Central Bureau for Astronomical Telegrams
IAUC 7333: 1999gl; GRB 991208
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Circular No. 7333
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 1999gl IN NGC 317B
G. M. Hurst, Basingstoke, England, reports the discovery by
Tom Boles, Wellingborough, of a supernova (mag 16.2) on unfiltered
CCD images obtained in the course of the U.K. Nova/Supernova Patrol
on Dec. 14.73 and 14.98 UT with a 0.36-m reflector. Boles measured
the position of SN 1999gl to be R.A. = 0h57m40s.07, Decl. =
+43o47'35".6 (equinox 2000.0; mean of two exposures). SN 1999gl
does not appear on an image obtained by Boles on Sept. 17.02
(limiting mag about 18). M. Armstrong, Rolvenden, confirmed the
presence of SN 1999gl on Dec. 14.976 and notes that it was not
present on his own CCD image taken on Dec. 4. The second Palomar
Sky Survey does not show anything at the position of SN 1999gl
(limiting mag about 20). Boles found the supernova to be at mag
16.6 on Dec. 15.92.
P. Garnavich, S. Jha, R. Kirshner, and P. Challis, Harvard-
Smithsonian Center for Astrophysics, report that a spectrum of SN
1999gl was obtained by P. Berlind with the Fred L. Whipple
Observatory 1.5-m Tillinghast telescope on Dec. 16.1 UT, showing
the supernova to be a type-II event near maximum. Broad H-alpha
and H-beta emissions, as well as He I 587.50nm, are evident in the
spectrum. A deep Na I absorption line due to interstellar gas in
the host galaxy has an equivalent width of 0.3 nm, implying that
the supernova is heavily extinguished by dust. Strong, narrow
emission lines from the host galaxy provide a redshift of 0.018.
GRB 991208
M. Bremer, Institut de Radio Astronomie Millimetrique (IRAM),
Grenoble; F. Bertoldi, Max-Planck-Institut fur Radioastronomie,
Bonn; U. Lisenfeld, IRAM, Granada; Alberto Castro-Tirado,
Laboratorio de Astrofisica Espacial y Fisica Fundamental del
Instituto Nacional de Tecnica Aerospacial Madrid, and Instituto de
Astrofisica de Andalucia, Granada; and T. Galama, California
Institute of Technology, report: 'The afterglow of GRB 991208 was
detected at 240 GHz with the Max-Planck Millimeter Bolometer
(MAMBO) array (80-GHz bandwidth) at the IRAM 30-m telescope on Pico
Veleta, at the position reported by Frail et al. (IAUC 7332).
Three on-off integrations yield the following flux densities: Dec.
11.77 UT, 2.6 +/- 0.8 mJy; 12.38, 1.9 +/- 0.6; 14.35, 2.2 +/- 0.7.
Combining all data, we obtain a flux density 2.4 +/- 0.5 mJy. The
source intensity appears to remain constant. We will continue to
monitor its flux."
(C) Copyright 1999 CBAT
1999 December 16 (7333) Daniel W. E. Green
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