Central Bureau for Astronomical Telegrams
IAUC 7143: 1999br; 1999bs; 1999bg
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Circular No. 7143
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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SUPERNOVA 1999br IN NGC 4900
P. Garnavich, S. Jha, P. Challis, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report that a spectrum of SN
1999br was obtained by M. Calkins with the 1.5-m Tillinghast
telescope on Apr. 15.3 UT. Broad Balmer emission lines on a very
blue continuum are seen, indicating that this is a type-II event
discovered at an early stage. H-alpha shows only a weak absorption
trough, but the later Balmer series have clear P-Cyg profiles. He
I 587.5-nm has an emission flux comparable to that of H-beta.
Narrow host-galaxy emission lines give a recession velocity of 965
km/s.
A. V. Filippenko, University of California at Berkeley,
reports that inspection of a CCD spectrum (range 560-860 nm) of SN
1999br, obtained on Apr. 15 by D. Stern (Berkeley) and M. Reuland
(Leiden) with the 3-m Shane reflector at Lick Observatory, reveals
that the object is indeed a supernova, possibly of type II.
However, the spectrum is peculiar, with emission lines at observed
wavelengths near 580, 720, and 790 nm whose strength is comparable
to that of the line near 660 nm (presumably H-alpha). If the
supernova is indeed associated with NGC 4900, it is very
subluminous, regardless of its type.
W. Li, University of California at Berkeley, reports that he
has searched the KAIT database for observations of NGC 4900 (cf.
IAUC 7141), and found no hint of SN 1999br on a poor frame
(limiting mag 17) taken on Apr. 4.4 UT. Also, a frame taken on
Mar. 27.4 shows no image of the supernova to limiting mag about
18.5.
SUPERNOVA 1999bs IN UGC 11093
Garnavich et al. also report that a spectrum of SN 1999bs (cf.
IAUC 7141) was obtained by Calkins on Apr. 15.5 UT. The spectrum
consists of a very blue continuum with weak absorption features at
H-beta and H-gamma, and possibly a broad H-alpha emission. SN
1999bs, like SN 1999br, is probably a type-II event caught at a
very early phase. CCD images obtained by L. Macri with the Fred L.
Whipple Observatory 1.2-m telescope, at the same time as the
spectra, give V = 16.8.
SUPERNOVA 1999bg IN IC 758
CCD magnitude estimates, unfiltered unless otherwise noted:
Mar. 31.593 UT, 15.6 (S. Yoshida and K. Kadota, Ageo City, Japan);
Apr. 4.829, R = 15.5 (D. Hanzl, Brno, Czech Republic); 12.845, R =
15.45 (Hanzl); 12.880, V = 15.83 (Hanzl).
(C) Copyright 1999 CBAT
1999 April 15 (7143) Daniel W. E. Green
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