Multi-messenger Time-domain Signatures Of Supermassive Black Hole Binaries

Charisi, Maria; Taylor, Stephen R.; Runnoe, Jessie; Bogdanovic, Tamara; Trump, Jonathan R.

doi:10.48550/arxiv.2110.14661

Cited by 5 publications

(7 citation statements)

References 121 publications

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“…Our results give tantalizing prospects for upcoming transient surveys of variable AGN (e.g. Charisi et al 2021) and population studies of binaries in general, by predicting accretion variability signatures, and effects of long term binary accretion on mass ratio distributions. While our results are scale-free and apply to stellar binaries as well as supermassive black holes, we point out that Mach numbers are expected to vary depending on the scale of the binary.…”

Section: Summary and Discussionmentioning

confidence: 75%

Preferential Accretion and Circumbinary Disk Precession in Eccentric Binary Systems

Siwek¹,

Weinberger²,

Muñoz³

et al. 2022

Preprint

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We present a suite of high resolution hydrodynamic simulations of binaries immersed in circumbinary accretion disks (CBDs). For the first time, we investigate the preferential accretion rate as a function of both eccentricity e b and mass ratio q b in a densely sampled parameter space, finding that when compared with circular binaries, (i) mass ratios grow more efficiently in binaries on moderately eccentric orbits (0.0 e b 0.4), and (ii) high eccentricities (e b 0.6) suppress mass ratio growth. We suggest that this non-monotonic preferential accretion behaviour may produce an observable shift in the mass ratio distributions of stellar binaries and massive black hole binaries. We further find that the response of a CBD can be divided into three regimes, depending on eccentricity and mass ratio: (i) CBDs around circular binaries always precess freely, whereas CBDs around eccentric binaries either (ii) undergo forced precession or (iii) remain locked at an angle with respect to the binary periapsis. Forced precession in eccentric binaries is associated with strong modulation of individual accretion rates on the precession timescale, a potentially observable signature in accreting binaries with short orbital periods.

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Section: Summary and Discussionmentioning

confidence: 75%

Preferential Accretion and Circumbinary Disk Precession in Eccentric Binary Systems

Siwek¹,

Weinberger²,

Muñoz³

et al. 2022

Preprint

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“…We then discuss the effect of Doppler brightening, which is often a central consideration when modeling binary quasar light curves (see e.g. D 'Orazio et al 2015;Charisi et al 2021). Finally, we discuss, as an illustrative example, a particular quasar with a claimed quasiperiodic light curve, to which our results may be relevant in the future.…”

Section: Discussionmentioning

confidence: 88%

“…Here α ν is the power spectral index at frequency ν, which is on the order of α ν −few×0.1 (for a very recent and extensive discussion, see Charisi et al 2021). For the purpose of estimation, we set α ν = −0.44 (as in Vanden Berk et al 2001;Charisi et al 2021) below and replace fluxes with luminosities F → L.…”

Section: Discussionmentioning

confidence: 99%

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Multiband light curves from eccentric accreting supermassive black hole binaries

Westernacher-Schneider

Zrake

MacFadyen

et al. 2022

Phys. Rev. D

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We use long-run, high-resolution hydrodynamics simulations to compute the multi-wavelength light curves (LCs) from thermal disk emission around accreting equal-mass supermassive black hole (BH) binaries, with a focus on revealing binary eccentricity. LCs are obtained by modeling the disk thermodynamics with an adiabatic equation of state, a local blackbody cooling prescription, and corrections to approximate the effects of radiation pressure. We find that modulation of multi-band LCs on the orbital time scale are generally in-phase (to within ∼ 2% of a binary orbital period), but they contain pulse substructure in the time domain that is not necessarily reflected in BH accretion rates Ṁ . We thus predict that binary-hosting AGN will exhibit highly correlated, in-phase, periodic brightness modulations in their low-energy disk emission. However, detectability of these modulations in multi-wavelength observing campaigns could be compromised because observed stochastic variability in AGNs typically has a higher amplitude than our proposed signal. It is possible that observations over temporal baselines of many binary periods may make the signal more prominent, but this would need to be analyzed carefully. If jet emission is predicted by Ṁ , then we predict a weaker correlation with low-energy disk emission due to the differing sub-peak structure. For the binary parameters we explore, we show that LC variability due to hydrodynamics likely dominates Doppler brightening for all equal-mass binaries with disk Mach numbers 20. A promising signature of eccentricity is weak or absent "lump" periodicity. We find hints that a significant lag exists between Ṁ and low-energy disk emission for circular binaries, but they are in-phase for eccentric binaries, which might explain some "orphan" blazar flares with no γ-ray counterpart.

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“…The methods for detecting the periodicity in blazars and quasars have proceeded practically independently, with little interactions between the communities cultivating the two fields. See, however, Holgado et al (2018), where the contributions of the two populations to the GW background, constrained by PTA observations, are compared and Charisi et al (2021) for future perspective of the field.…”

Section: Introductionmentioning

confidence: 99%

Detecting the periodicity of highly irregularly sampled light-curves with Gaussian processes: the case of SDSSJ025214.67-002813.7

Covino,

Tobar,

Treves

2022

Preprint

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Based on a 20-year-long multiband observation of its light-curve, it was conjectured that the quasar SDSS J025214.67-002813.7 has a periodicity of ∼ 4.4 years. These observations were acquired at a highly irregular sampling rate and feature long intervals of missing data. In this setting, the inference over the light-curve's spectral content requires, in addition to classic Fourier methods, a proper model of the probability distribution of the missing observations. In this article, we address the detection of the periodicity of a light-curve from partial and irregularly-sampled observations using Gaussian processes, a Bayesian nonparametric model for time series. This methodology allows us to evaluate the veracity of the claimed periodicity of the abovementioned quasar and also to estimate its power spectral density. Our main contribution is the confirmation that considering periodic component definitely improves the modeling of the data, although being the source originally selected by a large sample of objects, the possibility that this is a chance result cannot be ruled out.

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Multi-messenger Time-domain Signatures Of Supermassive Black Hole Binaries

Cited by 5 publications

References 121 publications

Preferential Accretion and Circumbinary Disk Precession in Eccentric Binary Systems

Preferential Accretion and Circumbinary Disk Precession in Eccentric Binary Systems

Multiband light curves from eccentric accreting supermassive black hole binaries

Detecting the periodicity of highly irregularly sampled light-curves with Gaussian processes: the case of SDSSJ025214.67-002813.7

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