Central Bureau for Astronomical Telegrams
IAUC 6538: 1997E; NEW X-RAY BURSTER
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Circular No. 6538
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 1997E IN NGC 2258
S. Nakano, Sumoto, Japan, reports the discovery by Reiki
Kushida, Yatsugatake South Base Observatory, of an apparent
supernova (mag 15.7) on seven unfiltered CCD frames taken around
Jan. 14.530 UT with a 0.40-m f/5 reflector. Y. Kushida provides
the following measurement of the position of SN 1997E from the
discovery frames: R.A. = 6h47m38s.10, Decl. = +74o29'51".0 (equinox
2000.0), which is 32" west and 57" north of the center of NGC 2258.
There is no star at the position of the new star on Kushida's
frames taken on 1996 Dec. 15, 29, and 1997 Jan. 4, nor is anything
present on the Digital Sky Survey.
P. Garnavich and R. Kirshner, Harvard-Smithsonian Center for
Astrophysics, communicate: "Spectrograms of SN 1997E were obtained
by J. Peters on Jan. 16.2 UT at the F.L. Whipple Observatory (FLWO)
1.5-m Tillinghast telescope, showing this to be a type-Ia supernova
at maximum. The relative strengths of the Si II features at 617.9
and 582.2 nm, and the narrow Si II feature at 491.3 nm, imply that
this supernova may have a fast-declining light curve similar to
that of SN 1992A. CCD images obtained on Jan. 16.4 by J. Raymond
with the FLWO 1.2-m telescope yield visual mag 15.6 for SN 1997E.
NEW X-RAY BURSTER
L. Piro, Istituto Astrofisica Spaziale (IAS), CNR, Frascati;
J. Heise and R. Jager, Space Research Organization of the
Netherlands (SRON), Utrecht; M. Feroci, IAS; G. D'Andreta, G.
Spoliti, and A. Coletta, BeppoSAX, Rome; H. Muller, BeppoSAX, Rome,
and SRON; and D. Ricci, BeppoSAX, Rome, write: "On Jan. 13.295011
UT, the BeppoSAX Wide Field Camera No. 1 (WFC1) detected an x-ray
burst in the range 2-20 keV, seen in the ratemeter as a single peak
and showing a fast rise (on the order of 10 s) with an exponential
decay lasting about 150 s. This event is likely to be an x-ray
burster and not a gamma-ray burst, as it was not seen by the
BeppoSAX Gamma Ray Burst Monitor. The derived position (R.A. =
12h49m50s, Decl. = -59o10'.8, equinox 2000.0; estimated 10' error
radius) does not correspond to any catalogued source. The peak
flux corresponds to about 1.9 Crab. The WFC1 observed the same
field for about 40 000 s before and 2500 s after the event, with no
positive detection, leading to an upper limit to the steady flux
from the burst source of about 10 mCrab."
(C) Copyright 1997 CBAT
1997 January 16 (6538) Daniel W. E. Green
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