GRB 021206

K. Hurley and T. Cline, on behalf of the Ulysses and Mars Odyssey GRB teams,

I. Mitrofanov, D. Anfimov, A. Kozyrev, M. Litvak and A. Sanin,
on behalf of the HEND/Odyssey GRB team, and

W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr,
on behalf of the GRS/Odyssey GRB team, report:

Ulysses and HEND observed this burst at 81155 +/- 1104 s.  The
uncertainty is due to the fact that no near-Earth spacecraft has yet
reported this event.  As observed by Ulysses, it had a duration of
approximately 20 seconds with a weak tail lasting perhaps another 40
seconds, a 25-100 keV fluence of approximately  1.6E-04 erg/cm2, and a
peak flux of approximately  2.9E-05 erg/cm2 s over 0.50 seconds.

We have triangulated it to a preliminary annulus centered at RA, Decl
(2000)= 328.915, -57.580 degrees, with radius 81.125 +/- 0.014
degrees.  (The uncertainty in the radius does not take into account the
fact that HEND was driven into saturation by this burst; we will
attempt to include this in later estimates).  As this annulus does not
pass near any of the known SGRs, we believe the event to be a GRB.

We are expecting confirmation of this event by a near-Earth spacecraft,
which will allow us to derive an error box for it.

K. Hurley and T. Cline, on behalf of the Ulysses, Konus, and Mars Odyssey GRB teams,

I. Mitrofanov, D. Anfimov, A. Kozyrev, M. Litvak and A. Sanin,
on behalf of the HEND/Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr,
on behalf of the GRS/Odyssey GRB team, and

E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, report:


We have triangulated this exceptionally bright burst (GCN 1727
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 ) to a
preliminary, 3 sigma error box whose approximate area is 57. sq.
arcmin. and whose coordinates are:

    RA(2000)                              DEC(2000)
 ERROR BOX CENTER:  16 h  0 m 43.43 s     -9 o 43 '  24.20 " 
 ERROR BOX CORNER 1: 16 h  1 m 47.11 s     -9 o 27 '  53.80 " 
 ERROR BOX CORNER 2: 16 h  0 m  0.64 s     -9 o 55 '  35.00 " 
 ERROR BOX CORNER 3: 16 h  1 m 25.66 s     -9 o 31 '  18.70 " 
 ERROR BOX CORNER 4: 15 h 59 m 38.66 s     -9 o 59 '   4.81 " 

This error box may be improved, but unfortunately it lies
only about 18 degrees from the Sun.

D. A. Frail (NRAO) reports on behalf of a larger collaboration:

"Using the VLA, we imaged the inner quarter of the initial IPN error
box of the exceptionally bright gamma-ray burst GRB 021206 (Hurley et
al. GCN#'s 1727, 1728). In initial observations made at 4.86 GHz
during the first week after the burst, there was an unresolved radio
source with a flux density of ~400 uJy located at r.a.=16:00:46.85,
dec.=-09:42:33.5 (J2000), with an uncertainty of about 0.6 arcsec.
Subsequent measurements at 4.86 and 8.46 GHz in February and March
2003 showed that the source has faded by a least a factor of five.
Future observations are planned to place tighter limits on the flux
density of this radio source.

Although the magnitude of the radio flux density and the temporal
behavior of the light curve are typical of past GRB afterglows, we
cannot rule out the possibility (probability <=0.02) that this is an
unrelated background variable (Frail et al. AJ, 125, 2299, 2003).
Given the recent RHESSI detection of polarized emission from this
burst (Coburn & Boggs, Nature, 423, 415, 2003) we encourage further
followup optical observations of this candidate afterglow."

This message may be cited.

K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey, and Konus GRB teams,

D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, 
and A. Zehnder, on behalf of the RHESSI GRB team,

I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and
A. Sanin, on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr,
on behalf of the GRS/Odyssey GRB team, 

E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, and

A. von Kienlin, G. Lichti, and A. Rau, on behalf of the
INTEGRAL SPI-ACS GRB team, report:

Using the final spacecraft timing and ephemeris data, we have combined
Ulysses, RHESSI, Mars Odyssey, Konus, and INTEGRAL (SPI-ACS) data to
obtain a final IPN error ellipse for this burst (GCN 1727
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 , 1728
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 ; Nature
423, 415, 2003) whose area is a factor of ~7 smaller than that of the
error box announced in GCN 1728
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 .  The 3 sigma error ellipse is centered
at RA, Decl (2000)=240.195, -9.710 degrees, with major axis 20.4
arcminutes, minor axis 0.53 arcminutes, and position angle ~18
degrees.  Its area is 8.6 square arcminutes.  The VLA source (GCN 2280
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 )
lies within both the earlier error box and within this ellipse, roughly
0.020 degrees from its center.  A map and a lightcurve have been posted
at ssl.berkeley.edu/ipn3/021206.

T. Fatkhullin reports on behalf of the SAO RAS follow-up team:

The field of GRB021206 (GCN #1727
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 , see also Coburn & Boggs 2003, Nature, 423,
415) was observed with 6 meter telescope of SAO RAS. The observations were
carried out with SCORPIO instument (see the Web-page
http://www.sao.ru/hq/moisav/scorpio/scorpio.html)
on 26 July 2003 during late evening twilight. The 15 1-min R-band exposures
were obtained starting from UT 26.7556 to 26.7896 July 2003. The field was
centered on the radio transient positions (Frail, GCN #2280
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 ). Astrometry of
the exposures sum was made using USNO A2.0 stars and errors obtained are
0.6 arcsec in R.A and Dec. Within the astrometry error circle at the position
of radio transient we did not detect any obvious optical source down to about
R=24.8 (3 sigma). But from about 2 arcsec to the North-West an extended dim
emission are observed. We should note that due to highlights from very bright
star on the image we caution about reality of this extended emission.
Photometric calibration was performed relatively to SExtractor (Bertin &
Arnouts 1996, A&AS, 117, 393) photometry of unsaturated USNO stars in our
field of  view. The sum of exposures can be seen at our anonymous FTP-site
ftp://ftp.sao.ru/pub2/grb/GRB021206/

This message can be cited.

H. Pedersen, B. L. Jensen (CUO), A. J�rvinen (NOT) and 
M. I. Andersen (AIP) report:

On 2003 August 2.92 UTC, we observed the position of the VLA 
afterglow candidate (GCN #2280
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 , #2341
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 ; Coburn & Boggs 2003, 
Nature, 423, 415) with the 2.5-m Nordic Optical Telescope, 
La Palma. We obtained 10 R-band exposures, each of 10 min 
duration, in a seeing of 0.9" FWHM.

According to a standard calibration, we estimate that any 
unresolved object at the VLA position is fainter than 
m(R) = 25.4 (2 sigma).

A box-car smoothed 45" x 45" section is displayed on:

http://www.astro.ku.dk/~holger/g/GRB021206.gif