GRB 130919A
GCN Circular 15232
Subject
GRB 130919A: Swift detection of a burst
Date
2013-09-19T11:18:50Z (12 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
H. A. Krimm (CRESST/GSFC/USRA), A. A. Breeveld (UCL-MSSL),
D. N. Burrows (PSU), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
C. B. Markwardt (NASA/GSFC), A. Melandri (INAF-OAB),
K. L. Page (U Leicester), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU) and T. N. Ukwatta (MSU) report on behalf of the
Swift Team:
At 11:07:24 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130919A (trigger=571271).
The BAT on-board calculated location is
RA, Dec 207.288, -10.355 which is
RA(J2000) = 13h 49m 09s
Dec(J2000) = -10d 21' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a broad peak of
at least 60 seconds duration. This was an image trigger, so the
currently available light curve does not show significant structure.
Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 23:23 UT on 2013 December 7. There will thus be no XRT
or UVOT data for this trigger before this time.
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 15234
Subject
GRB 130919A, Swift-BAT refined analysis
Date
2013-09-20T02:27:56Z (12 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
A. Y. Lien (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130919A (trigger #571271)
(Krimm, et al., GCN Circ. 15232). The BAT ground-calculated position is
RA, Dec = 207.281, -10.353 deg which is
RA(J2000) = 13h 49m 07.5s
Dec(J2000) = -10d 21' 11.0"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 77%.
The burst came into the BAT field of view at ~T-60 seconds, following a pre-planned
slew and another slew took it out of the field at around T+215 seconds.
mask-weighted light curve shows a broad peak from T-30 s to T+70 s, with at least
six subpeaks superimposed. T90 (15-350 keV) is 97.3 +- 25.1 sec (estimated error
including systematics).
The time-averaged spectrum from T-20.15 to T+108.07 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.54 +- 0.73,
and Epeak of 71.7 +- 31.8 keV (chi squared 58.75 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T-6.49 sec in the 15-150 keV band is
0.5 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.52 +- 0.14 (chi squared 65.60 for 57 d.o.f.). 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/571271/BA/
GCN Circular 15235
Subject
GRB 130919A: Skynet PROMPT-CTIO optical upper limits
Date
2013-09-20T04:04:19Z (12 years ago)
From
Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet <atrotter@physics.unc.edu>
A. Trotter, D. Reichart, J. Haislip, A. LaCluyze, J. Moore, N. Frank, K.
Ivarsen, M. Nysewander, A. Foster, T. Berger, H. T. Cromartie, R. Egger,
M. Maples, and J. A. Crain report:
Skynet observed the Swift-BAT localization of GRB 130919A (Krimm et al.,
GCN 15232; Lien et al., GCN 15234, Swift trigger=571271) with three 16"
telescopes of the PROMPT array at CTIO, Chile (V, R, and I bands).
Starting at 2013-09-19, 23:29 UT and continuing until 2013-09-20, 00:00
UT (t=12.40-12.93h post-trigger), Skynet took a total of 49 160s
exposures, at high airmass >3. In stacked images, we do not detect any
uncatalogued optical source in any band in or near the Swift-BAT error
circles. The 3-sigma limiting magnitudes of our images are:
==================================
tmid scope expos fil limit
==================================
12.67h Prompt5 12x160s I >19.44
12.55h Prompt4 7x160s R >19.24
12.63m Prompt1 10x160s V >19.54
==================================
Magnitudes are in the Vega System, calibrated to 8 APASS-DR7 stars in
the field. Magnitudes have not been corrected for line-of-sight Milky
Way dust extinction, with expected E(B-V)=0.057 (Schlegel et al. 1998).
No further Skynet observations are scheduled.