Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6798: GRB 971227; 1997ef; C/1997 D1

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 6797 SEARCH Read IAUC 6799

View IAUC 6798 in .dvi or .ps format.
IAUC number 

                                                 Circular No. 6798
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)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


GRB 971227
     P. M. Woods, University of Alabama in Huntsville; C.
Kouveliotou, Universities Space Research Association; and G. J.
Fishman, Marshall Space Flight Center, NASA, report on behalf of
the BATSE Team: "GRB 971227 (IAUC 6796, 6797) was recorded as BATSE
trigger No. 6546.  It was a weak, short event of duration about 6 s
that exhibits two well distinguished peaks, separated by 2.5 s.
The burst fluence (above 25 keV) was 9.3 (+/- 1.4) x 10E-7 erg
cmE-2 and its peak flux (between 50 and 300 keV) was 3.3 +/- 0.2
photons cmE-2 sE-1.  The burst was not detected above 300 keV."


SUPERNOVA 1997ef IN UGC 4107
     P. Garnavich, S. Jha, R. Kirshner, and P. Challis, Harvard-
Smithsonian Center for Astrophysics; and D. Balam, University of
Victoria, report: "Recent CCD images of SN 1997ef obtained with the
Whipple Observatory 1.2-m telescope by P. Berlind, with the MDM
2.4-m telescope by J. Thorstensen, and with the Dominion
Astrophysical Observatory's 1.8-m Plaskett telescope indicate that
this object has begun to decline in brightness.  Visual magnitude
estimates relative to the star (V = 17.05) located 1' southwest of
UGC 4107:  Dec. 16.3 UT, 16.56; 27.3, 16.84; 28.3, 16.94.  Spectra
obtained at the Tillinghast telescope by Berlind and L. Macri, and
at the MDM 2.4-m telescope by Thorstensen, between Dec. 17 and 27
show that the rapid velocity shift seen in the major spectral
features has slowed.  After correcting for the redshift of UGC
4107, a number of peaks can now be identified at 397 nm (Ca II),
457 nm (?), 486 nm (H-beta), 547 nm (?), 587 nm (He I), 614 nm (?),
and 655 nm (H-alpha).  The H-alpha emission peak is rounded, while
the unidentified maxima have a triangular shape.  Currently, the
spectrum appears similar to the peculiar type-Ib supernovae 1988L
(Filippenko 1988, A.J. 96, 1941) and 1983I (Wheeler et al. 1987,
Ap.J. 313, L69), which also displayed broad maxima near the
wavelength of H-alpha.  These objects and SN 1997ef appear to be
extreme examples of massive stars that have lost all but a small
amount of hydrogen through mass loss."


COMET C/1997 D1 (MUELLER)
     Visual m_1 estimates:  Nov. 1.00 UT, 11.7 (M. Lehky, Hradec
Kralove, Czech Republic, 0.42-m reflector); Dec. 21.83, 12.1
(Lehky); 28.66, 13.4 (A. Pearce, Cadoux, W. Australia, 0.41-m
reflector).

                      (C) Copyright 1997 CBAT
1997 December 30               (6798)            Daniel W. E. Green

Read IAUC 6797 SEARCH Read IAUC 6799

View IAUC 6798 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!