WeCAPP -Wendelstein Calar Alto pixellensing project I

Riffeser, A.; Fliri, J.; Gössl, Claus; Bender, Ralf; Hopp, U.; Bärnbantner, O.; Ries, C.; Barwig, H.; Seitz, S.; Mitsch, Wolfgang

doi:10.1051/0004-6361:20011288

Cited by 43 publications

(61 citation statements)

References 34 publications

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“…The rms of the solution is 0.10 in declination and 0.12 in right ascension. The coordinates derived here agree perfectly with the ones derived in Riffeser et al (2001) and Riffeser et al (2003). The reduction package includes full error propagation for each pixel through all reduction steps.…”

Section: Astrometrysupporting

confidence: 68%

“…Detecting an asymmetry in the event rates would thus help to distinguish between both kinds of events. Several "pixellensing" surveys -AGAPE (Ansari et al 1997), POINT-AGAPE (Auriere et al 2001), WeCAPP (Riffeser et al 2001), MEGA (de Jong et al 2004), SLOTT/AGAPE (Calchi Novati et al 2002) -therefore observed the bulge and parts of the disk of M 31 fairly continuously, and also generated catalogues of variable sources as a by-product of these experiments. The work presented in this paper thus overlaps with the work resulting from the AGAPE (Ansari et al 2004) and POINT-AGAPE ) data sets.…”

Section: Introductionmentioning

confidence: 99%

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The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M 31 variable star catalogue

Fliri¹,

Riffeser

Seitz³

et al. 2005

A&A

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In this paper we present the WeCAPP catalogue of variable stars found in the bulge of M 31. Observations in the WeCAPP microlensing survey (optical R and I bands) for a period of three years (2000)(2001)(2002)(2003) resulted in a database with unprecedented time coverage for an extragalactic variable star study. We detected 23781 variable sources in a 16.1 × 16.6 field centered on the nucleus of M 31. The catalogue of variable stars contains the positions, the periods, and the variation amplitudes in the R and I bands. We classified the variables according to their position in the R-band period-amplitude plane. Three groups can be distinguished; while the first two groups can be mainly associated with Cepheid-like variables (population I Cepheids in group I; type II Cepheids and RV Tauri stars in group II), the third one consists of Long Period Variables (LPVs). We detected 37 RV Tauri stars and 11 RV Tauri candidates, which makes this catalogue one of the largest collections of this class of stars to date. The classification scheme is supported by Fourier decomposition of the light curves. Our data shows a correlation of the low-order Fourier coefficients Φ 21 with Φ 31 for classical Cepheids, as well as for type II Cepheids and RV Tauri stars. Correlating our sample of variable stars with X-ray based catalogues of Kaaret (2002, ApJ, 578, 114) and Kong et al. (2002, ApJ, 577, 738) results in 23 and 31 coincidences, 8 and 12 of which are M 31 globular clusters. The number density of detected variables is clearly not symmetric, which has to be included in the calculations of the expected microlensing event rate towards M 31. This asymmetry is due to the enhanced extinction in the spiral arms superimposed on the bulge of M 31, which reduces the number of sources to about 60%, if compared to areas of equivalent bulge brightness without enhanced extinction present.

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Section: Astrometrysupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M 31 variable star catalogue

Fliri¹,

Riffeser

Seitz³

et al. 2005

A&A

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“…This nova candidate was discovered in the WeCAPP survey (Riffeser et al 2001) on 2005-02-18. An X-ray counterpart was discovered in our first Chandra observation, 472 days after the optical outburst.…”

Section: M31n 2005-02amentioning

confidence: 95%

“…This nova candidate was discovered in the context of the Wendelstein Calar Alto Pixellensing Project (WeCAPP, Riffeser et al (2001), see also PHS2007) on 2001-01-19. In X-rays, there is a faint counterpart (see Table 5), which was only found in the merged XMM-Newton data.…”

Section: M31n 2001-01amentioning

confidence: 99%

X-ray monitoring of classical novae in the central region of M 31

Henze

Pietsch

Haberl

et al. 2010

A&A

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Context. Classical novae (CNe) have recently been reported to represent the major class of supersoft X-ray sources (SSSs) in the central region of our neighbour galaxy M 31. Aims. We carried out a dedicated monitoring of the M 31 central region with XMM-Newton and Chandra in order to find SSS counterparts of CNe, determine the duration of their SSS phase and derive physical outburst parameters. Methods. We systematically searched our data for X-ray counterparts of CNe and determined their X-ray light curves and spectral properties. Additionally, we determined luminosity upper limits for all novae from previous studies which are not detected anymore and for all CNe in our field of view with optical outbursts between May 2005 and March 2007. Results. We detected eight X-ray counterparts of CNe in M 31, four of which were not previously known. Seven sources can be classified as SSSs, one is a candidate SSS. Two SSSs are still visible more than nine years after the nova outburst, whereas two other nova counterparts show a short SSS phase of less than 150 days. Of the latter sources, M31N 2006-04a exhibits a short-time variable X-ray light curve with an apparent period of (1.6 ± 0.3) h. This periodicity could indicate the binary period of the system. There is no X-ray detection for 23 out of 25 CNe which were within the field of view of our observations and had their outburst from about one year before the start of the monitoring until its end. From the 14 SSS nova counterparts known from previous studies, ten are not detected anymore. Additionally, we found four SSSs in our XMM-Newton data without a nova counterpart, one of which is a new source. Conclusions. Out of eleven SSSs detected in our monitoring, seven are counterparts of CNe. We therefore confirm the earlier finding that CNe are the major class of SSSs in the central region of M 31. We use the measured SSS turn-on and turn-off times to estimate the mass ejected in the nova outburst and the mass burned on the white dwarf. Classical novae with short SSS phases seem to be an important contributor to the overall population.

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“…In a search for X-ray emission from optical novae, Pietsch et al (2005a Riffeser et al 2001) and novae from the literature. Within the ROSAT lists, PFF2005 identified five novae.…”

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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WeCAPP -Wendelstein Calar Alto pixellensing project I

Cited by 43 publications

References 34 publications

The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M 31 variable star catalogue

The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M 31 variable star catalogue

X-ray monitoring of classical novae in the central region of M 31

X‐ray emission from optical novae in M 31

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