The second ROSAT PSPC survey of M 31 and the complete ROSAT PSPC source list

Supper, R.; Hasinger, G.; Lewin, W. H. G.; Magnier, E. A.; Paradijs, J. van; Pietsch, W.; Read, A. M.; Trümper, J.

doi:10.1051/0004-6361:20010495

Cited by 123 publications

(205 citation statements)

References 28 publications

(33 reference statements)

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“…A ROSAT PSPC mosaic of 6 contiguous pointings with an exposure time of 25 ks each was performed in July 1991 (first M 31 survey; Supper et al 1997, hereafter SHP97). A second survey was made in July/August 1992 and January and July 1993 (Supper et al 2001. Several SSS candidates were identified.…”

Section: X-ray Detection Of Optical Novae In M 31mentioning

confidence: 99%

X‐ray emission from optical novae in M 31

Pietsch

2010

Astron Nachr

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The first supersoft source (SSS) identification with an optical nova in M 31 was based on ROSAT observations. Twenty additional X-ray counterparts (mostly identified as SSS by their hardness ratios) were detected using archival ROSAT, XMM-Newton and Chandra observations obtained before July 2002. Based on these results optical novae seem to constitute the major class of SSS in M 31. An analysis of archival Chandra HRC-I and ACIS-I observations obtained from July 2004 to February 2005 demonstrated that M 31 nova SSS states lasted from months to about 10 years. Several novae showed short X-ray outbursts starting within 50 d after the optical outburst and lasting only two to three months. The fraction of novae detected in soft X-rays within a year after the optical outburst was more than 30 %. Ongoing optical nova monitoring programs, optical spectral follow-up and an up-to-date nova catalogue are essential for the X-ray work. Re-analysis of archival nova data to improve positions and find additional nova candidates are urgently needed for secure recurrent nova identifications. Dedicated XMM-Newton/Chandra monitoring programs for X-ray emission from optical novae covering the centre area of M 31 continue to provide interesting new results (e.g. coherent 1105 s pulsations in the SSS counterpart of nova M31N 2007-12b). The SSS light curves of novae allow us -together with optical informationto estimate the mass of the white dwarf, of the ejecta and the burned mass in the outburst. Observations of the central area of M 31 allow us -in contrast to observations in the Galaxy -to monitor many novae simultaneously and proved to be prone to find many interesting SSS and nova types.

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Section: X-ray Detection Of Optical Novae In M 31mentioning

confidence: 99%

X‐ray emission from optical novae in M 31

Pietsch

2010

Astron Nachr

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“…The most extensive study of supersoft sources in an external spiral galaxy similar to our own and M81 is the ROSAT survey of M31 (Supper et al 1997;Kahabka 1999). Based on hardness ratios, Supper et al (1997) identified 15 supersoft source candidates not associated with supernova remnant (SNR) or foreground objects in a 6.3 deg 2 M31 field.…”

Section: Observations Of Other Galaxiesmentioning

confidence: 99%

“…Based on hardness ratios, Supper et al (1997) identified 15 supersoft source candidates not associated with supernova remnant (SNR) or foreground objects in a 6.3 deg 2 M31 field. Kahabka (1999), using a slightly modified selection criteria, identified an additional 26 candidates in the field.…”

Section: Observations Of Other Galaxiesmentioning

confidence: 99%

“…The brightest source cannot easily be explained by prevailing theory, while the other two sources for which reliable spectral fits can be made show strong similarities to the hot close binary accreting white dwarf (WD) systems CAL 87 and CAL 83. Some prospects for future observations are discussed (x 6), and a comparison is made to the supersoft source populations observed in M31 with ROSAT (Supper et al 1997;Kahabka 1999) and in M101 with Chandra (Pence et al 2001). …”

Section: Introductionmentioning

confidence: 99%

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ChandraDiscovery of Luminous Supersoft X‐Ray Sources in M81

