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Confining the time of outburst of an optical nova candidate in M 31

ATel #2896; W. Pietsch, J. Lloyd, M. Henze, V. Burwitz (Max-Planck-Institut fuer extraterrestrische Physik), A. Knaur, D. Hartmann (Clemson University), P. Milne, G. Williams (University of Arizona), A. Liakos, D. Hatzidimitriou, P. Niarchos (Dept. Physics, University of Athens)
on 1 Oct 2010; 12:56 UT
Credential Certification: Wolfgang Pietsch (wnp@mpe.mpg.de)

Subjects: Optical, Cataclysmic Variable, Nova

Referred to by ATel #: 2898, 2909

We confirm a nova candidate in M 31 reported to us by K. Nishiyama and F. Kabashima and present a pre-discovery detection and upper limit that allows us to tightly constrain the time of outburst for this object. New observations show that the source is still increasing in brightness.

The nova candidate was discovered by Nishiyama and Kabashima (Miyaki-Argenteus observatory, Japan) on 2010 September 30.566 UT, with no object visible at its position on September 28.606 UT (private communication).

We detect the object on a 12x60s and 10x60s stacked R filter CCD image obtained with the robotic 60cm telescope with an E2V CCD (2kx2k, 13.5 micron sq. pixels) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA) on 2010 September 30.412 UT and October 1.180 UT with magnitude of 17.7 and 16.6, respectively. The position for the nova candidate is RA = 00h43m45.35s, Dec = +41d07'54.7"(J2000, accuracy of 0.2"), which is 690" east and 494" south of the core of M 31.

We do not detect the object on a 10x60s stacked unfiltered CCD image obtained at the 40-cm Cassegrain telescope with a focal reducer (F/5.1) equipped with a 2184 x 1472 pixel ST-10XME CCD camera (pixel size 6.8 microns square) at the Athens University Observatory, Greece on 2010 September 29.958 UT with a limiting magnitude of 18.5.

The first detection is 3.7 hours before the discovery by Nishiyama and Kabashima, the upper limit 1.35 days after their last upper limit, thus strongly constraining the time of outburst of the nova candidate. There is no entry in VizieR/CDS for this object and no minor planet could be found on this position using the MPC/IAU Minor Planet Checker (see http://scully.harvard.edu/~cgi/CheckMP ).

All magnitudes given are obtained from a photometric solution using R magnitudes of the Local Group Survey M 31 catalogue (Massey et al. 2006, AJ, 131, 2478).