GRB 140508A
GCN Circular 16266
Subject
GRB 140508A: VLA detection
Date
2014-05-14T21:23:46Z (12 years ago)
From
Assaf Horesh at Caltech <assafh@astro.caltech.edu>
A. Horesh (Weizmann Institute), L. P. Singer (Caltech), S. B. Cenko (NASA/GSFC), M. M. Kasliwal (Carnegie Observatories/Princeton), and D. Perley (Caltech) report on behalf of a larger collaboration:
We observed iPTF14aue, the afterglow candidate of GRB140508A (Yu & Goldstein, GCN 16224; Hurley et al., GCN 16225; Singer et al., GCN 16226) with the Jansky Very Large Array (VLA). The observations were undertaken on 2014 May 13 UT, 5.2 days after the Fermi trigger. We detected the source at 6.1 GHz (C-band) with a flux of 127 +/- 9 micro Jy. The source was also detected at 22 GHz (K-band).
We thank the VLA staff for scheduling this target of opportunity.
GCN Circular 16260
Subject
GRB 140508A: Mondy upper limit
Date
2014-05-13T14:17:02Z (12 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), E. Klunko (ISTP), M. Eselevich (ISTP), I. Korobtsev
(ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of GRB 140508A (Yu et al., GCN 16224) with
AZT-33IK telescope of of Sayan observatory (Mondy) starting on May, 12
(UT) 15:32:03. Within enhanced Swift-XRT error circle (Amarel-Rogers et
al., GCN 16232) we do not detect the optical source reported by Singer
et al. (GCN 16226).
Details of the photometry are the following:
date UT start t-T0 Exp. Filter UpperLimit
(mid, days) (s) (3sigma)
2014-05-12 15:32:03 4.56124 60x120 R 22.9
The photometry is based on a reference star from SDSS-DR9,
(R mag, transformation by Lupton 2005):
SDSS_id R(Lupton) err
J170144.75+464707.7 18.272 0.018
GCN Circular 16259
Subject
GRB 140508A: MITSuME Akeno Optical observation
Date
2014-05-13T13:52:06Z (12 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
T. Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi,
S. Kurita, Y.Ono , Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 140508A (H.Yu et al., GCN Circular #16224) with the
optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2014-05-09 11:07:31 UT (32.1h after the burst).
We detected the optical afterglow of GRB140508A in the g',Rc and Ic band.
The measured magnitudes were listed below.
T0+[h] T-EXP[sec] g' Rc Ic
----------------------------------------------------------------------------------------
35.3 19800 20.16+/-0.22 19.74+/-0.24 18.85+/-0.17
----------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 16254
Subject
Swift Observations of GRB 140508A
Date
2014-05-13T05:30:00Z (12 years ago)
From
Alex Amaral-Rogers at U.of Leicester <aar14@leicester.ac.uk>
Alex Amaral-Rogers reports on behalf of the Swift-XRT team:
Swift has reobserved the field of GRB 140508A for a further 4.6 ks from 253.9 ks
to 288.1 ks after the Fermi/GBM trigger.
The source reported in GCN 16232 has been observed in the XRT to be fading;
consistent with a power-law decay with an index of alpha = 1.48 (+0.15, -0.14).
We now confirm the the source is the afterglow of GRB 140508A.
GCN Circular 16246
Subject
GRB 140508A: Continued RATIR Optical and NIR Observations
Date
2014-05-12T16:15:45Z (12 years ago)
From
Nat Butler at UC berkeley <natxbutler@gmail.com>
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
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:
We observed the field of GRB 140508A (Yu, et al., GCN 16224) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2014/05 10.31 to 2014/05 10.48 UTC (52.29 to
56.42 hours after the BAT trigger), obtaining a total of 2.49 hours
exposure in the r and i bands and 1.04 hours exposure in the Z, Y, J, and H
bands and again from 2014/05 11.23 to 2014/05 11.48 UTC (74.56 to 80.45
hours after the BAT trigger), obtaining a total of 3.91 hours exposure in
the r and i bands and 1.64 hours exposure in the Z, Y, J, and H bands.
