Configuration files for CMC

The cmc command-line executable cannot run without a configuration file. These ini files are designed to contain all the stellar evolution physics to generate a COSMIC population (i.e. the initial conditions for CMC) and all the dynamical options. Note that there are two distinct modes you might want to run CMC in: either as a purely dynamics code, with no real stars or stellar evolution, or with all the bells and whistles, to produce realistic models of clusters. These are sufficiently different that we have included two ini files in the examples directory:

KingProfile.ini is designed to run a cluster with most of the available physics. Use this for realistic star cluster simulations (it is what is described as “default” below). The ini file can be found Here

PlummerSphere.ini is designed to run a cluster with pure dynamics; no stars or stellar evolution, and will halt once the cluster reaches core collapse. Use this for classical dynamics studies and learning the code. The ini file can be found Here

Warning

The parameter names are case insensitive, and we’ve tried to include everything currently used in the code here. If you forget one, CMC will substitute a default value. However, note that there are several default values still in the code that are NOT described here. These are largely from either deprecated features, or parts of the code that are not working yet in the parallel version. If they work at all, we would strongly advise against using them for any type of production run.

[cmc]

Although this is all one section, we have grouped the flags/parameters which get passed to the dynamics and binary stellar evolution codes into (rough) categories. Each group will start with a note to indicate. the type of parameter or flag.

SNAPSHOT FLAGS

SNAPSHOTTING	Turn snapshotting on or of (doesn’t control black hole snapshots below) 0 : Off 1 : On SNAPSHOTTING = 1
SNAPSHOT_DELTACOUNT	How many timesteps to write a snapshot SNAPSHOT_DELTACOUNT = 1000
BH_SNAPSHOTTING	Turn on snapshots for just the black holes (in the output.blackhole.snapshots.h5 file) 0 : Off 1 : On BH_SNAPSHOTTING = 0
BH_SNAPSHOT_DELTACOUNT	write the black hole snapshots every X timesteps BH_SNAPSHOT_DELTACOUNT = 500
SNAPSHOT_CORE_COLLAPSE	write additional snapshots around core collapse (in the output.snapshots.h5 file) 0 : Off 1 : On SNAPSHOT_CORE_COLLAPSE = 0
SNAPSHOT_WINDOWS	write snapshots every X units of time into the <output>.window.snapshots.h5 file. Format is: start_w0,step_w0,end_w0:start_w1,step_w1,stop_w1 … etc SNAPSHOT_WINDOWS = “0,0.1,13.8” (will write one snapshot to snapshot.h5 every 100 Myr)
SNAPSHOT_WINDOW_UNITS	What units should the snapshot windows be in. Options are: Gyr : gigayears Trel : relaxation times Tcr : crossing times SNAPSHOT_WINDOW_UNITS = Gyr

RELAXATION FLAGS

RELAXATION	perform two-body relaxation (0=off, 1=on) 0 : Off 1 : On RELAXATION = 1
CMC_GAMMA	Value of the Coulomb Logarithm (lambda = log(gamma*N)). Suggested values are: 0.11 : equal-mass clusters Giersz & Heggie (1994) 0.01 : realistic initial mass functions Rodriguez et al., (2018) CMC_GAMMA = 0.01
THETASEMAX	Maximum value of theta during two-body encounters. Suggested values are: 1.412 : sqrt(2), for equal mass clusters 1 : for point-mass clusters THETASEMAX = 1.412

