GRB 040403

D. Gotz, S. Mereghetti (IASF, Milano), J. Borkowski, M. Beck (ISDC) on
behalf of the IBAS Localization Team, S. Shaw on behalf of the INTEGRAL
Science data Centre (ISDC) and the INTEGRAL Science Working Team report:

A 35 s long GRB has been detected with the INTEGRAL Burst Alert System
(IBAS) on April 3 at 05:08:08 UT. The GRB has been detected with
IBIS/ISGRI in the 15-200 keV band. Its coordinates (J2000) are:

R.A. 07h 40m 55s
Dec. 68deg 12' 39''

with an uncertainty of 3 arcmin.

The preliminary peak flux in the 20-200 keV range is about 0.4
photons/cmsq/s (3 x 10^-8 erg/cmsq/s) (1 s integration time). From the
preliminary spectral analysis this GRB seems to be X-ray rich.

Further analysis is underway.

This message can be cited.

J. Moran, M. Nysewander, and D. Reichart report on behalf of the FUN GRB
Collaboration:

We imaged the entire ~30 square arcminute error circle of the INTEGRAL GRB
040403 (Gotz et al., GCN 2560
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 ) with the 0.6-meter Morehead Observatory
telescope beginning 70 minutes after the burst.  We integrated in Rc for
4440 seconds under non-ideal conditions.

Visual comparison to the DSS/POSS2-Red reveals no obvious new source to our
limiting magnitude (Rc ~ 19 mag).

I. Khamitov, Z. Aslan, M. Parmaksizoglu (TUG), 
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), 
I. Bikmaev, N. Sakhibullin (KSU)

report:

We observed the entire error circle of INTEGRAL GRB 040403 (Gotz et al., GCN
2560
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 ) in R band, with 1.5-m Russian-Turkish Telescope RTT150 at Bakyrlytepe,
Turkey. The observations were started at 17:22 UT and lasted for few hours
under bad seeng conditions (2--3'') and bright moon. We detected no source
brighter than R=21.0, which is variable for more than 0.2 mag.

This message may be cited.

P. Tikkanen and A. Oksanen on behalf of Nyrola observatory GRB Team 
and AAVSO International High Energy Network report:

A 24 x 16 arcmin field covering the INTEGRAL error circle of GRB
040403 (GCN 2560
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 ) was imaged with the 0.4m SCT of the Nyrola
Observatory starting at April 3, 2004 20:05 UT, 15.0 hours 
after the burst. Observation was taken under quite poor conditions,
bright moonlight, northern lights and moderate seeing.
 
Total of 53 four minute Rc-exposures, exposure time of 12720 seconds, 
were sigma reject combined and compared against the Digitized Sky 
Survey (DSS2R). 

No new objects brighter than DSS2 plate limit was detected, but some 
fainter objects were also present inside error circle. The faintest 
stars on the combined image are about Rc=20.4 (USNOA2.0 reference).

The combined image is available on web:
http://nyrola.jklsirius.fi/grb/grb040403

Nyrola observatory wants to express gratitude to AAVSO for loaning
the CCD camera and to Wihuri foundation for generous grants for the 
observatory.

The AAVSO International High Energy network is grateful for a
generous grant from the Curry Foundation and to NASA for the 
financial support for the High Energy Workshops for Amateur 
Astronomers.

Kuntal Mishra on behalf of the GRB team reports:

We observed the error circle of INTEGRAL GRB 040403 (Gotz et al., GCN
2560
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 ) in R band,
with 1.0-m telescope at Nainital (India) on April 03, 2004 starting at
16:44 UT. We found no
new source brighter than R = 19.5 when comparing with DSS-2 R-band chart
(USNOA2.0 reference).


Ms.KUNTAL MISHRA (JRF)                email: kuntal@upso.ernet.in
STATE OBSERVATORY,                         : kuntal_mishra@yahoo.com
MANORA PEAK, NAINITAL                 Phone: (91-05942) 235136, 235583
UTTARANCHAL 263 129                   Fax  : (91-05942) 235126, 235053
INDIA.                                Gram : Astronomy

V.Rumyantsev (CrAO) and A.Pozanenko (IKI) report:

We have obtained 10 unfiltered images (300 s exposure each) of the GRB040403
error box (D.Gotz et al., GCN 2560
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 ). The images were taken with the AT-64
telescope  of Crimean Astrophysical observatory and cover the period  UT
17:48:54 - 18:37:24 of  April 3, 2004.

No afterglow candidate was  found in comparison with DSS2. We estimated the
limiting magnitudes of combined image (S/N=3) as following

Start time (UT)       telescope   exposure    limiting mag.
Apr. 03  17:48        AT-64     10x300 s      20.0

Combined image can be found at http://grb.rssi.ru/GRB040403/

This message can be cited.

GRB 040403, deep optical observations
----------------------------------------------

A. de Ugarte, A. Sota, J. Gorosabel and A. J. Castro-Tirado
(Instituto de Astrofísica de Andalucía, IAA-CSIC, Granada),
and J. M. Castro Cerón (STScI, Baltimore)

communicate:

"We observed the field of the X-ray rich GRB 040403 detected
by INTEGRAL (GCN Circ. 2560
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 , Gotz et al.) starting on 3 Apr
2004 (20:00 UT)  with the 1.5 m telescope at the Observatorio
de Sierra Nevada in Granada. Imagery was obtained in the R-
band (6 x 600 s). Comparison images were adquired on 4 and 20
Apr 2004 (9 x 600 s). No optical variable source is detected
within the 3' radius error box provided by IBIS/IGRIS down
to a limiting magnitude of 22.2 (3 sigma) 15 hr after the
event. This might be indicative of a dark GRB."

This message may be cited.