M81N 2010-12a , the SIMBAD biblio

Kamil Hornoch, Astronomical Institute, Ondrejov; and Peter Garnavich and James Pagnini, University of Notre Dame, report their discovery of an apparent nova in the galaxy M81 on a co-added 2970-s unfiltered CCD frame taken by Hornoch on Dec. 5.147 UT with the 0.65-m telescope at Ondrejov and on a co-added 580-s R-band CCD frame taken by Garnavich and Pagnini with the Vatt4k imager on the 1.83-m Vatican Advanced Technology Telescope on Dec. 5.515 UT. The new object, designated M81N 2010-12a, is visible on single 200-s and 60-s images used for the co-added 1.83-m R-band image, as well as on S-Vilnius-band CCD frames taken by Garnavich and Pagnini on Dec. 5.534 with the same instrumentation. M81N 2010-12a is about 0.6 mag brighter in S-Vilnius-filtered images than are other field stars with the same R-band magnitude due to its H_alpha emission, which also suggest that it is nova. M81N 2010-12a is not present on numerous archive images from the 2.54-m Isaac Newton Telescope, the 4.2-m William Herschel Telescope, the 4-m Mayall telescope, and the 8.4-m Large Binocular Telescope (Prieto et al., 2008, Ap.J. 673, 59) down to limiting magnitudes as faint as Sloan r' = 23.0, R = 23.1, V = 23.5, and H-alpha = 22.1. M81N 2010-12a is located at R.A. = 9:55:48.63, Decl. = +69:03:11.6 (equinox 2000.0), which is 82".9 east and 43".5 south of the center of M81. Available magnitudes measured by Hornoch: 2010 June 11.164 UT, [22.9 (P. Garnavich, C. Littlefield, N. Paul, and S. Bouzid, 1.83-m Vatican Advanced Technology Telescope + R filter); Nov. 14.192, [22.3 (Hornoch, 0.65-m telescope at Ondrejov; unfiltered, using R-band magnitudes from comparison stars); Dec. 5.147, 20.9 ± 0.3 (Hornoch); 5.515, R = 21.3 ± 0.15 (Garnavich and Pagnini, 1.83-m Vatican Advanced Technology Telescope).