The stochastic gravitational-wave background from massive black hole binary systems: implications for observations with Pulsar Timing Arrays

By A. Sesana, Alberto Vecchio, C. Colacino. 2008

384 citations recorded by the source corpus.

Massive black hole binary systems, with masses in the range � 10 4 10 10 M⊙, are among the primary sources of gravitational waves in the frequency window � 10 −9 Hz 0.1Hz. Pulsar Timing Arrays (PTAs) and the Laser Interferometer Space Antenna (LISA) are the observational means by which we will be able to observe gravitational radiation from these systems. We carry out a systematic study of the generation of the stochastic gravitational-wave background from the cosmic population of massive black hole binaries. We consider a wide variety of assembly scenarios and we estimate the range of signal strength in the frequency band accessible to PTAs. We show that regardless of the specific model of massive black hole binaries formation and evolution, the characteristic amplitude hc of the gravitational wave stochastic background at 10 −8 Hz varies by less than a factor of 2. However, taking into account the uncertainties surrounding the actual key model parameters, the amplitude lies in the interval hc(f = 10 −8 Hz) � 5×10 −16 8×10 −15 . The most optimistic predictions place the signal level at a factor of � 3 below the current sensitivity of Pulsar Timing Arrays, but within the detection range of the complete Parkes PTA for a wide variety of models, and of the future Square-Kilometer-Array PTA for all the models considered here. We also show that at frequencies > 10 −8 Hz the frequency dependency of the generated background follows a power-law significantly steeper than hc / f −2/3 , that has been considered so far; the value of the spectral index depends on the actual assembly scenario and provides therefore an additional opportunity to extract astrophysical information about the cosmic population of massive black holes. Finally we show that LISA observations of individual resolvable massive black hole binaries are complementary and orthogonal to PTA observations of a stochastic background from the whole population in the Universe. In fact, the detection of gravitational radiation in both frequency windows will enable us to fully characterise the cosmic history of massive black holes.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/75c1a1a76ae48a493f9497e6f36ad2b5d1cdad48

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In Astronomy and Astrophysics

1. L. Hernquist
2. P. Hopkins
3. M. Volonteri
4. A. Sesana
5. G. Hobbs
6. Volker Springel
7. Zoltán Haiman
8. R. Manchester

Citations in the corpus

• European Pulsar Timing Array Limits on Continuous Gravitational Waves from Individual Supermassive Black Hole Binaries (2015, background): “Consisting of a superposition of several thousands of sources randomly distributed over the sky (Sesana et al. 2008), the signal has classically been described as a stochastic GW background (GWB, Rajagopal & Romani 1995; Jaffe & Backer 2003; Wyithe & Loeb 2003; Sesana et al. 2004).”
• The International Pulsar Timing Array project: using pulsars as a gravitational wave detector (2009, neutral): “The European project (EPTA; Janssen et al. 2008) currently ‡ see Sesana et al. (2008) for a more accurate model combines data from four European telescopes (Effelsberg, Jodrell Bank, Nançay and Westerbork – a new telescope in Sardinia is currently being commissoned).”
• European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background (2015, methodology): “Sesana et al. (2008) exploited semianalytical merger trees from Volonteri, Haardt & Madau (2003) to estimate a plausible range for the amplitude of a GWB of 5 × 10−16 < A < 3 × 10−15.”
• THE NANOGRAV NINE-YEAR DATA SET: OBSERVATIONS, ARRIVAL TIME MEASUREMENTS, AND ANALYSIS OF 37 MILLISECOND PULSARS (2015, background): “A number of predictions for the expected strength of the SMBHB gravitational wave background have been made (e.g., Jaffe & Backer 2003; Sesana et al. 2008; Sesana 2013; McWilliams et al. 2014), with a = -2 3 and expected values for Agw ranging from ∼5 × 10−16 to 4 × 10−15.”
• Gravitational-wave sensitivity curves (2014, methodology): “The main target for PTAs is a stochastic background of GWs produced by a population of supermassive black-hole binaries at cosmological distances (Sesana et al 2008).”
• The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background (2023, background): “…in nuclei (see, e.g., Merritt & Milosavljević 2005 for a review), by appreciable eccentricity in SMBHB orbits (Enoki & Nagashima 2007), and by low-number SMBHB statistics (Sesana et al. 2008). hdγ parameter recovery may also be biased if intrinsic pulsar noise is not modeled well by a power law.”
• Pulsar timing signal from ultralight scalar dark matter (2013, background): “A signal of similar magnitude is expected from the stochastic gravitational wave background produced by massive black hole binary systems [9, 10].”
• Black-hole binaries, gravitational waves, and numerical relativity (2010, background): “This band is expected to dominated by gravitational waves from a very large population of unresolved MBH binaries (Sesana et al., 2008) with possibly a few discrete sources (Sesana et al.”
• Massive Black Hole Binary Mergers in Dynamical Galactic Environments (2016, background): “For a complete and pedagogical derivation of the GWB spectrum see, e.g., Sesana et al. (2008).”
• The Parkes Pulsar Timing Array Project (2006, background): “…for the rate of supermassive black hole binary coalescence events following galaxy mergers result in values of the GW background amplitude Ag that are potentially detectable by pulsar timing experiments (e.g., Jaffe & Backer 2003; Wyithe & Loeb 2003; Enoki & Nagashima 2007; Sesana et al. 2008).”
• Expected properties of the first gravitational wave signal detected with pulsar timing arrays (2015, background): “The black thick line gives the mean hc over all realisations at each frequency bin, which is consistent with previous predictions for the amplitude of the GWB (Rajagopal & Romani 1995; Wyithe & Loeb 2003; Sesana et al. 2008; Rosado 2011; Ravi et al. 2015).”
• Gravitational waves from resolvable massive black hole binary systems and observations with Pulsar Timing Arrays (2008, background): “The possible level of the GW background, and the consequences for observations have been explored by several authors (see e.g. Rajagopal & Romani 1995; Phinney 2001, Jaffe & Backer 2003; Jenet et al. 2005; Jenet et al. 2006; Sesana et al. 2008).”