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IAUC 8446: 2004gk, 2004gl; 2004ex

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                                                  Circular No. 8446
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)

SUPERNOVAE 2004gk AND 2004gl
     R. Quimby, C. Gerardy, P. Hoeflich, and J. C. Wheeler,
University of Texas, report the discovery, in unfiltered CCD images
taken on Nov. 25.5 and 26.5 UT with the McDonald Observatory 0.45-m
ROTSE-IIIb telescope (software via the Supernova Cosmology Project
and the 'Nearby Supernova Factory'), of a supernova (mag about 13.3),
designated 2004gk, located at R.A. = 12h25m33s.21, Decl. =
+12o15'39".9 (equinox 2000.0), which is 1".5 east (not west, as on
CBET 99) and 2".7 north of the center of IC 3311.  ROTSE-IIIb
images from June 12.17 (limiting mag about 17.9) showed nothing at
this position.  Gerardy et al. add that an optical spectrogram
(500-1000 nm), obtained on Nov. 27.52 with the 9.2-m Hobby/Eberly
telescope (+ Marcario Low-Resolution Spectrograph) by M. Shetrone
and V. Riley, suggests that the supernova is of type Ic; the
spectrum roughly resembles that of SN 1994I near maximum light
(e.g., Clocchiatti et al. 1996, Ap.J. 462, 462).  Additional
unfiltered CCD magnitudes:  Nov. 27.46, 13.6 (J. McGaha, Tucson, AZ;
position end figures 33s.25, 40".4; object not visible on Palomar
Sky Survey photographs); 27.744, 13.7 (K. Kadota, Ageo, Japan,
0.25-cm f/7.0 reflector; communicated via S. Nakano; position end
figures 33s.23, 40".1).
     Further to IAUC 8444, T. Boles reports the discovery, on
unfiltered CCD images taken on Nov. 21.110 and 25.959 UT, of an
apparent supernova (mag 18.4), designated 2004gl, located at R.A. =
8h50m04s.89, Decl. = +49o14'43".8, which is approximately 0".4 west
and 6".5 south of the center of MCG +08-16-31.  SN 2004gl is not
present on Boles' images from 2003 Apr. 25 and Mar. 18 (limiting
mag 19.5) or on Digitized Sky Survey plates (1991 Feb. 12, limiting
red mag 21.0; 1997 Feb. 4, limiting blue mag 20.5).

     A. Harutyunyan, M. Turatto, S. Benetti, G. Blanc, H.
Navasardyan, and L. Zampieri, Osservatorio Astronomico di Padova;
and A. Pastorello, Max Planck Institut, report that inspection of a
spectrogram of SN 2004ex (cf. IAUCs 8418, 8420), obtained on Nov.
16.97 UT with the Asiago 1.8-m telescope (+ AFOSC; range 355-780 nm,
resolution 2.4 nm), shows prominent 587.6-, 667.8-, and 706.5-nm He
I lines and relatively faint H_alpha, all with P-Cyg profiles.  The
spectrum closely resembles that of SN 1993J at 41 days after
explosion (Barbon et al. 1995, A.Ap. Suppl. 110, 513), however,
with a much fainter H_alpha emission.  The expansion velocity,
deduced from the H_alpha-emission minimum, is still very high
(about 10600 km/s).  This therefore redefines the spectroscopic
classification of SN 2004ex as type IIb.

                      (C) Copyright 2004 CBAT
2004 November 27               (8446)            Daniel W. E. Green

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