GRB 140719A
GCN Circular 16606
Subject
GRB 140719A: Swift detection of a burst
Date
2014-07-19T06:14:30Z (11 years ago)
From
Rhaana Starling at U of Leicester <rlcs1@star.le.ac.uk>
R. L. C. Starling (U Leicester), C. J. Mountford (U Leicester),
K. L. Page (U Leicester) and T. Sakamoto (AGU) report on behalf of the
Swift Team:
At 05:53:55.2 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140719A (trigger=605612). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 171.592, -50.135 which is
RA(J2000) = 11h 26m 22s
Dec(J2000) = -50d 08' 03"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multiple
structure with a duration of about 15 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 05:55:14.4 UT, 79.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 171.6008, -50.1350
which is equivalent to:
RA(J2000) = 11h 26m 24.20s
Dec(J2000) = -50d 08' 06.1"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 20 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 in excess of the Galactic value (1.63 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 1.1
(+1.09/-0.78) x 10^22 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 83 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Data from the 2.7'x2.7' sub-image are
not available at this time. The 8'x8' region for the list of sources generated
on-board covers 100% of the BAT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.14.
Burst Advocate for this burst is R. L. C. Starling (rlcs1 AT star.le.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 16607
Subject
GRB 140719A: Enhanced Swift-XRT position
Date
2014-07-19T10:49:35Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 962 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 140719A, 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 = 171.60118, -50.13491 which is equivalent
to:
RA (J2000): 11h 26m 24.28s
Dec (J2000): -50d 08' 05.7"
with an uncertainty of 2.0 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 16608
Subject
GRB 140719A: Swift-XRT refined Analysis
Date
2014-07-19T18:14:05Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
V. Mangano (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), B. Sbarufatti (INAF-OAB/PSU), P.
D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M.C. Stroh (PSU), D.N. Burrows
(PSU) and R.L.C. Starling report on behalf of the Swift-XRT team:
We have analysed 8.8 ks of XRT data for GRB 140719A (Starling et al.
GCN Circ. 16606), from 64 s to 24.1 ks after the BAT trigger. The
data comprise 8 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Evans et al. (GCN Circ.
16607).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.1 (+1.5, -0.8). At T+276 s the decay
flattens to an alpha of -0.6 (+0.5, -0.8) before breaking again at
T+2558 s to a final decay with index alpha=0.76 (+/-0.15).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.09 (+0.23, -0.21). The
best-fitting absorption column is 2.8 (+0.9, -0.8) x 10^21 cm^-2, in
excess of the Galactic value of 1.6 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.5 x 10^-11 (5.3 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.8 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^21 cm^-2
Excess significance: 2.4 sigma
Photon index: 2.09 (+0.23, -0.21)
If the light curve continues to decay with a power-law decay index of
0.76, the count rate at T+24 hours will be 0.013 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.4 x
10^-13 (6.8 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/00605612.
This circular is an official product of the Swift-XRT team.
GCN Circular 16611
Subject
GRB 140719A: GROND Afterglow candidate
Date
2014-07-20T07:32:00Z (11 years ago)
From
Jan Bolmer at MPE/Garching <jan@bolmer.de>
J. Bolmer, F. Knust, K. Valera and J. Greiner (all MPE Garching)
report on behalf of the GROND team:
We observed the field of GRB 140719A (Swift trigger 605612; Cummings et al.,
GCN 16606) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 22:59 UT on July 19, 2014, 16.8 hrs after
the GRB trigger. They were performed at an average seeing of 1.1��� and
at an average airmass of 1.5.
We find a faint source inside the XRT error circle given in Evans et al.
(GCN 16607) at coordinates RA, Dec = 171.60123, -50.13466, which is
equal to:
RA (J2000): 11:26:24.3
Dec (J2000): -50:08:04.8
with an uncertainty of 0.5 arcsec in each coordinate.
Based on a total exposures of 3000 seconds in g'r'i'z' and 1200 seconds
in JHK, at a mid-time of 18.4 hrs after the burst, we measure the
following preliminary magnitudes (all in AB):
g' > 25.3,
r' = 23.7 +/- 0.2,
i' = 22.9 +/- 0.2,
z' > 23.8,
J > 21.4,
H > 20.9 and
K > 19.5.
At present we cannot confirm whether the source is fading.
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) = 0.12 mag
in the direction of the burst (Schlegel et al. 1998).
[GCN OPS NOTE(20jul14): Per author's request, the author list was added
and the arcsec symbol was replaced.]
GCN Circular 16612
Subject
GRB 140719A: FTS observations
Date
2014-07-20T11:50:28Z (11 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi, S. Dichiara (U. Ferrara), C.G. Mundell (LJMU)
on behalf of a large collaboration report:
The 2-m Faulkes Telescope South began observing Swift GRB 140719A
(Starling et al. GCN Circ 16606) on July 19 at 09:27:35 UT, i.e.
~3.6 hours after the BAT trigger, with the r' and i' filters.
Within the enhanced XRT error circle (Evans et al. GCN Circ. 16607)
and, in particular, at the position of the GROND candidate
(GCN Circ. 16611) we found nothing down to the following limit:
Mid time from Total Exp Filter Magnitude
trigger (hr) (s)
-------------------------------------------------
3.64 120x4 r' > 21.0
3.80 120x4 i' > 20.2
-------------------------------------------------
Magnitudes are calibrated against nearby USNO-B1 stars.
GCN Circular 16613
Subject
GRB 140719A, Swift-BAT refined analysis
Date
2014-07-20T13:02:06Z (11 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
T. N. Ukwatta (MSU), 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), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU),
R. L. C. Starling (U Leicester), J. Tueller (GSFC),
(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 140719A (trigger #605612)
(Starling, et al., GCN Circ. 16606). The BAT ground-calculated position is
RA, Dec = 171.571, -50.115 deg which is
RA(J2000) = 11h 26m 17.1s
Dec(J2000) = -50d 06' 55.1"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 75%.
The mask-weighted light curve shows a single peak starting at ~T-5 s sec,
peaking at ~T+0 sec, and ending at T+20 sec. T90 (15-350 keV) is 48 +- 23 sec
(estimated error including systematics).
The time-averaged spectrum from T-31.5 to T+16.5 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.9 +- 0.3. The fluence in the 15-150 keV band is 4.3 +- 0.8 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+8.01 sec in the 15-150 keV band
is 0.2 +- 0.1 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/605612/BA/
GCN Circular 16618
Subject
GRB 140719A: Swift/UVOT Upper Limits
Date
2014-07-21T21:41:59Z (11 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and R. L. C. Starling (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140719A
83 s after the BAT trigger (Starling et al., GCN Circ. 16606).
No optical afterglow consistent with the optical position
(Bolmer et al. GCN Circ. 16611) or the enhanced XRT position
(Evans et al. GCN Circ. 16607) is detected in the initial UVOT exposures.
Nearby bright sources in this crowded field make estimating the
background more difficult than usual.
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 83 233 147 >20.9
u_FC 296 546 246 >20.2
white 83 1026 334 >21.3
v 626 4558 178 >19.2
b 552 745 39 >19.5
u 296 720 265 >20.2
w1 676 870 39 >19.0
m2 651 845 39 >21.0
w2 602 1052 58 >19.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.14 in the direction of the burst
(Schlegel et al. 1998).