GRB 020812

G.Beskin, A.Birjukov, S.Koposov, O.Spiridonova (SAO), S.Bondar' (Kosmoten)
and A.Pozanenko (IKI) report:



We have observed the error box of GRB020812 (HETE trigger 2257, GCN 1468
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 )
with Zeiss-1000 telescope of Special Astrophysical Observatory (SAO) on
August 13 20:01 UT. R-band image of  6.9'x 6.9' with exposure time of 303
sec was centered to coordinates reported in GCN 1481
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 .  The limiting
magnitude of the image is R~22 (3 sigma). No new objects were found in
comparison with DSS2.



The image may be found at http://grb.rssi.ru/GRB020812



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G. Masi, F. Mallia and U. Tagliaferri (Campo Catino Astronomical
Observatory, Italy) report:

On Aug. 14.069 2002 UT, we imaged the field around the position provided
by Pozanenko et al. (GCN 1479
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 ) with the 0.8m-f/8 + CCD from Campo Catino
Astronomical Observatory. The R-images, covering a field of about 5.5' x
5.5', do show nothing obvious down to R = 19.0 (based on USNO A2.0).

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M. Uemura, R. Ishioka, T. Kato (Kyoto U) and H. Yamaoka (Kyushu U) report
on behalf of VSNET-grb collaboration:

  "We have performed a full analysis of the unfiltered images of GRB
020812 field taken at Kyoto University.  A 30-cm telescope observed
the central part of the on-board HETE WXM error box, and a 25-cm
telescope observed three fields of view, each of which covered a part
of HETE WXM error box (GCN 1468
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 )
(http://www.rc.kyushu-u.ac.jp/~yamaoka/GRB020812/FOVkyoto.gif). 
The limiting magnitudes are measured by compareing with USNO-A2.0 red
magnitudes.  

FOV	  25-cm 1	 25-cm 2	 25-cm 3 	30-cm 
epoch	 11:36-13:25	13:27-13:57	13:57-15:32	11:40-13:26 Aug. 12 UT+
exp.	 85		25.5		80		83.5	minutes
lim.mag  18.7		18.6		18.8		19.1	in R

  By comparison with DSS 2 red image and Ouda images (GCN 1515
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 ),
no new source brighter than the limits nor notable variable is
detected."

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H. Ohashi, T. Kato, T. Senda, H. Mii, K. Mizuno, Y. Yasaka (Kyoto U)
and H. Yamaoka (Kyushu U) report on behalf of VSNET-grb collaboration:

  "We have performed a full analysis of the R band images of GRB 020812
field taken at Ouda (GCN 1469
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 ).  Three fields of view (14 arcminutes
square) were observed, each of which covered a part of HETE WXM error
box (GCN 1468
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 ) (http://www.rc.kyushu-u.ac.jp/~yamaoka/GRB020812/FOVouda.gif).
The limiting magnitudes are measured by compareing with USNO-A2.0 red
magnitudes.  "Coverage" shows the percentage of covered area of the
HETE WXM error box.

FOV	   1		   2		   3
center	 20:38:28.8	20:38:21.0	20:38:53.3	R.A.
(J2000) -05:17:58	-05:17:24	-05:23:45	Dec.
epoch	 11:08-12:03	12:05-13:27	13:34-16:59	Aug. 12 UT + 
exp.	 38		73		156		minutes
lim.mag  18.9		20.2		21.2		in R
coverage 48%		30%		58%		
remark	 twilight

  By the comparison with DSS 2 red image, no new source brighter than
the limit of DSS 2 is detected.

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A. Arkharov (1), V. Larionov (2), A. Di Paola (3),
A. Antonelli (3)

1) Pulkovo Observatory (RU)
2) St.Petersburg University (RU)
3) Rome Astronomical Observatory (IT)

on the behalf of the GROAR Team, report:

We have imaged the error box of the GRB020812
(G. Ricker et al. GCN 1468
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 ) from Campo Imperatore
Observatory with the 1.1 meters AZT-24 telescope
and the SWIRCAM Near Infra-Red camera. Observations
started on 12-08-2002 20:19:44 UT and ended on 
12-08-2002 01:27:10 UT.

