scholarly journals Constraining astrophysical observables of galaxy and supermassive black hole binary mergers using pulsar timing arrays

2019 ◽  
Vol 488 (1) ◽  
pp. 401-418 ◽  
Author(s):  
Siyuan Chen ◽  
Alberto Sesana ◽  
Christopher J Conselice

ABSTRACT We present an analytic model to describe the supermassive black hole binary (SMBHB) merger rate in the Universe with astrophysical observables: galaxy stellar mass function, pair fraction, merger time-scale, and black hole–host galaxy relations. We construct observational priors and compute the allowed range of the characteristic spectrum hc of the gravitational wave background (GWB) to be 10−16 < hc < 10−15 at a frequency of f = 1 yr−1. We exploit our parametrization to tackle the problem of astrophysical inference from pulsar timing array (PTA) observations. We simulate a series of upper limits and detections and use a nested sampling algorithm to explore the parameter space. Corroborating previous results, we find that the current PTA non-detection does not place significant constraints on any observables; however, either future upper limits or detections will significantly enhance our knowledge of the SMBHB population. If a GWB is not detected at a level of hc(f = 1 yr−1) = 10−17, our current understanding of galaxy and SMBHB mergers is disfavoured at a 5σ level, indicating a combination of severe binary stalling, overestimating of the SMBH–host galaxy relations, and extreme dynamical properties of merging SMBHBs. Conversely, future detections of a Square Kilometre Array (SKA)-type instrument will allow to constrain the normalization of the SMBHB merger rate in the Universe, the time between galaxy pairing and SMBHB merging, the normalization of the SMBH–host galaxy relations and the dynamical binary properties, including their eccentricity and density of stellar environment.

2009 ◽  
Vol 697 (2) ◽  
pp. 1621-1633 ◽  
Author(s):  
László Árpád Gergely ◽  
Peter L. Biermann

2020 ◽  
Vol 492 (2) ◽  
pp. 2936-2954 ◽  
Author(s):  
Fabio Antonini ◽  
Mark Gieles

ABSTRACT Black hole (BH) binary mergers formed through dynamical interactions in dense star clusters are believed to be one of the main sources of gravitational waves (GWs) for Advanced LIGO and Virgo. Here, we present a fast numerical method for simulating the evolution of star clusters with BHs, including a model for the dynamical formation and merger of BH binaries. Our method is based on Hénon’s principle of balanced evolution, according to which the flow of energy within a cluster must be balanced by the energy production inside its core. Because the heat production in the core is powered by the BHs, one can then link the evolution of the cluster to the evolution of its BH population. This allows us to construct evolutionary tracks of the cluster properties including its BH population and its effect on the cluster and, at the same time, determine the merger rate of BH binaries as well as their eccentricity distributions. The model is publicly available and includes the effects of a BH mass spectrum, mass-loss due to stellar evolution, the ejection of BHs due to natal and dynamical kicks, and relativistic corrections during binary–single encounters. We validate our method using direct N-body simulations, and find it to be in excellent agreement with results from recent Monte Carlo models of globular clusters. This establishes our new method as a robust tool for the study of BH dynamics in star clusters and the modelling of GW sources produced in these systems. Finally, we compute the rate and eccentricity distributions of merging BH binaries for a wide range of cluster initial conditions, spanning more than two orders of magnitude in mass and radius.


2020 ◽  
Vol 900 (2) ◽  
pp. L42
Author(s):  
Khai Nguyen ◽  
Tamara Bogdanović ◽  
Jessie C. Runnoe ◽  
Stephen R. Taylor ◽  
Alberto Sesana ◽  
...  

2020 ◽  
Vol 500 (3) ◽  
pp. 2896-2907
Author(s):  
Pratyusava Baral ◽  
Soumendra Kishore Roy ◽  
Supratik Pal

ABSTRACT Gravitational waves from supermassive black hole binary mergers along with an electromagnetic counterpart have the potential to shed ‘light’ on the nature of dark energy in the intermediate redshift regime. Accurate measurement of dark energy parameters at intermediate redshift is extremely essential to improve our understanding of dark energy, and to possibly resolve a couple of tensions involving cosmological parameters. We present a Fisher matrix forecast analysis in the context of eLISA to predict the errors for three different cases: the non-interacting dark energy with constant and evolving equation of state (EoS), and the interacting dark sectors with a generalized parametrization. In all three cases, we perform the analysis for two separate formalisms, namely, the standard EoS formalism and the Om parametrization which is a model-independent null diagnostic for a wide range of fiducial values in both phantom and non-phantom regions, to make a comparative analysis between the prospects of these two diagnostics in eLISA. Our analysis reveals that it is wiser and more effective to probe the null diagnostic instead of the standard EoS parameters for any possible signature of dark energy at intermediate redshift measurements like eLISA.


2018 ◽  
Vol 856 (1) ◽  
pp. 42 ◽  
Author(s):  
Alberto Sesana ◽  
Zoltán Haiman ◽  
Bence Kocsis ◽  
Luke Zoltan Kelley

2017 ◽  
Vol 13 (S338) ◽  
pp. 46-52
Author(s):  
Tingting Liu ◽  
Suvi Gezari

AbstractWe conducted a systematic search for periodically varying quasars, which are predicted manifestations of sub-pc supermassive black hole binaries (SMBHBs), in the Pan-STARRS1 Medium Deep Survey (PS1 MDS). Since the normal variability of quasars can also mimic periodicity over a small number of cycles, we have extended the temporal baseline by monitoring the candidates with the Discovery Channel Telescope and the Las Cumbres Observatory telescopes. We have also adopted a more rigorous method to evaluate the significance of the periodic candidates, by considering in the light curves a “red noise” background modeled as the Damped Random Walk process. While none of the candidates can be resolved by the current pulsar timing arrays (PTAs) as individual gravitational wave sources, the Large Synoptic Survey Telescope is capable of finding more periodic candidates, some of which are likely to be detected by the PTA experiment with the Square Kilometre Array.


2009 ◽  
Vol 5 (S267) ◽  
pp. 189-194
Author(s):  
Kayhan Gültekin

AbstractWe derive improved versions of the relations between supermassive black hole mass MBH and host-galaxy bulge velocity dispersion σ and luminosity L (the MBH–σ and MBH–Lbulge relations), based on ~ 50 MBH measurements and ~ 20 upper limits. Particular attention is paid to recovery of the intrinsic scatter (ϵ0) in both relations. We find the scatter to be significantly larger than estimated in most previous studies. The large scatter requires revision of the local black hole mass function, and it implies that there may be substantial selection bias in studies of the evolution of the MBH–σ and MBH–Lbulge relations. When only considering ellipticals, the scatter decreases. These results appear to be insensitive to a wide range of assumptions about the measurement errors and the distribution of intrinsic scatter. We also investigate the effects on the fits of culling the sample according to the resolution of the black hole's sphere of influence.


2015 ◽  
Vol 452 (3) ◽  
pp. 2540-2545 ◽  
Author(s):  
D. J. D'Orazio ◽  
Z. Haiman ◽  
P. Duffell ◽  
B. D. Farris ◽  
A. I. MacFadyen

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