The nature of ULX source M101 X-1: optically thick outflow from a stellar mass black hole

Shen, Rong-Feng; Duran, R. Barniol; Nakar, Ehud; Piran, Tsvi

doi:10.1093/mnrasl/slu183

Cited by 31 publications

(57 citation statements)

References 19 publications

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“…The authors find signatures that accretion is happening from a stellar wind rather than Roche-Lobe overflow. Shen et al (2015) find for this source signatures of a thick outflow.…”

Section: Weak Ulxs -Proofs Of Super-eddington Accretionmentioning

confidence: 70%

Ultraluminous X‐ray sources: Three exciting years

Bachetti

2016

Astron Nachr

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The extreme extragalactic sources known as Ultraluminous X-ray Sources (ULX) represent a unique testing environment for compact objects population studies and the accretion process. Their nature has long been disputed. Their luminosity, well above the Eddington luminosity for a stellar-mass black hole, can imply the presence of an intermediate-mass black hole or a stellar black hole accreting above the Eddington limit. Both these interpretations are important to understand better the accretion process and the evolution of massive black holes. The last few years have seen a dramatic improvement of our knowledge of these sources. In particular, the super-Eddington interpretation for the bulk of the ULX population has gained a strong consensus. Nonetheless, exceptions to this general trend do exist, and in particular one ULX was shown to be a neutron star, and another was shown to be a very likely IMBH candidate. In this paper, I will review the progress done in the last few years.

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“…The authors find signatures that accretion is happening from a stellar wind rather than Roche-Lobe overflow. Shen et al (2015) find for this source signatures of a thick outflow.…”

Section: Weak Ulxs -Proofs Of Super-eddington Accretionmentioning

confidence: 70%

Ultraluminous X‐ray sources: Three exciting years

Bachetti

2016

Astron Nachr

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“…Observing at such inclinations may then explain the extremely bright UV emission seen in ultraluminous UV sources (e.g. Kaaret et al 2010), the supersoft ULX, M101 (Kong & Di Stefano 2005;Shen et al 2015), and the UV excess of SS433 (Dolan et al 1997). As the X-ray luminosity is expected to be low, the source may not fall into the empirical class of bright or even faint ULXs (see as possible examples Soria et al 2010Soria et al , 2014).…”

Section: Source/population Evolution: Spectral Hardness Versus Variabmentioning

confidence: 99%

A spectral-timing model for ULXs in the supercritical regime

Middleton¹,

Heil

Pintore

et al. 2015

Monthly Notices of the Royal Astronomical Society

188

298

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Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTUltraluminous X-ray sources (ULXs) with luminosities lying between ∼3 × 10 39 and 2 × 10 40 erg s −1 represent a contentious sample of objects as their brightness, together with a lack of unambiguous mass estimates for the vast majority of the central objects, leads to a degenerate scenario where the accretor could be a stellar remnant (black hole or neutron star) or intermediate-mass black hole (IMBH). Recent, high-quality observations imply that the presence of IMBHs in the majority of these objects is unlikely unless the accretion flow somehow deviates strongly from expectation based on objects with known masses. On the other hand, physically motivated models for supercritical inflows can re-create the observed X-ray spectra and their evolution, although have been lacking a robust explanation for their variability properties. In this paper, we include the effect of a partially inhomogeneous wind that imprints variability on to the X-ray emission via two distinct methods. The model is heavily dependent on both inclination to the line of sight and mass accretion rate, resulting in a series of qualitative and semiquantitative predictions. We study the time-averaged spectra and variability of a sample of well-observed ULXs, finding that the source behaviours can be explained by our model in both individual cases as well as across the entire sample, specifically in the trend of hardness-variability power. We present the covariance spectra for these sources for the first time, which shed light on the correlated variability and issues associated with modelling broad ULX spectra.Key words: accretion, accretion discs -X-rays: binaries. I N T RO D U C T I O NUltraluminous X-ray sources (ULXs) have been widely observed in the local Universe, with inferred isotropic luminosities above 10 39 erg s −1 (Roberts 2007;Feng & Soria 2011). Those below ∼3 × 10 39 erg s −1 can be readily associated with accretion on to stellar mass black holes (BHs) (∼10 M ) accreting close to or at their Eddington limit (see Sutton, Roberts & Middleton 2013, and references therein). There is now strong evidence to support this assertion, with the discovery of extremely bright ballistic jets from a ULX in M31 Middleton, Miller-Jones & Fender 2014b), which unambiguously links the flow with Eddington rate accretion (Fender, Belloni & Gallo 2004), and the first dynamical mass measurement of the compact object in a ULX, from M101 E-mail: mjm@ast.cam.ac.uk ULX-1 (Liu et al. 2013). Ob...

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“…As the accretion rate exceeds the Eddington limit, an analytical solution for the accretion flow becomes increasingly difficult (Abramowicz et al 1978(Abramowicz et al , 1988Begelman 2002;Gu et al 2016), but analytical analysis indicates that the disk must be inflated and powerful winds will be launched due to radiation pressure (Shakura & Sunyaev 1973;King & Pounds 2003;Poutanen et al 2007;Shen et al 2015). Numerical simulations generally confirm the presence of massive outflows despite inconsistent details between different groups (e.g., Ohsuga & Mineshige 2011;Jiang et al 2014;Narayan et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Evidence for Precession due to Supercritical Accretion in Ultraluminous X-Ray Sources

Weng

Feng

2018

ApJ

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Most ultraluminous X-ray sources (ULXs) are thought to be supercritical accreting compact objects, where massive outflows are inevitable. Using the long-term monitoring data with the Swift X-ray Telescope, we identified a common feature in bright, hard ULXs: they display a quasi-periodic modulation in their hard X-ray band but not in their soft band. As a result, some sources show a bimodal distribution on the hardness intensity map. We argue that these model-independent results can be well interpreted in a picture that involves supercritical accretion with precession, where the hard X-ray emission from the central funnel is more or less beamed, while the soft X-rays may arise from the photosphere of the massive outflow and be nearly isotropic. It implies that precession may be ubiquitous in supercritical systems, such as the Galactic microquasar SS 433. How the hard X-rays are modulated can be used to constrain the angular distribution of the hard X-ray emission and the geometry of the accretion flow. We also find that two ULX pulsars (NGC 5907 ULX-1 and NGC 7793 P13) show similar behaviors but no bimodal distribution, which may imply that they have a different beaming shape or mechanism.

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The nature of ULX source M101 X-1: optically thick outflow from a stellar mass black hole

Cited by 31 publications

References 19 publications

Ultraluminous X‐ray sources: Three exciting years

Ultraluminous X‐ray sources: Three exciting years

A spectral-timing model for ULXs in the supercritical regime

Evidence for Precession due to Supercritical Accretion in Ultraluminous X-Ray Sources

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