For a source positionally coincident with the iPTF optical transient
(Singer, et al., GCN 16226), in comparison with the SDSS DR9 and 2MASS, we
obtain the following detections:
t+54.4 hrs t+77.5 hrs
r 20.63 +/- 0.03 21.25 +/- 0.05
i 20.47 +/- 0.03 21.08 +/- 0.05
Z 20.29 +/- 0.05 21.04 +/- 0.08
Y 20.24 +/- 0.07 20.76 +/- 0.10
J 20.17 +/- 0.06 20.79 +/- 0.11
H 19.92 +/- 0.08 20.58 +/- 0.13
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. Including our initial set of
observations (Butler, et al., GCN 16236), the source appears to have faded
as t^(-1.5) in all bands.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 16244
Subject
GRB 140508A: HCT spectroscopy
Date
2014-05-10T16:45:53Z (12 years ago)
From
Varun Bhalerao at IUCAA <varunb@iucaa.ernet.in>
V. Bhalerao, D. K. Sahu report:
We obtained optical spectroscopy of the iPTF afterglow candidate of GRB140508A (Yu & Goldstein GCN 16224; Hurley et al., GCN 16225; Singer et al., GCN 16226) with the HFOSC instrument on the 2-m Himalayan Chandra Telescope (HCT). We obtained two spectra of 1800 sec each, spanning the wavelength range from 3800-8400A, at a mean time of 15.5 hours after the trigger. The spectrum shows weak absorption features, consistent with the Fe II and Mg II at redshift ~1.03, as identified by Malesani et al. (GCN 16229) and Wiersema et al. (GCN 16231).
GCN Circular 16243
Subject
GRB 140508A: Swift/UVOT Detection
Date
2014-05-09T19:03:14Z (12 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F.E. Marshall (NASA/GSFC) and A. Amarel-Rogers (U. of Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140508A
68965 s after the GBM trigger (Yu and Goldstein, GCN Circ. 16224).
A source consistent with the optical position
(Singer et al., GCN Circ. 16226) and the X-ray position
(Amarel-Rogers, GCN Circ. 16232)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 17:01:51.95 = 255.46647 (deg.)
Dec (J2000) = +46:46:49.5 = 46.78043 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).
Preliminary detections 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
v 68965 69792 814 19.38 +/- 0.10
b 70632 71427 782 19.59 +/- 0.06
u 69799 70626 814 18.81 +/- 0.05
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.031 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 16236
Subject
GRB 140508A: RATIR Optical and NIR Observations
Date
2014-05-09T14:34:57Z (12 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
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
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:
We observed the field of GRB 140508A (Yu, et al., GCN 16224) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2014/05 9.19 to 2014/05 9.46 UTC (25.61 to
32.04 hours after the BAT trigger), obtaining a total of 4.27 hours
exposure in the r and i bands and 1.79 hours exposure in the Z, Y, J, and H
bands.
For a source positionally coincident with the iPTF optical transient
(Singer, et al. , GCN 16226), in comparison with the SDSS DR9 and 2MASS, we
obtain the following detections:
r 19.65 +/- 0.02
i 19.52 +/- 0.02
Z 19.36 +/- 0.03
Y 19.20 +/- 0.03
J 19.18 +/- 0.03
H 18.98 +/- 0.03
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The source fades in time
approximately as t^(-1.5) in all bands during our observation.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 16235
Subject
GRB 140508A: Optical Observations via Virtual Telescope
Date
2014-05-09T11:40:39Z (12 years ago)
From
Gianluca Masi at Bellatrix Astronomical Obs <gianluca@bellatrixobservatory.org>
G. Masi (Ceccano, Italy) reports:
On May 09.06569 2014 UT (22.5 hours after the burst), we imaged the field around
GRB 140508A (Singer et al. GCN 16226) remotely using the the 0.43m-f/6.8
robotic unit part of the Virtual Telescope robotic facility in Italy.
The source is visible on 300 seconds unfiltered CCD images at the following
coordinates (J2000.0):
R.A. = 17 01 51.94
Decl. +46 46 49.2
We also performed photometry, assuming R-mags from UCAC-4 for the stars in the
field, getting an estimate for the magnitude of 19.3CR).
