GRB 140523A
GCN Circular 16348
Subject
GRB 140523A: further Swift-XRT observations
Date
2014-06-02T20:59:57Z (11 years ago)
From
Valerio D'Elia at ASDC <delia@asdc.asi.it>
V. D'Elia (ASDC) reports on behalf of the Swift-XRT team:
We have observed again the field of the Fermi GRB 140523A (von Kienlin
and Connaughton, GCN 16321; Vianello et al. GCN 16322), to search for
variability of the X-ray afterglow candidates.
In the 5 ks of XRT data acquired, starting on 2014-05-31 at 02:33:06
UT (i.e., ~ 8 days after the burst), all X-ray candidates are still
detected with no hint of afterglow-like variability behavior.
We thus conclude that none of the candidate sources is the X-ray
afterglow of GRB 140523A.
More details about this analysis can be found on:
http://www.swift.ac.uk/xrt_products/TILED_GRB00026
GCN Circular 16329
Subject
GRB 140523A: NOT observation
Date
2014-05-25T12:03:59Z (11 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
D. Malesani (DARK/NBI), D. Xu (DARK/NBI), A. Somero (NOT), A. de Ugarte
Postigo (IAA/CSIC and DARK/NBI), Z. Cano (Univ. Iceland), and P.
Jakobsson (Univ. Iceland), report on behalf of a larger collaboration:
We observed the field of the Fermi GRB 140523A (von Kienlin &
Connaughton, GCN 16321; Vianello et al., GCN 16322; Golenetskii et al.,
GCN 16327) with the NOT equipped with the AlFOSC camera. Observations
were started on 2014 May 24 at 21:23 UT (1.76 days after the GRB), using
an SDSS r filter. Exposure time was 20 or 30 min, depending on the
pointing. We targeted the XRT sources reported by Evans (GCN 16323; see
also D'Elia & Izzo, GCN 16324):
http://www.swift.ac.uk/xrt_products/TILED_GRB00026/
XRT source #3 is spatially coincident with the bright star BD+25 2008
and is likely unrelated to the GRB. XRT source #1 is inconsistent with
the IPN triangulation annulus (Golenetskii et al., GCN 16327).
Within or close to the positions of XRT sources #1, 2, 4, and 5, several
objects are visible in our images. Some of them may be responsible for
the X-ray emission.
A pointlike object consistent with XRT source #3 (at RA = 08:52:25.38,
Dec = +24:57:27.3) is found to be brighter by about 0.5 mag in the NOT
image compared to its archival SDSS magnitude r = 19.50 +- 0.02 (AB).
Given the bright historical counterpart and lack of spatial extension,
this is unlikely to be related to the GRB.
None of the other objects have significantly varied compared to their
catalog values. Within the position of XRT source #5, an extended object
(possibly an interacting galaxy, or a blend of sources) is apparent.
Consistent with XRT source #2, an extra, dim object is visible (r ~ 24),
fainter than the SDSS limit. A bright pointlike source (r = 19.8) is
consistent with the position of XRT source #1.
Our data do not reveal any obvious candidate optical afterglow for this
GRB. We encourage further Swift/XRT follow-up in order to ascertain
whether any of the X-ray sources is variable. Our analysis suggests that
XRT sources #3 and #4 are not related to the GRB, as also indicated in
the web page by Evans (GCN 16323). Sources #2 and #5 remain viable
afterglow candidates.
GCN Circular 16328
Subject
Konus-Wind observation of GRB 140523A
Date
2014-05-24T15:57:50Z (11 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lyssenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration, intense GRB 140523A
(Fermi-GBM detection: Stanbro, GCN 16319;
Fermi-LAT detection: von Kienlin and Connaughton, GCN 16321;
IPN triangulation: Golenetskii et al., GCN 16327)
triggered Konus-Wind at T0=11157.811 s UT (03:05:57.811).
The light curve shows a multi-peaked structure with total duration
of ~22 s. The emission is seen up to ~7 MeV.
