[IAUC] CBET 2358: 20100708 : APPARENT NOVA IN M31: M31N 2010-07a

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                                                  Electronic Telegram No. 2358
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
 Sciences; Harvard University; 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbat en iau.org; cbatiau en eps.harvard.edu
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APPARENT NOVA IN M31:  M31N 2010-07a
     Kamil Hornoch, Astronomical Institute, Ondrejov; and Petr Zasche,
Astronomical Institute, Charles University, Prague, report their discovery
of an apparent nova in the galaxy M31 on a co-added 2160-s R-band CCD frame
taken by Zasche on July 8.060 UT with the 0.65-m telescope at Ondrejov.  The
new object is well visible on single images used for the co-added frame and
faintly visible on a pre-discovery co-added R-band CCD frame taken by Hornoch
with the same instrumentation on July 7.036 UT, but it is not present on
numerous archive images taken at Lelekovice and Ondrejov.  M31N 2010-07a is
located at R.A. = 0h43m20s.13, Decl. = +41o21'23".7 (equinox 2000.0), which
is 403" east and 315" north of the center of M31.  Available R-band magnitudes
for M31N 2010-07a, as measured by Hornoch:  July 4.005 UT, [21.1 (K. Hornoch,
0.65-m telescope at Ondrejov); 4.956, [20.9 (Hornoch); 7.036, 20.2 +/- 0.3
(Hornoch); 8.060, 18.25 +/- 0.1 (P. Zasche, 0.65-m telescope at Ondrejov).

     M. Henze, Max-Planck-Institut fuer Extraterrestrische Physik, (MPE);
V. Burwitz, MPE and Observatorio Astronomico de Mallorca (OAM); W. Pietsch,
MPE; J. Rodriguez, OAM; and C. A. Haswell, S. Holmes, U. Kolb, and R. Lucas,
The Open University (TOU), confirm M31N 2010-07a after being notified by
Hornoch.  The new object is visible at a corresponding R magnitude of 18.4
on two stacks of five 120-s unfiltered CCD images obtained with the TOU/OAM
PIRATE 0.35-m f/11 Schmidt-Cassegrain telescope (+ SBIG STL-1001E CCD camera)
at Costitx, Mallorca, Spain, on July 8.02 and 8.07 UT, with position end
figures 20s.11, 23".7 (uncertainty 0".3), which is 403" east and 314" north
of the core of M31.  No object is visible at this position on a PIRATE image
from June 26.08 (limiting R magnitude 19.0).  M31N 2010-07a was already
active during an observation with the UltraViolet/Optical Telescope (UVOT)
onboard the Swift satellite one day before the optical discovery.  The 3815-s
UVW1-filter observation (range 181-321 nm) starting on July 7.07 UT shows
M31N 2010-07a at mag 20.6 +/- 0.3 at a position consistent with the
coordinates of the optical source; no source is visible at this position
in an earlier UVW1-filter observation starting on June 24.02 (limiting
magnitude 21.0).  The optical magnitudes were obtained from a photometric
solution using R magnitudes of the Local Group Survey M31 catalogue (Massey
et al. 2006, A.J. 131, 2478); the ultraviolet magnitudes are on the UVOT
photometric system (Poole et al. 2008, MNRAS 383, 627) and have not been
corrected for extinction.  The Swift team is thanked for scheduling the
Target-of-Opportunity observations.


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                         (C) Copyright 2010 CBAT
2010 July 8                      (CBET 2358)              Daniel W. E. Green