GRB 100324A
GCN Circular 10544
Subject
GRB 100324A found in ground analysis of BAT data
Date
2010-03-24T17:57:55Z (15 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <james.r.cummings@nasa.gov>
J. R. Cummings (GSFC/UMBC) and D. M. Palmer (LANL)
on behalf of the Swift team
At 00:21:27 on March 24, 2010, Swift-BAT detected a rate increase. The
source was found onboard, but not at sufficient significance to trigger
an automated GRB followup response. A significant source was found in
ground analysis at RA, Dec 98.612, -9.735, which is:
RA (J2000) 06h 34m 26.8s
Dec (J2000) -9d 44' 6.4"
with an estimated uncertainty of 2.5 arcmin (radius, 90% containment).
The burst had multiple peaks with a T90 of about 6 seconds.
The spectrum of the burst is best fit with a simple powerlaw with a
rather soft index of 2.4 +- 0.3. The fluence in the range 15-150 keV
was 7 +- 3 x 10^-8 erg/cm^2 (68% confidence). The 1-second peak flux
from T-0.3 sec was 0.3 +- 0.1 photons/cm^2.
Because the burst was not triggered onboard, there are no automated
data products. A Swift TOO has been requested.
GCN Circular 10545
Subject
GRB 100324A: GROND observations
Date
2010-03-26T13:59:40Z (15 years ago)
From
Felipe Olivares Estay at MPE <felipe@mpe.mpg.de>
A. Updike (Clemson University), M. Nardini, A. Rau, F. Olivares, and
J.Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 100324A (ground analysis of Swift/BAT
data, Cummings et al., GCN #10544) simultaneously in g'r'i'z'JHK with
GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO
telescope at La Silla Observatory (Chile). Observations started on 24
March 2010 at 23:41 UT, 23.3 hours after the GRB. The field was
observed during a second epoch, starting at 00:10 UT on 26 March 2010,
47.9 hours after the burst.
Our i'-band and H-band observations cover 95% and 100% of the 2.5' BAT
error circle, respectively. Image subtraction between the two
observing epochs does not reveal any variable source. The first image,
consisting of 24.8 min exposure in g'r'i'z' and 20 min in JHK, yields
the following 3-sigma upper limits (both AB magnitudes):
i' > 23.6 mag
H > 21.6 mag
which were obtained using the GROND zero points and 2MASS field stars
as reference. The given magnitudes are not corrected for the
significant Galactic extinction corresponding to a reddening of E(B-V)
= 0.71 mag (Schlegel et al. 1998).