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IAUC 7618: Poss. SN IN NGC 3079; 2001ad; 2001ax

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IAUC number

                                                  Circular No. 7618
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)

     B. Swift, W. D. Li, and A. V. Filippenko, University of
California at Berkeley, report the discovery by LOTOSS (cf. IAUC
7514) of an apparent supernova in unfiltered images taken with the
Katzman Automatic Imaging Telescope (KAIT):  "The new object is
located at R.A. = 10h01m57s.33, Decl. = +55o41'14".6 (equinox
2000.0), which is 6".3 west and 25".4 north of the well-known
starburst galaxy NGC 3079.  Available photometry for the new object
(measured after subtracting a template image observed on 1998 Nov.
21 UT):  2001 Apr. 17.2 UT, > 19.0; 25.2, 18.3; 26.2, 18.4; May
1.2, 18.1; 2.2, 17.7 (under bad conditions).  Adopting a distance
modulus of 30.75 for NGC 3079 from LEDA (http://cisr.univ-lyon1.fr/
~leda/), the absolute magnitude of the new star is only about
-12.7, similar to the type-IIn SN 1997bs (Van Dyk et al. 2000, PASP
112, 1532); this may be a superoutburst of a luminous blue variable
rather than a genuine supernova.  Other explanations for the
apparent faintness of this new star is that it is intrinsically
faint, or suffers from huge amount of extinction in the very dusty
host galaxy, or both.  A finding chart can be found at

SUPERNOVA 2001ad IN NGC 6373
     R. Chornock, M. Modjaz, and A. V. Filippenko, University of
California at Berkeley, report that inspection of a CCD spectrum
(range 330-780 nm), obtained on Apr. 30 UT with the Shane 3-m
reflector at Lick Observatory, reveals that SN 2001ad (cf. IAUC
7596, 7597) is actually an unusual 'type-IIb' supernova like SN
1987K (Filippenko 1988, A.J. 96, 1941) and SN 1993J (Filippenko et
al. 1993, Ap.J. 415, L103):  lines of He I with P-Cyg profiles are
now prominent.

     P. Nugent and L. Wang, Lawrence Berkeley National Laboratory,
report:  "A spectrum (range 400-800 nm) obtained on Apr. 29.43 UT
at the Kitt Peak 2.1-m telescope (+ GCAM) shows that SN 2001ax (cf.
IAUC 7608) is a type-II supernova more than a month after peak
brightness.  The redshift of the supernova is about 6000 km/s.  The
supernova shows a broad H-alpha emission feature, a strong Ca II
infrared-triplet P-Cyg profile, and Fe II absorption lines."

                      (C) Copyright 2001 CBAT
2001 May 4                     (7618)            Daniel W. E. Green

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