THE MASS DISTRIBUTION OF STELLAR-MASS BLACK HOLES

By W. Farr, N. Sravan, Andrew G. Cantrell, Laura Kreidberg, C. Bailyn, Ilya Mandel, Vicky Kalogera. 2010

322 citations recorded by the source corpus.

We perform a Bayesian analysis of the mass distribution of stellar-mass black holes using the observed masses of 15 low-mass X-ray binary systems undergoing Roche lobe overflow and 5 high-mass, wind-fed X-ray binary systems. Using Markov Chain Monte Carlo calculations, we model the mass distribution both parametrically—as a power law, exponential, Gaussian, combination of two Gaussians, or log-normal distribution—and non-parametrically—as histograms with varying numbers of bins. We provide confidence bounds on the shape of the mass distribution in the context of each model and compare the models with each other by calculating their relative Bayesian evidence as supported by the measurements, taking into account the number of degrees of freedom of each model. The mass distribution of the low-mass systems is best fit by a power law, while the distribution of the combined sample is best fit by the exponential model. This difference indicates that the low-mass subsample is not consistent with being drawn from the distribution of the combined population. We examine the existence of a “gap” between the most massive neutron stars and the least massive black holes by considering the value, M1%, of the 1% quantile from each black hole mass distribution as the lower bound of black hole masses. Our analysis generates posterior distributions for M1%; the best model (the power law) fitted to the low-mass systems has a distribution of lower bounds with M1%>4.3 M☉ with 90% confidence, while the best model (the exponential) fitted to all 20 systems has M1%>4.5 M☉ with 90% confidence. We conclude that our sample of black hole masses provides strong evidence of a gap between the maximum neutron star mass and the lower bound on black hole masses. Our results on the low-mass sample are in qualitative agreement with those of Ozel et al., although our broad model selection analysis more reliably reveals the best-fit quantitative description of the underlying mass distribution. The results on the combined sample of low- and high-mass systems are in qualitative agreement with Fryer & Kalogera, although the presence of a mass gap remains theoretically unexplained.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ebe31797d65f137f798099f8c999efcb0f0b0d43

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Citations in the corpus

GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run (2021, unknown): “VII.”
Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets (2013, unknown): “2 M ⊙ (¨Ozel et al. 2010; Farr et al. 2011).”
MISSING BLACK HOLES UNVEIL THE SUPERNOVA EXPLOSION MECHANISM (2011, background): “The most recent measurements and independent sophisticated statistical analyses have further established this “mass gap” (Ozel et al. 2010; Farr et al 2011).”
GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs (2018, background): “To date, no binary components have been observed in either of the two putative mass gaps [132, 133] – one between NSs and BHs and the other one due to pair instability supernovae [130, 203].”
Massive runaway and walkaway stars (2018, background): “(16) in Fryer et al. (2012), corresponding to their “rapid SN engine” which reproduces the NS-BH mass gap between ∼2−5 M (e.g., Farr et al. 2011, however see also Wyrzykowski et al. 2016 regarding the existence of this mass gap).”
ON THE MASS DISTRIBUTION AND BIRTH MASSES OF NEUTRON STARS (2012, background): “This panel highlights the substantial mass gap that exists between the black hole population and even the heaviest neutron star population (see the discussion in Özel et al. 2010a and Farr et al. 2011).”
Where Are LIGO’s Big Black Holes? (2017, methodology): “…detections of binary black holes (BBHs), the sample of ∼ 20 BHs in X-ray binary systems was used to infer the BH mass distribution (Özel et al. 2010; Farr et al. 2011), providing strong evidence for the existence of a mass gap between the heaviest neutron star (NS) (∼ 2–3M ) and the lightest BH…”
THE LANDSCAPE OF THE NEUTRINO MECHANISM OF CORE-COLLAPSE SUPERNOVAE: NEUTRON STAR AND BLACK HOLE MASS FUNCTIONS, EXPLOSION ENERGIES, AND NICKEL YIELDS (2014, background): “The gap between neutron star and black hole masses is found in black-hole low-mass X-ray binaries, where the probability distribution peaks at ∼ 5M⊙ (e.g. Bailyn et al. 1998; Özel et al. 2010; Farr et al. 2011; Kreidberg et al. 2012).”
Extracting distribution parameters from multiple uncertain observations with selection biases (2018, methodology): “This evidence can be used to select between different models for representing the distribution, as in Farr et al. (2011).”
PROGENITOR-EXPLOSION CONNECTION AND REMNANT BIRTH MASSES FOR NEUTRINO-DRIVEN SUPERNOVAE OF IRON-CORE PROGENITORS (2012, result): “Correspondingly, we find a wide gap between the maximum NS birth mass (around 1.8M⊙ gravitational mass) and the minimum BH mass (roughly 6M⊙), compatible with conclusions from observed compact remnant masses (e.g., Özel et al. 2010; Valentim et al. 2011; Farr et al. 2011).”
Merging black holes in young star clusters (2019, background): “H Seven out of ten binary BH (BBH) mergers observed by the LIGO-Virgo collaboration harbour BHs with mass >∼ 30 M , significantly higher than the range inferred from dynamical measurements of BH masses in nearby X-ray binaries (Orosz 2003; Özel et al. 2010; Farr et al. 2011).”