GRB 130518A
GCN Circular 14725
Subject
GRB 130518A: Suzaku WAM observation of the prompt emission
Date
2013-05-30T10:45:47Z (12 years ago)
From
Takafumi Kawano at Hiroshima U/Suzaku-HXD-WAM <tkawano@hep01.hepl.hiroshima-u.ac.jp>
T. Kawano, M. Ohno, K. Takaki, R. Nakamura, S. Furui, Y. Fukazawa
(Hiroshima U.),
T. Yasuda, M. Tashiro, Y. Terada, Y. Ishida, H. Ueno, S. Sugimoto (Saitama U.),
M. Yamauchi, N. Ohmori, M. Akiyama (Univ. of Miyazaki),
K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun,
T. Takahashi (ISAS/JAXA), W. Iwakiri(RIKEN), Y. Hanabata (ICRR),
Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo)
on behalf of the Suzaku WAM team, report:
The bright, long GRB 130518A (Fermi-GBM detection: Xiong, GCN 14674;
Fermi-LAT detection: Omodei and Julie McEnery, GCN 14675;
Swift-BAT trigger 556113: Cummings, GCN 14676)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at UT 13:54:50.635(=T0).
The observed light curve shows a bright peak followed by a weaker emission seen
up to T0+24 s with a duration (T90) of about 22 seconds.
The fluence in 100 - 1000 keV was 7.05 (-0.34, +0.20) x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+11 s was 15.9 (-0.89, +0.61) photons/cm^2/s
in the same energy range.
Preliminary result shows that the time-averaged spectrum from
T0-5 s to T0+30 s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -1.42 (-0.18, +0.26),
the high-energy photon index beta: -2.27 (-0.22, +0.12),
and the peak energy Epeak: 550 (-91, +99) keV, (chi^2/d.o.f = 74.0/68).
Due to the brightness of this burst, a 5% systematic error was added
for low energy channels.
All the quoted errors are at statistical 90% confidence level.
The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular 14689
Subject
GRB 130518A: mm detection at PdBI
Date
2013-05-21T16:39:02Z (12 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
A. J. Castro-Tirado (IAA-CSIC Granada), M. Bremer and J.-M. Winters (IRAM
Grenoble), on behalf of a larger collaboration, report:
"We conducted mm observations towards GRB 130518A (Xiong et al. GCNC
14674, Omodei et al. GCNC 14675) starting at 61 hr post burst with the
PdBI at 86.7 GHz. At the position of the optical afterglow (Evans et al.
GCNC 14678, Troja et al. GCNC 14579), we detect a ~2 mJy point source.
Further mm observations are planned."
GCN Circular 14687
Subject
GRB 130518A: Gemini Redshift confirmation
Date
2013-05-21T05:20:33Z (12 years ago)
From
Antonino Cucchiara at UCSC/UCO Lick <acucchia@ucolick.org>
A. Cucchiara (UCSC), S. B. Cenko (UC Berkeley) report on behalf
of a larger collaboration:
"We obtained spectroscopy of the afterglow of the LAT-GRB 130518A
(Xiong et al. GCN 14674, Omodei et al. GCN 14675, Evans et al.
GCN 14678) with Gemini-North / GMOS, beginning a May 20.60 UT
roughly 2.05 days after the burst.
Two different central wavelengths were observed giving a coverage
from ~3850-6730 A.
We identify several absorption features, including Lyman-alpha,
SiIV(1394,1402), SiII1526, and CIV(1548,1550) at the common
redshift of z=2.488.
This result is consistent with the one reported by S�nchez-Ram�rez
et al. (GCN 14685).
We thank the Gemini-staff for their help in performing these
observations."
