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Circular No. 8442
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)
SUPERNOVA 2004gc IN ARP 327
Independent discovery reports have been received of an
apparent supernova in Arp 327 by A. del Olmo, A. Martinez, S.
Pedraz, and M. Alises at Calar Alto (2.2-m telescope + CAFOS focal
reducer; B, V, R, and I images) on Nov. 18.106 and 19.014 UT and
by O. Trondal and M. Schwartz (cf. IAUC 8419; Tenagra II 0.81-m
telescope, unfiltered CCD images) on Nov. 18.4 and 19.2 (at mag
about 17.4). Schwartz provides the following position for the
new object: R.A. = 5h21m49s.95, Decl. = +6o40'33".7, which is 2".0
east and 3".1 south of the galaxy's nucleus. Nothing is visible at
this location on a Tenagra II image taken on 2002 Oct. 26.4
(limiting mag about 19.5).
SUPERNOVA 1999bw IN NGC 3198
B. Sugerman and M. Meixner, Space Telescope Science Institute;
and J. Fabbri and M. Barlow, University College, London, report the
detection of the type-IIn supernova 1999bw in archival Spitzer IRAC
images of NGC 3198 obtained by the SINGS Legacy program on 2004 May
1.4 UT. A source was detected in all four IRAC bands at R.A. =
10h19m46s.80, Decl. = +45o31'35".4 (equinox 2000.0; +/- 0".3 in
each coordinate), in close agreement with the optical position
(IAUC 7149). The measured flux densities (mJy) at 3.6, 4.5, 5.8,
and 8.0 microns are 0.02 +/- 0.01, 0.04 +/- 0.01, 0.11 +/- 0.02,
and 0.19 +/- 0.04, respectively. This rise is fitted by a 450-K
blackbody with integrated flux 3.1 x 10**-13 erg cm**-2 s**-1,
which, for a distance to NGC 3198 of 14.5 Mpc (Kelson et al. 1999,
Ap.J. 514, 614), corresponds to a luminosity of 6.2 x 10**38 ergs
s**-1 and a blackbody radius of 1.6 x 10**16 cm. This size is
consistent with ejecta expanding at 1000 km/s in the five years
since core collapse, suggesting the reported emission may be from
dust that condensed within the ejecta. A convolved companion
source is also detected, separated by 3".9 at p.a. 209 deg, with
3.6-, 4.5-, 5.8-, and 8.0-micron fluxes of 0.08 +/- 0.01, 0.07
+/- 0.01, 0.33 +/- 0.04, and 0.88 +/- 0.08 mJy, respectively.
SUPERNOVA 2004et IN NGC 6946
Visual magnitude estimates: Sept. 29.774 UT, 12.8 (K. Hornoch,
Lelekovice, Czech Republic); Oct. 3.86, 12.9 (J. Carvajal, Madrid,
Spain); 11.908, 12.8 (Hornoch); 15.483, 12.4 (S. Yoshida, Gunma,
Japan); Nov. 9.490, 12.7 (Yoshida).
(C) Copyright 2004 CBAT
2004 November 20 (8442) Daniel W. E. Green
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