GRB 010629

GRB010629: A Gamma-ray Burst Localized by HETE

G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team;

R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor; N. 
Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. 
Pizzichini, and G. Prigozhin, on behalf of the HETE Operations and 
HETE Optical-SXC Teams;

N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, K.Torii, T. 
Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, and  C. Graziani, on 
behalf of the HETE WXM Team;

J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf 
of the HETE FREGATE Team;

write:


At 12:21:07.75 UTC (44467.75 s UT) on 29 June, the HETE FREGATE and 
WXM instruments detected and localized a bright GRB. The coordinates 
(J2000) of the 29 June burst are:

R.A. = 248.158 deg. (16h32m38s.3)

Dec. =  -18.723 deg. (-18o43'24")

The error circle for this localization is 15 arcmin in radius.

The burst duration in the 8-40 keV band was ~20 s, with two peaks 
separated by ~12 s. A total of ~11600 counts above background were 
detected during that interval, corresponding to a fluence of ~2 x 
10-6 ergs cm-2 . The peak flux was >3 x 10-7 ergs cm-2 s-1 (ie >10 x 
Crab flux).


Follow-up observations of this transient are encouraged.

Additional information on this burst detection (including light 
curves), as well as for the HETE mission, will be available at:

http://space.mit.edu/HETE/

Acronyms: HETE=High Energy Transient Explorer
FREGATE=French Gamma Ray Telescope
WXM=Wide Field X-ray Monitor
SXC=Soft X-ray Camera

This message is citeable.

K. Hurley, on behalf of the Ulysses GRB team, and E. Montanari,
C. Guidorzi, and F. Frontera, on behalf of the Beppo-SAX GRBM
team, report:

Ulysses and the BeppoSAX GRBM observed GRB010629 (HETE-II observation
in GCN 1075
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 ).  As observed by Ulysses, its duration was approx.
20 s, its 25-100 keV fluence was approx. 9 x 10^-5 erg/cm^2,
and its peak flux over 0.5 s was 1.4 x 10^-6 erg/cm^2 s. 

Triangulation gives an annulus centered at RA(2000),
Decl. (2000) = 198.208 deg., -37.333 deg., with radius 47.083 +/-
0.130 deg.  (3 sigma).  One circle of the annulus roughly bisects the
HETE-II error circle with intersection points RA(2000), Decl(2000)=

16 h 33 m 12 s, -18 o 55' 58" and
16 h 32 m 02 s, -18 o 31' 06"

The other circle of the annulus lies slightly outside the error 
circle, but comes close to grazing it at RA(2000), Decl(2000)=

16 h 31 m 43 s, -18 o 50' 07" .

Thus the combined HETE/IPN error region has a total area
of about 350 sq. arcmin., or approximately one-half that 
of the HETE error circle alone.

This annulus may be improved somewhat.

A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:

We have acquired single I-band images forming a mosaic
that covers about 90 percent of the intersection between the
HETE error circle (Ricker et al., GCN 1075
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 )
and the IPN annulus (Hurley et al., GCN 1076
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 ) for GRB010629.  The
images were taken around 010630.32 UT (19hrs after the burst)
with the NOFS 1.0m telescope under poor conditions.
Comparing with the DPOSS-II red plate for
this region, we estimate a limiting magnitude of about I=19.
No new objects are seen.  One object is most likely a
high proper motion star and is located approximately at
16:31:49.3 -18:31:38 (J2000)
with an I magnitude of 18.5; we provisionally match it with
a faint object about 10arcsec west on the POSS-II plate.
The lack of galaxies in this field suggests high extinction;
the field is at galactic latitude 19 degrees, but is
immediately above the galactic center (longitude=359).

J. P. Halpern & N. Mirabal (Columbia U.) report on behalf
of the MDM Observatory GRB team:

"Using the MDM 1.3m telescope, we obtained R-band images
covering the error box of GRB 010629 as defined by the
overlap of the HETE error circle (Ricker et al. GCN #1075
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 )
and the IPN annulus (Hurley et al. GCN #1076
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 ) beginning on
June 30 3:35 UT and ending at 7:50 UT.  These images are
deeper than the DSS.  We don't see any new object, but an
asteroid passed through the error box.  Moving west at a
rate of 27"/hour, it was located at 16:32:17.9, -18:49:59
(J2000) on June 30 4:34 UT.

Concerning the possible high proper motion star reported by
Henden (GCN #1077
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 ), we see both it and its neighbor 10" to
the west.  Therefore, it is a `new' object, but one of many
that are near the limit of the DSS.

The proximity of the moon has prevented useful follow-up
coverage from being made."

This message may be cited, although we can't imagine why.

M. I. Andersen (U. of Oulu), 
B. L. Jensen, J. Hjorth, H. Pedersen (U. of Copenhagen),
H. Kjeldsen, (U. of Aarhus), 
J. Gorosabel (DSRI, Copenhagen), J. U. Fynbo (ESO) report:

We have obtained optical follow-up observations of the central part 
of the HETE-2/IPN error box of GRB 010629 (cf. GCN ##1075,1076)
starting 11h 41m after the burst trigger. Using DFOSC on the
1.54-m Danish telescope, La Silla, covering a 13.7' by 13.7'
field of view, the following images were acquired:

2001 June 29 00:02 - 00:52 UT   Gunn I ; 3x900s  seeing = 1.50"
2001 June 30 02:50 - 03:57 UT   Gunn I ; 4x900s  seeing = 0.75"

centered on

RA(J2000)  =  16 32 27.5,  Dec(J2000) = -18 43 32

Our data analysis does not reveal any obvious afterglow candidate in 
this field, to an estimated limiting magnitude of 20.5. As noted by 
Henden (GCN #1077
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 ) this field has a high Galactic extinction 
(A_I=1.18 according to Schlegel et al. 1998), making the search for 
an afterglow intrinsically less deep. The proposed high proper motion 
star mentioned by Henden is not covered by our images, while the astroid 
mentioned by Halpern & Mirabal (GCN #1079
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 ) is seen in the images from 
June 30th.