Swartz

Ghosh

Suleimanov

et al. 2002

ApJ

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A Chandra ACIS-S imaging observation of the nearby galaxy M81 (NGC 3031) reveals nine luminous soft X-ray sources. The local environments, X-ray spectral properties, and X-ray light curves of the sources are presented and discussed in the context of prevailing physical models for supersoft sources. It is shown that the sample falls within expectations based on population synthesis models taken from the literature, although the high observed luminosities (L obs $ 2 Â 10 36 -3 Â 10 38 ergs s À1 in the 0.2-2.0 keV band) and equivalent blackbody temperatures (T eff $ 40 80 eV) place the brightest detected M81 objects at the high-luminosity end of the class of supersoft sources defined by previous ROSAT and Einstein studies of nearby galaxies. This is interpreted as a natural consequence of the higher sensitivity of Chandra to hotter and more luminous systems. Most of the sources can be explained as canonical supersoft sources: accreting white dwarfs powered by steady surface nuclear burning with X-ray spectra well fitted by hot white dwarf local thermodynamic equilibrium atmosphere models. An exceptionally bright source is scrutinized in greater detail since its estimated bolometric luminosity, L bol $ 1:5 Â 10 39 ergs s À1 , greatly exceeds theoretical estimates for supersoft sources. This source may be beyond the stability limit and undergoing a phase of mass outflow under extreme conditions. Alternatively, a model in which the observed X-ray spectrum arises from an accretion disk around a black hole of mass $1200=ðcos iÞ 1=2 M (viewed at an inclination angle i) cannot be excluded.

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“…Observations of sources in the Milky Way and Local Group galaxies show that many of the brightest X-ray sources are high-and low-mass X-ray binaries (HMXBs, LMXBs), but there are also sources associated with supernova remnants (SNRs) and H ii regions. For example, the ROSAT survey of M31 (Supper et al 2001) revealed a total of 560 X-ray sources, 16 of which have been optically identified with SNRs and 33 with globular clusters. Most of the bulge sources in M31 have been identified on the basis of their X-ray spectra as low-mass X-ray binaries (Trinchieri et al 1999;Primini, Forman, & Jones 1993).…”

Section: Introductionmentioning

confidence: 99%

Classifying X‐Ray Sources in External Galaxies from X‐Ray Colors

Prestwich

Irwin

Kilgard

et al. 2003

ApJ

155

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The X-ray populations of Local Group galaxies have been classified in detail by Einstein, ROSAT, and ASCA, revealing a mix of binaries, supernova remnants (SNRs), and H ii regions. However, these observatories were unable to resolve X-ray sources in galaxies beyond the Local Group. With Chandra's exquisite spatial resolution, we are able to resolve sources in a sample of nearby galaxies. We show that there are highly significant differences in the X-ray colors of sources in bulge and disk systems. In particular, we find that there is a population of X-ray-soft, faint sources in disk galaxies not seen in bulges and a smaller population of hard sources also seen preferentially in disk systems. These differences can be used as a basis to classify sources as low-and high-mass X-ray binaries, SNRs, and supersoft sources. We suggest that the soft sources seen preferentially in disks are probably dominated by SNRs, although we cannot rule out the possibility that they are a new population of absorbed, faint, supersoft accretion sources associated with the young stellar population. The hard sources seen in disks but not bulges we identify as high-mass X-ray binaries. While it is impossible to classify any individual source on the basis of X-ray color alone, the observations presented here suggest that it is possible to separate sources into groups dominated by one or two source types. This classification scheme is likely to be very useful in population studies, where it is crucial to distinguish between different classes of objects.

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The second ROSAT PSPC survey of M 31 and the complete ROSAT PSPC source list

Cited by 123 publications

References 28 publications

X‐ray emission from optical novae in M 31

X‐ray emission from optical novae in M 31

ChandraDiscovery of Luminous Supersoft X‐Ray Sources in M81

Classifying X‐Ray Sources in External Galaxies from X‐Ray Colors

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