Does Matter Matter? Using the mass distribution to distinguish neutron stars and black holes

Fishbach, Maya; Essick, Reed; Holz, Daniel E.

doi:10.48550/arxiv.2006.13178

Cited by 8 publications

(11 citation statements)

References 61 publications

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“…Furthermore, we find that if the black hole mass spectrum extends down to 3 M , it likely turns over at ∼ 7.8 +2.2 −2.1 M . This suggests that there may be a dearth of systems between NS and black hole masses (Fishbach et al 2020a). However, the O3a observation of GW190814 (Abbott et al 2020c), with a secondary mass m 2 = 2.59 +0.08 −0.09 M , complicates this picture.…”

Section: What Is the Minimum Black Hole Mass? Usingmentioning

confidence: 99%

Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog

Abbott,

Abraham

et al. 2020

Preprint

103

240

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We report on the population properties of the 47 compact binary mergers detected with a false-alarm rate (FAR) < 1 yr −1 in GWTC-2, including all Advanced LIGO-Virgo observing runs through the most recent observing run O3a. We investigate the mass distribution, spin distribution, and merger rate as a function of redshift. We observe several binary black hole (BBH) population characteristics not discernible until now. First, we find that the primary mass spectrum contains structure beyond a power-law distribution with a sharp high-mass cut-off; it is more consistent with a broken power law with a break at 39.7 +20.3 −9.1 M , or a power law with a Gaussian feature peaking at 33.5 +4.5 −5.5 M (90% credible interval). While the primary mass distribution must extend to ∼ 65 M or beyond, only 2.9 +3.4 −1.7 % of systems have primary masses greater than 45 M . At low masses, we find that the primary mass spectrum has a global maximum at 7.8 +2.2 −2.1 M , consistent with a gap between ∼ 2.6 M and ∼ 6 M . Second, we find evidence that a nonzero fraction of BBH systems have component spins misaligned with the orbital angular momentum, giving rise to precession of the orbital plane. Moreover, we infer that 12% to 44% of BBH systems have spins tilted by more than 90 • with respect to their orbital angular momentum, giving rise to a negative effective inspiral spin parameter. Third, we provide improved estimates for merger rates using astrophysically motivated mass distributions: for BBH, R BBH = 23.9 +14.9 −8.6 Gpc −3 yr −1 and for binary neutron stars (BNS), R BNS = 320 +490 −240 Gpc −3 yr −1 . We constrain the BBH merger rate as a function of redshift and find that the rate likely increases with redshift (85% credibility), but not faster than the star-formation rate (87% credibility). Additionally, we examine recent exceptional events in the context of our population models, finding that the asymmetric masses of GW190412 and the high component masses of GW190521 are consistent with our population models, but the low secondary mass of GW190814 makes it an outlier. We discuss the implications of these results for compact binary formation and for the evolution of massive stars.

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Section: What Is the Minimum Black Hole Mass? Usingmentioning

confidence: 99%

Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog

Abbott,

Abraham

et al. 2020

Preprint

103

240

View full text Add to dashboard Cite

show abstract

“…Already several interesting proposals have been made (see, e.g., Abbott et al 2020;Most et al 2020;Fishbach et al 2020;Tan et al 2020;Lehmann et al 2020;Vattis et al 2020;Essick & Landry 2020;Zevin et al 2020;Safarzadeh & Loeb 2020;Sedrakian et al 2020). Since it is well known that rotations provide additional support to the pressure balancing the gravity, leading to a NS maximum mass at the Kepler frequency about 20% higher than that of the static NS for a given nuclear Equation of State (EOS) (see, e.g., Cook et al 1994;Lasota et al 1996;Lattimer & Prakash 2004;Krastev et al 2008a;Haensel et al 2008Haensel et al , 2009Breu & Rezzolla 2016;Wei et al 2017), the possibility for the GW190814's secondary as a rapidly rotating NS was first studied by the LIGO/Virgo Collaboration (Abbott et al 2020).…”

Section: Introductionmentioning

confidence: 99%

GW190814's secondary component with mass $(2.50-2.67)$ M$_{\odot}$ as a super-fast pulsar

Zhang,

2020

Preprint

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Using Stergioulas's RNS code for investigating fast pulsars with Equation of States (EOSs) on the causality surface (where the speed of sound equals that of light) of the high-density EOS parameter space satisfying all known constraints from both nuclear physics and astrophysics, we show that one possible explanation for the GW190814's secondary component of mass (2.50 − 2.67) M ⊙ is that it is a super-fast pulsar spinning faster than 971 Hz about 42% below its Kepler frequency. If confirmed, it would be the fastest pulsar with the highest mass observed presently. There is a large and physically allowed EOS parameter space below the causality surface where pulsars heavier than 2.50 M ⊙ are supported if they can rotate even faster with critical frequencies depending strongly on the highdensity behavior of nuclear symmetry energy.

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“…Assuming that BH and NS mass distributions do not overlap, it might be ex-tracted from population studies or observations of BHs, e.g., Refs. [8][9][10], or from nuclear-physics considerations, e.g., Refs. [11,12].…”

mentioning

confidence: 99%

On the nature of GW190814 and its impact on the understanding of supranuclear matter

Tews,

Pang,

Dietrich

et al. 2020

Preprint

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The observation of a compact object with a mass of 2.50 − 2.67M on August 14, 2019, by the LIGO Scientific and Virgo collaborations (LVC) has the potential to improve our understanding of the supranuclear equation of state. While the gravitational-wave analysis of the LVC suggests that GW190814 likely was a binary black hole system, the secondary component could also have been the heaviest neutron star observed to date. We use our previously derived nuclear-physics-multimessenger astrophysics framework to address the nature of this object. Based on our findings, we determine GW190814 to be a binary black hole merger with a probability of > 99.9%. Even if we weaken previously employed constraints on the maximum mass of neutron stars, the probability of a binary black hole origin is still ∼ 86%. Furthermore, we study the impact that this observation has on our understanding of the nuclear equation of state by analyzing the allowed region in the massradius diagram of neutron stars for both a binary black hole or neutron star -black hole scenario. We find that the unlikely scenario in which the secondary object was a neutron star requires rather stiff equations of state with a maximum speed of sound cs ≥ √ 0.6 times the speed of light, while the binary black hole scenario does not offer any new insight.

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Does Matter Matter? Using the mass distribution to distinguish neutron stars and black holes

Cited by 8 publications

References 61 publications

Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog

Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog

GW190814's secondary component with mass $(2.50-2.67)$ M$_{\odot}$ as a super-fast pulsar

On the nature of GW190814 and its impact on the understanding of supranuclear matter

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