Central Bureau for Astronomical Telegrams
IAUC 8203: 2003gx and 2003hy; 2003ib, 2003ic, 2003id
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Circular No. 8203
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)
SUPERNOVAE 2003gx and 2003hy
T. Matheson, P. Challis, and R. Kirshner, Center for
Astrophysics, report that a spectrum (range 370-750 nm) of SN
2003gx (cf. IAUC 8178), obtained by M. Calkins on Sept. 18.42 UT
with the Mt. Hopkins 1.5-m telescope (+ FAST), shows it to be a
type-II supernova. Adopting the NASA/IPAC Extragalactic Database
(NED) recession velocity of 10203 km/s for the host galaxy, the
expansion velocity derived from the minimum of the H_beta line is
6300 km/s. A spectrum of SN 2003hy (cf. IAUC 8200), obtained by
Calkins on Sept. 18.28, shows an object with a blue continuum and
narrow (FWHM approximately 300 km/s) P-Cyg lines of hydrogen.
Adopting the NED recession velocity of 7355 km/s for the host
galaxy, the expansion velocity derived from the minimum of the
H_beta line is only 1000 km/s. The broader component of the Balmer
lines often seen in type-IIn supernovae is not readily apparent.
The spectrum of SN 2003hy is similar to the spectra of the type-IIn
supernovae 1997bs (Van Dyk et al. 2000, PASP 112, 1532) and 2001ac
(IAUC 7597). SN 2003hy may be a super-outburst of a luminous blue
variable (LBV) rather than a true supernova, but the reported
magnitude at discovery is brighter than that of a typical LBV
outburst.
SUPERNOVAE 2003ib, 2003ic, 2003id
N. Morrell and M. Hamuy, Carnegie Observatories, report that a
spectrum (range 400-730 nm) of SN 2003ib (cf. IAUC 8201), obtained
on Sept. 18.17 UT with the Las Campanas Dupont 2.5-m telescope (+
Modular Spectrograph), shows it to be a young type-II supernova
characterized by a blue continuum and H_alpha, H_beta, and He I
5876 lines exhibiting P-Cyg profiles. A redshift of approximately
0.024 +/- 0.001 is derived, based on the maximum of the H_alpha
emission; assuming this redshift, the minimum of the H_beta line
yields an expansion velocity of -7700 km/s. A spectrum of SN
2003ic (cf. IAUC 8201), obtained on Sept. 18.25, shows it to be a
type-Ia supernova; the spectrum is similar to that of SN 1994D
taken 5 days before maximum. The minimum of the Si II 635.5-nm
line yields an expansion velocity of -12200 km/s (adopting the NED
host-galaxy recession velocity of 16690 km/s). A spectrum of SN
2003id (cf. IAUC 8201), obtained on Sept. 18.33, shows it to be a
type-Ic supernova. The spectrum, which has strong absorptions
centered at 491 nm (possibly Fe II blends) and 607 nm together with
a P-Cyg profile whose minimum is centered at 645 nm, bears some
resemblance to that of SN 1994I taken 4 days before maximum
(Filippenko 1997, ARAA 35, 309).
(C) Copyright 2003 CBAT
2003 September 19 (8203) Daniel W. E. Green
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