GRB 060424
GCN Circular 5000
Subject
GRB 060424: Swift detection of a burst
Date
2006-04-24T04:36:02Z (19 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
E. Rol (U Leicester), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL) and
D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 04:16:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060424 (trigger=206773). Swift was not able to slew to the
burst due to its proximity to the Sun. The BAT on-board calculated
location is RA,Dec 7.355, +36.820 {00h 29m 25s, +36d 49' 11"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a small spike on top
of a weak peak starting about T-5 sec to about T+5 sec.
The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec
after the trigger.
Because of the Sun observing constraint, there will not be any XRT
or UVOT follow-up observations on this burst for at least 24 days.
GCN Circular 5001
Subject
GRB 060424: Refined analysis of the Swift-BAT burst
Date
2006-04-24T15:20:49Z (19 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
D. Hullinger (BYU-Idaho), L. Barbier (GSFC), S.D. Barthelmy (GSFC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-240 to T+734 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 060424 (trigger #206773)
(E.Rol, et al., GCN 5000). The BAT ground-calculated position
is RA,Dec = 7.354,+36.789 deg {0h 29m 25.1s,+36d 47' 20.7"} (J2000)
+- 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 53%.
The mask-weighted lightcurve has 5 main peaks at T-18, T-4, T+2,
T+9, and T+20 sec with widths ranging from 4 to 8 sec FWHM.
T90 (15-350 keV) is 37 +- 2 sec (estimated error including systematics).
Swift did not automatically slew to this new burst because of the
Sun observing constraint. It did slew to a pre-planned observing target
at T+160 sec and the new burst went out of the BAT FOV at T+240 sec.
The time-averaged spectrum from T-19.6 to T+20.6 is best fit by
a simple power-law model. The power law index of the
time-averaged spectrum is 1.72 +- 0.19. The fluence in the
15-150 keV band is 6.8 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak
photon flux measured from T+0.11 sec in the 15-150 keV band is
1.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90%
confidence level.
GCN Circular 5003
Subject
GRB060424: optical afterglow detection
Date
2006-04-25T08:25:50Z (19 years ago)
From
Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr <cthoene@astro.ku.dk>
Christina C. Thoene, Kim Nilsson, Brian L. Jensen, Johan Fynbo (Dark
Cosmology Centre) report
We observed the BAT error circle of GRB060424 (GCN 5000) in I with the NOT
and ALFOSC on La Palma, starting at UT 05:03:40 at very high airmass.
Inside the BAT revised error circle (GCN 5001) we detect a new source at
the position (J2000)
RA = 00:29:25.8
Dec =+36:47:58.7
The preliminary I magnitude obtained from 5x300s stacked images with a
mean time of about 1h after the burst is
I = 19.1
(compared to a nearby USNO star)
The source is not visible in observations obtained the following night and
therefore likely to be the afterglow of GRB060424
A finding chart will be available soon at:
http://www.astro.ku.dk/~brian_j/grb/grb060424.178/