Central Bureau for Astronomical Telegrams
IAUC 8228: 2003ir, 2003it, 2003iu, 2003iv,, 2003iw; 2003id
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Circular No. 8228
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)
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URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)
SUPERNOVAE 2003ir, 2003it, 2003iu, 2003iv, AND 2003iw
T. Matheson, P. Challis, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics, report on spectra (range 370-750 nm) of
several recently discovered supernovae, with all the spectrograms
obtained by M. Calkins at the Mt. Hopkins 1.5-m telescope (+ FAST).
The following type-Ia supernovae are listed with the time the
spectrogram was obtained, the supernova spectral-feature age (given
in days prior to maximum light), and their expansion velocities for
Si II (rest 635.5 nm), with the adopted NASA/IPAC Extragalactic
Database (NED) recession velocity for the host galaxies given
parenthetically: SN 2003it (cf. IAUC 8225), Oct. 19.18 UT, 4 +/-
2, 11900 km/s (7531 km/s); SN 2003iu (cf. IAUC 8226), Oct. 20.38, 0
+/- 2, 10400 (12320); SN 2003iv (cf. IAUC 8226), Oct. 19.38, 2 +/-
2, 11100 (10285). A spectrogram of SN 2003ir (cf. IAUC 8221),
obtained on Oct. 20.50, shows it to be a type-II supernova;
adopting the NED recession velocity of 7657 km/s for the host
galaxy, the expansion velocity derived from the minimum of the
H_beta line is 5700 km/s. A spectrogram of SN 2003iw (cf. IAUC
8226), obtained on Oct. 20.14, shows a blue, almost featureless
continuum; there is a weak feature that may be an incipient P-Cyg
line of H_alpha, implying that this is an early type-II supernova.
SUPERNOVA 2003id IN NGC 895
M. Hamuy and M. Roth, Carnegie Observatories, report that a
spectrogram (range 380-930 nm) of SN 2003id (cf. IAUC 8201, 8203),
obtained on Oct. 16.27 UT with the Dupont 2.5-m telescope (+ WFCCD)
at Las Campanas, reveals unusual features. While the spectrum is
characterized by strong absorptions between 466 and 536 nm
(presumably due to Fe II blends) that are seen in other type-Ic
events, a strong unidentified absorption centered at 562 nm
distinguishes it from other type-Ic or type-Ib supernovae. This
feature is blended with another strong absorption centered at 579
nm. The spectrum shows a strong Ca II triplet line exhibiting a
broad P-Cyg profile; adopting the NED host-galaxy recession
velocity of 2288 km/s, the minimum of the Ca II triplet at 826 nm
implies an expansion velocity of -13000 km/s, which is very high
for a supernova that is at least one month old. The optical
lightcurves are also unusual: the V-band flux decreased by about
0.25 mag between Sept. 19 and 25; a plateau phase (V = 17.25)
ensued through Oct. 3; and the flux has been dropping afterwards,
reaching V = 18.6 on Oct. 16. Further observations at optical and
other wavelengths would be useful.
(C) Copyright 2003 CBAT
2003 October 20 (8228) Daniel W. E. Green
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