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IAUC 6871: 1998an; CI Cam; IRAS 18325-5926

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                                                 Circular No. 6871
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 1998an IN UGC 3683
     Ron Arbour, South Wonston, Hants, England, reports his
discovery of an apparent supernova (mag about 15.3) on an
unfiltered CCD image obtained with a 0.30-m f/4.5 reflector on Apr.
6.871 UT.  The new star is located at R.A. = 7h08m17s.04, Decl. =
+46o06'55".3 (equinox 2000.0), which is about 32" east and 3" south
of the center of UGC 3683.  T. Boles, Wellingborough, confirmed the
star on two exposures taken at about the same time, and Arbour
obtained a total of twelve images on the discovery night and
another image on the following night.  The object was not visible
during Arbour's previous observation of the same galaxy on Mar. 30,
nor does it appear on the Digitized Sky Survey.

     R. I. Hynes, P. Roche, and C. A. Haswell, University of
Sussex; J. Telting, Isaac Newton Group; and M. Lehnert and Y. Simis,
University of Leiden, report:  "UBVRI photometry of CI Cam was
obtained with the Jacobus Kapteyn Telescope at La Palma on Apr.
3.87 UT.  We find U = 10.3, B = 10.7, V = 9.7, R = 8.6, I = 7.9,
with errors of about 0.1 mag.  The source had therefore faded by
0.5 mag in B and V since the observation 18 hr earlier of Garcia et
al. (IAUC 6865).  Our colors are very similar to those of Bergner
et al. (1995, A.Ap. Suppl. 112, 221), indicating that the outburst
optical spectral energy distribution is the same as that in
quiescence, but brighter.  Assuming visual extinction of 1.5 mag
(Chkhikvadze 1970, Astrofizika 6, 65), the intrisic flux
distribution is approximately a power-law, with a power-law index
of -1.2."

IRAS 18325-5926
     A. C. Fabian, J. C. Lee, and K. Iwasawa, Institute of
Astronomy, Cambridge; K. Jahoda, Goddard Space Flight Center; W. N.
Brandt, Pennsylvania State University; and C. S. Reynolds, JILA,
University of Colorado, report: "The 11-hr periodicity found in the
power spectrum of the RXTE x-ray lightcurve of the active galaxy
IRAS 18325-5926 (IAUC 6835) is an artifact produced by the standard
background-modeling software.  There are therefore no indications
of an imminent blackhole merger.  The evidence for a 16-hr
periodicity of the source in Mar. 1997 (Iwasawa et al. 1998, MNRAS
295, L20) is unaffected, since it was taken with the imaging x-ray
satellite ASCA."

                      (C) Copyright 1998 CBAT
1998 April 8                   (6871)            Daniel W. E. Green

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