2010CBET.2358....2H

M. Henze, Max-Planck-Institut fuer Extraterrestrische Physik, (MPE); V. Burwitz, MPE and Observatorio Astronomico de Mallorca (OAM); W. Pietsch, MPE; J. Rodriguez, OAM; and C. A. Haswell, S. Holmes, U. Kolb, and R. Lucas, The Open University (TOU), confirm M31N 2010-07a after being notified by Hornoch. The new object is visible at a corresponding R magnitude of 18.4 on two stacks of five 120-s unfiltered CCD images obtained with the TOU/OAM PIRATE 0.35-m f/11 Schmidt-Cassegrain telescope (+ SBIG STL-1001E CCD camera) at Costitx, Mallorca, Spain, on July 8.02 and 8.07 UT, with position end figures 20s.11, 23".7 (uncertainty 0".3), which is 403" east and 314" north of the core of M31. No object is visible at this position on a PIRATE image from June 26.08 (limiting R magnitude 19.0). M31N 2010-07a was already active during an observation with the UltraViolet/Optical Telescope (UVOT) onboard the Swift satellite one day before the optical discovery. The 3815-s UVW1-filter observation (range 181-321 nm) starting on July 7.07 UT shows M31N 2010-07a at mag 20.6 ± 0.3 at a position consistent with the coordinates of the optical source; no source is visible at this position in an earlier UVW1-filter observation starting on June 24.02 (limiting magnitude 21.0). The optical magnitudes were obtained from a photometric solution using R magnitudes of the Local Group Survey M31 catalogue (Massey et al. 2006, A.J. 131, 2478); the ultraviolet magnitudes are on the UVOT photometric system (Poole et al. 2008, MNRAS 383, 627) and have not been corrected for extinction. The Swift team is thanked for scheduling the Target-of-Opportunity observations.