Nova 2015-02a in M31 brightens up again

ATel #7818; E. Ovcharov (University of Sofia, Bulgaria), A. Kostov (Institute of Astronomy and NAO, Sofia, Bulgaria), V. Bozhilov, P. Nedialkov, A. Valcheva (University of Sofia, Bulgaria)
on 20 Jul 2015; 17:29 UT
Credential Certification: Evgeni Ovcharov (evgeni@phys.uni-sofia.bg)

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We report the optical re-brightening of the Fe II class nova 2015-02a in M31 (ATel #7065, ATel #7076, ATel #7104, ATel #7158). The images are obtained with the 50/70 cm Schmidt telescope at Rozhen NAO, Bulgaria. The BR-magnitudes are:

2015 July 18.993 UT, R=19.94+/-0.44 (3x300s)
2015 July 19.001 UT, B=19.82+/-0.20 (1x300s)

2015 July 20.014 UT, R=19.66+/-0.33 (3x300s)
2015 July 20.026 UT, B=19.55+/-0.14 (3x300s)

There is nothing visible at this position in the Rozhen R-band images with limiting magnitude up to 20.5, taken on the nights of 24 and 31 May, 01 and 02 June and 10, 11, 12 and 13 July 2015.
The observed re-brightening may indicate that this nova belongs to the rare C-class novae (Strope, Schaefer & Henden 2010).


Furthermore, the reported probable nova in ATel #7795 is observable with R=20.17+/-0.13 (2015 July 18.993) and R=20.28+/-0.15 (2015 July 20.014), and is not visible in the B-band images up to 20.3 limiting magnitude.