Electronic Telegram No. 2411 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbat@iau.org; cbatiau@eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html APPARENT NOVAE IN M31 Kamil Hornoch, Astronomical Institute, Ondrejov; and Jesus M. Corral- Santana and Jorge Casares, Instituto de Astrofisica de Canarias and Universidad de La Laguna, report their discovery of a probable nova in the galaxy M31 on co-added 720-s narrow-band H_alpha and 360-s Sloan r' CCD frames taken by Corral-Santana and Casares with the 2.54-m Isaac Newton Telescope (+ WFC) at La Palma on July 10.210 and 10.200 UT, respectively. The new object, designated M31N 2010-07b, is visible on single images used for the co-added frame and is faintly visible also on many pre-discovery co-added frames taken during June, but it is not present on numerous archival images taken at Ondrejov and other observatories. M31N 2010-07b is located at R.A. = 0h43m07s.50, Decl. = +41o17'58".6 (equinox 2000.0), which is 261" east and 110" north of the center of M31. Available R-band magnitudes for M31N 2010-07b, measured by Hornoch: 2005 June 11.211 UT, [22.0 (D. Mackey, 2.54-m Isaac Newton Telescope + narrow-band H_alpha filter); Oct. 8.369, [22.9 (P. Garnavich and C. Kennedy, 1.83-m Vatican Advanced Technology Telescope + R filter); 2010 Jan. 31.784, [21.9 (P. Kubanek, N. Morales, J. L. Ortiz, J. Gorosabel, and M. Jelinek, 1.23-m telescope at Calar Alto + R filter); June 4.135, R = 20.7 +/- 0.2 (Morales, Ortiz, Gorosabel, Kubanek, and Jelinek, 1.23-m telescope at Calar Alto); 9.459, R = 20.9 +/- 0.3 (Garnavich, C. Littlefield, N. Paul, and S. Bouzid, 1.83-m Vatican Advanced Technology Telescope); 17.152, R = 20.8 +/- 0.2 (Kubanek, Gorosabel, O. Lara Gil, and Jelinek, 1.23-m telescope at Calar Alto); July 10.200, Sloan r' = 20.9 +/- 0.2 (Corral-Santana and Casares, 2.54-m Isaac Newton Telescope); 10.210, [H_alpha] = 18.8 +/- 0.15 (Corral-Santana and Casares); 11.210, Sloan r' = 20.9 +/- 0.2 (Corral-Santana and Casares); 19.186, Sloan r' = 20.8 +/- 0.2 (D. Pinfield, B. Sipocz, and G. Kovacs, 2.54-m Isaac Newton Telescope); 19.191, [H_alpha] = 18.7 +/- 0.15 (Pinfield, Sipocz, and Kovacs); 20.069, [H_alpha] = 18.8 +/- 0.15 (Gorosabel, Lara Gil, Jelinek, Kubanek, and P. Martorell, 1.23-m telescope at Calar Alto). When comparing measurements in Sloan r' and H_alpha, they notice strong excess in H_alpha emission, suggesting that the object is a nova well after the outburst. Hornoch also reports additional R-band photometry of recent M31 novae as measured by himself from images taken with the 0.65-m telescope at Ondrejov. Magnitudes for M31N 2010-05a (cf. CBETs 2305, 2319, 2341, and 2391): July 9.035 UT, 18.6 +/- 