Central Bureau for Astronomical Telegrams
IAUC 5966: 1994I
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Circular No. 5966
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
SUPERNOVA 1994I IN NGC 5194
M. Richmond, Princeton University, reports on a possible
progenitor for SN 1994I: "Hubble Space Telescope PC images taken
on 1992 July 14 show a stellar object at a position close to that
of the supernova, R.A. = 13h27m47s.9, Decl. = +47o26'59" (equinox
1950.0; based on the FITS header), in fair agreement with the
positions reported on IAUC 5961 and 5963. Two images yield HST
instrumental F555W magnitudes of about 23.8. An HST image taken
with the F664N filter on 1991 Dec. 20 (exposure not very long)
shows no H-alpha emission near the position; a red progenitor is
possibly favored."
B. Schmidt, P. Challis, and R. Kirshner, Center for Astrophysics,
report: "A spectrogram obtained with the F. L. Whipple Observatory
1.5-m telescope (+ FAST) on Apr. 5 by P. Berland confirms the
conclusion by Filippenko et al. (IAUC 5964) that SN 1994I is not a
type-II supernova, as had been reported earlier. The spectrum has
strong lines at observed wavelengths 745, 611, 569, 492, 478, 434,
and 377 nm, and no hydrogen is detected. M. Phillips, Cerro Tololo
Interamerican Observatory, has pointed out that this object's
spectrum resembles the pre-maximum spectrum of the type-Ic object
SN 1983V."
R. A. Sramek and M. P. Rupen, National Radio Astronomy
Observatory; S. D. Van Dyk, University of California at Berkeley;
K. W. Weiler, Naval Research Laboratory; and N. Panagia, Space
Telescope Science Institute, report: "New observations with the
Very Large Array in its highest-resolution (A) configuration have
detected SN 1994I for the first time at 2 and 6 cm, and show that
the 1.3- and 3.6-cm flux densities are rising rapidly. Following
are listed the time of observation (UT), the frequency (GHz), the
flux density (mJy), and the rms noise in image (mJy/beam): Apr.
4.11, 8.44, 0.91 +/- 0.16, 0.054; 4.15, 14.94, 3.16 +/- 0.52, 0.11;
4.16, 22.46, 4.64 +/- 0.80, 0.42; 5.29, 1.43, <0.28 (3-sigma),
0.093; 5.32, 22.46, 13.1 +/- 3.5, 0.26; 5.36, 14.94, 7.15 +/- 1.05,
0.14; 5.38, 8.44, 1.66 +/- 0.15, 0.044; 5.40, 4.86, 0.57 +/- 0.08,
0.062. The uncertainties include both random and systematic
(calibration) errors. The basic behavior---the flux densities
rising rapidly, first at higher frequencies and later at lower
frequencies---is consistent with the circumstellar interaction model
and with the behavior of previously-known radio supernovae (as
discussed, e.g., in Weiler et al. 1986, Ap.J. 301, 790)."
1994 April 6 (5966) Daniel W. E. Green
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