GCN Circular 14685
Subject
GRB 130518A: 10.4m GTC/OSIRIS redshift
Date
2013-05-20T15:32:04Z (12 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
R. S�nchez-Ram�rez (IAA-CSIC), J. Gorosabel (UPV-EHU, IAA-CSIC), A. J.
Castro-Tirado (IAA-CSIC), J. Cepa and G. G�mez-Velarde (IAC), on behalf of
a larger collaboration, report:
We observed the location of the Fermi GRB 130518A (Xiong et al. GCNC 14674,
Omodei et al. GCNC 14675) -also detected by Swift and Konus (Cummings et
al. GCNC 14676, Golenetskii et al. GCNC 14677)- with the OSIRIS
spectrograph mounted at the 10.4m GTC located at Roque de los
Muchachos Observatory (La Palma, Spain). Observations began on May 20.1995
UT (i.e. 38.9 hr post burst). The optical afterglow (Evans et al. GCNC
14678, Troja et al. GCNC 14579) is well detected with the blue (R1000B)
grism and in the resulting spectrum we see a strong, broad damped-Lya
absorption feature at ~4100A, combined with many metal lines including
SII, SiII, CII, SiIV, CIV, FeII, AlII and AlIII at a common redshift of
z=2.49.
We thank E. Troja and the RATIR Team for providing the ID-chart.
[GCN OPS NOTE(20may13): Per author's request, (a) the "40.9 hr post burst"
was changed to "38.9 hr post burst", and (b) the "We thank E. Troja"
was changed to "We thank E. Troja and the RATIR Team".]
GCN Circular 14684
Subject
GRB 130518A: Continued RATIR Optical Observations - Fading
Date
2013-05-20T15:30:09Z (12 years ago)
Edited On
2024-11-07T19:54:40Z (a year ago)
From
Eleonora Troja at GSFC <eleonora.troja@nasa.gov>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),
Chris Klein (UCB), Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom
(UCB), Antonino Cucchiara (UCSC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:
We again observed the field of GRB 130518A (Xiong, et al., GCN 14674;
Omodei, et al., GCN 14675) with the Reionization and Transients Infrared
Camera (RATIR;www.ratir.org) on the 1.5m Harold Johnson Telescope at
the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from
2013/05 20.43 to 2013/05 20.46 UTC (44.41 to 45.24 hours after the GBM
trigger), obtaining a total of 0.71 hours exposure in the r' and i' bands.
In comparison with SDSS DR8, we obtain the following detections of the source
reported earlier (Troja, et al., GCN 14678; Cenko, GCN 14680):
r' 20.47 ± 0.04
i' 20.19 ± 0.04
These magnitudes are in the AB system and not corrected for Galactic
extinction in the direction of the GRB.
In comparison with our earlier observations (Troja, et al., GCN 14678), the source
has faded by slightly more than 1 magnitude in r' and i' between about 21 hours
and 45 hours after the trigger. This confirms that the source corresponds to the
afterglow of GRB 130518A.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 14681
Subject
GRB 130518A: Confirmation of the X-ray afterglow.
Date
2013-05-20T09:05:11Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U.Leicester), M.C. Stroh (PSU) and M. H. Siegel (PSU) report
on behalf of the Swift-XRT team:
Swift has performed a second observation of GRB 130518A. We collected
1 ks of data, starting 122.5 ks after the Fermi trigger (Xiong, GCN
Circ. 14674; Omodei & McEnery, GCN Circ. 14675). The XRT source reported
by Evans et al. (GCN Circ. 14678) is detected at a level of 0.013 ��
0.005 ct/sec, significantly below the level in the previous
observations, confirming that it has faded. The best-fitting power-law
decay index is 1.1 (+0.5, -0.3).
We therefore conclude that this object is the afterglow of GRB 130518A.
This circular is an official product of the Swift-XRT team.
GCN Circular 14680
Subject
GRB 130518A: P60 Afterglow Observations
Date
2013-05-20T04:03:37Z (12 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:
We have imaged the location of the Fermi GBM (Xiong et al., GCN 14674),
LAT (Omodei et al., GCN 14675), Swift BAT (Cummings et al., GCN 14676),
and Konus-Wind (Golenetskii et al., GCN 14677) GRB 130518A with the
robotic Palomar 60 inch telescope. Observations were obtained in the r'
and i' filters beginning at 10:24 UT on 2013 May 19 (~ 0.85 d after the
GBM trigger).
We detect the optical afterglow (Evans et al., GCN 14678; Troja et al.,
GCN 14679) in both filters. Using several nearby point sources from SDSS
for calibration, we measure a magnitude of r' = 19.3 at this time.
