THE ULTRALUMINOUS X-RAY SOURCES NGC 1313 X-1 AND X-2: A BROADBAND STUDY WITH<i>NuSTAR</i>AND<i>XMM-Newton</i>

Bachetti, Matteo; Rana, V.; Walton, D. J.; Barret, D.; Harrison, Fiona A.; Boggs, Steven E.; Christensen, Finn Erland; Craig, William W.; Fabian, A. C.; Fürst, Felix; Grefenstette, Brian W.; Hailey, Charles J.; Hornschemeier, A. E.; Madsen, Kristin K.; Miller, J. M.; Ptak, Andrew; Stern, Daniel; Webb, N.; Zhang, William W.

doi:10.1088/0004-637x/778/2/163

Cited by 197 publications

(267 citation statements)

References 67 publications

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“…An extended hot halo is a characteristic feature of the best-studied eclipsing X-ray binary, the low-mass Galactic system EXO 0748−676 (Bonnet-Bidaud et al 2001). Soft X-ray residuals consistent with thermal-plasma emission (and/or absorption) have been reported in several other (non-eclipsing) ULXs such as NGC 5408 X-1 (Middleton et al 2014(Middleton et al , 2015bSutton et al 2015;Pinto et al 2016b), NGC 6946 X-1 (Middleton et al 2014), Ho II X-1 (Miyaji et al 2001;Dewangan et al 2004), NGC 4395 X-1 (Stobbart et al 2006), NGC 4559 X-1 ), NGC 7424 ULX-2 (Soria et al 2006), NGC 1313 X-1 (Bachetti et al 2013;Pinto et al 2016b), and Ho IX X-1 . The last two of those ULXs are hard ultraluminous sources, while all the others are classified as soft ultraluminous.…”

Section: Spectral Properties: Broadened Disks Comptonization and Thementioning

confidence: 72%

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: Spectral Properties: Broadened Disks Comptonization and Thementioning

confidence: 72%

Two Eclipsing Ultraluminous X-Ray Sources in M51

Urquhart

Soria

2016

ApJ

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“…As these features are not commonly observed in Galactic XRBs, they imply a new spectral regime, which is usually referred to as the 'ultraluminous state' (Roberts 2007;Gladstone et al 2009), and may be associated with super-Eddington accretion. A few luminous ULXs have very recently been observed with NuSTAR, resulting in spectra which demonstrate that the highenergy curvature persists above 10 keV (Bachetti et al 2013;Walton et al 2013a;Rana et al 2015), confirming this result. The spectral curvature may arise either from Comptonization in a cold, optically thick corona lying above an accretion disc (e.g.…”

mentioning

confidence: 65%

The ultraluminous X-ray source NGC 5643 ULX1: a large stellar mass black hole accreting at super-Eddington rates?

Pintore

Zampieri

Sutton

et al. 2016

Mon. Not. R. Astron. Soc.

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A sub-set of the brightest ultraluminous X-ray sources (ULXs), with X-ray luminosities well above 10 40 erg s −1 , typically have energy spectra which can be well described as hard power-laws, and short-term variability in excess of ∼ 10%. This combination of properties suggests that these ULXs may be some of the best candidates to host intermediate mass black holes (IMBHs), which would be accreting at sub-Eddington rates in the hard state seen in Galactic X-ray binaries. In this work, we present a temporal and spectral analysis of all of the available XMM-Newton data from one such ULX, the previously poorly studied 2XMM J143242.1−440939, located in NGC 5643. We report that its high quality EPIC spectra can be better described by a broad, thermal component, such as an advection dominated disc or an optically thick Comptonising corona. In addition, we find a hint of a marginal change in the short-term variability which does not appear to be clearly related to the source unabsorbed luminosity. We discuss the implications of these results, excluding the possibility that the source may be host an IMBH in a low state, and favouring an interpretation in terms of super-Eddington accretion on to a black hole of stellar origin. The properties of NGC 5643 ULX1 allow us to associate this source to the population of the hard/ultraluminous ULX class.

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“…This model has also been used to fit other ULX spectra (e.g. Foschini et al 2006;Vierdayanti et al 2006;Godet et al 2012;Bachetti et al 2013). The parameters of the slim disc fit are listed in Table 5.…”

Section: Discussionmentioning

confidence: 99%

“…With sensitivity above 10 keV, recent observations with the Nuclear Spectroscopic Telescope Array (NuStar ) have confirmed a spectral cutoff in ULXs such as NGC 1313 X-1 (Bachetti et al 2013). Gladstone et al (2009) suggested that the high energy roll-over and soft spectral feature seen in many ULX spectra may correspond to a super-Eddington state of ac-cretion onto a stellar-mass BH (the 'ultraluminous' state).…”

Section: Introductionmentioning

confidence: 99%

Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1

Marlowe

Kaaret

Lang

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We observed the Ultraluminous X-ray Source IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that is much softer than observed previously and is well modelled by a thermal accretion disc spectrum. No significant radio emission above the rms noise level was observed within the region of the ULX, consistent with the interpretation as a thermal state though other states cannot be entirely ruled out with the current data. We estimate the mass of the black hole using the modelled inner disc temperature to be 30 M ⊙ M √ cosi 200 M ⊙ based on a Shakura-Sunyaev disc model. Through a study of the hardness and high-energy curvature of available X-ray observations, we find that the accretion state of X-1 is not determined by luminosity alone.

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THE ULTRALUMINOUS X-RAY SOURCES NGC 1313 X-1 AND X-2: A BROADBAND STUDY WITHNuSTARANDXMM-Newton

Cited by 197 publications

References 67 publications

Two Eclipsing Ultraluminous X-Ray Sources in M51

Two Eclipsing Ultraluminous X-Ray Sources in M51

The ultraluminous X-ray source NGC 5643 ULX1: a large stellar mass black hole accreting at super-Eddington rates?

Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1

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