A new optical Nova in M31

ATel #1162; W. Pietsch (Max-Planck-Institut fuer extraterrestrische Physik, MPE), V. Burwitz (MPE & Observatorio Astronomico de Mallorca, OAM), D. Hatzidimitriou (Department of Physics, University of Crete, UoC), H. Steinle (MPE), ), A. Slowikowska (UoC), A. Stefanescu (MPE), P. Reig (UoC), G. Papamastorakis (UoC), S. Cikota (Observatorio Astronomico de La Sagra, OLS), A. Cikota (OLS), S. Sanchez (OAM), F. Haberl (MPE), G. Sala (MPE), J. Greiner (MPE)
on 29 Jul 2007; 12:33 UT
Credential Certification: Wolfgang Pietsch (wnp@mpe.mpg.de)

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We report the discovery of an optical nova in M31 at RA(2000) = 00h 42m 59.49s , Dec(2000) = +41° 15' 06.5" with an accuracy of 0.2". The observations were obtained at the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5µm sq. pixels). The observations were taken through a Johnson standard R filter (4*100 s stacked) and a broad H-alpha filter (3*300 s stacked).
The object has been rising during five days, with R magnitudes of 19.4, 19.1, 18.8, 18.6 on July 24.046, 25.942, 26.972, 28.084, while on the 29.071 the object appeared bright in H-alpha at R(HA)=17.4. An R image from 2007 July 22.072 shows no object at the position of the nova brighter than the limiting magnitude of ~19.7. Moreover, no object is seen at the location of the nova on an H-alpha image from 19.070 (limiting magnitude of ~18.7). All magnitudes given are from a photometric solution using R magnitudes of the Massey M31 catalog.

The object can also be seen on unfiltered 240 s images obtained with 0.45m f/2.8 reflector and a SBIG STL-11000E CCD Camera (3008 pixels x 2674 pixels each 9 x 9 micron square), of the Observatorio Astronomico de La Sagra, Spain on July 28.097 at a magnitude of 18.3, and on 29.101 at 17.6 (photometric solution based on USNO-B1.0 catalogue).

The nova was also detected with the Swift UVOT on ~ 1600 s UVW2 filter images. Observations and magnitudes are [20.9(3sigma), [20.23(3sigma), 20.10+-0.30, 20.23+-0.31, 20.08+-0.28, 20.15+-0.33 on July 18.91, 24.19, 25.56, 26.46, 27.50, and 28.50, respectively.

We would like to thank the Swift Team for making these observations possible, in particular N. Gehrels, the duty scientists as well as the science planners.