GCN Circular 14679
Subject
GRB 130518A: RATIR Optical and NIR Observations
Date
2013-05-19T17:59:08Z (12 years ago)
Edited On
2024-11-07T18:57:41Z (a year ago)
From
Eleonora Troja at GSFC <eleonora.troja@nasa.gov>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),
Chris Klein (UCB), Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom
(UCB), Antonino Cucchiara (UCSC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:
We observed the field of GRB 130518A (Xiong, et al., GCN 14674; Omodei,
et al., GCN 14675) with the Reionization and Transients Infrared Camera
(RATIR;www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astronómico Nacional on Sierra San Pedro Mártir from
from 2013/05 19.44 to 2013/05 19.47 UTC (20.54 to 21.49 hours after
the GBM trigger), obtaining a total of 0.64 hours exposure in the r'
and i' bands, 0.27 hours exposure in the Z and Y bands, and 0.15 hours
exposure in the J, and H bands.
We detect a new, uncatalogued source at RA,Dec = 355.66781, +47.46493
(J2000) with an uncertainty of 0.5 arcsec.
This position is 5 arcsec from the XRT localization, just outside the
XRT error circle (Evans, et al., GCN 14678). In comparison with SDSS DR8
and 2MASS, we obtain the following detections:
r' 19.38 ± 0.02
i' 19.10 ± 0.02
Z 18.83 ± 0.04
Y 18.65 ± 0.04
J 18.28 ± 0.07
H 18.47 ± 0.11
These magnitudes are in the AB system and not corrected for Galactic
extinction in the direction of the GRB. We have evidence at the 2-3 sigma
level of fading in r' and i' over the duration of our observations.
Further observations are planned.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 14678
Subject
GRB 130518A: Swift XRT and UVOT possible afterglow
Date
2013-05-19T16:05:05Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U.Leicester), M. de Pasquale (MSSL/UCL), M.C. Stroh (PSU)
and M. H. Siegel (PSU) report on behalf of the Swift team:
Swift conducted a series of observations, tiled on the sky, of the
Fermi/LAT GRB 130518A. In these observations we find an uncatalogued
source at RA,Dec = 355.6658, +47.4653 degrees (J2000.0) which is
equivalent to:
RA(J2000.0) = 23h 42m 39.79s
Dec (J2000.0) = +47d 27' 55.2"
with an uncertainty of 3.6 arcsec (radius, 90% confidence).
This source shows weak evidence of fading: a power-law fit gives a decay
index of 0.66 (+/- 0.80); at this level we therefore cannot confirm
whether this is the afterglow of GRB 130518A.
The spectrum of this source can be fitted with an absorbed power-law
with a spectral index of 2.5 (+0.8, -0.6). The best-fitting absorption
column is 2.4 (+2.2, -1.4) x 10^21 cm^-2, consistent with the Galactic
value of 1.0 x 10^21 cm^-2 (Kalberla et al., 2005).
UVOT observed the field of the XRT source in u filter between 30.5 ks
and 59.9 ks after the trigger, for a total exposure time of 2.7 ks. We
detect an optical object with magnitude u = 19.0 � 0.1 just outside the
3.6 arcsec XRT error circle. The source shows weak indication of fading
between the beginning and the end of observations.
This circular is an official product of the Swift team.
GCN Circular 14677
Subject
Konus-Wind observation of GRB 130518A
Date
2013-05-19T13:50:14Z (12 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long-duration intense GRB 130518A
(Fermi-GBM detection: Xiong, GCN 14674;
Fermi-LAT detection: Omodei and Julie McEnery, GCN 14675;
Swift-BAT trigger 556113: Cummings, GCN 14676)
triggered Konus-Wind at T0=50097.501s UT (13:54:57.501)
against very high and variable solar particles background.
The light curve shows a bright hard pulse from ~T0-10 s to ~T0+20s,
followed by a weaker count rate increase at ~T0+33s
and a tail of soft extended emission, which is traceable out to ~T0+100s.
