Mapping the Likelihood of GW190521 with Diverse Mass and Spin Priors
| Autor: | Seth Olsen, Matias Zaldarriaga, Horng Sheng Chia, Javier Roulet, Tejaswi Venumadhav, Liang Dai, Barak Zackay |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
High Energy Astrophysical Phenomena (astro-ph.HE) FOS: Physical sciences General Relativity and Quantum Cosmology (gr-qc) Mass ratio 01 natural sciences General Relativity and Quantum Cosmology Black hole Binary black hole Physics - Data Analysis Statistics and Probability 0103 physical sciences Prior probability Gravitational collapse Sensitivity (control systems) Statistical physics Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Instrumentation and Methods for Astrophysics 010306 general physics 010303 astronomy & astrophysics Instrumentation and Methods for Astrophysics (astro-ph.IM) Mass gap Data Analysis Statistics and Probability (physics.data-an) Spin-½ |
| DOI: | 10.48550/arxiv.2106.13821 |
| Popis: | We map the likelihood of GW190521, the heaviest detected binary black hole (BBH) merger, by sampling under different mass and spin priors designed to be uninformative. We find that a source-frame total mass of $\sim$$150 M_{\odot}$ is consistently supported, but posteriors in mass ratio and spin depend critically on the choice of priors. We confirm that the likelihood has a multi-modal structure with peaks in regions of mass ratio representing very different astrophysical scenarios. The unequal-mass region ($m_2 / m_1 < 0.3$) has an average likelihood $\sim$$e^6$ times larger than the equal-mass region and a maximum likelihood $\sim$$e^2$ larger. Using ensembles of samples across priors, we examine the implications of qualitatively different BBH sources that fit the data. We find that the equal-mass solution has poorly constrained spins and at least one black hole mass that is difficult to form via stellar collapse due to (pulsational) pair instability. The unequal-mass solution can avoid this mass gap entirely but requires a negative effective spin and a precessing primary. Both of these scenarios are more easily produced by dynamical formation channels than field binary co-evolution. Drawing representative samples from each region of the likelihood map, we find a sensitive comoving volume-time $\mathcal{O}(10)$ times larger in the mass gap region than the gap-avoiding region. Accounting for this distance effect, the likelihood still reverses the advantage to favor the gap-avoiding scenario by a factor of $\mathcal{O}(100)$ before including mass and spin priors. Posterior samplers can be driven away from this high-likelihood region by common prior choices meant to be uninformative, making GW190521 parameter inference sensitive to the choice of mass and spin priors. This may be a generic issue for similarly heavy events given current detector sensitivity and waveform degeneracies. 14 pages, 11 figures, 2 tables, latest version has minor updates to match the version published in Physical Review D |
| Databáze: | OpenAIRE |
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