Nainital microlensing survey -- long-term photometric study of two novae in M31

Y. C. Joshi1 and D. Narasimha2
1ARIES, Manora Peak, Naini Tal 263 129, Uttarakhand, India
2ata Institute of Fundamental Research, Mumbai 400 005, India

Abstract. Two classical novae were detected in the disk of M 31. The photometric observations were taken in Cousins R and I bands during the four year Naini Tal Microlensing Survey which was being carried out during 1998-2002 with the aim of detecting microlensing events in the direction of M 31. The first nova, NMS-1, which had an outburst in 2000 and was monitored before the outburst as well as after, showed an R-magnitude of 17.2 on 2000 October 20, and a fast decline of 0.11 mag/day. For the second nova NMS-2, outburst at peak was not detected; however, this nova was observed during the declining phase in 2001. The rate of decline of NMS-2 suggests that either it was a slow nova or we started monitoring it at late phase of its outburst. In the follow-up observations which were carried out from 2-m Hanle telescope in 2004-2005, we find that both the novae have reached their pre-outburst level flux, though the Rc-Ic color could be slilightly different.

Keywords: classical novae -- recurrent novae -- cataclysmic variables -- optical spectroscopy -- optical photometry

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