The X‐ray source population of the Andromeda galaxy M 31

Pietsch, W.

doi:10.1002/asna.200710905

Cited by 4 publications

(4 citation statements)

References 29 publications

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“…The X-ray content of the local group is not directly relevant to the ULX population as it is mostly composed of typical X-ray binaries and supernovae remnants and it has already been thoroughly studied (e.g. Sturm et al 2013;Pietsch 2008). Therefore, for the remainder of this paper we focus most of our attention to sources hosted by galaxies at D > 1 Mpc.…”

Section: Ulx Distribution and Abundancesmentioning

confidence: 99%

An expanded ultraluminous X-ray source catalogue

Bernadich

Schwope

Kovlakas

et al. 2022

A&A

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Context. Ultraluminous X-ray sources (L X ×10 39 erg s −1 , ULXs) are excellent probes for extreme accretion physics, star formation history in galaxies, and intermediate-mass black holes searches. As the sample size of X-ray data from modern observatories such as XMM-Newton and Chandra increases, producing extensive catalogues of ULXs and studying their collective properties has become both a possibility and a priority. Aims. Our aim is to build a clean updated ULX catalogue based on one of the most recent XMM-Newton X-ray serendipitous survey data releases, 4XMM-DR9, and the most recent and exhaustive catalogue of nearby galaxies, HECATE. We performed a preliminary population study to test if the properties of the expanded XMM-Newton ULX population are consistent with previous findings. Methods. We performed positional cross-matches between XMM-Newton sources and HECATE objects to identify host galaxies, and we used distance and luminosity arguments to identify ULX candidates. We flagged interlopers by finding known counterparts in external catalogues and databases such as Gaia DR2, SSDS, Pan-STARRS1, the NASA/IPAC Extragalactic Database, and SIMBAD. Source, galaxy and variability parameters from 4XMM-DR9, HECATE, and 4XMM-DR9s were used to study the spectral, abundance, and variability properties of the ULX sample. Results. We identify 779 ULX candidates, 94 of which hold L X 5 × 10 40 erg s −1 . Spiral galaxies are more likely to host ULXs. For early spiral galaxies the number of ULX candidates per star-forming rate is consistent with previous studies, while a significant ULX population in elliptical and lenticular galaxies also exists. Candidates hosted by late-type galaxies tend to present harder spectra and to undergo more extreme inter-observation variability than those hosted by early-type galaxies. Approximately 30 candidates with L X > 10 41 erg s −1 are also identified, constituting the most interesting candidates for intermediate-mass black hole searches. Conclusions. We have built the largest ULX catalogue to date. Our results on the spectral and abundance properties of ULXs confirm the findings made by previous studies based on XMM-Newton and Chandra data, while our population-scale study on variability properties is unprecedented. Our study, however, provides limited insight into the properties of the brightest ULX candidates due to the small sample size. The expected growth of X-ray catalogues and potential future follow-ups will aid in drawing a clearer picture.

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Section: Ulx Distribution and Abundancesmentioning

confidence: 99%

An expanded ultraluminous X-ray source catalogue

Bernadich

Schwope

Kovlakas

et al. 2022

A&A

View full text Add to dashboard Cite

show abstract

“…For instance, M31, M33 and the Magellanic Clouds alone already concentrate a 17% of all sources of quality. The X-ray content of the local group is not directly relevant to the ULX population, as it is mostly composed of typical X-ray binaries and supernovae remnants and it has already been thoroughly studied (e.g., Sturm et al 2013;Pietsch 2008). Therefore, during the raeminder of this paper we focus most of our attention to sources hosted by galaxies at D > 1 Mpc.…”