As observed by Konus-Wind, the burst had a fluence
of 5.5(-0.4,+0.4)x10^-5 erg/cm2, and a 64-ms peak flux,
measured from T0+0.640 s, of 1.6(-0.1,+0.1)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst (measured from T0 to T0+27.648 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.22 (-0.09,+0.10),
the high energy photon index beta = -2.7 (-0.4,+0.2),
the peak energy Ep = 212 (-17,+18) keV,
chi2 = 118/97 dof.
The spectrum near the peak count rate (measured from T0 to T0+4.864 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.58 (-0.14,+0.16),
the high energy photon index beta = -2.7 (-0.4,+0.2),
the peak energy Ep = 287 (-26,+29) keV,
chi2 = 100/97 dof.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140523_T11157/
All the quoted errors are at the 90% sigma confidence level.
All the quoted values are preliminary.
GCN Circular 16327
Subject
IPN Triangulation of GRB 140523A
Date
2014-05-24T15:50:16Z (11 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and
T. Cline, on behalf of the Konus-Wind team,
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein,
on behalf of the Fermi GBM team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on
behalf of the Swift-BAT team, report:
The long-duration, bright GRB 140523A (von Kienlin and Connaughton, GCN
Circ. 16321) has been observed by Fermi (GBM), Konus-Wind, INTEGRAL
(SPI-ACS), Swift (BAT) and MESSENGER (GRNS), so far, at about 11157 s UT
(03:05:57). The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
------------------------------------------------
RA(2000), deg Dec(2000), deg
------------------------------------------------
Corners:
1: 133.480 (08h 53m 55s) +25.815 (+25d 48' 56")
2: 133.425 (08h 53m 42s) +25.820 (+25d 49' 11")
3: 132.929 (08h 51m 43s) +24.467 (+24d 28' 02")
4: 132.267 (08h 49m 04s) +21.927 (+21d 55' 36")
5: 132.459 (08h 49m 50s) +21.913 (+21d 54' 46")
6: 132.669 (08h 50m 41s) +22.509 (+22d 30' 32")
-----------------------------------------------
The error box area is ~0.7 sq.deg, and its maximum dimension is 4.0 deg
(the minimum one is 12 arcmin).
This box can be improved.
The box partially overlaps the LAT error circle (Vianello, Racusin, and
Arimoto, GCN Circ. 16322).
The possible X-ray afterglow candidate (D'Elia and Izzo, GCN Circ.
16324) is marginally consistent with the box.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB140523_T11157/IPN/
Details of the Konus-Wind observation will be given in a forthcoming GCN
Circular.
GCN Circular 16326
Subject
GRB 140523A: Nanshan optical upper limit
Date
2014-05-24T15:43:48Z (11 years ago)
From
Dong Xu at DARK/NBI <dong.dark@gmail.com>
D. Xu (DARK/NBI), C.-H. Bai, J. Xu, A. Esamdin, L. Ma (XAO) report:
We observed the field of the possible XRT afterglow (D'Elia et al.,
GCN 16324) of GRB 140523A (von Kienlin et al., GCN 16321; Vianello et
al., GCN 16322) using the 1m telescope located at Nanshan, Xinjiang,
China. Observations started at 15:06:12 UT on 2014-05-24 (i.e., 36.0
hr after the burst), and 2x180s and 2x600s R-band frames were
obtained.
No optical source is detected at the XRT position down to a limiting
magnitude of R=20.5, calibrated with the SDSS field.
GCN Circular 16324
Subject
GRB 140523A: possible X-ray afterglow candidate from tiled Swift/XRT observations
Date
2014-05-24T07:51:23Z (11 years ago)
From
Valerio D'Elia at ASDC <delia@asdc.asi.it>
V. D'Elia (ASDC) and L. Izzo (URoma/ICRA) report on behalf of the
Swift/XRT Team:
Swift began a series of observations, tiled on the sky, of the
Fermi/GBM and /LAT GRB 140523A (von Kienlin et al. GCN 16321, Vianello
et al. GCB 16322).