DYNAMICS FLAGS

BINBIN	Turn on Fewbody encounters between two binaries 0 : Off 1 : On BINBIN = 1
BINSINGLE	Turn on Fewbody encounters between binaries and single objects 0 : Off 1 : On BINSINGLE = 1
BH_CAPTURE	Turn on post-Newtonian corrections for black holes. NOTE: this activates GW captures for both single BHs and during fewbody encounters. Note if SS_COLLISION=0 and BH_CAPTURE=1, GW captures will happen only in fewbody. 0 : Off 1 : On BH_CAPTURE = 1
BH_RADIUS_MULTIPLYER	Factor to multiply the radii of BHs by for collisions in fewbody (default is 5, since PN breaks down at ~10M) BH_RADIUS_MULTIPLYER = 5
THREEBODYBINARIES	Turn on three-body binary formation semi-analytic treatment from Morscher et al., 2013 0 : Off 1 : On THREEBODYBINARIES = 1
ONLY_FORM_BH_THREEBODYBINARIES	Only form three-body binaries if the three objects are black holes 0 : Off 1 : On ONLY_FORM_BH_THREEBODYBINARIES = 1
MIN_BINARY_HARDNESS	Minimum hardness ratio for forming three-body binaries (or breaking wide binaries if BINARY_BREAKING_MIN = 1) MIN_BINARY_HARDNESS = 5
BINARY_BREAKING_MIN	whether to use 10% of the interparticle seperation (0, default) or MIN_BINARY_HARDNESS (1) as the criterion for breaking wide binaries 0 : interparticle seperation 1 : MIN_BINARY_HARDNESS BINARY_BREAKING_MIN = 0
SS_COLLISION	enable collisions between stars. NOTE: this activates collisions between single stars AND during fewbody encounters 0 : Off 1 : On SS_COLLISION = 1
TIDAL_CAPTURE	Enable collisions bewteen giants and other individual stars. Can lead to binary formation. Uses cross sections from Lombardi et al., 2006. Only activated if SS_COLLISION = 1 0 : Off 1 : On TIDAL_CAPTURE = 0
TC_POLYTROPE	Enable tidal captures during single-single interactions. Uses polytropic stellar models for stars. Uses cross sections from Kim & Lee 1999. Only activated if SS_COLLISION = 1 0 : Off 1 : On TC_POLYTROPE = 0
COLL_FACTOR	Set the multiplying factor for direct collisions. Default = 1.0 (sticky sphere) COLL_FACTOR = 1.0
BHNS_TDE	Treat BH(NS)–MS TDEs in TDE vs direct collision limit. Follows prescription in Kremer et al., 2020 0 : collision 1 : TDE BHNS_TDE = 0

INPUT OPTIONS

INPUT_FILE

the input hdf5 file for our intial conditions generated using COSMIC INPUT_FILE = input.hdf5

TIDAL FIELD OPTIONS

TIDALLY_STRIP_STARS	Tidally strip stars that pass the tidal boundary 0 : Off 1 : On TIDALLY_STRIP_STARS = 1
TIDAL_TREATMENT	choose the tidal cut-off criteria for removing stars 0 : radial criterion, \({r_{\rm apo} > r_{t}}\) 1 : Energy criterion, \({\alpha E > \Phi(r_t)}\), following Giersz et al. (2008) TIDAL_TREATMENT = 0
USE_TT_FILE	whether to take the tidal boundary from a file (i.e. a tidal tensor) 0 : Off 1 : On USE_TT_FILE = 0
TT_FILE	name of tidal tensor file to take tidal boundary from. Should be formatted as Time [Myr] T_xx T_yy T_zz T_xy T_xz T_yz [1/Myr^2] TT_FILE=NULL

