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IAUC 8415: 2004et; 2004er; V1187 Sco

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                                                  Circular No. 8415
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

SUPERNOVA 2004et IN NGC 6946
     C. J. Stockdale, Marquette University; K. W. Weiler, Naval
Research Laboratory; S. D. Van Dyk, Spitzer Science Center,
California Institute of Technology; R. A. Sramek, National Radio
Astronomy Observatory; N. Panagia, European Space Agency and Space
Telescope Science Institute; and J. M. Marcaide, University of
Valencia, report the detection of radio emission from the type-II
supernova 2004et (IAUC 8413, 8414) with the Very Large Array in 'A'
configuration:  "Radio-flux densities on Oct. 5.128 UT of 1.33 +/-
0.20 mJy at 22.460 GHz (wavelength 1.3 cm) and 0.34 +/- 0.06 = mJy
at 8.460 GHz (wavelength 3.6 cm) were observed at R.A. =
20h35m25s.36, Decl. = +60o07'17".7 (equinox 2000.0; +/- 0".1 in
each coordinate).  This is in close agreement with the reported
optical position.  On Sept. 30.18, no radio emission was detected
at that position, with 3-sigma upper limits of 1.29 mJy at 22.460
GHz and 0.29 mJy at 8.460 GHz.  This is the eighth supernova
recorded in NGC 6946 in the modern era, four of which have been
radio-detected; NGC 6946 is the most prolific supernova-producing
galaxy known.  SN 2004et has clearly been caught during its turn-on
phase for the centimeter radio emission, and observations in other
wavebands are urged.  Radio observations are continuing."

SUPERNOVA 2004er IN MCG -01-7-24
     M. Modjaz, P. Challis, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics, report that a spectrum (range 350-740 nm)
of SN 2004er (cf. IAUC 8412), obtained by M. Calkins on Oct. 5.40
UT with the Mt. Hopkins 1.5-m telescope (+ FAST spectrograph),
shows it to be a type-II supernova.  The spectrum consists of a
blue continuum and P-Cyg lines of hydrogen and helium.  Adopting
the NASA/IPAC Extragalactic Database recession velocity of 4411
km/s for the host galaxy, the expansion velocity derived from the
minimum of the H_beta line is about 12000 km/s.

     R. K. Zamanov, Liverpool John Moores University, reports the
following CCD magnitude estimates (uncertainties about 0.03 mag)
obtained with the 2-m Liverpool telescope on La Palma by M. Bode,
I. A. Steele, T. J. O'Brien, and himself:  Sept. 26.836 UT, B =
15.46, V = 14.38, R = 12.48, I = 12.13; 27.838, 15.61, 14.43,
12.58, 12.22; 28.831, 15.63, 14.43, 12.61, 12.26; 29.829, 15.61,
14.44, 12.63, 12.27.

                      (C) Copyright 2004 CBAT
2004 October 6                 (8415)            Daniel W. E. Green

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