’ samples from a uniform eccentricity distribution ‘sana12’ samples from the eccentricity distribution from Sana+2012 <https://ui.adsabs.harvard.edu/abs/2012Sci…337..444S/abstract>_ ‘circular’ assumes zero eccentricity for all systems DEFAULT = ‘sana12’
- aRL_over_aratio of the minimum seperation (where RL overflow starts)
to the sampled semi-major axis. Use this to truncate the eccentricitiy
- sizeint, optional
number of eccentricities to sample this is set in cosmic-pop call as Nstep
- Returns:
- eccarray
array of sampled eccentricities with size=size
- sample_porb(mass1, mass2, rad1, rad2, porb_model, porb_max=None, size=None, **kwargs)
Sample the orbital period according to the user-specified model
- Parameters:
- mass1array
primary masses
- mass2array
secondary masses
- rad1array
radii of the primaries.
- rad2array
radii of the secondaries
- porb_modelstr or dict
selects which model to sample orbital periods, choices include: log_uniform : semi-major axis flat in log space from RRLO < 0.5 up to 1e5 Rsun according to Abt (1983) and consistent with Dominik+2012,2013 and then converted to orbital period in days using Kepler III sana12 : power law orbital period between 0.15 < log(P/day) < 5.5 following Sana+2012 <https://ui.adsabs.harvard.edu/abs/2012Sci…337..444S/abstract>_ renzo19 : power law orbital period for m1 > 15Msun binaries from Sana+2012 <https://ui.adsabs.harvard.edu/abs/2012Sci…337..444S/abstract>_ following the implementation of Renzo+2019 <https://ui.adsabs.harvard.edu/abs/2019A%26A…624A..66R/abstract>_ and flat in log otherwise raghavan10 : log normal orbital periods in days with mean_logP = 4.9 and sigma_logP = 2.3 between 0 < log10(P/day) < 9 following Raghavan+2010 <https://ui.adsabs.harvard.edu/abs/2010ApJS..190….1R/abstract>_ moe19 : log normal orbital periods in days with mean_logP = 4.9 and sigma_logP = 2.3 between 0 < log10(P/day) < 9 following Raghavan+2010 <https://ui.adsabs.harvard.edu/abs/2010ApJS..190….1R/abstract>_ but with different close binary fractions following Moe+2019 <https://ui.adsabs.harvard.edu/abs/2019ApJ…875…61M/abstract>_ Custom power law distribution defined with a dictionary with keys “min”, “max”, and “slope” (e.g. porb_model={“min”: 0.15, “max”: 0.55, “slope”: -0.55}) would reproduce the Sana+2012 distribution.
- metfloat
metallicity of the population
- Returns:
- porbarray
orbital period with array size equalling array size of mass1 and mass2 in units of days
- aRL_over_a: array
ratio of radius where RL overflow starts to the sampled seperation used to truncate the eccentricitiy distribution
- sample_primary(primary_model='kroupa01', size=None, **kwargs)
Sample the primary mass (always the most massive star) from a user-selected model
kroupa93 follows Kroupa (1993), normalization comes from Hurley 2002 between 0.08 and 150 Msun salpter55 follows Salpeter (1955) between 0.08 and 150 Msun kroupa01 follows Kroupa (2001) <https://arxiv.org/abs/astro-ph/0009005> between 0.08 and 100 Msun
- Parameters:
- primary_modelstr, optional
- model for mass distribution; choose from:
- kroupa93 follows Kroupa (1993), normalization comes from
- `Hurley 2002 <https://arxiv.org/abs/astro-ph/0201220>`_
- valid for masses between 0.1 and 100 Msun
- salpter55 follows
- `Salpeter (1955) <http://adsabs.harvard.edu/abs/1955ApJ…121..161S>`_
- valid for masses between 0.1 and 100 Msun
- kroupa01 follows Kroupa (2001), normalization comes from
- `Hurley 2002 <https://arxiv.org/abs/astro-ph/0009005>`_
- valid for masses between 0.1 and 100 Msun
- custom is a generic piecewise power law that takes in the power
- law slopes and break points given in the optional input lists (alphas, mcuts)
- default alphas and mcuts yield an IMF identical to kroupa01
- Default kroupa01
- sizeint, optional
- number of initial primary masses to sample
- NOTE: this is set in cosmic-pop call as Nstep
- alphasarray, optional
- absolute values of the power law slopes for primary_model = ‘custom’
- Default [-1.3,-2.3,-2.3] (identical to slopes for primary_model = ‘kroupa01’)
- mcutsarray, optional, units of Msun
- break points separating the power law ‘pieces’ for primary_model = ‘custom’
- Default [0.08,0.5,1.0,150.] (identical to breaks for primary_model = ‘kroupa01’)
- Optional kwargs are defined in `get_independent_sampler`
- Returns:
- a_0array
- Sampled primary masses
- np.sum(a_0)float
- Total amount of mass sampled
- sample_secondary(primary_mass, q_power_law=0, **kwargs)
Sample a secondary mass using draws from a uniform mass ratio distribution motivated by Mazeh et al. (1992) and Goldberg & Mazeh (1994)
NOTE: the lower lim is set by either qmin or m2_min which are passed as kwargs
- Parameters:
- primary_massarray
sets the maximum secondary mass (for a maximum mass ratio of 1)
- Optional kwargs are defined in `get_independent_sampler`
- Returns:
- secondary_massarray
sampled secondary masses with array size matching size of primary_mass
- set_kstar(mass)
Initialize stellar types according to BSE classification kstar=1 if M>=0.7 Msun; kstar=0 if M<0.7 Msun
- Parameters:
- massarray
array of masses
- Returns:
- kstararray
array of initial stellar types
- set_reff(mass, metallicity, zsun=0.02)
Better way to set the radii from BSE, by calling it directly
takes masses and metallicities, and returns the radii
Note that the BSE function is hard-coded to go through arrays of length 10^5. If your masses are more than that, you’ll need to divide it into chunks
- cosmic.sample.sampler.independent.get_independent_sampler(final_kstar1, final_kstar2, primary_model, ecc_model, porb_model, SF_start, SF_duration, binfrac_model, met, size=None, total_mass=inf, sampling_target='size', trim_extra_samples=False, q_power_law=0, **kwargs)
Generates an initial binary sample according to user specified models
- Parameters:
- final_kstar1int or list
Int or list of final kstar1
- final_kstar2int or list
Int or list of final kstar2
- primary_modelstr
Model to sample primary mass; choices include: kroupa93, kroupa01, salpeter55, custom if ‘custom’ is selected, must also pass arguemts: alphas : array
list of power law indicies
- mcutsarray
breaks in the power laws.
