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IAUC 5850: 1993X; RX J1940.2-1025

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                                                  Circular No. 5850
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


SUPERNOVA 1993X IN NGC 2276
     R. R. Treffers, A. V. Filippenko, B. Leibundgut, Y. Paik, and
L. F. M. Lee, University of California at Berkeley; and M. W.
Richmond, Princeton University, report their discovery of an
apparent supernova in NGC 2276 (R.A. = 7h10m31s, Decl. = +85o50'.9,
equinox 1950.0), located about 30" east and 69" north of the galaxy's
nucleus.  The object was found during the Leuschner Observatory
Supernova Search, which uses an automated 0.76-m telescope
equipped with the Lawrence Berkeley Laboratory CCD camera.  It was
visible at mag R = 16.3 +/- 0.4 on Aug. 22 UT, with confirmation at
about the same brightness on Aug. 23 and 25.  It could not be
detected to limiting mag R = 17.5-18.0 in images obtained on Mar. 6,
Apr. 2, May 1, and 8.


RX J1940.2-1025
     S. Rosen, C. Done, and M. Watson, University of Leicester; and
G. Madejski, Goddard Space Flight Center, report:  "We have an
optical identification for an x-ray source close to the Seyfert
galaxy NGC 6814.  This source is now believed to be the origin of the
periodic signals previously associated with the galaxy (Done et al.
1992, Ap.J. 400, 138).  The x-ray source (RX J1940.2-1025), discovered
in a recent ROSAT PSPC observation, has an average PSPC count
rate of 1.4 counts/s.  It lies about 37' from NGC 6814, but close
enough to be in the field-of-view of non-imaging x-ray detectors,
and the x-ray data clearly show the 3.4-hr period previously
associated with NGC 6814.  The ROSAT PSPC spectrum is consistent with
it being an AM Her-type star (although other interpretations are
possible).  Using the ROSAT PSPC position, the x-ray object was
identified on Aug. 18 using the Anglo-Australian Telescope (+ RGO
spectrograph).  The counterpart is an emission-line object of mag
16-17 showing strong Balmer and He II 468.6-nm emission lines.  The
width of the lines (FWZI up to 3000 km/s), and the large He II
468.6-nm/H-beta line ratio strongly support the AM Her classification
of this object.  The position of the object determined by
astrometry of the POSS plates is R.A. = 19h40m11s.38, Decl. =
-10o25'24".5 (equinox 2000.0; estimated error 1").  The optical
light curve of this object reconstructed from the time-resolved
spectroscopy shows a strong and complex modulation."


1993 August 27                 (5850)            Daniel W. E. Green

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