Central Bureau for Astronomical Telegrams
IAUC 5771: 1993K; 1993J
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Circular No. 5771
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 1993K IN NGC 2223
M. Hamuy, Cerro Tololo Interamerican Observatory, obtained a
low-dispersion spectrogram (range 320-750 nm) of SN 1993K with the
CTIO 4.0-m telescope on Apr. 21.05 UT. These data show that strong,
P-Cyg emission lines of H I and Fe II have developed, confirming
earlier suspicions that this object is a type-II event (cf. IAUC
5733, 5736). The spectrum closely resembles that of the type-IIP
supernova 1990E obtained 17 days after discovery (see Schmidt et
al. 1993, A.J., in press).
SUPERNOVA 1993J IN NGC 3031
A. Tomaney and A. Crotts, Columbia University, communicate:
"Ten-hr pre-explosion CCD exposures in both B and H-alpha (7.5-nm
bandpass) of the field of SN 1993J were obtained using the McDonald
Observatory 2.1-m telescope during 1990 Feb. and Mar. The source
is within 0".4 of the SN 1993J position given by Richmond on IAUC
5737. Images with seeing 2".3 FWHM or better show the object to be
extended (FWHM of 3".0 and 3".6 in B and H-alpha, respectively).
Lucy-deconvolution of the images yields FWHM of 2".9 in H-alpha and
2".6 in B for the source, compared to 1".3 for nearby stars, but
reveals no substructure within the source. The H-alpha flux in a
4"-radius aperture was 2.92 (+/- 0.05) x 10E-17 erg sE-1 cmE-2 AE-1,
in good agreement with the 1992 Jan. measurement by Magnier et al.
(IAUC 5741). This is roughly equivalent to an R magnitude of 19.3,
very close to the R-band measure in 1990 Mar. by Perelmuter (IAUC
5736), indicating that no strong H-alpha emission was associated
with the source at that time. The source sits on a ridge of
diffuse, unresolved starlight roughly 3" wide and 20" long with p.a.
40 deg, appearing stronger in B than H-alpha. Differential photometry
using nearby stars yields a source magnitude of B = 20.44 +/-
0.03 in a 4"-radius aperture, versus B = 21.2 in a 1" aperture, the
latter being closer to previous estimates. CCD saturation of stars
brighter than mag 16 necessitated a calibration of fainter stars in
the field. The magnitudes quoted here are made relative to a star
23".2 west and 56".5 south of the supernova, where we measure 2.66
(+/- 0.01) x 10E-16 erg sE-1 cmE-2 AE-1 for the H-alpha flux and B
= 18.95 +/- 0.03."
1993 April 21 (5771) Daniel W. E. Green
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