Electronic Telegram No. 3250 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network PROBABLE NOVA IN M33 = PNV J01325723+3024260 W. Zheng, University of Michigan; F. V. Ferrante, Southern Methodist University; R. Quimby, IPMU, University of Tokyo; J. Vinko, University of Szeged; G. H. Marion, Harvard-Smithsonian Center for Astrophysics; G. Dhungana and Bob Kehoe, Southern Methodist University; A. Romadan and C. Akerlof, University of Michigan; F. Yuan, Australian National University; and J. C. Wheeler and E. Chatzopoulos, University of Texas, on behalf of the ROTSE collaboration, report the discovery of an optical transient in the outskirts of M33 in unfiltered CCD images taken with the ROTSE-IIIb telescope at McDonald Observatory. The object is located at R.A. = 1h32m57s.28, Decl. = +30o24'27".3 (equinox 2000.0; uncertainty < 1"), which is 15'10" west and 11'32" south of the core of M33. Available approximate ROTSE magnitudes for the variable (calibrated relative to USNO-B1.0-catalogue magnitudes): Sept. 23 and earlier, [18; Oct. 3.17 UT, 17.1; 4.17, 16.6. A finding chart for the variable can be viewed at website URL http://tinyurl.com/9g8twg7. A spectrogram, obtained on Oct. 5.19 UT with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by J. Caldwell, shows a blue continuum with many narrow absorption lines, including H-alpha, H-beta, H-gamma, and O I features. These features appear blueshifted by about 400 km/s in the rest frame of M33. The spectrum is also contaminated by features at zero redshift, including Na I D at -78 km/s. Despite the lack of either emission lines or P-Cyg features, the spectrum may be consistent with that of a very young nova, shortly after outburst. The observed magnitude, corresponding to absolute mag about -8, is consistent with the expected brightness of a young nova. An independent discovery of the possible nova was reported by Koichi Nishiyama (Kurume, Japan) and Fujio Kabashima (Miyaki, Japan) on eight 40-s unfiltered CCD frames (limiting magnitude 19.1) taken around Oct. 6.661 UT using a Meade 200R 0.40-m f/9.8 reflector (+ SBIG STL1001E camera). They reported the object to be of mag 17.2 and located at R.A. = 1h32m57s.23, Decl. = +30d24'26".0 (equinox 2000.0), which is 693" west and 911" south of the center of the galaxy M33. They add that nothing is visible at this position on their frames taken on Oct. 2.535 (limiting magnitude 18.8), but that it was visible at mag 15.8 on a prediscovery frame taken on Oct. 4.583. Also, nothing is visible at that position Digitized Sky Survey plates taken on 1991 Oct. 5 (limiting red mag 19.5) and 1989 Dec. 4 (limiting infrared mag 19.5). The variable was designated PNV J01325723+3024260 when it was posted at the Central Bureau's TOCP webpage. D. Denisenko, V. Yurkov, E. Sinyakov, E. Gorbovskoy, and V. Lipunov (on behalf of the large MASTER team) report an auto-detection of the apparent nova in two unfiltered 60-s images taken with the MASTER-Amur telescopic system, reporting magnitudes 16.0 on Oct. 5.534 and 16.4 on Oct. 5.565, adding that nothing was visible in a red reference image taken on Jan. 6.436 (limiting mag 19.1); they measured position end figures 57s.28, 24".8. The MASTER-Amur images are posted at website URL http://master.sai.msu.ru/static/OT/013257.28302424.8.png. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 October 9 (CBET 3250) Daniel W. E. Green