TERMINATION OPTIONS

T_MAX_PHYS	maximum integration time (Gyr) T_MAX_PHYS = 13.8
T_MAX	maximum integration time (relaxation time) T_MAX = 100
T_MAX_COUNT	maximum number of timesteps T_MAX_COUNT = 10000000
MAX_WCLOCK_TIME	maximum amount of wallclock time to integrate for (seconds) MAX_WCLOCK_TIME = 604800
CHECKPOINT_INTERVAL	how often to save checkpoint files (seconds) CHECKPOINT_INTERVAL = 7200
CHECKPOINTS_TO_KEEP	how many previous checkpoints to keep at once CHECKPOINTS_TO_KEEP = 2
TERMINAL_ENERGY_DISPLACEMENT	energy change calculation stopping criterion (i.e. if \(e/e_0\) changes by this much, stop calculation) TERMINAL_ENERGY_DISPLACEMENT = 10
STOPATCORECOLLAPSE	stop once the cluster reaches core collapse (< 100 stars in core) 0 : Off 1 : On STOPATCORECOLLAPSE = 0
USE_DF_CUTOFF	whether to compute a lifetime according to dynamical friction criterion. This controls whether an external file (DF_FILE) is used 0 : Off 1 : On USE_DF_CUTOFF = 0
DF_FILE	name of dynamical friction file to use as potential termination criterion. Should be formatted as Time[Myr] Radius[Kpc] V_circ[km/s] M_enc[solMass] sigma[km/s] J[Kpc*km/s] DF_FILE = NULL
DF_INTEGRATED_CRITERION	dynamical friction criterion to use for terminating the simulation 0 : \({t_{\rm df} > \rm{TotalTime}}\) 1 : \({\int\frac{dt}{t_{\rm df}} > 1}\) DF_INTEGRATED_CRITERION = 1

OUTPUT OPTIONS

MASS_PC	mass fractions for Lagrange radii, i.e. what fractions to actually print in the laggard files MASS_PC = 0.0001,0.0003,0.0005,0.0007,0.0009, 0.001,0.003,0.005,0.007,0.009,0.01, 0.03,0.05,0.07,0.09,0.1,0.2,0.3,0.4, 0.5,0.6,0.7,0.8,0.9,0.99
MASS_BINS	mass ranges for calculating derived quantities, i.e. what bins to use in mass for the different mass files MASS_BINS = 0.1,1.0,10.0,100.0,1000.0
WRITE_EXTRA_CORE_INFO	Write out information about cores that are defined differently from the standard 0 : Off 1 : On WRITE_EXTRA_CORE_INFO = 0
WRITE_BH_INFO	Write out information about BHs each timestep 0 : Off 1 : On WRITE_BH_INFO = 1
WRITE_PULSAR_INFO	Write out information about pulsars 0 : Off 1 : On WRITE_PULSAR_INFO = 0
WRITE_MOREPULSAR_INFO	Write a ton more information about neutron stars every PULSAR_DELTACOUNT timesteps 0 : Off 1 : On WRITE_MOREPULSAR_INFO = 0
PULSAR_DELTACOUNT	Pulsar output interval in time steps PULSAR_DELTACOUNT = 1000
WRITE_STELLAR_INFO	Write out information about stellar evolution for each single and binary star. Warning, this creates a TON of output 0 : Off 1 : On WRITE_STELLAR_INFO = 0

CMC Parameters

Parameters for controlling the CMC run.

Warning

Don’t touch these unless you know what you’re doing. And even then I probably wouldn’t.

AVEKERNEL	one half the number of stars over which to average certain quantities AVEKERNEL = 20
BH_AVEKERNEL	Same, but for three-body binary formation (which is fundamentally more local) BH_AVEKERNEL = 3
MIN_CHUNK_SIZE	minimum size of chunks that get partitioned across processors in the parallel code MIN_CHUNK_SIZE = 40 (this is just twice the AVEKERNEL)
IDUM	Random number generator seed. Note this is different from the BSE RNG seed IDUM = 1234
BSE_IDUM	The random number seed used by kick.f and setting initial pulsar spin period and magnetic field BSE_IDUM = 1234
TIMER	Do profiling of the code, and print it out to the timers file. Note that this introduces many MPI barriers 0 : Off 1 : On TIMER = 0
FORCE_RLX_STEP	Force a relaxation timestep (useful when RELAXATION=0) 0 : Off 1 : On FORCE_RLX_STEP = 0
DT_HARD_BINARIES	calculate the binary interaction time steps by only considering hard binaries 0 : Off 1 : On DT_HARD_BINARIES = 0
``HARD_BINARY_KT ``	The minimum binary binding energy (in units of kT) for a binary to be considered ‘hard’ for the time step calculation. HARD_BINARY_KT = 0.7
SAMPLESIZE	Number of samples keys to use for the parallel sample-sort algorithm SAMPLESIZE = 1024
NUM_CENTRAL_STARS	The number of central stars to use for calculating different qualities related to the timestep NUM_CENTRAL_STARS = 300

[bse]

Note

Although this is all one section, we have grouped the flags/parameters which get passed to the binary stellar evolution code into types. Each group will start with a note to indicate the type of parameter or flag.

