Circular No. 8308
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2003lw AND GRB 031203
     G. Tagliaferri, S. Covino, D. Fugazza, Istituto Nazionale di
Astrofisica (INAF), Brera; G. Chincarini, Milano-Bicocca University
and INAF, Brera; D. Malesani, Scuola Internazionale Superiore di
Studi Avanzati, Trieste; M. Della Valle, INAF, Arcetri; and L.
Stella, INAF, Rome, on behalf of a larger collaboration, report on
optical and near-infrared sub-arcsecond observations, made with the
European Southern Observatory's Very Large Telescope (VLT) at
Paranal and New Technology Telescope (+ SofI) at La Silla, of the
apparent host galaxy of GRB 031203
(http://gcn.gsfc.nasa.gov/gcn/gcn3/2459.gcn3; GCN 2475), made up to
3 months after the discovery of GRB 031203.  The object is located
at R.A. = 8h02m30s.2, Decl. = -39o51'03" (equinox 2000.0; GCN 2473,
2490).  Preliminary analysis of the R- and I-band photometric data
shows a variability fully consistent with the evolution of a
supernova, similar to that of SN 1998bw (Galama et al. 1998, Nature
395, 670) at z = 0.105 (GCN 2482), whose maximum occurred about 20
(observed) days after the gamma-ray outburst; R magnitudes (typical
relative errors 0.02 mag, plus 0.05-mag calibration uncertainty):
2003 Dec. 15.31 UT, 20.23; 17.28, 20.22; 23.3, 20.17; 28.3, 20.18;
30.24, 20.19; 2004 Jan. 16.19, 20.37; Feb. 20.10, 20.48.  This may
suggest that the gamma-ray burst and the supernova went off almost
simultaneously (+/- 4 days).  Three FORS1 and FORS2 VLT spectra
(range 380-750 nm; resolution about 0.5 nm); were taken on 2003
Dec. 20, 30, and 2004 Mar. 1.  After subtracting the contribution
of the host galaxy from the spectra obtained on Dec. 20.31 and
30.27 (1.5 hr each), broad bumps were detected at approximately 540
nm and 650 nm, similar to those observed in the spectrum of the
peculiar type-Ic supernova 1998bw near maximum light (Patat et al.
2001, Ap.J. 555, 900), leading to the conclusion that the observed
rebrightening is due to a supernova component, hereby designated as
SN 2003lw.


SUPERNOVAE 2004at AND 2004au
     Corrigendum.  Matheson et al. erroneously reported their
spectroscopic information concerning SN 2004au (cf. IAUC 8305)
under the heading "SN 2004at" (thus the erroneous labelling on
IAUC 8304).  They add that a spectrum of SN 2004at (cf. IAUC
8302), obtained by P. Berlind on Mar. 19.24 UT, shows it to be a
type-Ia supernova a few days before maximum; adopting the NED
recession velocity of 6935 km/s for the host galaxy, the supernova
expansion velocity is 12700 km/s for Si II (rest 635.5 nm).

                      (C) Copyright 2004 CBAT
2004 March 19                  (8308)            Daniel W. E. Green