Prospects of probing dark energy with eLISA: Standard versus null diagnostics

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.

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THE SPIN-FLIP PHENOMENON IN SUPERMASSIVE BLACK HOLE BINARY MERGERS

The Astrophysical Journal ◽

10.1088/0004-637x/697/2/1621 ◽

2009 ◽

Vol 697 (2) ◽

pp. 1621-1633 ◽

Cited By ~ 42

Author(s):

László Árpád Gergely ◽

Peter L. Biermann

Keyword(s):

Black Hole ◽

Supermassive Black Hole ◽

Spin Flip ◽

Binary Mergers ◽

Black Hole Binary

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Population synthesis of black hole binary mergers from star clusters

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3584 ◽

2020 ◽

Vol 492 (2) ◽

pp. 2936-2954 ◽

Cited By ~ 13

Author(s):

Fabio Antonini ◽

Mark Gieles

Keyword(s):

Black Hole ◽

Globular Clusters ◽

Initial Conditions ◽

Star Clusters ◽

Population Synthesis ◽

Wide Range ◽

Binary Mergers ◽

Cluster Properties ◽

Black Hole Binary ◽

Merger Rate

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.

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ACCRETION AND ORBITAL INSPIRAL IN GAS-ASSISTED SUPERMASSIVE BLACK HOLE BINARY MERGERS

The Astrophysical Journal ◽

10.3847/0004-637x/827/2/111 ◽

2016 ◽

Vol 827 (2) ◽

pp. 111 ◽

Cited By ~ 18

Author(s):

Roman R. Rafikov

Keyword(s):

Black Hole ◽

Supermassive Black Hole ◽

Binary Mergers ◽

Black Hole Binary

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1722 ◽

2019 ◽

Vol 488 (1) ◽

pp. 401-418 ◽

Cited By ~ 10

Author(s):

Siyuan Chen ◽

Alberto Sesana ◽

Christopher J Conselice

Keyword(s):

Black Hole ◽

Mass Function ◽

Host Galaxy ◽

Supermassive Black Hole ◽

Pulsar Timing ◽

Upper Limits ◽

Binary Mergers ◽

Black Hole Binary ◽

Merger Rate ◽

The Universe

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.

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