Central Bureau for Astronomical Telegrams
IAUC 7346: C/2000 A1; 1999gt, 1999gu
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Circular No. 7346
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)
COMET C/2000 A1 (MONTANI)
J. Montani, Lunar and Planetary Laboratory, reports his
discovery of a faint comet on CCD images taken with the 0.90-m
Spacewatch telescope at Kitt Peak (discovery observation below).
The comet shows a coma with diameter 5"-6", slightly elongated in
p.a. 245-250 deg. An R CCD image taken by S. Kern with the 2.3-m
Steward telescope on Jan. 13 shows the comet to be clearly extended
toward the southwest, and she derived mag 18.1. W. Shook found the
object to be nonstellar with a 2".6 tail toward the southwest on an
image taken with the 3.5-m WIYN telescope on Jan. 13. Full
astrometry and parabolic orbital elements appear on MPEC 2000-A46.
2000 UT R.A. (2000) Decl. m1
Jan. 12.32564 8 02 08.15 +23 15 21.2 18.9
SUPERNOVAE 1999gt AND 1999gu
E. Cappellaro, A. Pastorello, L. Rizzi, M. Salvo, and M.
Turatto, Padua; J. Danziger and P. Mazzali, Trieste; F. Patat,
European Southern Observatory (ESO); and S. Benetti, Telescopio
Nazionale Galileo, La Palma, report the discovery of two supernovae
on a CCD frame taken on 1999 Dec. 29.17 UT with the ESO/MPI 2.2-m
telescope (+ Wide Field Imager) and centered on the AXAF deep
field. SN 1999gt (V = 22.1) is located at R.A. = 3h32m10s.28,
Decl. = -28o06'16".0 (equinox 2000.0), which is 1".4 west of the
host galaxy's nucleus. SN 1999gu (V about 22.2) is located at R.A.
= 3h33m00s.15, Decl. = -27o51'40".1, which is 0".4 east and 2".4
south of the host galaxy's nucleus. The two supernovae were not
present on a frame taken on Dec. 13.20 (limiting mag V = 23.5).
Spectra (range 600-1000 nm, resolution 2 nm) of the new objects
were obtained with the ESO 3.6-m telescope (+ EFOSC2) on 2000 Jan.
11.10 by P. Leisy and E. Pompei (ESO). The spectrum of the parent
galaxy of SN 1999gt shows H-alpha, H-beta, and [O III] emission
lines, providing a redshift of 0.274. Given this redshift, the
spectrum of SN 1999gt resembles that of a type-Ia supernova, 1-2
weeks past maximum, though the Si II 615-nm absorption is not
prominent. The spectrum of SN 1999gu shows a broad (FWHM = 9000
km/s) emission at 750 nm and an associated blue-shifted absorption.
This feature is identified with the H-alpha, P-Cyg profile emission
of a type-II supernova shortly after maximum. The expansion
velocity of the ejecta is 10 000 km/s. On top of this line, a
spatially extended, narrow H-alpha emission from the parent galaxy
gives a redshift of 0.147.
(C) Copyright 2000 CBAT
2000 January 14 (7346) Daniel W. E. Green
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