A Comparison of Intermediate-Mass Black Hole Candidate Ultraluminous X-Ray Sources and Stellar-Mass Black Holes

Miller, J. M.; Fabian, A. C.; Miller, M. Coleman

doi:10.1086/425316

Cited by 178 publications

(184 citation statements)

References 32 publications

(21 reference statements)

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“…Alternatively, we replaced the three mekal components with a cemekl, which is a multi-temperature thermal-plasma model with a power-law distribution of temperatures. The best-fitting cemekl + diskbb + comptt model has c = ( ) km are consistent with the characteristic temperatures and sizes of the soft thermal components seen in other ULXs (e.g., Miller et al 2004;Stobbart et al 2006;Kajava & Poutanen 2009). The direct luminosity contribution of the disk in the 0.3-8 keV band is » 4 1 10 38 ( ) erg s −1 .…”

Section: Continuum and Line Luminosity Of Ulx-1supporting

confidence: 71%

Two Eclipsing Ultraluminous X-Ray Sources in M51

Urquhart

Soria

2016

ApJ

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We present the discovery, from archival Chandra and XMM-Newton data, of X-ray eclipses in two ultraluminous X-ray sources (ULXs), located in the same region of the galaxy M51: CXOM51 J132940.0+471237 (ULX-1, for simplicity) and CXOM51 J132939.5+471244 (ULX-2). Three eclipses were detected for ULX-1 and two for ULX-2. The presence of eclipses puts strong constraints on the viewing angle, suggesting that both ULXs are seen almost edge-on and are certainly not beamed toward us. Despite the similar viewing angles and luminosities ( »Ĺ 2 10 X 39 erg s −1 in the 0.3-8 keV band for both sources), their X-ray properties are different. ULX-1 has a soft spectrum, well fitted by Comptonization emission from a medium with electron temperature » kT 1 keV e . ULX-2 is harder, well fitted by a slim disk with » kT 1.5 in -1.8 keV and normalization consistent with a ∼10 M e black hole. ULX-1 has a significant contribution from multi-temperature thermal-plasma emission ( »Ĺ 2 10 X,mekal 38 erg s −1 ). About 10% of this emission remains visible during the eclipses, proving that the emitting gas comes from a region slightly more extended than the size of the donor star. From the sequence and duration of the Chandra observations in and out of eclipse, we constrain the binary period of ULX-1 to be either »6.3 days, or ≈12.5-13 days. If the donor star fills its Roche lobe (a plausible assumption for ULXs), both cases require an evolved donor, most likely a blue supergiant, given the young age of the stellar population in that Galactic environment.

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Section: Continuum and Line Luminosity Of Ulx-1supporting

confidence: 71%

Two Eclipsing Ultraluminous X-Ray Sources in M51

Urquhart

Soria

2016

ApJ

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“…A great deal of progress has been made in recent years on the basis of Chandra and XMM-Newton spectra, firstly identifying soft excesses consistent with the cool accretion disc signature one would expect from a ∼ 1000M ⊙ intermediate-mass black hole (e.g. Miller et al 2003;Miller, Fabian & Miller 2004). Latterly this interpretation has been strongly challenged by the detection of a spectral break at energies of a few keV, identified in the best quality XMMNewton data for a wide range of ULXs.…”

Section: Introductionmentioning

confidence: 99%

(No) dynamical constraints on the mass of the black hole in two ULXs

Roberts¹,

Gladstone²,

Goulding³

et al. 2011

Astron Nachr

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We present the preliminary results of two Gemini campaigns to constrain the mass of the black hole in an ultraluminous X-ray source (ULX) via optical spectroscopy. Pilot studies of the optical counterparts of a number of ULXs revealed two candidates for further detailed study, based on the presence of a broad He II 4686Å emission line. A sequence of 10 long-slit spectra were obtained for each object, and the velocity shift of the ULX counterpart measured. Although radial velocity variations are observed, they are not sinusoidal, and no mass function is obtained. However, the broad He II line is highly variable on timescales shorter than a day. If associated with the reprocessing of X-rays in the accretion disc, its breadth implies that the disc must be close to face-on.

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“…This phenomena can be explained by several mechanisms, including a short-term super-Eddington phase [36], beaming [37], or normal accretion by an IMBH. Although the debate has not been settled, evidence favoring the IMBH mechanism over the other two has accumulated in recent years; these come in various forms, including spectral analysis [20,38], evidence for a low temperature ( 0:1 keV) black-body component [39], analysis of break frequencies of the power density spectrum [40], and observation of broad Fe lines and quasiperiodic oscillations (QPO) [41]. It seems that at least a fraction of the ULXs, in particular, the most luminous ones, are IMBHs.…”

Section: A Evidence For Imbhmentioning

confidence: 99%

Dark matter annihilation from intermediate-mass black holes: Contribution to the extragalactic gamma-ray background

Horiuchi

Ando

2006

Phys. Rev. D

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We investigate contributions to the extragalactic gamma-ray background (EGB) due to neutralino dark matter (DM) pair-annihilation into photons, from DM density enhancements (minispikes) surrounding intermediate-mass black holes (IMBHs). We focus on two IMBH formation scenarios; our conservative scenario where IMBHs are remnants of Population-III stars, and our optimistic scenario where IMBHs are formed in protogalactic disks. In both scenarios, their formation in pregalactic halos at high redshift lead to the formation of minispikes that are bright sources of gamma-ray photons. Taking into account minispike depletion processes, we only sum contributions from a cosmological distribution of IMBHs with maintained minispikes. Our conservative scenario (BH mass 10 2 M with a r ÿ3=2 minispike) predicts gamma-ray fluxes that are an order larger than the equivalent flux, using the same DM parameters (mass 100 GeV and annihilation cross section 3 10 ÿ26 cm 3 s ÿ1 ), from the host halo without IMBH minispikes. Our optimistic scenario (BH mass 10 5 M with a r ÿ7=3 minispike) predicts fluxes that are three orders larger, that can reach current EGB observations taken by EGRET (DM parameters as above). This fact may serve interesting consequences for constraining DM parameters and elucidating the true nature of IMBHs. Additionally, we determine the spectra of DM annihilation into monochromatic gamma rays, and show that its flux can be within observational range of GLAST, providing a potential ''smoking-gun'' signature of DM.

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A Comparison of Intermediate-Mass Black Hole Candidate Ultraluminous X-Ray Sources and Stellar-Mass Black Holes

Cited by 178 publications

References 32 publications

Two Eclipsing Ultraluminous X-Ray Sources in M51

Two Eclipsing Ultraluminous X-Ray Sources in M51

(No) dynamical constraints on the mass of the black hole in two ULXs

Dark matter annihilation from intermediate-mass black holes: Contribution to the extragalactic gamma-ray background

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