GRB 010412

BeppoSAX GRB ALERT: GRB010412


On Apr. 12, 21:46 U.T. a  GRB has been detected simultaneously by the GRBM and WFC1
aboard BeppoSAX.

Preliminary  coordinates from WFC are:

R.A.(2000)= 294.89
DEC.(2000)= 13.62

The error radius at this stage of analysis is 10'.

We are not planning a follow-up observation of this burst, due to the
on-going pointing of another TOO

Luigi Piro
BeppoSAX Mission Scientist

GRB010412: refined positions


Refined  coordinates from WFC are:

R.A.(2000)= 294.913
DEC.(2000)= 13.618

The error radius  is 6'.

Luigi Piro
BeppoSAX Mission Scientist

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

Ulysses and BeppoSAX GRBM observed this burst (GCN 1035
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 ).
As observed by Ulysses, it had a duration ~80 s, a 25-100
keV fluence of 9.4x10^-6 erg/cm^2, and a peak flux over
0.5 s of ~9 x 10^-7 erg/cm^2 s.  These numbers are subject
to more than the usual uncertainties because Ulysses is
recording a solar proton event which raises its background
by a factor of 2 or so.  Triangulation gives an annulus
centered at RA(2000), Decl(2000)=3.671, -21.012 deg., with
radius 75.856 +/- 0.034 deg. (3 sigma).  This intersects the
WFC error circle to form an error box whose area is approximately
47 sq. arcmin. and whose corners are at

          RA(2000)                             DEC(2000)
     294.842577=19 h 39 m 22.22 s      13.545103= 13 o 32 ' 42.37 "
     294.929439=19 h 39 m 43.07 s      13.716716= 13 o 43 '  0.18 "
     294.906675=19 h 39 m 37.60 s      13.518189= 13 o 31 '  5.48 "
     294.990525=19 h 39 m 57.73 s      13.683762= 13 o 41 '  1.54 "

This error box can be refined by further processing.

A. Paolino, BeppoSAX Scientific Operation Centre (SOC), Telespazio, Rome,
R.G. Kaptein, SOC and Space Research Organisation Netherlands (SRON),
Utrecht, J.J.M. in 't Zand, Astronomical Institute, Utrecht University
and SRON, C. Guidorzi and F. Frontera, Phys. Dept. University of Ferrara, 
L. Amati, Istituto TESRE / CNR, Bologna and  L. Piro, Istituto di
Astrofisica Spaziale / CNR, report:
 
"GRB010412 was triggered by the BeppoSAX Gamma Ray Burst Monitor (GRBM)
on April 12.907280 U.T and was also detected by the Wide Field
Camera (WFC) unit 1 onboard the same satellite.  A preliminary analysis of
the GRBM data shows a very complex, multi-pulse time profile.  The
duration is about 75 s and the peak count rate 1896 +/- 59 cts/s,
corresponding to a 1 s peak flux of (1.71 +/- 0.06) x 10^(-6) erg/cm2/s
in the 40-700 keV energy band.  The WFC data show a duration of about 90 s
and a peak flux of 2.3 Crab (2-28  keV).  The position of the X-ray
counterpart is R.A.= 19h 39m 39.0s, Decl.=+13d 37'06.6' (equinox 2000.0)
with an error radius of 6', that includes uncertainties due to a
non-optimum attitude control configuration.  No follow-up observation with
the BeppoSAX NFI was scheduled, due to an on-going other TOO."
 
This message may be cited.

P.A. Price, T.S. Axelrod and B.P. Schmidt (RSAA, ANU) report:

"We have observed the error box of GRB 010412 (Piro et al., GCN #1033
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 ;
Hurley et al., GCN #1036
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 ) with the robotic 50-inch telescope at Mount
Stromlo Observatory at 2001 Apr 13.73 UT.  Our 3x300 sec exposures
cover the entire error box to a limiting magnitude of R ~ 20.0 mag,
based on common stars with the USNO-A2.0 catalogue.  We do not detect
any optical transient within the error box, based on visual comparison
with the Digital Palomar Sky Survey.  The high stellar density and large
Galactic reddening (A_V ~ 1.5 mag) at this low Galactic latitude (-4.2 deg)
may, however, obscure a potential OT."

This message may be cited.

P.A. Price (Caltech/RSAA,ANU), P. Gorham (JPL), S.A. Yost and S.R. Kulkarni
(Caltech) report on behalf of the larger Caltech/NRAO/CARA GRB collaboration:

"P. Gorham observed the error box of GRB 010412 with the Palomar 60-inch
telescope around 2001 Apr 13.5 UT (0.6 days after the GRB).  The observations
consisted of 2x450 sec integrations in I-band at each of four pointings to
cover the entire original error-circle (GCN #1033
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 ).  Within the IPN error-box
(GCN #1036
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 ), we find no optical transient, on visual comparison with the
Digital Palomar Observatory Sky Survey plates.  We estimate the limiting
magnitude of our images to be I ~ 20.5 mag."

This message may be cited.

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

We have acquired shallow BVRcIc all-sky photometry for
an 11x11 arcmin field that covers the center of the
error box for GRB010412 with the USNOFS 1.0-m telescope
on one photometric night.  Stars brighter than
V=13.5 are saturated and should be used with care.
We have placed the photometric data on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb010412.dat
The current photometry has a potential external zero-point
error of about two percent.  The astrometry in this file
is based on linear plate solutions with respect to USNO-A2.0.
The internal errors are less than 100mas.
  Since this is a crowded field, you should check the DSS images
and only use stars for calibration that do not have neighbors.
Further calibration of this field will be performed if
an optical afterglow is identified.