GRB 120714A
GCN Circular 13464
Subject
GRB 120714A: Swift detection of a burst
Date
2012-07-14T07:57:26Z (13 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
C. J. Saxton (UCL-MSSL), V. D'Elia (ASDC), S. R. Oates (UCL-MSSL),
K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of
the Swift Team:
At 07:46:46 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120714A (trigger=526593). Swift could not immediately
slew to the location due to the Earth limb constraint.
The BAT on-board calculated location is
RA, Dec 167.970, -30.632 which is
RA(J2000) = 11h 11m 53s
Dec(J2000) = -30d 37' 54"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 20 sec. The peak count rate
was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+51
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is C. J. Saxton (cjs2 AT mssl.ucl.ac.uk).
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 13466
Subject
GRB 120714A: Swift-XRT observations
Date
2012-07-14T09:44:51Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
D.N. Burrows (PSU), J.A. Kennea (PSU), S. Campana (INAF-OAB), G.
Cusumano (INAF-IASF PA), P.A. Evans (U. Leicester) and J.P. Osborne (U.
Leicester) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 120714A at 08:41:02.2 UT,
3255.5 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 167.98413,
-30.62769 which is equivalent to:
RA(J2000) = 11h 11m 56.19s
Dec(J2000) = -30d 37' 39.7"
with an uncertainty of 4.2 arcseconds (radius, 90% containment). This
location is 46 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 6.09
x 10^20 cm^-2 (Kalberla et al. 2005).
GCN Circular 13467
Subject
GRB120714A: UVOT non-detection
Date
2012-07-14T09:57:51Z (13 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N.P.M. Kuin, S.R. Oates, and C.J. Saxton (UCL/MSSL) report on behalf
of the UVOT Team.
Swift UVOT took a finding chart exposure of GRB120714A (Saxton et al.,
GCN Circ. 13464) of 150 seconds with the White filter starting 3259
seconds after the BAT trigger. No credible afterglow candidate is
found in the initial data products. At the XRT position (Burrows et al.,
GCN Circ. 13466) a 3-sigma upper limit of 20.4 mag. is found.
No correction has been made for the expected extinction corresponding to
E(B-V) of 0.06.
GCN Circular 13470
Subject
GRB 120714A: Enhanced Swift-XRT position
Date
2012-07-14T20:45:15Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2408 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 120714A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 167.98288, -30.62740 which is equivalent
to:
RA (J2000): 11h 11m 55.89s
Dec (J2000): -30d 37' 38.6"
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 13472
Subject
GRB 120714A: Swift-BAT refined analysis
Date
2012-07-14T21:56:19Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), C. J. Saxton (UCL-MSSL), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120714A (trigger #526593)
(Saxton, et al., GCN Circ. 13464). The BAT ground-calculated position is
RA, Dec = 167.975, -30.625 deg, which is
RA(J2000) = 11h 11m 54.1s
Dec(J2000) = -30d 37' 29.8"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 40%.
The mask-weighted light curve shows a single FRED-like pulse starting at
~T-1 sec, peaking at ~T+4 sec, and ending at ~T90 sec.
T90 (15-350 keV) is 16.2 +- 4.0 sec (estimated error including systematics).
The time-averaged spectrum from T-0.74 to T+17.78 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.62 +- 0.16. The fluence in the 15-150 keV band is 8.2 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+3.58 sec in the 15-150 keV band
is 1.5 +- 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/526593/BA/
GCN Circular 13476
Subject
GRB 120714A: Swift-XRT refined Analysis
Date
2012-07-15T05:26:49Z (13 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
K.L. Page (U. Leicester) and C. J. Saxton (UCL-MSSL) report on behalf
of the Swift-XRT team:
We have analysed 16 ks of XRT data for GRB 120714A (Saxton et al. GCN
Circ. 13464), from 3.3 ks to 46.3 ks after the BAT trigger. The data
comprise 1.2 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN. Circ 13470).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.77 (+0.18, -0.17).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.9 (+0.5, -0.4). The
best-fitting absorption column is 4.1 (+1.4, -1.5) x 10^21 cm^-2, in
excess of the Galactic value of 6.1 x 10^20 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.0 x 10^-11 (1.0 x 10^-10) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.1 (+1.4, -1.5) x 10^21 cm^-2
Galactic foreground: 6.1 x 10^20 cm^-2
Excess significance: 3.9 sigma
Photon index: 2.9 (+0.5, -0.4)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00526593.
This circular is an official product of the Swift-XRT team.
GCN Circular 13479
Subject
GRB 120714A: GROND upper limits
Date
2012-07-15T08:55:35Z (13 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
A. Nicuesa Guelbenzu, S. Klose (both TLS Tautenburg), and J. Greiner (MPE
Garching) report on behalf of the GROND team:
We observed the field of GRB 120714A (Swift trigger 526593; Saxton et al.,
GCN 13464) simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla
Observatory (Chile).
Observations started at 23:12 UT on 2012-07-14, 15.5 hrs after the GRB
trigger, at a airmass of 1.3, and a mean seeing of 1.6". We do not find
any source in the XRT error circle (Burrows et al., GCN 13466). Based on
an exposure of 1500 seconds in the optical and 1200 seconds in the NIR,
at a mean time of 00:00 UT we derive the following upper limits (all AB
magnitudes):
g' > 23.9
r' > 23.9
i' > 23.1
z' > 23.1
J > 20.9
H > 20.2
Ks > 19.2.
The magnitudes are derived based on GROND zeropoints (g'r'i'z') and 2MASS
stars (JHK). We note that the Galactic reddening along the line of sight
is E_(B-V)= 0.06 mag (Schlegel et al. 1998).
GCN Circular 13482
Subject
GRB120714A: Swift/UVOT upper limits
Date
2012-07-15T19:44:42Z (13 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (MSSL-UCL) and C. J. Saxton (UCL-MSSL) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120714A
3259 s after the BAT trigger (Saxton et al., GCN Circ. 13464).
No optical afterglow consistent with the XRT position (Beardmore etal.,
GCN Circ. No. 13470) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 3259 3409 147 >19.9
white 3259 28944 2696 >21.8
v 3416 21584 2027 >20.4
b 4237 28344 2135 >21.1
u 4031 27431 1278 >20.7
w1 3826 23171 1058 >21.0
m2 3621 22489 1279 >21.0
w2 4648 17394 1667 >21.5
A possible source was marginally present in the u band during the first two
images, but not seen later, nor in any of the other bands.
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).