Comptonized Photon Spectra of Supercritical Black Hole Accretion Flows With Application to Ultraluminous X-Ray Sources

Kawashima, Tomohisa; Ohsuga, Ken; Mineshige, Shin; Yoshida, Tessei; Heinzeller, Dominikus; Matsumoto, Ryoji

doi:10.1088/0004-637x/752/1/18

Cited by 120 publications

(161 citation statements)

References 35 publications

Supporting

Mentioning

143

Contrasting

Order By: Relevance

“…We do not have direct information on the geometry of the emitting region in ULX-1. However, analytical models and numerical simulations of near-Eddington and super-Eddington sources predict mild geometrical beaming; that is, most of the X-ray flux is emitted along the direction perpendicular to the disk plane (Kawashima et al 2012;Jiang et al 2014;Saḑowski & Narayan 2016), and the emission should appear fainter and down-scattered in a disk wind when a source is observed at high inclination (as in our case, given the presence of eclipses). Therefore, we choose to use the simplest angle-dependent expression for the luminosity…”

Section: Continuum and Line Luminosity Of Ulx-1mentioning

confidence: 62%

Two Eclipsing Ultraluminous X-Ray Sources in M51

Urquhart

Soria

2016

ApJ

View full text Add to dashboard Cite

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.

show abstract

Section: Continuum and Line Luminosity Of Ulx-1mentioning

confidence: 62%

Two Eclipsing Ultraluminous X-Ray Sources in M51

Urquhart

Soria

2016

ApJ

View full text Add to dashboard Cite

show abstract

“…Even models withṀ ∼ 1Ṁ Edd (e.g., model r012 3d) show pronounced beaming, as does Fig. 1 in Kawashima et al (2012). The beaming is stronger, and shows lessṀ dependence, than the empirical model of King (2009).…”

Section: Summary and Discussionmentioning

confidence: 79%

Spectra of black hole accretion models of ultraluminous X-ray sources

Narayan

Sądowski

Soria

2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present general relativistic radiation MHD simulations of super-Eddington accretion on a 10M black hole. We consider a range of mass accretion rates, black hole spins, and magnetic field configurations. We compute the spectra and images of the models as a function of viewing angle, and compare them with the observed properties of ultraluminous X-ray sources (ULXs). The models easily produce apparent luminosities in excess of 10 40 erg s −1 for pole-on observers. However, the angle-integrated radiative luminosities rarely exceed 2.5 × 10 39 erg s −1 even for mass accretion rates of tens of Eddington. The systems are thus radiatively inefficient, though they are energetically efficient when the energy output in winds and jets is also counted. The simulated models reproduce the main empirical types of spectra -disk-like, supersoft, soft, hard -observed in ULXs. The magnetic field configuration, whether MAD ("magnetically arrested disk") or SANE ("standard and normal evolution"), has a strong effect on the results. In SANE models, the X-ray spectral hardness is almost independent of accretion rate, but decreases steeply with increasing inclination. MAD models with non-spinning black holes produce significantly softer spectra at higher values ofṀ , even at low inclinations. MAD models with rapidly spinning black holes are quite different from all other models. They are radiatively efficient (efficiency factor ∼ 10 − 20%), super-efficient when the mechanical energy output is also included (70%), and produce hard blazar-like spectra. In all models, the emission shows strong geometrical beaming, which disagrees with the more isotropic illumination favoured by observations of ULX bubbles.

show abstract

“…Super-Eddington accretion is predicted to give rise to powerful electromagnetic emission. However, this emission may be highly anisotropic (e.g., King et al 2001, Kawashima et al 2012, Ohsuga & Mineshige 2011. In some cases, this may even prevent observing direct emission from the inner parts of the disk if the observer line of sight is sufficiently far from the disk axis.…”

Section: Discussion On the Mass Accretion Ratementioning

confidence: 99%

Implications of the Delayed 2013 Outburst of Eso 243-49 HLX-1

Godet

Lombardi

Antonini

et al. 2014

ApJ

View full text Add to dashboard Cite

After showing four quasi-periodic outbursts spaced by ∼1 yr from 2009 to 2012, the hyper luminous X-ray source ESO 243-49 HLX-1, currently the best intermediate mass black hole (IMBH) candidate, showed an outburst in 2013 delayed by more than a month. In Lasota et al., we proposed that the X-ray light curve is the result of enhanced mass transfer episodes at periapsis from a donor star orbiting the IMBH in a highly eccentric orbit. In this scenario, the delay can be explained only if the orbital parameters can change suddenly from orbit to orbit. To investigate this, we ran Newtonian smooth particle hydrodynamical simulations starting with an incoming donor approaching an IMBH on a parabolic orbit. We survey a large parameter space by varying the star-to-black hole mass ratio (10 −5 -10 −3 ) and the periapsis separation r p from 2.2 to 2.7r t with r t , the tidal radius. To model the donor, we choose several polytropes (Γ = 5/2, n = 3/2, Γ = 3/2, n = 2, Γ = 5/3, n = 2, and Γ = 5/3, n = 3). Once the system is formed, the orbital period decreases until reaching a minimum that may be shallow. Then, the period tends to increase over several periapsis passages due to tidal effects and increasing mass transfer, leading ultimately to the ejection of the donor. We show that the development of stochastic fluctuations inside the donor by adding or removing orbital energy from the system could lead to sudden changes in the orbital period from orbit to orbit with the appropriate order of magnitude to that which has been observed for HLX-1. We also show that given the constraints on the black hole (BH) mass (M BH > 10 4 M ) and assuming that the HLX-1 system is currently near a minimum in period of ∼1 yr, the donor has to be a white dwarf or a stripped giant core. We predict that if HLX-1 is indeed emerging from a minimum in orbital period, then the period would generally increase with each passage, although substantial stochastic fluctuations can be superposed on this trend.

show abstract

Comptonized Photon Spectra of Supercritical Black Hole Accretion Flows With Application to Ultraluminous X-Ray Sources

Cited by 120 publications

References 35 publications

Two Eclipsing Ultraluminous X-Ray Sources in M51

Two Eclipsing Ultraluminous X-Ray Sources in M51

Spectra of black hole accretion models of ultraluminous X-ray sources

Implications of the Delayed 2013 Outburst of Eso 243-49 HLX-1

Contact Info

Product

Resources

About