SAMPLING FLAGS

pts1	determines the timesteps chosen in each evolution phase as decimal fractions of the time taken in that phase for Main Sequence (MS) stars pts1 = 0.001 following Bannerjee+2019
pts2	determines the timesteps chosen in each evolution phase as decimal fractions of the time taken in that phase for Giant Branch (GB, CHeB, AGB, HeGB) stars pts2 = 0.01 following Hurley+2000
pts3	determines the timesteps chosen in each evolution phase as decimal fractions of the time taken in that phase for HG, HeMS stars pts3 = 0.02 following Hurley+2000

METALLICITY FLAGS

zsun	Sets the metallicity of the Sun which primarily affects stellar winds. zsun = 0.014 following Asplund 2009

WIND FLAGS

windflag	Selects the model for wind mass loss for each star 0 : Standard SSE/BSE (Hurley+2000) 1 : StarTrack (Belczynski+2008) 2 : Metallicity dependence for O/B stars and Wolf Rayet stars (Vink+2001, Vink+2005) 3 : Same as 2, but LBV-like mass loss for giants and non-degenerate stars beyond the Humphreys-Davidson limit windflag = 3
eddlimflag	Limits the mass-loss rate of low-metallicity stars near the Eddington limit (see Grafener+2011, Giacobbo+2018). 0 : does not apply Eddington limit 1 : applies Eddington limit eddlimflag = 0
neta	Reimers mass-loss coefficent (Equation 106 SSE). Note: this equation has a typo. There is an extra \({\eta}\) out front; the correct rate is directly proportional to \({\eta}\). See also Kurdritzki+1978, Section Vb for discussion. positive value : supplies \({\eta}\) to Equation 106 SSE neta = 0.5
bwind	Binary enhanced mass loss parameter. See Equation 12 BSE. positive value : supplies Bw to Equation 12 BSE bwind = 0, inactive for single
hewind	Helium star mass loss parameter: 10-13 hewind L2/3 gives He star mass-loss. Equivalent to 1 - \({\mu}\) in the last equation on page 19 of SSE. hewind = 0.5
beta	Wind velocity factor: vwind 2 goes like beta. See Equation 9 of Hurley+2002. negative value : StarTrack (Belczynski+2008) positive value : supplies \({\beta}\)w to Equation 9 of Hurley+2002 beta = -1.0
xi	Wind accretion efficiency factor, which gives the fraction of angular momentum lost via winds from the primary that transfers to the spin angular momentum of the companion. Corresponds to \({\mu}\)w in Equation 11 of Hurley+2002. positive value : supplies \({\mu}\)w in Equation 11 of Hurley+2002 xi = 0.5
acc2	Bondi-Hoyle wind accretion factor where the mean wind accretion rate onto the secondary is proportional to acc2. See Equation 6 in Hurley+2002. positive value : supplies \({\alpha}\)w in Equation 6 in Hurley+2002 acc2 = 1.5

