GRB 030601

V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski,
I.Chilingarian, M.Kuznetsov,  S.Potanin, V.Vitrischak, G.Antipov

Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow

After GRB030601 alert (HETE 2728) MASTER robotic telescope
(http://observ.pereplet.ru) had automatically pointed to the corresponding
area of the sky (105 seconds after trigger time). There were clouds near
the horizont and they were imaged on the CCD frame. First measurable image
of the error box area was taken 55 minutes after the burst. No optical
counterpart was visible up to 12th magnitude in R band. We had been
observing about 90% of the error box area for almost 3 hours. On the last
image taken on 21:26UT (3h13m after the burst) no optical counterpart is
visible up to 15th magnitude in R band. We had to stop our observations
because of rain with possible thunderstorm.

Observations were made under bad weather conditions (clouds + low altitude
above the horizont, 25 degrees at culmination + bright sky because of high
Moscow's latitude).

These are preliminary results.

This message may be cited.

K. Hurley, on behalf of the Ulysses GRB team,

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

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

T. Cline, on behalf of the Ulysses and Konus GRB teams, report:

Ulysses, Konus-Wind, and INTEGRAL (SPI-ACS)  observed this GRB at 79919
seconds.  As observed by Ulysses, it had a duration of approximately 20
seconds, a 25-100 keV fluence of approximately  6.5E-06 erg/cm2, and a
peak flux of approximately  7.5E-07 erg/cm2 s over 0.25 seconds.

We have triangulated it to a preliminary annulus centered  at RA,
Decl(2000)= 151.992, +33.205 degrees, whose radius is 89.122 +/-  0.029
degrees (3 sigma).

This annulus can be constrained and/or improved, but as the event was
not observed by Mars Odyssey, a small error box cannot be derived for
it.