About 40% of the error box has been imaged at IR
wavelengths both in J and K bands. No new source has
been detected and the counterpart reported by A.Pozanenko
(GCN 1481
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 ) is not detected down to a limiting magnitude
of J 18 and K 17.

The images can be found at http://grb.mporzio.astro.it.

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Subject:  GRB020812: optical observations

E.Pavlenko (CrAO), V.Doroshenko (GAISh), S.Sergeev (CrAO),
O.Dudka (CrAO), A.Baklanov (Odessa Univ.),
N.Primak (Kiev Univ.), and A. Pozanenko (IKI) report:

We have observed the field 15'x15' of GRB 020812 (HETE trigger 2257, Seq. 3)
at two telescopes of the Crimean Astrophysical Observatory.
The optical candidate was not detected.
Following is the summary of observations.

Telescope  time (UT)   Exposure  Filter  Limit. mag
70 cm     Aug 12 20:18    120 c     R       17.5
38 cm     Aug.12 20:57    300 c     R       17

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T. Kawabata (BAO), T. Morishita (OPU), T. Hatayama (BAO visitor),
Y. Urata (Titech / RIKEN), and H. Yamaoka (Kyushu U) report:

  "A full analysis of Bisei Astronomical Observatory (BAO) images (GCN
1489
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 ) of GRB 020812 was performed.  The entire error box was imaged
five times with 12 no-filter pointing observations (60 seconds
exposure each) by 1.01-m BAO telescope.  
 
 set     Time(UT)
  1  Aug 12 14:00-14:28
  2  Aug 12 14:31-14:55
  3  Aug 13 15:19-15:40
  4  Aug 13 15:43-16:02
  5  Aug 13 16:07-16:28
 
  The limiting magnitude for each images is mag 19.1 (3 sigma,
compared with USNO-A2.0 red magnitudes), although some images are poor
because of thin clouds.  

  Comparison with DSS II red images, no new object was detected down
to the limiting magnitude.  Also, the comparison between our 
observations, no notable variable object was detected."

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T. Kawabata (BAO), T. Morishita (OPU), T. Hatayama 
T. Miyata, S. Nishiura, H. Mito on behalf of KISO GRB team, 
Y. Urata (Titech / RIKEN), H. Yamaoka (Univ. Kyushu) report: 


We have imaged the entire error box of GRB020812 (G. Ricker et al.=
GCN1468
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  ) with the Bisei Astronomical Observatory (BAO) 1.01 m
telescope (FOV 7.8'x5.2') with 12 nonfilter pointing observations
starting at Aug 12 14:00 UT and at Aug 13 14:30 UT.  

The optical transient candidate reported by A. Pozanenko et
al. (GCN1481
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 ) was not detected at either epoch with a limit comparable
to that of the DSS2 red image, or approximately R=19 estimated by
comparison with USNO-A2.0 (U0825_18548790).  

We also covered the entire error box with the KISO observatory 1.05 m
Schmidt telescope (FOV 50'x50') starting at Aug 12 15:08 UT.  The OT
candidate was not detected.  

Following is the summary of the observations.  

   Site   Time (UT)  Exptime  Filter Limit mag.
   BAO     14:20      60 s    no     19  
   BAO     14:48      60 s    no     19  
   KISO    15:08     900 s     R     17

Further analysis is in progress.  

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A. Piccioni, C. Bartolini, I.Bruni, A. De Blasi, A. Guarnieri (Bologna 
University and Bologna Astronomical Observatory), F. Giovannelli 
(Istituto di Astrofisica Spaziale-CNR) and G. Pizzichini (IASF-CNR, 
Sezione di Bologna) report: 

On 2002 August 12, 20h18m35s UT we started observations of the error box 
of GRB 020812 (GCN 1468
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 ) with the 152 cm telescope in Loiano, (R band, 
2x600 + 2x780 + 10x900 sec exposures). Observations of the field ended on 
August 13, 01h49m42s UT.
Coverage of the entire error box was performed two times.
By visual inspection in our frames there is no new source brighter than 
the limit of DssII.
The field containing the brigt object mentioned in GCN 1479
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  was imaged on 
August 12, 21h17m54s UT, i.e. 2.5 hours after the detection of the possible
afterglow candidate. Our frame, somewhat deeper than DssII, does not reveal 
any new object. 
Our images can be retrieved by sftp at 'ermione.bo.astro.it', 
username 'publicGRB', password 'GRB_bo', starting on August 16.