COMMON ENVELOPE FLAGS

Note: there are cases where a common envelope is forced regardless of the critical mass ratio for unstable mass transfer. In the following cases, a common envelope occurs regardless of the choices below:

contact : the stellar radii go into contact (common for similar ZAMS systems)

periapse contact : the periapse distance is smaller than either of the stellar radii (common for highly eccentric systems)

core Roche overflow : either of the stellar radii overflow their component’s Roche radius (in this case, mass transfer from the convective core is always dynamically unstable)

alpha1	Common-envelope efficiency parameter which scales the efficiency of transferring orbital energy to the envelope. See Equation 71 in Hurley+2002. positive values : supplies \({\alpha}\) to Equation 71 in Hurley+2002 alpha1 = 1.0
lambdaf	Binding energy factor for common envelope evolution. The initial binding energy of the stellar envelope goes like 1 / \({\lambda}\). See Equation 69 in Hurley+2002. positive values : uses variable lambda prescription detailed in appendix of Claeys+2014 where lambdaf is the fraction of the ionization energy that can go into ejecting the envelope; to use this prescription without extra ionization energy, set lambdaf=0 negative values : fixes \({\lambda}\) to a value of -1.0* lambdaf lambdaf = 0.0
ceflag	Selects the de Kool 1990 model to set the initial orbital energy using the total mass of the stars instead of the core masses as in Equation 70 of Hurley+2002. 0 : Uses the core mass to calculate initial orbital energy as in Equation 70 of Hurley+2002 1 : Uses the de Kool 1990 model ceflag = 0
cekickflag	Selects which mass and separation values to use when a supernova occurs during the CE and a kick needs to be applied. 0 : uses pre-CE mass and post-CE sep (BSE default) 1 : uses pre-CE mass and sep values 2 : uses post-CE mass and sep cekickflag = 2
cemergeflag	Determines whether stars that begin a CE without a core-envelope boundary automatically lead to merger in CE. These systems include: kstars = [0,1,2,7,8,10,11,12]. 0 : allows the CE to proceed 1 : causes these systems to merge in the CE cemergeflag = 0
cehestarflag	Uses fitting formulae from Tauris+2015 for evolving RLO systems with a helium star donor and compact object accretor. NOTE: this flag will override choice made by cekickflag if set 0 : does NOT use Tauris+2015 at all 1 : uses Tauris+2015 fits for final period only 2 : uses Tauris+2015 fits for both final mass and final period cehestarflag = 0
qcflag	Selects model to determine critical mass ratios for the onset of unstable mass transfer and/or a common envelope during RLO. NOTE: this is overridden by qcrit_array if any of the values are non-zero. 0 : follows Section 2.6 of Hurley+2002 (Default BSE) 1 : same as 0 but with Hjellming & Webbink 1987 for GB/AGB stars 2 : follows Table 2 of Claeys+2014 3 : same as 2 but with Hjellming & Webbink 1987 for GB/AGB stars 4 : follows Section 5.1 of Belcyznski+2008 except for WD donors which follow BSE 5 : follows Section 2.3 of Neijssel+2020 Mass transfer from stripped stars is always assumed to be dynamically stable qcflag = 1 Comparison of Q Crit Values (Donor Mass/Accretor Mass) For Each Donor Kstar Type Across Flag Options kstar qc=0 qc=1 qc=2 qc=3 qc=4 qc=5 0 0.695 0.695 0.695 / 1.0 0.695 / 1.0 3.0 1.717 1 3 3 1.6 / 1.0 1.6 / 1.0 3.0 1.717 2 4 4 4.0 / 4.7619 4.0 / 4.7619 3.0 3.825 3 Eq.2 Eq.1 Eq.2 / 1.15 Eq.1 / 1.15 3.0 Eq.1 4 3 3 3.0 / 3.0 3.0 / 3.0 3.0 3 5 Eq.2 Eq.1 Eq.2 / 1.15 Eq.1 / 1.15 3.0 Eq.1 6 Eq.2 Eq.1 Eq.2 / 1.15 Eq.1 / 1.15 3.0 Eq.1 7 3 3 3.0 / 3.0 3.0 / 3.0 1.7 inf 8 0.784 0.784 4.0 / 4.7619 4.0 / 4.7619 3.5 inf 9 0.784 0.784 0.784 / 1.15 0.784 / 1.15 3.5 inf 10-14 0.628 0.628 3.0 / 0.625 3.0 / 0.625 0.628 0.628 Eq.1: qc = 0.362 + 1.0/(3.0*(1.0 - massc(j1)/mass(j1))), which is from Hjellming & Webbink 1983 Eq.2: qc = (1.67d0-zpars(7)+2.d0*(massc(j1)/mass(j1))**5)/2.13d0, which is from Claeys+ 2014
qcrit_array	Array with length: 16 for user-input values for the critical mass ratios that govern the onset of unstable mass transfer and a common envelope. Each item is set individually for its associated kstar, and a value of 0.0 will apply prescription of the qcflag for that kstar. Note: there are cases where a common envelope is forced regardless of the critical mass ratio for unstable mass transfer; in the following cases, a common envelope occurs regardless of the qcrit or qcflag qcrit_array = [0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0]

