First optical identification of a supersoft X-ray source in 
M31

Nedialkov, P.; Orio, Marina; Birkle, K.; Conselice, Christopher J.; Valle, M. Della; Greiner, J.; Magnier, E. A.; Тихонов, Н. А.

doi:10.1051/0004-6361:20020575

Cited by 15 publications

(19 citation statements)

References 33 publications

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“…Several SSS candidates were identified. In a search for counterparts, only one recent nova (which erupted in 1990 in M 31) was found on optical images (Nedialkov et al 2002). The population of SSS in M 31 has been studied by Greiner et al (2004Greiner et al ( , 1996, in particular their variability.…”

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

confidence: 99%

“…One of the surprising results was that more fading than rising sources have been found. Coincidentally, one of these faders was the above-mentioned nova (RX J0044.0+4118; Nedialkov et al 2002). This led to speculation that the difference in the numbers of faders and risers is due to a fraction of classical novae for which the X-ray rising phase could be much shorter than the fading phase.…”

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

confidence: 99%

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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%

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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“…Another important result obtained with ROSAT was the establishment of supersoft sources (SSSs) as a new class of M 31 X-ray sources (cf. Kahabka 1999) and the identification of the first SSS with an optical nova in M 31 (Nedialkov et al 2002). Garcia et al (2000) report on first observations of the nuclear region of M 31 with Chandra.…”

Section: Introductionmentioning

confidence: 97%

The deepXMM-NewtonSurvey of M 31

Stiele

Pietsch

Haberl

et al. 2011

A&A

150

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Aims. The largest Local Group spiral galaxy, M 31, has been completely imaged for the first time, obtaining a luminosity lower limit ∼10 35 erg s −1 in the 0.2-4.5 keV band. Our XMM-Newton EPIC survey combines archival observations along the major axis, from The main goal of the paper is to study the X-ray source population of M 31.Methods. An X-ray catalogue of 1897 sources was created, with 914 detected for the first time. Source classification and identification were based on X-ray hardness ratios, spatial extent of the sources, and cross correlation with catalogues in the X-ray, optical, infrared, and radio wavelengths. We also analysed the long-term variability of the X-ray sources and this variability allows us to distinguish between X-ray binaries and active galactic nuclei (AGN). Furthermore, supernova remnant classifications of previous studies that did not use long-term variability as a classification criterion could be validated. Including previous Chandra and ROSAT observations in the long-term variability study allowed us to detect additional transient or at least highly variable sources, which are good candidate X-ray binaries. Results. Fourteen of the 30 supersoft source (SSS) candidates represent supersoft emission of optical novae. Many of the 25 supernova remnants (SNRs) and 31 SNR candidates lie within the 10 kpc dust ring and other star-forming regions in M 31. This connection between SNRs and star-forming regions implies that most of the remnants originate in type II supernovae. The brightest sources in X-rays in M 31 belong to the class of X-ray binaries (XRBs). Ten low-mass XRBs (LMXBs) and 26 LMXB candidates were identified based on their temporal variability. In addition, 36 LMXBs and 17 LMXB candidates were identified owing to correlations with globular clusters and globular cluster candidates. From optical and X-ray colour-colour diagrams, possible high-mass XRB (HMXB) candidates were selected. Two of these candidates have an X-ray spectrum as is expected for an HMXB containing a neutron star primary. Conclusions. While our survey has greatly improved our understanding of the X-ray source populations in M 31, at this point 65% of the sources can still only be classified as "hard" sources; i.e. it is not possible to decide whether these sources are X-ray binaries or Crab-like supernova remnants in M 31 or X-ray sources in the background. Deeper observations in X-ray and at other wavelengths would help classify these sources.

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“…The nova outburst in November 2001 happened 53 days before the detection as SSS. After the first SSS in M 31 identified with a nova, M31N 1990-09a (Nedialkov et al 2002(Nedialkov et al ) and M31N 2001(Nedialkov et al -10f, M31N 2001 is already the third optical nova in M 31 for which the optical outburst was detected when searching for optical counterparts of supersoft X-ray sources.…”

Section: Introductionmentioning

confidence: 99%

X-ray monitoring of optical novae in M 31 from July 2004 to February 2005

Pietsch¹,

Haberl²,

Sala³

et al. 2007

A&A

Self Cite

116

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Context. Optical novae have recently been identified as the major class of supersoft X-ray sources in M 31 based on ROSAT and early XMM-Newton and Chandra observations. Aims. This paper reports on a search for X-ray counterparts of optical novae in M 31 based on archival Chandra HRC-I and ACIS-I as well as XMM-Newton observations of the galaxy center region obtained from July 2004 to February 2005. Methods. We systematically determine X-ray brightness or upper limit for counterparts of all known optical novae with outbursts between November 2003 to the end of the X-ray coverage. In addition, we determine the X-ray brightnesses for counterparts of four novae with earlier outbursts. Results. For comparison with the X-ray data we created a catalogue of optical novae in M 31 based on our own nova search programs and on all novae reported in the literature. We collected all known properties and named the novae consistently following the CBAT scheme. We detect eleven out of 34 novae within a year after the optical outburst in X-rays. While for eleven novae we detect the end of the supersoft source phase, seven novae are still bright more than 1200, 1600, 1950, 2650, 3100, 3370 and 3380 d after outburst. One nova is detected to turn on 50 d, another 200 d after outburst. Three novae unexpectedly showed short X-ray outbursts starting within 50 d after the optical outburst and lasting only two to three months. The X-ray emission of several of the novae can be characterized as supersoft from hardness ratios and/or X-ray spectra or by comparing HRC-I count rates with ACIS-I count rates or upper limits. Conclusions. The number of detected optical novae at supersoft X-rays is much higher than previously estimated (>30%). We use the X-ray light curves to estimate the burned masses of the White Dwarf and of the ejecta.

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First optical identification of a supersoft X-ray source in M31

Cited by 15 publications

References 33 publications

X‐ray emission from optical novae in M 31

X‐ray emission from optical novae in M 31

The deepXMM-NewtonSurvey of M 31

X-ray monitoring of optical novae in M 31 from July 2004 to February 2005

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