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Swift UVOT light curves of recent M 31 nova candidates

ATel #4988; F. Hofmann, W. Pietsch, J. Greiner (Max-Planck-Institut fuer extraterrestrische Physik)
on 17 Apr 2013; 13:49 UT
Credential Certification: Wolfgang Pietsch (wnp@mpe.mpg.de)

Subjects: Ultra-Violet, Nova

From monitoring observations of the central region of the Andromeda Galaxy with the Ultra-violet/Optical Telescope (UVOT) on board the Swift satellite from 2013-01-23.41 to 2013-03.08.01 UT, we derived UV light curves (UVW1 filter, 181-321 nm) for three recently discovered nova candidates. The following table shows the UVW1 magnitudes (Vega system) and 1&sigma statistical uncertainties. Candidate nova name and first detection of the outburst in the optical (in Modified Julian Date MJD) are indicated at the top of each column (see M 31 (apparent) optical nova catalogue and references therein). We identify the observation by the last two digits of the identification number (00035336000 + ID) and give MJD at the observation start. 3&sigma upper limits ('>') are given for observations adjacent to a nova detection.

 
 ID  MJD       2012-12a         2013-01a         2013-02b 
               (56271.0)        (56296.5)        (56345.1) 
 90  56315.41  18.5±0.3         17.8±0.1   
 91  56320.62  > 19.3           18.0±0.2   
 92  56323.49                   18.3±0.2   
 93  56327.09                   18.5±0.2   
 94  56331.10                   18.9±0.3   
 95  56335.84                   > 19.9            
 96  56338.51  > 19.9           19.7±0.5   
 97  56343.52  18.7±0.2         > 19.9           > 20.2 
 98  56347.28  > 19.1                            18.2±0.2 
 99  56351.47  > 19.9                            17.5±0.1 
100  56355.21  18.4±0.2                          17.6±0.1 
101  56359.01  18.1±0.2                          17.7±0.1 

M31N 2012-12a re-brightened three times within 90 days after outburst (first UV detection see ATel #4757) and may be classified from its UV light curve as a J-class nova following the optical classification criteria of Strope et al. 2010 (AJ, 140, 34). M31N 2013-01a (see ATel #4757) reached its UVW1 maximum about 12 days after the optical detection and then faded continuously by two magnitudes in about 27 days. The first detection of M31N 2013-02b is discussed in ATel #4833, it reached its UVW1 maximum after about 6 days and may be slowly declining by 0.2 mag in the following two observations (within 8 days).
These novae were also in the field of view of the Swift M 31 center monitoring (ObsIDs 00032702001-00032702030) from 2013-02-08.90 to 2013-03-09.27 UT. These observations used four different UVOT filters. Light curves including this additional Swift UVOT monitoring data are shown at M 31 (apparent) optical nova catalogue.
All magnitudes are on the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) and have not been corrected for extinction. 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.