KICK FLAGS

kickflag	Sets the particular natal kick prescription to use Note that sigmadiv, bhflag, bhsigmafrac, aic, and ussn, which are described below, are only used when kickflag=0 0 : The standard COSMIC kick prescription, where kicks are drawn from a bimodal distribution with standard FeCCSN getting a kick drawn from a Maxwellian distribution with dispersion parameter sigma and ECSN are drawn according to sigmadiv. This setting has additional possible options for bhflag, bhsigmafrac, aic and ussn. -1 : Natal kicks are drawn according to sigma and scaled by the ejecta mass and remnant mass following Eq. 1 of Giacobbo & Mapelli 2020 -2 : Natal kicks are drawn according to sigma and scaled by just the ejecta mass following Eq. 2 of Giacobbo & Mapelli 2020 -3 : Natal kicks are drawn according to Eq. 1 of Bray & Eldridge 2016 default=0
sigma	Sets the dispersion in the Maxwellian for the SN kick velocity in km/s positive value : sets Maxwellian dispersion default=265.0
bhflag	Sets the model for how SN kicks are applied to BHs where bhflag != 0 allows velocity kick at BH formation 0 : no BH kicks 1 : fallback-modulated kicks following Fryer+2012 2 : kicks decreased by ratio of BH mass to NS mass (1.44 Msun); conserves linear momentum 3 : full strength kick drawn from Maxwellian with dispersion = sigma selected above bhflag = 1
ecsn	Allows for electron capture SN and sets the maximum ECSN mass range at the time of SN 0 : turns off ECSN positive values : BSE (Hurley+2002) and StarTrack (Belczynski+2008) use ecsn = 2.25, while Podsiadlowksi+2004 use ecsn = 2.5 ecsn = 2.5
ecsn_mlow	Sets the low end of the ECSN mass range positive values : BSE (Hurley+2002) use ecsn_mlow = 1.6, while StarTrack (Belczynski+2008) use ecsn_mlow = 1.85, while Podsiadlowksi+2004 use ecsn_mlow = 1.4 ecsn_mlow = 1.4
sigmadiv	Sets the modified ECSN kick strength positive values : divide sigma above by sigmadiv negative values : sets the ECSN sigma value sigmadiv = -20.0
aic	reduces kick strengths for accretion induced collapse SN according to sigmadiv 0 : AIC SN receive kicks drawn from Maxwellian with dispersion = sigma above 1 : sets kick strength according to sigmadiv NOTE: this will applies even if ecsn = 0.0 aic = 1
ussn	Reduces kicks according to the sigmadiv selection for ultra-stripped supernovae which happen whenever a He-star undergoes a CE with a compact companion 0 : USSN receive kicks drawn from Maxwellian with dispersion = sigma above 1 : sets kick strength according to sigmadiv ussn = 0
pisn	Allows for (pulsational) pair instability supernovae and sets either the model to use or the maximum mass of the remnant. 0 : no pulsational pair instability SN -1 : uses the formulae from Spera & Mapelli 2017 -2 : uses a polynomial fit to Table 1 in Marchant+2018 -3 : uses a polynomial fit to Table 5 in Woosley 2019 positive values : turns on pulsational pair instability SN and sets the maximum mass of the allowed remnant pisn = 45.0
bhsigmafrac	Sets a fractional modification which scales down sigma for BHs. This works in addition to whatever is chosen for bhflag, and is applied to sigma before the bhflag prescriptions are applied values between [0, 1] : reduces sigma by bhsigmafrac bhsigmafrac = 1.0
polar_kick_angle	Sets the opening angle of the SN kick relative to the pole of the exploding star, where 0 gives strictly polar kicks and 90 gives fully isotropic kicks values between [0, 90] : sets opening angle for SN kick polar_kick_angle = 90.0
natal_kick_array	Array of dimensions: (2,5) which takes user input values for the SN natal kick, where the first row corresponds to the first star and the second row corresponds to the second star and columns are: [vk, phi, theta, mean_anomaly, rand_seed]. NOTE: any numbers outside these ranges will be sampled in the standard ways detailed above. vk : valid on the range [0, inf] phi : co-lateral polar angle in degrees, valid from [-90, 90] theta : azimuthal angle in degrees, valid from [0, 360] mean_anomaly : mean anomaly in degrees, valid from [0, 360] rand_seed : supplied if restarting evolution after a supernova has already occurred natal_kick_array = [[-100.0,-100.0,-100.0,-100.0,0.0][-100.0,-100.0,-100.0,-100.0,0.0]]

