X-ray observations of ultraluminous X-ray sources
By Timothy P Roberts. 2007
135 citations recorded by the source corpus.
Abstract Ultraluminous X-ray sources (ULXs) are amongst the most intriguing of X-ray source classes. Their extreme luminosities—greater than 1039 erg s−1 in the 0.3–10 keV band alone—suggest either the presence of black holes larger than those regularly encountered in our own Galaxy (the Galactic centre excepted), or sources apparently radiating well above the Eddington limit. We review the insights afforded us by studies of their X-ray emission, focussing on what this reveals about the underlying compact object. In particular, we discuss recent deep observations of ULXs by the XMM-Newton observatory, and how the unprecedented data quality provided by this mission is starting to discriminate between the different physical models for these extraordinary X-ray emitters.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Radiation
View Paper: https://www.semanticscholar.org/paper/b28c33581a33ed791ab2159bafa247db4b977f41
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Citations in the corpus
- Ultraluminous X-ray sources in the Chandra and XMM-Newton era (2011, background): “Other authors (Roberts 2007; Soria 2007; Gladstone et al. 2009; Weng & Zhang 2011) have suggested that the soft excess does come from the disk surface, but much further away than the innermost stable orbit, where the disk may be obscured or replaced by an outflow or a scattering corona (Section…”
- The ultraluminous state revisited: fractional variability and spectral shape as diagnostics of super-Eddington accretion (2013, background): “…that some of the highest quality XMM–Newton ULX spectra were well represented by a model consisting of two thermal (or thermal-like) components, different to the spectra shown by typical sub-Eddington black holes, suggestive of a new, super-Eddington ‘ultraluminous’ accretion state (Roberts 2007).”
- The Ultraluminous State (2009, background): “Ithas also, of course, been used as the basis for claims of IMBHs underlying ULXs (see introduction).”
- What drives the growth of black holes (2011, background): “ULXs likely comprise a heterogenous population (see King et al. 2001; Begelman 2002; Roberts 2007 and Gladstone et al. 2009 for a broader discussion of the nature of ULXs), of which a sizeable fraction are stellar-mass BHs accreting at super-Eddington rates.”