The (Re)appearance of NGC 925 ULX-3, a New Transient ULX

Earnshaw, Hannah P.; Heida, Marianne; Brightman, Murray; Fürst, Felix; Harrison, Fiona A.; Jaodand, Amruta; Middleton, Matthew; Roberts, T. P.; Sathyaprakash, R.; Stern, Daniel; Walton, D. J.

doi:10.3847/1538-4357/ab77b8

Cited by 22 publications

(25 citation statements)

References 63 publications

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“…This is a key consideration here, since the latter are now being detected in increasing numbers as our X-ray archives continue to grow (e.g. Middleton et al 2012Middleton et al , 2013Soria et al 2012;Pintore et al 2018Pintore et al , 2020Earnshaw et al 2019aEarnshaw et al , 2020van Haaften et al 2019;Brightman et al 2020b;Walton et al 2021), and may be of particular interest in the context of identifying good ULX pulsar candidates (e.g. Tsygankov et al 2016;Earnshaw, Roberts & Sathyaprakash 2018;Song et al 2020).…”

Section: Step 2 -Luminosity Cutmentioning

confidence: 99%

A multimission catalogue of ultraluminous X-ray source candidates

Walton

Mackenzie

Gully

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We present a new, multimission catalogue of ultraluminous X-ray source (ULX) candidates, based on recent data releases from each of the XMM–Newton, Swift, and Chandra observatories (the 4XMM-DR10, 2SXPS, and CSC2 catalogues, respectively). This has been compiled by cross-correlating each of these X-ray archives with a large sample of galaxies primarily drawn from the HyperLEDA archive. Significant efforts have been made to clean the sample of known non-ULX contaminants (e.g. foreground stars, background active galactic nuclei, supernovae), and also to identify ULX candidates that are common to the different X-ray catalogues utilized, allowing us to produce a combined ‘master’ list of unique sources. Our sample contains 1843 ULX candidates associated with 951 different host galaxies, making it the largest ULX catalogue compiled to date. Of these, 689 sources are catalogued as ULX candidates for the first time. Our primary motivation is to identify new sources of interest for detailed follow-up studies, and within our catalogue we have already found one new extreme ULX candidate that has high S/N data in the archive: NGC 3044 ULX1. This source has a peak luminosity of LX,peak ∼ 1040 erg s−1, and the XMM–Newton spectrum of the source while at this peak flux is very similar to other, better-studied extreme ULXs that are now understood to be local examples of super-Eddington accretion. This likely indicates that NGC 3044 ULX1 is another source accreting at super-Eddington rates. We expect that this catalogue will be a valuable resource for planning future observations of ULXs – both with our current and future X-ray facilities – to further improve our understanding of this enigmatic population.

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Section: Step 2 -Luminosity Cutmentioning

confidence: 99%

A multimission catalogue of ultraluminous X-ray source candidates

Walton

Mackenzie

Gully

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…This is the latest member of the growing population of transient ULXs (e.g. Soria et al 2012;Middleton et al 2012Middleton et al , 2013Pintore et al 2018Pintore et al , 2020Earnshaw et al 2019aEarnshaw et al , 2020Brightman et al 2020). Remarkably, ULX3 is the third such source in the galaxy NGC 7090 alone (e.g.…”

Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 98%

“…Furthermore, as the archive of X-ray data continues to grow, and along with it the number of nearby galaxies with multiple observing epochs, an increasing number of new/transient ULXs are being reported (e.g. Soria et al 2012;Middleton et al 2012Middleton et al , 2013Pintore et al 2018Pintore et al , 2020Earnshaw et al 2019aEarnshaw et al , 2020van Haaften et al 2019;Brightman et al 2020). The high-amplitude long-term variability Although this is distinct behaviour from the known ULX pulsars, which spend extended periods at highly super-Eddington luminosities, these may be interesting objects in terms of connecting ULX pulsars to the sub-Eddington X-ray pulsar population.…”

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confidence: 99%

A new transient ultraluminous X-ray source in NGC 7090

Walton

Heida

Bachetti

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We report on the discovery of a new, transient ultraluminous X-ray source (ULX) in the galaxy NGC 7090. This new ULX, which we refer to as NGC 7090 ULX3, was discovered via monitoring with Swift during 2019–20, and to date has exhibited a peak luminosity of LX ∼ 6 × 1039 erg s−1. Archival searches show that, prior to its recent transition into the ULX regime, ULX3 appeared to exhibit a fairly stable luminosity of LX ∼ 1038 erg s−1. Such strong long-timescale variability may be reminiscent of the small population of known ULX pulsars, although deep follow-up observations with XMM-Newton and NuSTAR do not reveal any robust X-ray pulsation signals. Pulsations similar to those seen from known ULX pulsars cannot be completely excluded, however, as the limit on the pulsed fraction of any signal that remains undetected in these data is ≲20%. The broadband spectrum from these observations is well modelled with a simple thin disc model, consistent with sub-Eddington accretion, which may instead imply a moderately large black hole accretor (MBH ∼ 40 M⊙). Similarly, though, more complex models consistent with the super-Eddington spectra seen in other ULXs (and the known ULX pulsars) cannot be excluded given the limited signal-to-noise of the available broadband data. The nature of the accretor powering this new ULX therefore remains uncertain.

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“…This is roughly the minimum rate at which accretion discs in (quasi)steady ULXs must be fed by the companion star. Some ULXs are transient (see, e.g., Earnshaw et al 2020;Brightman et al 2020). If this luminosity variability is due to the disk thermal-viscous instability, then the MT rate should be lower than the value mentioned above (Hameury & Lasota 2020).…”

Section: Eddmentioning

confidence: 95%

Wind-powered Ultraluminous X-ray Sources

Wiktorowicz

Lasota

Belczyński

et al. 2021

ApJ

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Although ultraluminous X-ray sources (ULX) are important for astrophysics because of their extreme apparent super-Eddington luminosities, their nature is still poorly known. Theoretical and observational studies suggest that ULXs could be a diversified group of objects that are composed of low-mass X-ray binaries, high-mass X-ray binaries and marginally also systems containing intermediate-mass black holes. Observational data on the ULX donors could significantly boost our understanding of these systems, but only a few have been detected. There are several candidates, mostly red supergiants (RSGs), but surveys are typically biased toward luminous near-infrared objects. In ULXs harbouring RSGs matter accreted onto the compact body would have to be provided by the stellar wind of the companion because a Roche-lobe overflow could be unstable for relevant mass-ratios. We present a comprehensive study of the evolution and population of wind-fed ULXs, and we provide a theoretical support for the link between RSGs and ULXs. Assuming a minimal model of stellar-wind emission, our estimated upper limit on contribution of wind-fed ULX to the overall ULX population is ∼75%-96% for young (<100 Myr) starforming environments, ∼49%-87% for prolonged constant star formation (e.g., disk of Milky Way), and 1% for environments in which star formation ceased long time (>2 Gyr) ago. We show also that some wind-fed ULXs (up to 6%) may evolve into merging double compact objects (DCOs). We demonstrate that the exclusion of wind-fed ULXs from population studies of ULXs might have lead to systematic errors in their conclusions.

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The (Re)appearance of NGC 925 ULX-3, a New Transient ULX

Cited by 22 publications

References 63 publications

A multimission catalogue of ultraluminous X-ray source candidates

A multimission catalogue of ultraluminous X-ray source candidates

A new transient ultraluminous X-ray source in NGC 7090

Wind-powered Ultraluminous X-ray Sources

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