Observations cover four contiguous fields, starting on May 23 at 18:34
UT, i.e., 15.5 h after the GBM detection. Each field was observed for
about 2 ks.
A possible XRT candidate counterpart for the GBM/LAT source is
detected at Ra, Dec 133.111250, +24.957111, which is equivalent to:
Ra(J2000) = 08h 52m 26.7s
Dec(J2000) = +24d 57' 25.6"
with an uncertainty of 6.4" (S/N~3). This location is 10.3 arcmins
from the LAT position, within the LAT error box.
No statement about fading can be made at this stage.
We note the presence of a SDSS galaxy (r=22.27) a few arcsec SW to the
center of the XRT detection, consistent with the X-ray position.
GCN Circular 16323
Subject
GRB 140523A Tiled Swift observations
Date
2014-05-23T18:43:43Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a series of observations, tiled on the sky, of the
Fermi/GBM GRB 140523A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00026
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the Fermi/GBM event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; and 2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular 16322
Subject
GRB 140523A: Fermi-LAT detection
Date
2014-05-23T18:39:14Z (11 years ago)
From
Giacomo Vianello at SLAC <giacomov@slac.stanford.edu>
G. Vianello (Stanford University), J. Racusin (NASA/GSFC), M. Arimoto
(Tokyio Tech)
report on behalf of the Fermi-LAT team:
At UT 03:05:57.62 on May 23, 2014, Fermi-LAT detected high-energy
emission from GRB 140523A, which was also detected by Fermi-GBM
(trigger 422507160 / 140523129, von Kienlin et al., GCN 16321).
The best LAT on-ground location is found to be
(RA, Dec) = 133.3, 24.95 (deg, J2000)
with an approximate error radius of 0.4 deg (90% containment,
statistical error only).
This was 60 deg from the LAT boresight at the time of the trigger. At
this large off-axis angle, the LAT PSF is not symmetric, therefore the
error region is elongated on the direction pointing towards the center
of the instrument.
An image with the 68% and 90% containment regions have been posted at:
http://www-glast.stanford.edu/Software/GRB140523A_localization.jpg
The data from the Fermi-LAT show a significant increase in the event
rate that is spatially and temporally correlated with the GBM emission
with high significance.
More than 20 photons above 100 MeV and 6 photons above 1 GeV are
observed within 300 seconds. After that the GRB went out of the LAT
FoV. It entered again around 4500 s after the trigger, but no further
emission is detected at that point. The highest-energy photon is a 6.5
GeV event which is observed 43 seconds after the GBM trigger.
A Swift ToO has been requested for this burst.
The Fermi-LAT point of contact for this burst is Makoto Arimoto
(arimoto@hp.phys.titech.ac.jp).
The Fermi-LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of
an international collaboration between NASA and DOE in the U.S. and
many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular 16321
Subject
GRB 140523A: Fermi GBM detection
Date
2014-05-23T15:02:50Z (11 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin(MPE) and V. Connaughton (UAH)
report on behalf of the Fermi GBM Team:
"At 03:05:57.62 UT on 23 May 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140523A (trigger 422507160 / 140523129).
The on-ground calculated location, using the GBM trigger
data, is RA = 128.7, DEC = 26.9 (J2000 degrees,
equivalent to 08 h 35 m, 26 d 54 '), with an uncertainty
of 1.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 60 degrees.
The GBM light curve consists of multiple peaks
with a duration (T90) of about 20 s (50-300 keV).
The time-averaged spectrum from T0+0.003 s to T0+22.720 s is
well fit by a Band function with Epeak = 270.7 (+8.1/-8.6) keV,
alpha = -1.05 +/- 0.01 , and beta = -2.73 (+0.14/-0.19).
The event fluence (10-1000 keV) in this time interval is
(5.13 +/- 0.04)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+7.232 s in the 10-1000 keV band
is 37.7 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."