Section: Ulx Distribution and Abundancesmentioning

confidence: 99%

An expanded ultraluminous X-ray source catalogue

Bernadich,

Schwope,

Kovlakas

et al. 2021

Preprint

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Context. Ultraluminous X-ray sources (ULXs) are non-nuclear, extragalactic, point-like X-ray sources whose luminosity exceeds that of the Eddington limit of an accreting stellar-mass black hole (M BH < 10M , L X > 10 39 erg s −1 ). They are excellent laboratories for extreme accretion physics, probes for the star formation history of galaxies, and constitute precious targets for the search of intermediate-mass black holes. As the sample size of X-ray data from modern observatories such as XMM-Newton and Chandra increases, producing extensive catalogues of ULXs and studying their collective properties has become both a possibility and a priority. Aims. We build a clean, updated ULX catalogue based on one of the most recent XMM-Newton X-ray serendipitous survey data releases, 4XMM-DR9, and the most recent and exhaustive catalogue of nearby galaxies, HECATE. We perform a preliminary population study to test if the properties of the expanded XMM-Newton ULX population are consistent with previous findings. Methods. We perform positional cross-matches between XMM-Newton sources and HECATE objects to identify host galaxies. We filter out known foreground and background sources and other interlopers by finding counterparts in external catalogues and databases such as Gaia DR2, SSDS, PanSTARRS1, NASA/IPAC Extragalactic Database and SIMBAD. Manual inspection of image data from PanSTARRS1 and the NASA/IPAC is occasionally performed to investigate the nature of some individual sources. We use distance and luminosity arguments to identify ULX candidates. Source parameters from 4XMM-DR9, galaxy parameters from HECATE, and variability parameters from 4XMM-DR9s are used to study the spectral, abundance and variability properties of the updated XMM-Newton ULX sample. Results. We identify 779 ULX candidates, 94 of which hold L X 5 × 10 40 erg s −1 . We find that spiral galaxies are more likely to host ULXs. For early-spiral galaxies we also find that the number of ULX candidates per star forming rate that is consistent with previous studies, while we also attest the existence of a significant ULX population in elliptical and lenticular galaxies. Candidates hosted by late-type galaxies tend to present harder spectra and to undergo more and more extreme inter-observation variability than the ones hosted by early-type galaxies. ∼30 candidates with L X > 10 41 erg s −1 are also identified, constituting the most interesting candidates for intermediate-mass black hole searches. Conclusions. We have built the largest ULX catalogue to this date. Our results regarding the spectral and abundance properties of ULXs confirm the findings made by previous studies based on XMM-Newton and Chandra data, while our population-scale study on variability properties is unprecedented. Our study, however, provides limited insight on the properties of the bright ULX candidates (L X 5 × 10 40 erg s −1 ) due to the small sample size. The expected growth of X-ray catalogues and potential future follow-ups will aid in drawing a more clear picture.

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“…The statistical analysis of X-ray source populations in nearby galaxies, e.g. number density, the X-ray luminosity function of various source types as well as variability patterns, have led to substantial progress in our understanding of the evolution of important underlying physical parameters like metallicity and star formation rate (Gilfanov 2004;Grimm et al 2003Grimm et al , 2005Townsley et al 2006;Pietsch 2008;Fabbiano 2010;Mineo et al 2012). As we are moving from the study of just the most luminous sources (L X > 10 37 erg/s) to fainter thresholds, sometimes already as low as a few times 10 35 erg/s, it becomes increasingly important to understand the variety of sources contributing in this luminosity range.…”

Section: Outlook -The Quest For a Massive Identification Program Of Rmentioning

confidence: 99%

Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes

Greiner

Richter

2015

A&A

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Context. The optical identification of large number of X-ray sources such as those from the ROSAT All-Sky Survey is challenging with conventional spectroscopic follow-up observations. Aims. We investigate two ROSAT All-Sky Survey fields of size 10 • × 10 • each, one at galactic latitude b = 83 • (26 Com), the other at b = −5 • (γ Sge), in order to optically identify the majority of sources. Methods. We used optical variability, among other more standard methods, as a means of identifying a large number of ROSAT All-Sky Survey sources. All objects fainter than about 12 mag and brighter than about 17 mag, in or near the error circle of the ROSAT positions, were tested for optical variability on hundreds of archival plates of the Sonneberg field patrol.Results. The present paper contains probable optical identifications of altogether 256 of the 370 ROSAT sources analysed. In particular, we found 126 active galactic nuclei (some of them may be misclassified cataclysmic variables, CVs), 17 likely clusters of galaxies, 16 eruptive double stars (mostly CVs), 43 chromospherically active stars, 65 stars brighter than about 13 mag, 7 UV Cet stars, 3 semiregular resp. slow irregular variable stars of late spectral type, 2 DA white dwarfs, 1 Am star, 1 supernova remnant and 1 planetary nebula. As expected, nearly all active galactic nuclei are found in the high-galactic latitude field, while the majority of CVs is located at low galactic latitudes. We identify in total 72 new variable objects. Conclusions. X-ray emission is, expectedly, tightly correlated with optical variability, and thus our new method for optically identifying X-ray sources is demonstrated to be feasible. Given the large number of optical plates used, this method was most likely not more efficient than e.g. optical spectroscopy. However, it required no telescope time, only access to archival data.

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The X‐ray source population of the Andromeda galaxy M 31

Cited by 4 publications

References 29 publications

An expanded ultraluminous X-ray source catalogue

An expanded ultraluminous X-ray source catalogue

An expanded ultraluminous X-ray source catalogue

Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes

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