Central Bureau for Astronomical Telegrams
IAUC 7891: 2002cs; 2002cr
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Circular No. 7891
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)
SUPERNOVA 2002cs IN NGC 6702
Independent reports have been received of the discoveries of
an apparent supernova on unfiltered CCD images obtained by LOTOSS
(cf. IAUC 7514; via M. Ganeshalingam and W. D. Li, University of
California at Berkeley) with the 0.8-m Katzman Automatic Imaging
Telescope (KAIT) and by M. Armstrong, Rolvenden, England, with a
0.36-m reflector. SN 2002cs is located at R.A. = 18h46m59s.96,
Decl. = +45o42'19".7 (equinox 2000.0), which is 24".8 east and 0".8
south of the nucleus of NGC 6702 (measurements by Li; Armstrong
gives the offsets as 24" east, 1" north). Unfiltered CCD
magnitudes: 2001 Oct. 3.2 UT, [19.0: (KAIT); 2002 May 5.133, 16.3
(Armstrong); 5.5, about 15.9 (KAIT); 6.3, about 15.6 (KAIT).
Armstrong adds that there is no trace of SN 2002cs on an earlier
image taken by himself or on second Palomar Sky Survey blue, red,
and infrared images.
SUPERNOVA 2002cr IN NGC 5468
T. Matheson, S. Jha, P. Challis, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report that a spectrum (range
370-750 nm) of SN 2002cr (cf. IAUC 7890), obtained by P. Berlind on
May 3.27 UT with the F. L. Whipple Observatory 1.5-m telescope (+
FAST spectrograph), shows it to be a type-Ia supernova before
maximum. Adopting the NASA/IPAC Extragalactic Database recession
velocity of 2845 km/s for the host galaxy, the supernova expansion
velocity is about 12400 km/s for Si II (rest 635.5 nm) and 15600
km/s for Ca II (rest 395.1 nm). The spectral-feature age of the
supernova (cf. IAUC 7774) is 5 +/- 2 days before maximum light.
P. Meikle, Imperial College, London, reports that K.-H. Mack,
and M. Marcha obtained a spectrum (range 382-722 nm, resolution 0.7
nm) of SN 2002cr on May 4.02 UT with the Isaac Newton Telescope at
La Palma. Comparison of the spectrum with those of SNe 1994D and
1998bu indicates that SN 2002cr is a typical type-Ia event, about 5
days before maximum light. The maximum expansion velocity measured
from the blue wing of the Si II absorption is 19100 km/s (after
correcting for the redshift of the host galaxy). A second spectrum
obtained on May 5.06 by the same observers shows relatively little
change in the spectral features.
Unfiltered CCD magnitudes: Apr. 16.4 UT, [19.0: (W. D. Li,
University of California at Berkeley, 0.8-m Katzman Automatic
Imaging Telescope); May 2.38, about 15.9 (Li; independent discovery
by LOTOSS); 3.716, 15.6 (L. A. G. Monard, Pretoria, S. Africa);
4.913, 15.2 (Monard); 5.639, 15.8 (R. Kushida, Yatsugatake South
Base Observatory); 5.764, 15.0 (Monard).
(C) Copyright 2002 CBAT
2002 May 6 (7891) Daniel W. E. Green
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