REMNANT MASS FLAGS

remnantflag	Determines the remnant mass prescription used for NSs and BHs. 0 : follows Section 6 of Hurley+2000 (default BSE) 1 : follows Belczynski+2002 2 : follows Belczynski+2008 3 : follows the rapid prescription from Fryer+2012, with updated proto-core mass from Giacobbo & Mapelli 2020 4 : delayed prescription from Fryer+2012 remnantflag = 3
mxns	Sets the boundary between the maximum NS mass and the minimum BH mass positive values : sets the NS/BH mass bounary mxns = 3.0
rembar_massloss	Determines the prescriptions for mass conversion from baryonic to gravitational mass during the collapse of the proto-compact object positive values : sets the maximum amount of mass loss, which should be about 10% of the maximum mass of an iron core (\({\sim 5 \mathrm{M}_\odot}\) Fryer, private communication) -1 < *rembar_massloss* < 0 : assumes that proto-compact objects lose a constant fraction of their baryonic mass when collapsing to a black hole (e.g., rembar_massloss = -0.1 gives the black hole a gravitational mass that is 90% of the proto-compact object’s baryonic mass) rembar_massloss = 0.5

REMNANT SPIN FLAGS

bhspinflag	Uses different prescriptions for BH spin after formation 0 : sets all BH spins to bhspinmag 1 : draws a random BH spin between 0 and bhspinmag for every BH 2 : core-mass dependent BH spin (based on Belczynski+2017 v1) bhspinflag = 0
bhspinmag	Sets either the spin of all BHs or the upper limit of the uniform distribution for BH spins values >= 0.0 : spin or upper limit value bhspinmag = 0.0

GR ORBITAL DECAY FLAG

Note

In CMC, GR orbital decay is handled separately from BSE for binary black holes, and is unaffected by the below flag

grflag

Turns on or off orbital decay due to gravitational wave radiation 0 : No orbital decay due to GR 1 : Orbital decay due to GR is included grflag = 1

