Central Bureau for Astronomical Telegrams
IAUC 7987: 2002ge; 2002gd
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Circular No. 7987
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 2002ge IN NGC 7400
R. Chassagne, Ste. Clotilde, Ile de Reunion, reports the
discovery of an apparent supernova (mag 14.1) on an unfiltered CCD
frame taken with a 0.30-m automated telescope on Oct. 7.90 UT. The
new object is located at R.A. = 22h54m21s.49, Decl. = -45o20'26".9
(equinox 2000.0), which is 4".0 east and 22".6 north of the center
of NGC 7400. SN 2002ge was also present on unfiltered CCD frames
taken on Oct. 8.63, but it does not appear on unfiltered images
taken by Chassagne on 2000 Oct. 1.82 (limiting mag about 18) or on
a U.K. Schmidt plate taken on 1976 Sept. 27 (limiting mag 21.0).
SUPERNOVA 2002gd IN NGC 7537
M. Hamuy, Carnegie Observatories, reports that a spectrum
(range 380-920 nm) of SN 2002gd (cf. IAUC 7986), obtained on Oct.
8.26 UT with the Las Campanas Dupont 2.5-m telescope (+ WFCCD),
shows it to be a type-II supernova with weak H-alpha, H-beta, and
He I 587.6-nm lines exhibiting P-Cyg profiles. The weakness of
these lines and the blue continuum suggest a young supernova. The
absorption components yield a low expansion velocity of 5300 km/s,
based on a redshift of 2560 km/s derived from the narrow Balmer
emission lines of the host galaxy.
S. Benetti, G. Altavilla, A. Pastorello, M. Riello, M.
Turatto, and L. Zampieri, Osservatorio Astronomico di Padova; E.
Cappellaro, Osservatorio Astronomico di Capodimonte; and L.
Germany, European Southern Observatory (ESO), on behalf of the
European Research and Training Network on the Physics of Type-Ia
Supernovae, report that a fully reduced CCD spectrum (range
333-1000 nm, resolution 1.2 nm) of SN 2002gd, obtained on Oct. 8.02
UT with the ESO 3.6-m telescope (+ EFOSC2), shows it to be a
type-II supernova caught soon after explosion. The spectrum is
dominated by a very blue continuum (T_bb about 13000 K) with
overimposed hydrogen Balmer and He I 587.6-nm lines showing P-Cyg
profiles. From the minima of the lines, an ejecta expansion
velocity of about 5000 km/s is derived. The low velocity and the
low intrinsic luminosity at such early phases are reminiscent of
the peculiar, low-luminosity type-II supernovae (Zampieri et al.
2002, MNRAS, in press).
A. V. Filippenko and R. Chornock, University of California,
Berkeley, also write that CCD spectra (range 310-930 nm) obtained
on Oct. 8 UT with the Keck-I 10-m telescope (+ Low Resolution
Imaging Spectrometer) reveal that SN 2002gd is a young type-II
supernova; low-contrast hydrogen Balmer lines with P-Cyg profiles
are present on a very blue continuum.
(C) Copyright 2002 CBAT
2002 October 8 (7987) Daniel W. E. Green
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