Central Bureau for Astronomical Telegrams
IAUC 6856: GRB 980326, GRB 980329; XTE J0421+560
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Circular No. 6856
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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GRB 980326 AND GRB 980329
M. S. Briggs, G. Richardson, R. M. Kippen, and P. M. Woods,
University of Alabama in Huntsville, report on behalf of the BATSE
team: "GRB 980326 (IAUC 6851) was observed with BATSE on Mar.
26.88811 UT as trigger 6660. The event lasted about 5 s and
exhibited three narrow pulses. Its peak flux (integrated over 0.5
s) and fluence (50-300 keV) are 8 x 10E-7 erg cmE-2 sE-1 and 1 x
10E-6 erg cmE-2, respectively. GRB 980329 (IAUC 6853) was observed
with BATSE on Mar. 29.15600 as trigger 6665; the event was very
intense and lasted about 55 s, exhibiting a 10-s-long, highly
structured peak. Its peak flux (integrated over 0.5 s) and
fluence (50-300 keV) are 8 x 10E-6 erg cmE-2 sE-1 and 5 x 10E-5 erg
cmE-2, respectively. The BATSE locations are consistent with the
locations of the reported optical transient for GRB 980326 (IAUC
6852) and the SAX/NFI x-ray counterpart for GRB 980329 (IAUC 6854).
Location maps can be found at
http://www.batse.msfc.nasa.gov/~kippen/batsebr."
S. A. Ilovaisky and C. Chevalier, Observatoire de Haute-
Provence (OHP), write: "Two 15-min R-band CCD exposures of the SAX
NRI error box for the GRB 980329 gamma-ray burst (IAUC 6853, 6854)
were taken by T. Bremnes, University of Basel, with the 1.2-m OHP
telescope on Mar. 31.87 UT (65 hr after the burst). More than 15
objects are seen down to mag 21 within the 1' error circle.
Comparison with a film copy of the second Palomar Sky Survey red
plate for this region reveals one object within the NFI error
circle that is present in our frames and not on the Palomar plate.
This object, for which we derive a preliminary magnitude of R =
20.6, is located near a bright (R = 15.8) star, and has coordinates
R.A. = 7h02m38s.8, Decl. = +38o50'27" (equinox 2000.0), as derived
using the Digitized Sky Survey and the USNO-A1 catalogue. This is
30" east of the center of the 1' radius error box. Our average
R-band image is available at
http://www.obs-hp.fr/~ilovaisky/grb980329.html. Further imaging of
this field is needed."
XTE J0421+560
W. Paciesas, University of Alabama in Huntsville; and G.
Fishman, Marshall Space Flight Center, NASA report for the
CGRO/BATSE team: "This new x-ray transient (IAUC 6855) was also
detected by BATSE, beginning on Mar. 31.91 UT, at a flux of 470 +/-
50 mCrab (20-100 keV). The source was not significantly detected
during Mar. 31.03-31.84, with an upper limit of 55 mCrab (3 sigma)."
(C) Copyright 1998 CBAT
1998 April 2 (6856) Daniel W. E. Green
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