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Spectroscopic Confirmation of Nova Candidates in M31

ATel #850; W. Pietsch (Max Planck Institut f. extraterr. Physik Garching MPE), V. Burwitz (MPE), J. Greiner (MPE), A. Rau (California Institute of Technology), G. Sala (MPE), R. Bender (MPE, Universitaets-Sternwarte Muenchen USM), J. Fliri (USM), A. Riffeser (MPE, USM), S. Seitz (USM), M. Alises (Centro Astronomico Hispano Aleman CAHA), A. Aguirre (CAHA), N. Cardiel (CAHA), F. Hoyo (CAHA)
on 3 Jul 2006; 11:59 UT
Credential Certification: Wolfgang Pietsch (wnp@mpe.mpg.de)

Subjects: Optical, Nova

We report on the spectroscopic confirmation of four recent optical nova candidates in M31 using the 2.2 m telescope and the Calar Alto Faint Object Spectrograph CAFOS at CAHA on Calar Alto, Spain. The spectra covered the range 400-850 nm (G-200), 490-780 nm (G-100) and 320-580 nm (B-100). The outburst of the apparent nova M31N 2006-06a (RA=00:43:11.81, dec=+41:13:44.7 (J2000)) occurred between May 12 and May 22, 2006 with an R band magnitude of 17.6 and white light magnitude of 18.0 at maximum (ATel #821, http://cfa-www.harvard.edu/iau/CBAT_M31.html , and ATel #844). Our spectrum obtained with the G-200 grism on June 27.12713, 2006 shows the object to be a Fe II nova with strong emission of H_alpha (FWHM about 1700 km/s), H_beta and H_gamma and the Fe II lines. The outburst of the apparent nova M31N 2005-09a (RA=00:42:52.30, dec=+41:19:58.3 (J2000)) occurred between Sep 12 and Sep 13, 2005 with a white light magnitude at maximum of 16.1 (see http://cfa-www.harvard.edu/iau/CBAT_M31.html ). Our spectrum obtained with the G-100 grism on Sep 19.08361, 2005 shows the object to be a Fe II nova with strong emission of H_alpha (FWHM about 2400 km/s) and H_beta and the Fe II lines. The outburst of the apparent nova M31N 2005-09b (RA=00:38:49.49, dec=+40:19:58.3 (J2000)) occurred between Aug 31 and Sep 1, 2005 with a white light magnitude at maximum of 16.5 (see ATel #600). An early spectrum identified the object as a young Fe II or hybrid nova (see http://cfa-www.harvard.edu/iau/CBAT_M31.html ). Our spectrum obtained with the G-100 grism on Sep 16.02629, 2005 shows strong emission of H_alpha (FWHM about 1900 km/s) and H_beta and the Fe II lines and weaker N II (568 nm) and possibly a blend of He I and Na I lines at 588 nm. The outburst of the apparent nova M31N 2005-06d (RA=00:45:05.20, dec=+41:33:39.8 (J2000)) occurred between Jun 8 and Jun 15, 2005 with a white light magnitude at maximum of 15.7 (see ATels #518 and #520). Our spectra obtained with the G-100 and B-100 grisms on Jun 16.12269 and Jun 16.14569, 2005 show the object to be a hybrid nova several days after outburst with strong broad emission of H_alpha (FWHM about 4000 km/s), H_beta, H_gamma and H_delta and Fe II and possibly weak He and N lines.