0.15 (Hornoch and M. Wolf); 26.985, 19.2 +/- 0.2 (Hornoch); 28.051, 19.2 +/- 0.2 (Hornoch and Wolf). R-band magnitudes for M31N 2010-06a (cf. CBETs 2341 and 2391): July 19.041 UT, 18.0 +/- 0.1 (Hornoch and P. Kusnirak); 20.070, 18.0 +/- 0.1 (Hornoch); 21.066, 18.0 +/- 0.1 (Kusnirak); 22.012, 17.8 +/- 0.1 (Hornoch and P. Zasche); 26.950, 18.5 +/- 0.1 (Hornoch); 28.015, 18.3 +/- 0.1 (Hornoch and Wolf); 28.051, 18.2 +/- 0.15 (Hornoch and Wolf); 29.044, 18.1 +/- 0.1 (Hornoch, Hornochova, and Zasche); Aug. 1.089, 18.5 +/- 0.1 (Kusnirak). R-band magnitudes for M31N 2010-06b (cf. CBETs 2342 and 2391): July 19.041 UT, 19.0 +/- 0.15 (Hornoch and Kusnirak); 20.070, 18.7 +/- 0.1 (Hornoch); 21.066, 18.6 +/- 0.1 (Kusnirak); 22.012, 18.7 +/- 0.1 (Hornoch and Zasche); 26.950, 19.4 +/- 0.15 (Hornoch); 28.015, 19.4 +/- 0.15 (Hornoch and Wolf); 29.044, 19.6 +/- 0.15 (Hornoch, Hornochova, and Zasche); Aug. 1.089, 19.8 +/- 0.2 (Kusnirak). R-band magnitudes for M31N 2010-06c (cf. CBETs 2343 and 2391): July 9.011 UT, 18.5 +/- 0.1 (Hornoch and Wolf); 14.050, 18.9 +/- 0.15 (Hornoch, Wolf, and P. Hornochova); 15.010, 18.9 +/- 0.1 (Hornoch and Wolf); 17.062, 19.1 +/- 0.15 (Hornoch and Hornochova); 19.041, 19.3 +/- 0.15 (Hornoch and Kusnirak); 20.070, 19.3 +/- 0.1 (Hornoch); 21.066, 19.2 +/- 0.15 (Kusnirak); 22.012, 19.3 +/- 0.15 (Hornoch and Zasche); 26.950, 19.6 +/- 0.2 (Hornoch); 28.015, 20.0 +/- 0.2 (Hornoch and Wolf); 29.044, 19.9 +/- 0.1 (Hornoch, Hornochova, and Zasche); Aug. 1.089, 20.2 +/- 0.2 (Kusnirak). R-band magnitudes for M31N 2010-06d (cf. CBETs 2347 and 2391): July 9.011 UT, 19.4 +/- 0.15 (Hornoch and Wolf); 9.035, 19.3 +/- 0.15 (Hornoch and Wolf); 14.050, 19.3 +/- 0.25 (Hornoch, Wolf, and Hornochova); 15.010, 19.2 +/- 0.15 (Hornoch and Wolf); 17.062, 19.6 +/- 0.2 (Hornoch and Hornochova); 19.041, 19.7 +/- 0.25 (Hornoch and Kusnirak); 20.070, 18.2 +/- 0.1 (Hornoch); 21.066, 17.7 +/- 0.1 (Kusnirak); 22.012, 17.7 +/- 0.1 (Hornoch and Zasche); 26.950, 19.0 +/- 0.15 (Hornoch); 28.015, 19.5 +/- 0.2 (Hornoch and Wolf); 28.051, 19.5 +/- 0.15 (Hornoch and Wolf); 29.044, 19.5 +/- 0.15 (Hornoch, Hornochova, and Zasche); Aug. 1.089, 19.5 +/- 0.15 (Kusnirak). R-band magnitudes for M31N 2010-07a (cf. CBETs 2358 and 2391): July 19.041 UT, 17.2 +/- 0.1 (Hornoch and Kusnirak); 20.070, 17.11 +/- 0.05 (Hornoch); 21.066, 17.1 +/- 0.1 (Kusnirak); 22.012, 17.1 +/- 0.1 (Hornoch and Zasche); 26.950, 16.9 +/- 0.1 (Hornoch); 28.015, 16.69 +/- 0.07 (Hornoch and Wolf); 28.051, 16.62 +/- 0.08 (Hornoch and Wolf); 29.044, 16.13 +/- 0.06 (Hornoch, Hornochova, and Zasche); Aug. 1.089, 16.53 +/- 0.10 (Kusnirak). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 August 13 (CBET 2411) Daniel W. E. Green