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IAUC 7665: 2001cy; V1494 Aql; BL Lac

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                                                  Circular No. 7665
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

SUPERNOVA 2001cy IN UGC 11927
     R. Chornock, M. Modjaz, and A. V. Filippenko, University of
California, Berkeley, write:  "Inspection of CCD spectra (range
330-1000 nm) taken on July 16 with the Shane 3-m reflector at Lick
Observatory shows that SN 2001cy (IAUC 7655) is a type-II supernova
soon after maximum light.  The spectrum exhibits well-developed H
Balmer and Fe II lines.  The H-alpha profile is unusual, with two
absorption minima in addition to a broad emission component,
similar to the peculiar SN 1999gk (IAUC 7332)."

     M. Bos, Auckland, New Zealand; A. Retter, Keele University; L.
Cook, Concord, CA; and R. Novak, Copernicus Observatory, Brno,
report:  "Unfiltered and R-band CCD photometry of V1494 Aql (N Aql
1999 No. 2) obtained on 12 nights during June-July shows a robust
change in the shape and amplitude of the 0.13467-d period (IAUC
7537).  It now has an eclipse shape with depth about 0.5 mag (10
times larger than in mid-2000).  A second shallow eclipse (about
0.1 mag deep) at phase 0.5 can also be seen.  The light curve may
be explained by a two-component model.  The non-eclipsing source,
presumably the white dwarf, has faded significantly, while the
luminosity of the eclipsing component (probably the accretion disk,
obscured by the companion) nearly stayed constant during the
observations.  This interpretation indicates a partial obscuration
of the disk, and it is thus predicted that the eclipse depth will
not exceed 0.75 mag (50 percent) with a further fading of the nova."

     J. A. Mattei, AAVSO, reports that this blazar prototype, which
brightens almost every year, has brightened again.  Observations in
the AAVSO International Database indicate that the most recent
brightenings have been in July 1997, May 1998, Oct. 1999, and Oct.
2000.  The rise to maximum may take several months, and maximum (at
average visual mag 13.7 and showing fluctuations) may last 2-3
months.  At minimum, BL Lac is between visual mag 15.0 and 16.0.
Recent AAVSO magnitudes:  Apr. 21.13 UT, 14.7 (G. Poyner, West
Midlands, England); May 30.03, 14.9 (Poyner); June 8.33, 13.7 (M.
Simonsen, Macomb, MI); 15.95, 13.8 (P. Dubovsky, Podbiel, Slovakia);
29.32, 13.8 (Simonsen); July 5.02, 14.4 (Poyner); 9.28, 13.3
(Simonsen); 10.92, 13.0 (Dubovsky); 12.35, 13.4 (Simonsen); 14.97,
13.9 (Dubovsky); 15.34, 13.9 (Simonsen).

                      (C) Copyright 2001 CBAT
2001 July 17                   (7665)            Daniel W. E. Green

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