[IAUC] CBET 2015: 20091114 : POSSIBLE RECURRENT NOVA IN M31: M31N 2009-11b

Sab Nov 14 17:19:34 ART 2009

                                                  Electronic Telegram No. 2015
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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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.


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                         (C) Copyright 2009 CBAT
2009 November 14                 (CBET 2015)              Daniel W. E. Green