GRB 140706A
GCN Circular 16531
Subject
GRB 140706A: Swift detection of a burst with an optical counterpart
Date
2014-07-06T19:42:34Z (11 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), J. R. Cummings (NASA/UMBC), J. A. Kennea (PSU),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:
At 19:33:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140706A (trigger=603587). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 49.306, -38.059 which is
RA(J2000) = 03h 17m 13s
Dec(J2000) = -38d 03' 33"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows two main peaks
with a total duration of about 55 sec. The peak count rate
was ~1700 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 19:34:46.0 UT, 72.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 49.29517, -38.05083 which
is equivalent to:
RA(J2000) = 03h 17m 10.84s
Dec(J2000) = -38d 03' 03.0"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 42 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density.
The initial flux in the 2.5 s image was 5.09e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 82 seconds after the BAT trigger. There is a candidate afterglow in
the list of sources generated on-board at
RA(J2000) = 03:17:10.40 = 49.29332
DEC(J2000) = -38:03:07.4 = -38.05205
with a 90%-confidence error radius of about 1.10 arc sec. This position is 4.5
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.05. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.02.
Burst Advocate for this burst is F. E. Marshall (marshall 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 16532
Subject
GRB 140706A: Enhanced Swift-XRT position
Date
2014-07-06T23:55:10Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.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 1464 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 140706A, 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 = 49.29426, -38.05194 which is equivalent
to:
RA (J2000): 03h 17m 10.62s
Dec (J2000): -38d 03' 07.0"
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 16534
Subject
GRB140706A: GROND detection of the Optical/NIR afterglow
Date
2014-07-07T10:05:11Z (11 years ago)
From
Patricia Schady at MPE/Swift <pschady@mpe.mpg.de>
P. Schady (MPE Garching), S. Klose (TLS Tautenburg) and J.Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 140706A (Swift-603587; Marshall et al., GCN #16531) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at 09:01UT on 7th-July, 13.5 hours after the GRB trigger, and are continuing. They were performed at an average seeing of 1.3� and at an average airmass of 1.5.
We found a single point source within the 2.2" Swift-XRT enhanced error circle reported by Beardmore et al. (GCN #16532) consistent with the UVOT position (Marshall et al., GCN #16531).
Based on the first 8 min exposure, we estimate preliminary magnitudes (all in AB system) of
g' = 22.4 +/- 0.1 mag,
r' = 22.1 +/- 0.1 mag,
i' = 21.9 +/- 0.1 mag,
z' = 21.5 +/- 0.1 mag,
J > 20.9 mag,
H > 20.3 mag, and
K > 18.8 mag.
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.02 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular 16537
Subject
GRB 140706A: Fermi GBM detection
Date
2014-07-07T16:43:23Z (11 years ago)
From
Binbin Zhang at UAH <binbin.zhang@uah.edu>
Bin-Bin Zhang (UAH) reports on behalf of the Fermi GBM Team:
"At 19:33:33.86 UT on 06 July 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140706A (trigger 426368016 / 140706815)
which was also detected by Swift (Marshall et al. 2014, GCN 16531).
The GBM on-ground location, using the Fermi GBM trigger data,
is consistent with the Swift/BAT location.
The GBM light curve consists of two main peaks with a total duration��
of about ��47.5 s (50-300keV). The time-averaged spectrum from T0-18 s��
to T0+39 s is well fit by a power law function with an exponential��
high-energy cutoff. The power law index is -1.37 +/- 0.15 and the��
cutoff energy, parameterized as Epeak, is 96 +/- 19 keV.
The event fluence (10-1000 keV) in this time interval is
(2.95 +/- 0.28)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+0.58 s in the 10-1000 keV band is 2.9 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final��
results will be published in the GBM GRB Catalog."
GCN Circular 16538
Subject
GRB 140706A: Swift-XRT refined Analysis
Date
2014-07-07T19:42:04Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA),
J.A. Kennea (PSU), V. Mangano (PSU), M.C. Stroh (PSU), A.P. Beardmore
(U. Leicester), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester)
and F.E. Marshall report on behalf of the Swift-XRT team:
We have analysed 4.6 ks of XRT data for GRB 140706A (Marshall et al.
GCN Circ. 16531), from 62 s to 34.8 ks after the BAT trigger. The
data comprise 56 s in Windowed Timing (WT) mode (the first 9 s were
taken while Swift was slewing) with the remainder in Photon Counting
(PC) mode. The enhanced XRT position for this burst was given by
Beardmore et al. (GCN Circ. 16532).
The light curve can be modelled with an initial power-law decay with an
index of alpha=3.55 (+0.25, -0.26), followed by a break at T+219 s to
an alpha of 0.62 (+/-0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.84 (+0.20, -0.19). The
best-fitting absorption column is 8.1 (+5.2, -4.6) x 10^20 cm^-2, in
excess of the Galactic value of 2.2 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.6 x 10^-11 (4.1 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 8.1 (+5.2, -4.6) x 10^20 cm^-2
Galactic foreground: 2.2 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index: 1.84 (+0.20, -0.19)
If the light curve continues to decay with a power-law decay index of
0.62, the count rate at T+24 hours will be 0.015 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.6 x
10^-13 (6.4 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00603587.
This circular is an official product of the Swift-XRT team.
GCN Circular 16539
Subject
GRB 140706A: Swift-BAT refined analysis
Date
2014-07-07T21:30:48Z (11 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(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 140706A (trigger #603587)
(Marshall, et al., GCN Circ. 16531). The BAT ground-calculated position is
RA, Dec = 49.269, -38.058 deg which is
RA(J2000) = 03h 17m 04.6s
Dec(J2000) = -38d 03' 28.6"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 77%.
The mask-weighted light curve shows several peaks starting at ~T-20 sec,
peaking at ~T-15, ~T+1 and ~T+28 sec, and ending at ~T+40 sec.
T90 (15-350 keV) is 48.3 +- 4.3 sec (estimated error including systematics).
The time-averaged spectrum from T-21.3 to T+39.6 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.8 +- 0.1. The fluence in the 15-150 keV band is 2.0 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.12 sec in the 15-150 keV band
is 1.8 +- 0.2 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/603587/BA/
GCN Circular 16541
Subject
GRB 140706A: Swift/UVOT Detection
Date
2014-07-07T23:46:26Z (11 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140706A
82 s after the BAT trigger (Marshall et al., GCN Circ. 16531).
A fading source consistent with the XRT position
(Beardmore et al. GCN Circ. 16532)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 03:17:10.39 = 49.29328 (deg.)
Dec (J2000) = -38:03:07.8 = -38.05218 (deg.)
with an estimated uncertainty of 0.45 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 82 232 147 19.04 +/- 0.06
white 573 1541 244 19.76 +/- 0.16
v 624 1592 117 >18.8
b 550 1517 97 >19.2
u (fc) 294 544 246 19.02 +/- 0.11
u 624 1591 116 >19.6
w1 674 1638 94 >19.1
w2 775 1394 58 >20.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).