Electronic Telegram No. 2015 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html POSSIBLE RECURRENT NOVA IN M31: M31N 2009-11b Koichi Nishiyama, Kurume, Fukuoka-ken, Japan; and Fujio Kabashima, Miyaki-cho, Saga-ken, Japan, report their discovery of an apparent nova (mag 18.4) on six 40-s unfiltered CCD frames (limiting magnitude 19.3) taken around Nov. 6.523 UT using a 0.40-m f/9.8 reflector; the position of the variable, designated M31N 2009-11b, was measured to be R.A. = 0h42m39s.58 +/- 0s.01, Decl. = +41o09'03".4 +/- 0".2 (equinox 2000.0), which is 53" west and 425" south of the center of the galaxy M31. Additional magnitudes measured for 2009-11b from Nishiyama, from their own frames unless noted "DSS" for Digitized Sky Survey (limiting magnitudes given parenthetically): 1986 Nov. 27, [18.7 (DSS, red); 1993 Oct. 21, [17.9 (DSS, infrared); Oct. 28.645, 29.537, and 30.768 UT, [19.0; Nov. 3.539, 19.0 (19.2); 4.470, 18.7 (19.2); 5.532, 18.6 (19.2); 7.572, 18.2 (19.2). Nishiyama notes that the position of 2009-11b is very near that of M31N 1997-11k (position end figures 39s.59, 04".0; cf. website URL http://www.mpe.mpg.de/~m31novae/opt/m31/M31_table.html), suggesting that 2009-11b may be a re-brightening of 1997-11k. K. Hornoch, Ondrejov Observatory, reports that he measured position end figures 39s.60, 02".9 and magnitude R = 18.6 +/- 0.1 from a co-added 450-s R-band CCD frame taken during software tests by P. Kubanek, J. Gorrosabel, and M. Jelinek with the 1.23-m telescope at Calar Alto on Oct. 31.132. M. Henze, W. Pietsch, P. Podigachoski, V. Burwitz, and F. Haberl, Max- Planck-Institut fuer Extraterrestrische Physik; A. Updike and D. Hartmann, Clemson University; P. Milne and G. Williams, University of Arizona; G. Papamastorakis and P. Reig, FORTH and Department of Physics, University of Crete; and A. Strigachev, Institute of Astronomy, Bulgarian Academy of Sciences, write that M31N 2009-11b is visible in twelve 60-s stacked R-band CCD images obtained with the robotic 60-cm telescope of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak) at position end figures 39s.61, 03".2 (uncertainty 0".2), providing the following magnitudes: Nov. 1.18 UT, 18.8; 2.18, 19.0; 3.33, 18.4; 6.25, 18.6; 8.25, 18.6; 9.25, 18.6. They note that the position of 2009-11b coincides with both M31N 1997-11k and M31N 2001-12b, which were already classified as a recurrent nova. However, the current outburst was already detected one month earlier in stacked H-alpha images obtained with the 1.3-m Ritchey Chretien f/7.5 telescope at Skinakas Observatory (Crete, Greece) using a broad (7.5-nm) H-alpha filter, yielding the following R magnitudes for 2009-11b: Sept. 27.10, [19.5; Oct. 2.10, faintly visible; 9.10, 18.7. M31N 2009-11b was also detected with the Swift Ultraviolet/ Optical Telescope UVW2 filter (range 112-264 nm), yielding the following ultraviolet magnitudes: June 7.95, 21.2 +/- 0.3; Oct. 22.61, 19.0 +/- 0.1; 28.29, 18.9 +/- 0.1; 31.24, 18.7 +/- 0.1; Nov. 3.58, 18.4 +/- 0.1. The ultraviolet outburst of the object is clearly connected to the optical outburst, but already detected about 10 days earlier. Due to the earlier start of the outburst in ultraviolet and H-alpha, compared to that in the R-band, and the short recurrence time (4.1 yr), Henze et al. suggest that the outburst could point towards a cataclysmic variable in the Milky Way (U Gem or SU UMa system), noting that similar events have been observed in the direction of M31 in the past and have initially been mistaken for novae (e.g., Sharov and Alksnis 1989, Sov. Astron. Let. 15, 382). A finding chart for 2009-11b from an R-band Super-LOTIS image is available at website URL http://www.mpe.mpg.de/~m31novae/opt/m31/data/finding_charts/nova_R_09_11_07.jpg. Additional details are given at http://www.astronomerstelegram.org/?read=2286. M. M. Kasliwal et al. (http://www.astronomerstelegram.org/?read=2290) report that observations obtained of 2009-11b with the Double Beam Spectrograph at the Palomar 5-m telescope on Nov. 8.35 UT yields a spectrum that shows prominent Balmer emission from H-alpha through H-delta; the emission peaks are blue-shifted by about 360 km/s, which is consistent with M31. The Gaussian FWHM of the H-alpha line is about 1280 km/s. Also, H-beta, H-gamma, and H-delta show P-Cyg profiles. This suggests that 2009-11b is a recurrent nova in M31. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 November 14 (CBET 2015) Daniel W. E. Green