Spinning up black holes with super-critical accretion flows

Sądowski, Aleksander; Bursa, Michal; Abramowicz, Marek A.; Kluźniak, W.; Lasota, Jean–Pierre; Moderski, R.; Safarzadeh, Mohammadtaher

doi:10.1051/0004-6361/201116702

Cited by 44 publications

(43 citation statements)

References 32 publications

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“…The currently preferred population model for LISA uses a Gaussian distribution of spins centered at 98% and capped off at the Thorne bound [3]. However in light of [20] EMRIs 5 Gargantua refers to the black hole featured in Nolan's science-fiction movie Interstellar, which according to Thorne [12] must be very rapidly spinning, with 1 − J/M 2 < 10 −14 to allow key pieces of the narrative. 6 See Table I of [13].…”

Section: Introductionmentioning

confidence: 99%

Gravitational waves from plunges into Gargantua

Compère

Fransen

Hertog

et al. 2018

Class. Quantum Grav.

116

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We analytically compute time domain gravitational waveforms produced in the final stages of extreme mass ratio inspirals of non-spinning compact objects into supermassive nearly extremal Kerr black holes. Conformal symmetry relates all corotating equatorial orbits in the geodesic approximation to circular orbits through complex conformal transformations. We use this to obtain the time domain Teukolsky perturbations for generic equatorial corotating plunges in closed form. The resulting gravitational waveforms consist of an intermediate polynomial ringdown phase in which the decay rate depends on the impact parameters, followed by an exponential quasi-normal mode decay. The waveform amplitude exhibits critical behavior when the orbital angular momentum tends to a minimal value determined by the innermost stable circular orbit. We show that either near-critical or large angular momentum leads to a significant extension of the LISA observable volume of gravitational wave sources of this kind.

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Section: Introductionmentioning

confidence: 99%

Gravitational waves from plunges into Gargantua

Compère

Fransen

Hertog

et al. 2018

Class. Quantum Grav.

116

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“…For example, in a radiatively efficient thin disk, Thorne (1974) found an asymptotic upper limit on aBH of amax ≈ 0.998. The exact value of this upper limit is sensitive to accretion rate and effective viscosity α but in most cases is amax 0.95 (Sadowski et al 2011, but see also references therein). However, our model for secondary-dominated Type II migration finds that BHBs generally accrete only a small fraction of their mass: even though they can accrete at super-Eddington rates, they also can harden much faster than a Salpeter time.…”

Section: Distribution Of Binary Parameters At Coalescencementioning

confidence: 99%

Assisted inspirals of stellar mass black holes embedded in AGN discs: solving the ‘final au problem’

Stone

Metzger²,

Haiman³

2016

Mon. Not. R. Astron. Soc.

478

454

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We explore the evolution of stellar mass black hole binaries (BHBs) which are formed in the self-gravitating disks of active galactic nuclei (AGN). Hardening due to threebody scattering and gaseous drag are effective mechanisms that reduce the semi-major axis of a BHB to radii where gravitational waves take over, on timescales shorter than the typical lifetime of the AGN disk. Taking observationally-motivated assumptions for the rate of star formation in AGN disks, we find a rate of disk-induced BHB mergers (R ∼ 3 yr −1 Gpc −3 , but with large uncertainties) that is comparable with existing estimates of the field rate of BHB mergers, and the approximate BHB merger rate implied by the recent Advanced LIGO detection of GW150914. BHBs formed thorough this channel will frequently be associated with luminous AGN, which are relatively rare within the sky error regions of future gravitational wave detector arrays. This channel could also possess a (potentially transient) electromagnetic counterpart due to super-Eddington accretion onto the stellar mass black hole following the merger.

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“…Very recently, in Ref. [49] the authors have studied the spin evolution for high accretion rates in a relativistic, advective, optically thick slim accretion disk model. They find that the BH spin evolution is hardly affected by the emitted radiation at high accretion rate (Ṁ 10Ṁ Edd , whereṀ Edd is the Eddington mass accretion rate) and that the equilibrium spin value is determined by the flow properties.…”

Section: Evolution Of the Spin Parametermentioning

confidence: 99%

“…They find that the BH spin evolution is hardly affected by the emitted radiation at high accretion rate (Ṁ 10Ṁ Edd , whereṀ Edd is the Eddington mass accretion rate) and that the equilibrium spin value is determined by the flow properties. ForṀ = 10Ṁ Edd and a viscosity parameter α = 0.01, they get a eq * = 0.9994 [49]. The spin evolution in non-Kerr space-times (non-Kerr BHs and compact objects without an event horizon) have been discussed in [30][31][32][33], but only in the case of accretion from thin disk.…”

Section: Evolution Of the Spin Parametermentioning

confidence: 99%

Super-spinning compact objects generated by thick accretion disks

Bambi

2013

J. Cosmol. Astropart. Phys.

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Abstract. If astrophysical black hole candidates are the Kerr black holes predicted byGeneral Relativity, the value of their spin parameter must be subject to the theoretical bound |a * | ≤ 1. In this work, we consider the possibility that these objects are either nonKerr black holes in an alternative theory of gravity or exotic compact objects in General Relativity. We study the accretion process when their accretion disk is geometrically thick with a simple version of the Polish doughnut model. The picture of the accretion process may be qualitatively different from the one around a Kerr black hole. The inner edge of the disk may not have the typical cusp on the equatorial plane any more, but there may be two cusps, respectively above and below the equatorial plane. We extend previous work on the evolution of the spin parameter and we estimate the maximum value of a * for the super-massive black hole candidates in galactic nuclei. Since measurements of the mean radiative efficiency of AGNs require η > 0.15, we infer the "observational" bound |a * | 1.3, which seems to be quite independent of the exact nature of these objects. Such a bound is only slightly weaker than |a * | 1.2 found in previous work for thin disks.

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Spinning up black holes with super-critical accretion flows

Cited by 44 publications

References 32 publications

Gravitational waves from plunges into Gargantua

Gravitational waves from plunges into Gargantua

Assisted inspirals of stellar mass black holes embedded in AGN discs: solving the ‘final au problem’

Super-spinning compact objects generated by thick accretion disks

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