GRB 000607

K. Hurley, on behalf of the Ulysses GRB team, T. Cline, on behalf
of the Konus Wind and NEAR GRB teams, and E. Mazets and S. Golenetskii,
on behalf of the Konus Wind GRB team, report:

Ulysses, Konus Wind, and NEAR observed this burst at 08689 s UT.
As observed by Ulysses, its duration was <150 milliseconds.  This
duration, as well as its intensity >150 keV, as observed by NEAR,
place this burst in the short-duration, hard-spectrum class.  This
is the first rapid, precise localization of such a burst, for which
no counterpart has yet been observed.  The 25-100 keV fluence was
~2x10^-7 erg/cm^2, and the 0.03125 s peak flux was ~3.5x10^-6 erg/cm^2 s.
We have localized this burst to a preliminary 30 sq. arcmin. error box whose
coordinates (3 sigma) are:

    RA(2000)                 DEC(2000)
  2 h 33 m 58.74 s     17 o  8 '  51.49 "  (CENTER)
  2 h 34 m  6.89 s     17 o 10 '   9.17 "  (CORNER)
  2 h 33 m 35.94 s     16 o 57 '  49.88 "  (CORNER)
  2 h 34 m 21.56 s     17 o 19 '  53.67 "  (CORNER)
  2 h 33 m 50.58 s     17 o  7 '  33.82 "  (CORNER)

This error box may be refined considerably.

D. A. Frail (NRAO), K. M. Becker (Oberlin), E. Berger, A. H. Diercks
and J. S. Bloom (Caltech) report on behalf of the Caltech-NRAO-CARA
GRB collaboration:
 
"We have observed the error box of GRB000607 (GCN #693
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 ) with the VLA
at 1.43 and 4.86 GHz on three occasions: May 8.59, May 8.79, and May
9.79. Within this error box there are three previously known radio
sources, cataloged by the NRAO VLA Sky Survey (NVSS) in 1993 (see
http://www.cv.nrao.edu/~jcondon/nvss.html). We see no evidence for
significant flux variability for any of these sources over our
observing time. No new radio sources were detected in the error box to
typical levels of 0.5 mJy (4.5-sigma) at 1.43 GHz and 0.37 mJy
(5-sigma) at 4.86 GHz."
 
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N. Masetti, E. Palazzi, E. Pian (ITESRE, CNR, Bologna), 
A.J. Castro-Tirado (LAEFF, IAA), R. Hudec, J. Soldan (ASU, Ondrejov),
M. Bernas and P. Pata (CVUT-FEL, Prague), 
J.M. Castro Ceron (ROA, San Fernando), C. Kouveliotou (USRA),
J. Hjorth (Univ. of Copenhagen), P.M. Vreeswijk, 
E.P.J. van den Heuvel (Univ. of Amsterdam), J. Greiner (AIP), 
M. Zoccali (Univ. of Padua) and O. Hainaut (ESO), 
on behalf of larger collaborations, report:


"We have obtained several unfiltered images of the IPN error box for the
short, hard burst GRB000607 (Hurley et al., GCN 693
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 ), with the 
narrow-field CCD attached to the 0.3-m telescope of BOOTES-1 
at El Arenosillo (Spain) on Jun 9.24 UT (51 hr after the event, 360 sec
exposure time).
The limiting magnitude of the summed image, covering the whole error box,
is ~16 due to the very poor observing conditions (the GRB field was
imaged close to dawn). None of the single images, as well as their sum, 
reveals any new, or strongly variable, source when compared with the
Digital Sky Survey (DSS-II).

We also acquired an optical R-band image of northern part of the error box
of this GRB just before dawn on 2000 June 9.44 UT (i.e. ~56 hr after 
the GRB trigger) with the 1.54-meter Danish telescope (plus DFOSC) 
at ESO - La Silla (Chile). Seeing was ~2 arcsec, and exposure time was
450 sec.
This image also could not be very deep as it was obtained during twilight
due to the unfavourable position of this GRB with respect to the Sun; 
indeed, the southern part of the error box could not be imaged because of
a too high sky level.
Photometric calibration was performed using USNO-A1.0 field stars.
The comparison with the DSS-II survey does not reveal any new or
substantially variable object brighter than R ~ 19.5.".


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