MASS TRANSFER FLAGS

eddfac	Eddington limit factor for mass transfer. 1 : mass transfer rate is limited by the Eddington rate following Equation 67 in Hurley+2002 values >1 : permit super-Eddington accretion up to value of eddfac eddfac = 1.0
gamma	Angular momentum prescriptions for mass lost during RLO at super-Eddington mass transfer rates -1 : assumes the lost material carries away the specific angular momentum of the primary -2 : assumes material is lost from the system as if it is a wind from the secondary >0 : assumes that the lost material takes away a fraction gamma of the orbital angular momentum gamma = -2.0
don_lim	Calculates the rate of thermal mass loss through Roche overflow mass transfer from the donor star -1 : donor mass loss rate is calculated following Hurley+2002 -2donor mass loss rate is calculated following Claeys+2014
acc_lim	Limits the amount of mass accreted during Roche overflow -1 : limited to 10x’s the thermal rate of the accretor for MS/HG/CHeB and unlimited for GB/EAGB/AGB stars -2 : limited to 1x’s the thermal rate of the accretor for MS/HG/CHeB and unlimited for GB/EAGB/AGB stars -3 : limited to 10x’s the thermal rate of the accretor for all stars -4 : limited to 1x’s the thermal rate of the accretor for all stars >=0 : sets overall accretion fraction of donor mass as in Belcyznski+2008 w/ acc_lim = 0.5

TIDES FLAGS

tflag	Activates tidal circularisation following Hurley+2002 0 : no tidal circularization 1 : activates tidal circularization tflag = 1
ST_tide	Activates StarTrack setup for tides following Belczynski+2008 0 : follows BSE 1 : follows StarTrack ST_tide = 1
fprimc_array	controls the scaling factor for convective tides each item is set individually for its associated kstar The releveant equation is Equation 21 of Hurley+2002 positive values : sets scaling factor of Equation 21 referenced above fprimc_array = [2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0, 2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0,2.0/21.0, 2.0/21.0,2.0/21.0]

WHITE DWARF FLAGS

ifflag	Activates the initial-final white dwarf mass relation from Han+1995 Equations 3, 4, and 5. 0 : no modifications to BSE 1 : activates initial-final WD mass relation ifflag = 0
wdflag	Activates an alternate cooling law found in the description immediately following Equation 1 in Hurley & Shara 2003. Equation 1 gives the BSE default Mestel cooling law. 0 : no modifications to BSE 1 : activates modified cooling law wdflag = 1
epsnov	Fraction of accreted matter retained in a nova eruption. This is relevant for accretion onto degenerate objects; see Section 2.6.6.2 in Hurley+2002. positive values between [0, 1] : retains epsnov fraction of accreted matter epsnov = 0.001

PULSAR FLAGS

bdecayfac	Activates different models for accretion induced field decay; see Kiel+2008. 0 : uses an exponential decay 1 : uses an inverse decay bdecayfac = 1
bconst	Sets the magnetic field decay time-scale for pulsars following Section 3 of Kiel+2008. negative values : sets k in Myr from Equation 8 to -1 * bconst bconst = -3000
ck	Sets the magnetic field decay time-scale for pulsars following Section 3 of Kiel+2008. negative values : sets \({\tau}\)b in Myr from Equation 2 to -1 * ck ck = -1000

MIXING VARIABLES

rejuv_fac	Sets the mixing factor in main sequence star collisions. This is hard coded to 0.1 in the original BSE release and in Equation 80 of Hurley+2002 but can lead to extended main sequence lifetimes in some cases. positive values : sets the mixing factor rejuv_fac = 1.0
rejuvflag	Sets whether to use the orginal prescription for mixing of main-sequence stars (based on equation 80 of Hurley+2002) or whether to use the ratio of the pre-merger He core mass at the base of the giant branch to the merger product’s He core mass at the base of the giant branch 0 : no modifications to BSE 1 : modified mixing times rejuvflag = 0
bhms_coll_flag	If set to 1 then if BH+star collision and if Mstar > Mbh, do not destroy the star default = 0

MAGNETIC BRAKING FLAGS

htpmb

Activates different models for magnetic braking 0 : no modifications to BSE 1 : follows Ivanona and Taam 2003 htpmb = 1

MISC FLAGS

ST_cr

Activates different convective vs radiative boundaries 0 : no modifications to BSE 1 : follows StarTrack ST_cr = 1