GRB 100331A
GCN Circular 10555
Subject
GRB 100331A: A long GRB detected by INTEGRAL
Date
2010-03-31T06:29:12Z (15 years ago)
From
Sandro Mereghetti at IASF/CNR <sandro@iasf-milano.inaf.it>
S.Mereghetti, A. Paizis, (IASF- Milano), D.Gotz (CES-Saclay), E. Bozzo,
C. Ferrigno, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on
behalf of the IBAS Localization Team report:
a long GRB has been detected by IBAS in IBIS/ISGRI data at 00:30:30 UT of
March 31. The refined coordinates (J200) are
RA: 261.0831 [degrees]
DEC: -58.943 [degrees]
with an uncertainty of 2.5 arcmin
The lightcurve shows a single peak lastiing about 15 s. A preliminary
analysis gives a 20-200 keV fluence of 4 10e-7 erg/cm2 and a peak flux of
0.5 ph/cm2/s (1 sec bin).
A plot of the light curve will be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
This message can be cited.
[GCN OPS NOTE(31mar10): Per author's request, the typo "January 31"
in the first sentence was changed to "March 31".]
GCN Circular 10557
Subject
GRB 100331A: BOOTES-3 observations
Date
2010-03-31T10:13:18Z (15 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (INAF-OAB), A.J. Castro-Tirado, J. Gorosabel,
M. Jelinek (IAA-CSIC), P. Kubanek (IPL UV, IAA-CSIC),
R. Cunniffe, S. Guziy (IAA-CSIC), P. Yock (Auckland Univ.), W.H.
Allen (Vintage Lane Obs.), I. Bond (Massey Univ.), G. Christie
(Stardome Obs.), report on behalf of a larger collaboration, report:
We have observed the field of the INTEGRAL GRB 100331A
(Mereghetti et al. GCN 10555) using the 0.6 Yock-Allen robotic
telescope (BOOTES-3) located in Blenheim, New Zealand starting
at 07:12 UT (6.7 hours after the burst). In a 35x60s combined exposure
with clear filter, obtained under non optimal conditions, we do not
detect any new source within the full INTEGRAL error circle down to a
3-sigma limiting magnitude of R~17.8. Further analysis is ongoing.
GCN Circular 10558
Subject
INTEGRAL trigger 5994 / GRB 100331A: GROND detection of a variable source
Date
2010-03-31T15:23:42Z (15 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
Adria Updike (Clemson University), Arne Rau, Felipe Olivares, and
Jochen Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 100331A (INTEGRAL trigger 5994; S.
Mereghetti et al., GCN 10555) simultaneously in g'r'i'z'JHK with GROND
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI
telescope at La Silla Observatory (Chile).
Observations started at 03:55 UT on March 31st 2010, 3.42 hours after the
Swift trigger, and a second epoch was obtained starting at 09:37 UT. They
were performed at an average seeing of 1" and at airmasses of 2.4
and 1.15, respectively.
We found a single variable point source within the 2.5' INTEGRAL error
circle reported by S. Mereghetti et al. at
RA (J2000.0) = 17h 24m 18.61s
DEC (J2000.0) = -58d 56' 52.0"
with an uncertainty of 0.5" in each coordinate. From the last epoch we
estimate preliminary magnitudes (all in AB system) of the
g' = 16.7 +/- 0.1 mag,
r' = 16.3 +/- 0.1 mag,
i' = 16.4 +/- 0.1 mag,
z' = 16.2 +/- 0.1 mag,
J = 16.3 +/- 0.1 mag,
H = 16.5 +/- 0.1 mag
K = 16.9 +/- 0.1 mag,
calibrated against GROND zeropoints, and not corrected for the expected
galactic foreground extinction of E(B-V)=0.12 mag (Schlegel et al. 1998).
During the observations the source varied by 0.4 mag in the g' and only
0.2 mag in J, with no obvious fading over the 5.5 hrs. Both, the SED shape
and the color evolution are different from any GRB afterglow observed so far
with GROND. Though the object lies within 20 arcsec of the center of the
INTEGRAL error circle, and the chance coincidence with a variable object
within the 2.5 arcmin error circle is about 10^-4, the relation of this
variable to the INTEGRAL trigger is likely, but cannot be proven at this
stage.
We note the presence of an object in both, USNO and 2MASS at the location
of the variable source. The 2MASS magnitudes are similar to our last epoch,
bright state measurement, indicating that this object is a long-term variable.
This excludes that this object is an host galaxy unresolved in our images.
Spectroscopic observations are encouraged to establish the nature of
this source.
GCN Circular 10559
Subject
INTEGRAL trigger 5994 (GRB100331A): Swift/XRT observations
Date
2010-03-31T23:33:37Z (15 years ago)
From
Valerio D'Elia at INAF-OAR <delia@oa-roma.inaf.it>
G. Stratta, V. D'Elia, M. Perri (ASDC) report on behalf of the Swift Team:
Swift began a target of opportunity observation of the INTEGRAL detected
GRB 100331A (Mereghetti et al., GCN #10555), at 14:29UT on March 31st, 2010,
approximately 14 hours after the INTEGRAL detection. In 1890 s of Photon
Counting mode data, no X-ray source is detected inside the INTEGRAL error cirlce.
This circular is an official product of the Swift-XRT team.
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