DOI: 10.5281/zenodo.10626209
title: Dynamical formation of black hole binaries in dense star clusters: the Rapster data

description: This dataset is part of the Rapster paper. It contains data from star cluster simulations performed with the Rapster code. Rapster is a rapid population synthesis code for binary black hole mergers in dynamical environments.The simulations have been performed on a grid of 16 (four by four) star clusters with different initial conditions, described below.There are two kinds of text files in this dataset:



mer_N*_rv*.txt files with each row representing each dynamically-formed binary black hole merger, and,

evo_N*_rv*.txt files with each row representing a particular time step in the evolution of star clusters.


where the asterisk * represents the value of the initial stellar number ``N’' or virial radius ``rv.‘’ Here N=2e5, 4e5, 8e5, 16e5 and rv=0.5, 1, 2, 4 pc. Moreover, the absolute metallicity was fixed to Z=0.002 and the initial galactocentric radius of each cluster to 20 kpc. Other initial conditions are matched to those of Kremer et al. (2020).We have made 2000, 1000, 300, and 100 realizations of N2e5_rv*, N4e5_rv*, N8e5_rv*, and N16e5_rv* models, respectively, with different seeds.Below we provide the columns of the mer* (27 columns) and evo* (59 columns) files, respectively, with a brief description in parentheses:



mer* column description:




‘seed’ (simulation seed number),

‘ind’ (unique random integer for each binary merger),

‘channel’ [formation channel of the merger, 1 for exchange processes, 2 for single-single capture, 3 for three-body induced binary, 4 for von Zaipel-Lidov-Kozai (ZLK) merger, 5 for ZLK remnant binary, and 6 for binary-single capture; a negative sign indicates the binary was ejected and merged outside the cluster],

‘a’ (semimajor axis when the binary enters the gravitational wave-dominated regime),

‘e’ (eccentricity when the binary enters the gravitational wave-dominated regime),

‘m1’ (primary merger mass),

‘m2’ (secondary merger mass),

‘s1’ (primary merger spin parameter),

‘s2’ (secondary merger spin parameter),

‘g1’ (primary generation),

‘g2’ (secondary generation),

‘theta1’ (angle between primary’s spin and orbital angular momentum),

‘theta2’ (angle between secondary’s spin and orbital angular momentum),

‘dPhi’ (angle between primary’s and secondary’s spin projections into the orbital plane),

‘t_form’ (binary formation time since cluster formation),

‘z_form’ (binary formation redshift),

‘t_merge’ (binary merger time since cluster formation),

‘z_merge’ (binary merger redshift),

‘m_rem’ (merger remnant mass),

‘s_rem’ (merger remnant spin parameter),

‘g_rem’ (merger remnant generation),

‘vGW_kick’ (merger remnant gravitational wave recoil speed),

‘s_eff’ (effective spin parameter),

‘q’ (mass ratio, between (0, 1]),

‘Mcl0’ (initial cluster mass),

‘rh0’ (initial cluster half-mass radius),

‘Z’ (metallicity), and

‘zCl_form’ (cluster formation redshift).


 



evo* column description:




‘seed’ (simulation seed number),

‘t’ (time),

‘z’ (redshift),

‘dt’ (time step),

‘m_avg’ (average mass),

‘Mcl’ (cluster mass),

‘rh’ (half-mass radius),

‘R_gal’ (galactocentric radius),

‘V_gal’ (galactocentric velocity),

‘t_rlx’ (half-mass relaxation time),

‘tBH_rlx’ (black hole half-mass relaxation time),

‘n_star’ (central stellar number density),

‘N_BH’ (number of black holes),

‘mBH_avg’ (average black hole mass),

‘mBH_max’ (maximum black hole mass),

‘rh_BH’ (black hole half-mass radius),

‘rc_BH’ (black hole core radius),

‘S’ (Spitzer parameter),

‘xi’ (equipartition parameter),

‘psi’ (multimass relaxation factor),

‘psi_BH’ (black hole multimass relaxation factor),

‘t_3bb’ (three-body binary formation time),

‘t_2cap’ (single-single capture time),

‘k_3bb’ (number of three-body binaries formed),

‘k_2cap’ (number of single-single captures),

‘N_me’ (cumulative number of black hole binary mergers),

‘N_BBH’ (number of black hole binaries),

‘N_meRe’ (number of merger remnants retained),

‘N_meEj’ (number of merger remnants ejected),

‘v_star’ (three-dimensional stellar velocity dispersion),

‘vBH’ (three-dimensional black hole velocity dispersion),

‘nh_BH’ (black hole half-mass number density),

‘nc_BH’ (black hole core number density),

‘na_BH’ (black hole average number density),

‘N_3bb’ (cumulative number of three-body binaries formed),

‘N_2cap’ (cumulative number of single-single captures),

‘N_3cap’ (cumulative number of binary-single captures),

‘N_BHej’ (cumulative number of single black holes ejected),

‘N_BBHej’ (cumulative number of binary black holes ejected),

‘N_dis’ (cumulative number of binary black hole disruptions),

‘N_ex’ (cumulative number of binary-single exchanges),

‘t_bb’ (binary-binary encounter time),

‘N_bb’ (cumulative number of binary-binary encounters),

‘N_meFi’ (cumulative number of ejected binaries merged in the field),

‘N_me2b’ (cumulative number of in-cluster two-body mergers),

‘t_ex1’ (star-star -> BH-star time, where BH stands for black hole),

‘t_ex2’ (BH-star -> BH-BH time),

‘k_ex1’ (number of star-star -> BH-star processes),

‘k_ex2’ (number of BH-star -> BH-BH processes),

‘N_ex1’ (cumulative number of star-star -> BH-star exchanges),

‘N_ex2’ (cumulative number of BH-star -> BH-BH exchanges),

‘N_BHstar’ (number of BH-star binaries),

‘t_pp’ (BH-star -- BH-star encounter time),

‘k_pp’ (number of BH-star -- BH-star encounters),

‘N_pp’ (cumulative number of BH-star -- BH-star interactions),

‘v_esc’ (escape velocity),

‘vBH_esc’ (black hole escape velocity),

‘N_triples’ (number of black hole triples), and

‘N_ZLK’ (number of ZLK mergers).


We use astrophysical units throughout, in which mass is measured in solar masses, distances/radii in pc, velocities in km/s, time in Myr, and angles in radians.