GRB 090708
GCN Circular 9621
Subject
GRB 090708: Swift detection of a burst
Date
2009-07-08T03:48:33Z (16 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. B. Markwardt (CRESST/GSFC/UMD), K. L. Page (U Leicester),
D. M. Palmer (LANL), A. Rowlinson (U Leicester),
T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU), M. A. Stark (PSU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:
At 03:38:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090708 (trigger=356776). Swift did not slew because of
Sun constraint. The BAT on-board calculated location is
RA, Dec 154.629, +26.637 which is
RA(J2000) = 10h 18m 31s
Dec(J2000) = +26d 38' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows single peak
with a duration of about 20 sec. The peak count rate
was ~900 counts/sec (15-350 keV), at ~3 sec after the trigger.
Due to an observing constraint, Swift cannot slew to the BAT position,
and it will not be observable until early October.
There will thus be no XRT or UVOT data for this trigger.
Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.nasa.gov).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular 9622
Subject
GRB 090708: ROTSE-III Optical Limits
Date
2009-07-08T03:58:49Z (16 years ago)
From
Fang Yuan at ROTSE <yuanfang@umich.edu>
F. Yuan (U Mich), E.S. Rykoff (UCSB), H. Flewelling (IfA/Hawaii), T.
Guver (U Arizona), S. B. Pandey (U Mich), W. Rujopakarn (Steward),
report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
090708 (Swift trigger 356776; Krimm et al., GCN 9621), producing
images beginning 7.4 s after the GCN notice time. An automated
response took the first image at 03:39:04.5 UT, 49.2 s after the
burst, under fair conditions. We took 10 5-sec, 10 20-sec and 10 60-
sec exposures. These unfiltered images are calibrated relative to USNO
A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle, for both single images and coadding
into sets of 10. Individual images have limiting magnitudes ranging
from 14.8-16.1; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
03:39:04.5 03:39:09.5 5 15.0 49.2 N
03:39:04.5 03:40:11.6 67 16.6 49.2 Y
03:40:27.8 03:45:35.8 308 17.4 132.5 Y
GCN Circular 9623
Subject
GRB 090708, Swift-BAT refined analysis
Date
2009-07-08T14:26:44Z (16 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 090708 (trigger #356776)
(Krimm, et al., GCN Circ. 9621). The BAT ground-calculated position is
RA, Dec = 154.632, 26.616 deg which is
RA(J2000) = 10h 18m 31.7s
Dec(J2000) = +26d 36' 58.7"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 27%.
The main pulse began at T-2 sec, peaked at ~T+4 sec and decayed by
~T+16 sec. There is a hint of some low-level emission out to ~T+100 sec.
At T+160 sec, a pre-planned slew took the burst out of the BAT field of
view. T90 (15-350 keV) is 15.0 +- 3.9 sec (estimated error including
systematics).
The time-averaged spectrum from T-1.3 to T+17.7 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.78 +- 0.22. The fluence in the 15-150 keV band is
6.9 +- 1.0 x 10-7 erg/cm2. The 1-sec peak photon flux measured from
T+3.37 sec in the 15-150 keV band is 1.3 +- 0.3 ph/cm2/sec. All the
quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/356776/BA/
GCN Circular 9624
Subject
GRB 090708: Early RAPTOR Optical Limits
Date
2009-07-08T20:31:21Z (16 years ago)
From
James Wren at LANL <jwren@nis.lanl.gov>
J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman
of Los Alamos National Laboratory report:
The RAPTOR telescope system responded to Swift trigger
356776 (Krimm et al., GCN 9621) under good observing conditions.
A nearly full moon was above the horizon at the time of the
observations, limiting sensitivity. Our narrow-field instruments
began observing the location at 03:39:05.87 UTC, 50.62 s after
the Swift trigger (6.9 s after receipt of GCN message). The data
from our R-band filtered system was calibrated to the USNO-B1
catalog. These data show no new source within the BAT error
circle (Palmer et al., GCN 9623) when compared to the DSS. We
can put the following R-band (Cousins) limits on the emission:
t-mid(s) exp(s) mag mag-err
[since trigger]
----------------------------------------------------
61.59 5.0 16.2 3 sigma limit
101.85 30.0 17.3 3 sigma limit
GCN Circular 9631
Subject
GRB 090708 : Fermi GBM detection
Date
2009-07-09T11:38:49Z (16 years ago)
From
Sheila McBreen at MPE <smcbreen@mpe.mpg.de>
S. McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:
"At 03:38:18.46 UT on 08 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090708 (trigger 268717100 / 090708152)
which was also detected by the Swift-BAT (Krimm et al. 2009, GCN 9621).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 55 degrees.
The GBM light curve consists of one pulse
with a duration of about 18 s (8-1000 keV).
The time-averaged spectrum from T0-2.0 s to T0+16.2 s is
adequately fit by a power law function with an exponential
high energy cutoff. The power law index is -1.29 (+0.41/-0.34)
and the cutoff energy, parameterized as Epeak, is
47.5 (+12.0/-9.5) keV (chi squared 359 for 361 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
about 4E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.1 s in the 8-1000 keV band
is 1.0 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."