2010CBET.2391....1H

Kamil Hornoch, Astronomical Institute, Ondrejov; and Jesus M. Corral- Santana and Jorge Casares, Instituto de Astrofisica de Canarias and Universidad de La Laguna, report Sloan r' and narrow-band H_alpha photometry of recently discovered transients in M31 designated M31N 2010-06a, M31N 2010-06b, M31N 2010-06c, M31N 2010-06d, and M31N 2010-07a. Sloan r' and narrow-band H_alpha CCD frames were taken by Corral-Santana with the 2.54-m Isaac Newton Telescope (+ WFC) at La Palma on July 10.200, 10.210, and 11.210 UT. When comparing measurements in Sloan r' and H_alpha, they notice strong excess in H_alpha emission, suggesting that these objects are novae. The only exception is M31N 2010-07a, but the measurements for this object are fully consistent with a young nova having still weak H_alpha emission. Sloan r' and [H_alpha] magnitudes measured by Hornoch for M31N 2010-06a (cf. CBET 2341): July 10.200 UT, r' = 17.86 ± 0.05; 10.210, [H_alpha] = 16.25 ± 0.07; 11.210, r' = 18.05 ± 0.05. Magnitudes for M31N 2010-06b (cf. CBET 2342): July 10.200, r' = 19.48 ± 0.08; 10.210, [H_alpha] = 17.7 ± 0.1; 11.210, r' = 19.54 ± 0.06. Magnitudes for M31N 2010-06c (cf. CBET 2343): July 10.200, r' = 18.89 ± 0.06; 10.210, [H_alpha] = 16.63 ± 0.07; 11.210, r' = 18.95 ± 0.04. Magnitudes for M31N 2010-06d (cf. CBET 2347): July 10.200, r' = 19.31 ± 0.07; 10.210, [H_alpha] = 18.1 ± 0.1; 11.210, r' = 19.24 ± 0.06. Magnitudes for M31N 2010-07a (cf. CBET 2358): July 10.200, r' = 17.31 ± 0.05; 10.210, [H_alpha] = 17.34 ± 0.08; 11.210, r' = 17.91 ± 0.04.