e.g. alphas=[-1.3,-2.3,-2.3],mcuts=[0.08,0.5,1.0,150.] reproduces standard Kroupa2001 IMF
- ecc_modelstr
Model to sample eccentricity; choices include: thermal, uniform, sana12
- porb_modelstr or dict
Model to sample orbital period; choices include: log_uniform, sana12, raghavan10, moe19 or a custom power law distribution defined with a dictionary with keys “min”, “max”, and “slope” (e.g. {“min”: 0.15, “max”: 0.55, “slope”: -0.55}) would reproduce the Sana+2012 distribution
- qminfloat
kwarg which sets the minimum mass ratio for sampling the secondary where the mass ratio distribution is flat in q if q > 0, qmin sets the minimum mass ratio q = -1, this limits the minimum mass ratio to be set such that the pre-MS lifetime of the secondary is not longer than the full lifetime of the primary if it were to evolve as a single star
- m_maxfloat
kwarg which sets the maximum primary and secondary mass for sampling NOTE: this value changes the range of the IMF and should not be used
as a means of selecting certain kstar types!
- m1_minfloat
kwarg which sets the minimum primary mass for sampling NOTE: this value changes the range of the IMF and should not be used
as a means of selecting certain kstar types!
- m2_minfloat
kwarg which sets the minimum secondary mass for sampling the secondary as uniform in mass_2 between m2_min and mass_1
- msortfloat
Stars with M>msort can have different pairing and sampling of companions
- qmin_msortfloat
Same as qmin for M>msort
- m2_min_msortfloat
Same as m2_min for M>msort
- SF_startfloat
Time in the past when star formation initiates in Myr
- SF_durationfloat
Duration of constant star formation beginning from SF_Start in Myr
- binfrac_modelstr or float
Model for binary fraction; choices include: vanHaaften, offner22, or a fraction where 1.0 is 100% binaries
- binfrac_model_msortstr or float
Same as binfrac_model for M>msort
- metfloat
Sets the metallicity of the binary population where solar metallicity is zsun
- sizeint
Size of the population to sample
- total_massfloat
Total mass to use as a target for sampling
- sampling_targetstr
Which type of target to use for sampling (either “size” or “total_mass”), by default “size”. Note that total_mass must not be None when sampling_target==”total_mass”.
- trim_extra_samplesstr
Whether to trim the sampled population so that the total mass sampled is as close as possible to total_mass. Ignored when sampling_target==size. Note that given the discrete mass of stars, this could mean your sample is off by 300 solar masses in the worst case scenario (of a 150+150 binary being sampled). In reality the majority of cases track the target total mass to within a solar mass.
- zsunfloat
optional kwarg for setting effective radii, default is 0.02
- q_power_lawfloat
Exponent for the mass ratio distribution power law, default is 0 (flat in q). Note that q_power_law cannot be exactly -1, as this would result in a divergent distribution.
- Returns:
- InitialBinaryTablepandas.DataFrame
DataFrame in the format of the InitialBinaryTable
- mass_singlesfloat
Total mass in single stars needed to generate population
- mass_binariesfloat
Total mass in binaries needed to generate population
- n_singlesint
Number of single stars needed to generate a population
- n_binariesint
Number of binaries needed to generate a population
- cosmic.sample.sampler.independent.register_sampler(data_format, data_class, function, force=False, usage=None)
Register a new method to InitialBinaryTable.sampler() for a given format
- Parameters:
- data_formatstr
name of the format to be registered
- data_classtype
the class that the sampler returns
- functioncallable
the method to call from
InitialBinaryTable.sampler()- forcebool, optional
overwrite existing registration for
data_formatif found, default: False