The emission in the main pulse is seen up to 12 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130518_T50097/
As observed by Konus-Wind, the burst
had a fluence of (1.5 � 0.15)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+1.856s,
of (2.1 � 0.2)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+20.224 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 = -0.92 � 0.08,
the high energy photon index beta = -1.97 � 0.08,
the peak energy Ep = 370 � 55 keV,
chi2 = 85/94 dof.
The spectrum at the maximum count rate
(measured from T0+0.768 to T0+2.304 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 = -0.80 � 0.09,
the high energy photon index beta = -2.04 � 0.11,
the peak energy Ep = 452 � 72 keV,
chi2 = 95/97 dof.
For both spectra, we note a hint of counts excess
over the model flux in the spectral channels around ~10 MeV.
All the quoted results are preliminary.
GCN Circular 14676
Subject
GRB 130518A Swift-BAT position from ground analysis
Date
2013-05-19T00:04:25Z (12 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <james.r.cummings@nasa.gov>
J. R. Cummings (UMBC/CRESST/GSFC) reports on behalf of the BAT team
At 13:55:07.4 UT, the Swift Burst Alert Telescope (BAT) triggered on the
Fermi GBM and LAT GRB 130518A (Xiong, GCN # 14674 and Omodei et al., GCN#
14675) (BAT trigger=556113). No significant source was found onboard. In
ground analysis, a significant source was found at RA, Dec 355.671, +47.478
which is:
RA(J2000) =23h 42m 41.1s
Dec(J2000) = +47d 28' 41.5"
with an uncertainty of 2.9 arcmin (radius, 90% containment, including
systematic uncertainty). This position is 11 arcmin from the LAT position,
within the LAT error circle. BAT partial coding was 5%. The unweighted
lightcurve shows two overlapping peaks with a duration of about 14 sec.
The peak count rate was ~9400 counts/sec (15-350 keV), at ~4 sec before the
trigger.
GCN Circular 14675
Subject
GRB 130518A: Fermi LAT detection
Date
2013-05-18T21:02:32Z (12 years ago)
From
Julie McEnery at NASA/GSFC <julie.e.mcenery@nasa.gov>
Nicola Omodei (Stanford) and Julie McEnery (GSFC) report on behalf of
the Fermi-LAT team:
At 13:54:37.53 UT on 18 May 2013, Fermi LAT detected high energy
emission from GRB 130518A, which was also detected by Fermi-GBM (trigger
390578080 /130518580, GCN 14674).
The best LAT on-ground location is found to be RA=355.809, DEC=47.641
(J2000) with an error radius of 0.34 deg (68% containment, statistical
error only).
The burst was about 43 deg from the LAT boresight at the time of the
trigger.
The data from the Fermi LAT shows emission lasting approximately 100
seconds with a TS of 50.
Multi-peaked emission lasting roughly 40 seconds can be seen using the
non-standard LAT Low Energy (LLE) with a significance of ~15 sigma.
A Swift TOO request has been submitted.
The Fermi LAT point of contact for this burst is Sara Cutini
(sara.cutini@asdc.asi.it).
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 14674
Subject
GRB 130518A: Fermi GBM detection
Date
2013-05-18T20:52:02Z (12 years ago)
From
Shaolin Xiong at UAH <sx0002@uah.edu>
Shaolin Xiong (UAH) reports on behalf of the Fermi GBM Team:
"At 13:54:37.53 UT on 18 May 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130518A (trigger 390578080 / 130518580).
High peak flux from the GRB caused GBM to issue a repoint request,
but the spacecraft did not slew to this burst due to the Solar TOO.
The on-ground calculated location, using the GBM trigger
data, is RA = 355.88, DEC = 46.05 (J2000 degrees,
equivalent to 23 h 43 m, 46 d 03 '), with an uncertainty
of 1 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 43 degrees.
The GBM light curve consists of several pulses
with a duration (T90) of about 48 s (50-300 keV).
The time-averaged spectrum from T0+10 s to T0+60 s is
adequately fit by a Band function with Epeak = 396 +/- 9 keV,
alpha = -0.86 +/- 0.01, and beta = -2.27 +/- 0.04.
The event fluence (10-1000 keV) in this time interval is
(9.3 +/- 0.06)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+25.6 s in the 10-1000 keV band
is 45.4 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."