BH-BH, BH-NS, NS-NS StarTrack models with BH spins (Jan 1, 2020)

Models (see the files at the bottom of the page) are from this paper

Sample results from one of our models are shown on the Figure below.

Detection weighted distribution of the effective spin parameter of BH-BH mergers for model M30.B with MESA efficient angular momentum transport and fallback decreased BH kicks (no BH kicks for massive BHs). We either do not allow for efficient tidal spin-up of WR stars that are the most common immediate progenitors of BHs in our models (natal BH spin is calculated directly from MESA stellar models), or we take it into account (natal BH spin is then calculated as described in Sec. 2.5 if the WR star progenitor was subject to an efficient tidal spin-up). For the "no WR tides" approach we find a rather narrow distribution of effective spins (-0.2<~Xeff<~0.2) that is peaked at positive values (average Xeff=0.15). For efficient "WR tides" the distribution is broad (-0.5<~Xeff<~1.0) with a peak at Xeff~0.15 (~73%) and a tail with Xeff>~0.25 (27%). For comparison we show the 90% credible limits (blue arrows) and the most likely values (blue stars) of the e ective spin parameter for ten LIGO/Virgo BH-BH mergers.

Comparison of the local merger rate densities of BH-BH and BH-NS mergers from all our models (see Tables 3 and 4) with the current limits: 9.7–101 Gpc^-3 yr^-1 for the BH-BH mergers (LIGO/Virgo O1/O2) and 1.6–60 Gpc^-3 yr^-1 for the BH-NS events (based on the LIGO/Virgo O3 candidate of the first BH-NS system, S190814bv (LVC 2019a,b); see Sec. 6.9 for details). Models consistent with the observational limits are: M13.A, M23.A, M33.A, M43.A, M23.B, M25.B, M30.B, M40.B, M50.B, M60.B, M70.B. Note also that the BH-NS merger rates from our models span the range between 0.48 and 297 Gpc^-3 yr^-1, which is consistent with the upper limit determined by their non-detection in O1/O2 LIGO/Virgo runs (< 610 Gpc^-3 yr^-1, Abbott et al. (2019b)).

Comparison of the local merger rate densities of BH-BH and NS-NS mergers from all our models (see Tables 3 and 4) with the current limits inferred from the O1/O2 LIGO/Virgo observational runs: 9.7–101 Gpc^-3 yr^-1 for the BH-BH mergers and 110–3840 Gpc^-3 yr^-1 for the NS-NS events (Abbott et al. 2019b). Models consistent with the observational limits are: M13.A, M23.A, M33.A, M43.A, M30.B, M40.B, M60.B, M70.B. Note that while some of the models are consistent with the observational constraints and others are not, it is not straightforward to draw conclusions about the physical ingredients of the models at this stage due to degeneracies in the impact of various assumptions on the theoretical merger rates (see Sect. 4.3.1).

This website will be kept updated with new models and observations as they appear.

Data Files

Please look here for the description of the results available below.