GCN Circular 5107
Subject
GRB 060510B: Swift-BAT Refined Analysis
Date
2006-05-10T19:33:16Z (18 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
S. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/ORAU),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho),
H. Krimm (GSFC/USRA), M. Koss (GSFC/UMD), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/JSPS/USRA), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
on behalf of the Swift-BAT team:
Using the data set from T-239.0 to T+423 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060510B
(trigger #209352) (Krimm, et al., GCN 5096). The BAT
ground-calculated position is (RA,Dec) = 239.215, 78.597 deg
{15h 56m 51.6s, 78d 35' 48.7"} (J2000) +- 1.9 arcmin,
(radius, sys+stat, 90% containment). The partial coding was 96%.
The mask-weighted light curve shows a very long period of emission extending
from T+ ~25 sec to T+ ~330 sec. There are numerous (6-10) overlapping peaks
in the light curve, with the two brightest peaks at T+ ~140 sec
and T+ ~290 sec. T90 (15-350 keV) is 276 +- 10 sec (estimated error
including systematics). This stretched-out emission is consistent
with this burst being at high redshift (z=4.9, Price, GCN 5104).
We have only fragmentary event data after T+423 sec, but the onboard
mask-tagged light curves show no significant emission after this time.
The time-averaged spectrum from T-16.3 sec to T+326.1 sec is best fit by
a simple power-law model. The power law index of the time-averaged spectrum
is 1.76 +- 0.08. The fluence in the 15-150 keV band is
4.2 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured
from T+136.24 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.
Given a redshift of z=4.9, we compute Eiso to be 2.04 X 10^53 ergs
(88.5 - 885 keV in the rest frame.) This assumes a cosmology with
Omega_M=0.3, Omega_lambda=0.7 and H0=65.