GRB 140614A
GCN Circular 16391
Subject
GRB 140614A: Swift detection of a burst
Date
2014-06-14T01:20:49Z (11 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
K. L. Page (U Leicester), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), F. E. Marshall (NASA/GSFC), T. Sakamoto (AGU),
M. H. Siegel (PSU) and C. A. Swenson (PSU) report on behalf of the
Swift Team:
At 01:04:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140614A (trigger=601646). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 231.232, -79.095 which is
RA(J2000) = 15h 24m 56s
Dec(J2000) = -79d 05' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). As is usual for an image trigger, the
immediately-available light curve does not show significant
variation.
The XRT began observing the field at 01:07:03.1 UT, 123.2 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
231.1723, -79.1291 which is equivalent to:
RA(J2000) = 15h 24m 41.34s
Dec(J2000) = -79d 07' 44.9"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 129 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.26
x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 7.34e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 131 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT 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 0.12.
Burst Advocate for this burst is K. L. Page (kpa 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 16392
Subject
GRB 140614A: GROND afterglow candidate
Date
2014-06-14T02:49:55Z (11 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
M. Tanga (MPE Garching), T. Kruehler (ESO, Santiago), S. Klose, D. A. Kann
(both TLS Tautenburg), and J. Greiner (MPE Garching) report:
We observed the field of GRB 140614A (Swift trigger 601646; Page et al.,
GCN 16391) 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 01:09:27 UT on June 14, about 5 min after the GRB
trigger. They were obtained at airmass 1.5 and a seeing of 2". Inside the
X-ray error circle we detect a source at coordinates RA, DEC (J2000) =
15:24:40.65, -79:07:43.5 with an error of 0".5. At a mean time of 01:40:20
UT, we measure the following preliminary AB magnitudes:
g' > 21.6,
r' = 20.6 +/- 0.2,
i' = 19.5 +/- 0.1,
z' = 19.2 +/- 0.1,
J = 19.0 +/- 0.2,
H = 18.5 +/- 0.2, and
K > 17.6.
We also detect clear fading in the J band. We propose this source to be
the afterglow of GRB 140614A.
Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') as
well as 2MASS (JHK) 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 Circular 16393
Subject
GRB 140614A: Enhanced Swift-XRT position
Date
2014-06-14T05:24:14Z (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 1478 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 140614A, 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 = 231.16955, -79.12882 which is equivalent
to:
RA (J2000): 15h 24m 40.69s
Dec (J2000): -79d 07' 43.8"
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 16396
Subject
GRB 140614A: Swift-XRT refined Analysis
Date
2014-06-14T13:21:02Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), J.A. Kennea
(PSU), V. Mangano (PSU), M.C. Stroh (PSU), C. Pagani (U. Leicester),
A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB) and K.L. Page
report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 140614A (Page et al. GCN
Circ. 16391), from 112 s to 19.0 ks after the BAT trigger. The data
comprise 141 s in Windowed Timing (WT) mode (the first 10 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. 16393).
The light curve can be modelled with an initial power-law decay with an
index of alpha=1.75 (+0.11, -0.09), followed by a break at T+948 s to
an alpha of 0.96 (+0.07, -0.09).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.73 (+0.14, -0.12). The
best-fitting absorption column is 1.45 (+0.53, -0.19) x 10^21 cm^-2,
consistent with the Galactic value of 1.3 x 10^21 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 1.78 (+0.11,
-0.09) and a best-fitting absorption column consistent with the
Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 3.8 x 10^-11 (4.3 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.26 (+0.23, -0.00) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.78 (+0.11, -0.09)
If the light curve continues to decay with a power-law decay index of
0.96, the count rate at T+24 hours will be 7.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x
10^-13 (3.4 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/00601646.
This circular is an official product of the Swift-XRT team.
GCN Circular 16397
Subject
GRB 140614A: Swift/UVOT Upper Limits
Date
2014-06-14T14:11:43Z (11 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and K. L. Page (U Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140614A
132 s after the BAT trigger (Page et al., GCN Circ. 16391).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 16393)
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 132 281 147 >21.5
u_FC 290 539 246 >20.5
white 132 763 186 >21.6
v 620 1668 39 >19.1
b 546 739 39 >19.6
u 290 714 265 >20.5
w1 670 1718 39 >19.1
m2 645 1693 39 >18.9
w2 596 783 34 >20.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.12 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 16401
Subject
GRB 140614A: X-shooter redshift
Date
2014-06-14T15:39:49Z (11 years ago)
From
Paul Vreeswijk at Weizmann Inst of Science <paul.vreeswijk@weizmann.ac.il>
T. Kruehler (ESO, Santiago), P. M. Vreeswijk (Weizmann),
J. P. U. Fynbo, D. Xu (DARK/NBI) report on behalf of the X-shooter GRB
collaboration:
We observed the optical afterglow (Tanga et al., GCN 16392) of GRB
140614A (Swift trigger 601646; Page et al., GCN 16391; Beardmore et
al., GCN 16393; Melandri et al., GCN 16396) with the VLT/X-shooter
spectrograph, equipped with the UVB/VIS/NIR arms and covering the
wavelength range 3000-25000 AA.
A spectral nodding sequence of 4x600s was started at June 14.20 (3.8
hours after the Swift trigger). A preliminary reduction shows the lack
of any signal in the UVB arm, but a clear trace, albeit with moderate
signal-to-noise ratio, in both the VIS and NIR arms starting at around
6450 AA. Several absorption features can be identified with the
transitions SiII 1526, CII 1334, CII* 1335, AlII 1670, AllIII 1854,
FeII 2344, 2382, 2600, and MgII 2796, 2803 at a common redshift of z=4.233.
We acknowledge excellent support from the observing staff at Paranal,
in particular Zahed Wahhaj, Jonathan Smoker, Yazan Momany and
Stephane Brillant.
GCN Circular 16402
Subject
GRB 140614A: Swift-BAT refined analysis
Date
2014-06-14T16:27:03Z (11 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
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), K. L. Page (U Leicester), 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 recent telemetry downlinks,
we report further analysis of BAT GRB 140614A (trigger #601646)
(Page, et al., GCN Circ. 16391). The BAT ground-calculated position is
RA, Dec = 231.171, -79.110 deg, which is
RA(J2000) = 15h 24m 41.1s
Dec(J2000) = -79d 06' 36.9"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 97%.
The mask-weighted light curvea shows a broad peak starting at ~T-80 sec,
peaking at ~T+55 sec, and returning to baseline at ~T+200 sec (and
possibly out to around T+600 sec). The formal T90 (15-350 keV) is 720 +- 160 sec,
but with the long weak possible tail of this event it is hard to determine
the true end of the event (estimated error including systematics).
The time-averaged spectrum from T+0.51 to T+957 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.50 +- 0.46. The fluence in the 15-150 keV band is 1.3 +- 0.4 x 10^-6 erg/cm2.
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/601646/BA/