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There was a misprint in GCN 1479
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  in the name of GRB.
The corrected text is below.

A.Pozanenko (IKI), S.Bondar' (Kosmoten),  G.Beskin  (SAO) and V.  Rumyantsev
(CrAO)  report:

We have observed the entire error box of GRB020812 with 600mm automated
telescope TT600 of Kosmoten observatory. Observation started after HETE
Ground Analysis (HETE 2257,  Seq_Num: 3). Unfiltered mosaic images were
obtained on Aug 12 between 18:52  - 18:55 (UT) with image exposure of 2.56
sec. Limiting magnitude of the observation is about 16.5.

We have found a new object, which is not present on DSS.
The coordinates of the object are:

RA=  20h38m51s  DEC= -05o31'14" (J2000)

with uncertainty of  4" in both coordinates.
Using USNO-A2.0 we estimate brightness of the object about 14.5 m.
We have no images taken later, so the nature of the object in unclear.

This message is citeable.

A.Pozanenko (IKI), S.Bondar' (Kosmoten),  G.Beskin  (SAO) and V.  Rumyantsev
(CrAO)  report:


We have observed the entire error box of GRB 020127 / HETE #1902 with 600mm
automated telescope (T600 of Kosmoten observatory. Observation started
after HETE Ground Analysis (HETE 2257,  Seq_Num: 3). Unfiltered mosaic
images were obtained on Aug 12  18:52  (UT) with fixed image exposure 2.56
sec. Limiting magnitude of the observation is about 16.5.

We have found a new object which is not present on DSS.
The coordinates of the object are:

RA=  20h38m51s  DEC= -05o31'14" (J2000)

with uncertainty of  4" in both coordinates.
Using USNO-A2.0 we estimate brightness of the object about 14.5 m.

This message is citable.

H. Ohashi, T. Kato, T. Senda, H. Mii, K. Mizuno, Y. Yasaka (Kyoto Univ.)
report on behalf of VSNET-grb collaboration:

"We have observed the field of GRB 020812 (HETE trigger 2257) with R band
exposures using the 60-cm RC telescope at Ouda station starting at Aug. 12
11:09 UT (28 min after the burst).  We imaged the field (field size 20
arcmin) centered at the first localization (HETE #2257, Seq_Num 2)
until 13:30 UT.  We have been imaging the field centered at the second
localozation (HETE #2257, Seq_Num 3) since 13:33 UT.  Preliminary
visual inspection of the images has not revealed a new object down
to R=18.  Further analysis and observation are in progress."

This message may be cited.

G. Ricker, J-L Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of
the HETE Science Team;

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

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

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

write:


At 10:41:43.98 UTC (38503.98 s UT) on 12 Aug 2002, the HETE FREGATE and
WXM instruments detected event H2257, a long GRB.  The WXM flight
localization was correct and was reported in a GCN Position Notice at
10:50:48 UT, 9 min 4 sec after the burst.  Ground analysis produced a
refined location, which was reported in a GCN Position Notice at
13:19:48 UT, 158 minutes after the burst.  This location can be
expressed as a 90% confidence rectangle that is 10 arcminutes by 25
arcminutes and is centered at

RA = 20h 38m 48s, Dec = -05o 23' 34" (J2000).


The corners of the location rectangle lie at the following J2000
coordinates:

RA = 20h 39m 18s, Dec = -05o 35' 06"
RA = 20h 38m 38s, Dec = -05o 36' 36"
RA = 20h 38m 17s, Dec = -05o 12' 03"
RA = 20h 38m 57s, Dec = -05o 10' 34".


In the FREGATE 8-40 keV band, the burst had a duration of ~20 seconds.
A  total of 1741 net counts were detected in the 8-40 keV band during
this interval, corresponding to a fluence of ~3.1 x 10-7 ergs cm-2.  The
peak flux averaged over 0.5 s was 4.9 x 10-8 ergs cm-2 s-1 (i.e., 1.6 x
Crab flux).  In the WXM 2-25 keV band, the burst had a duration of ~20
seconds.  The WXM localization SNR was 6.3 in the X-detector and 8.3 in
the Y-detector.

Further information (including a light curve) for GRB020812 is provided
at the following URL:

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

This message is citable.