This message can be cited.
GCN Circular 16234
Subject
Konus-Wind observation of GRB 140508A
Date
2014-05-09T11:20:08Z (12 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, very intense GRB 140508A
(Fermi-GBM detection: Yu and Goldstein, GCN 16224;
IPN triangulation: Hurley et al., GCN 16225)
triggered Konus-Wind at T0=11038.423 s UT (03:03:58.423).
The light curve shows multiple emission episodes with decaying
peak intensity. A total duration of the burst is ~80 s.
The emission is seen up to ~9 MeV.
A hint of an extended emission in softer energy channels
can be traced to at least 250 s after the trigger; however,
its attribution to GRB 140508A is unclear due to the variable
solar particle background.
As observed by Konus-Wind, the burst had a fluence
of 7.4(-0.7,+0.8)x10^-5 erg/cm2, and a 64-ms peak flux,
measured from T0+2.576 s, of 3.0(-0.2,+0.2)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the first bursting episode
(measured from T0 to T0+72.448 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.11 (-0.08,+0.09),
the high energy photon index beta = -2.5 (-0.4,+0.2),
the peak energy Ep = 213 (-20,+23) keV,
chi2 = 70/86 dof.
The spectrum near the peak count rate (measured from T0 to T0+4.864 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.0 (-0.1,+0.1),
the high energy photon index beta = -2.4 (-0.2,+0.1),
the peak energy Ep = 345 (-47,+59) keV,
chi2 = 65/64 dof.
Assuming the redshift z=1.03 (Malesani et al., GCN 16229;
Wiersema et al., GCN 16231)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~2.1x10^53 erg,
the peak luminosity L_iso is ~1.8x10^53 erg/s,
and the rest-frame peak energy, Ep,i, is ~430 keV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140508_T11038/
All the quoted errors are at the 90% sigma confidence level.
All the quoted values are preliminary.
GCN Circular 16232
Subject
GRB 140508A: Swift-XRT observations
Date
2014-05-09T06:26:12Z (12 years ago)
From
Alex Amaral-Rogers at U.of Leicester <aar14@leicester.ac.uk>
reports on behalf of the Swift-XRT team:
We have analysed 3.0 ks of XRT data for the Fermi/GBM-detected burst:
GRB 140508A, from 69.0 ks to 75.2 ks after the Fermi/GBM trigger. The
data are entirely in Photon Counting (PC) mode. An X-ray source is
detected within the Fermi/GBM error circle. Using 2973 s of PC mode
data and 3 UVOT images, we find an enhanced XRT position (using the
XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 255.46650, +46.78033 which is equivalent to:
RA (J2000): 17h 01m 51.96s
Dec(J2000): +46d 46' 49.2"
with an uncertainty of 1.8 arcsec (radius, 90% confidence). This
position is 0.3 arcsec from the iPTF optical transient candidate (GCN
Circ. 16226). The late-time light curve (from T0+69.0 ks) is
consistent with a constant source of mean count rate 2.0e-01 ct/sec.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.01 (+0.25, -0.23). The
best-fitting absorption column is 7.8 (+5.9, -5.1) x 10^20 cm^-2, in
excess of the Galactic value of 2.1 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 3.3 x 10^-11 (3.9 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.8 (+5.9, -5.1) x 10^20 cm^-2
Galactic foreground: 2.1 x 10^20 cm^-2
Excess significance: 1.8 sigma
Photon index: 2.01 (+0.25, -0.23)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020376.
This circular is an official product of the Swift-XRT team.
GCN Circular 16231
Subject
GRB 140508A: WHT spectroscopy
Date
2014-05-09T03:06:22Z (12 years ago)
From
Klaas Wiersema at U Leicester <kw113@leicester.ac.uk>
K. Wiersema (Leicester), N. Tanvir (Leicester), A. Levan (Warwick),
R. Karjalainen (ING) report:
We observed the afterglow candidate of GRB 140508A (Singer et al. GCN 16226)
with the 4.2m William Herschel Telescope using the ACAM instrument.
We acquired 3x600s spectroscopic exposures, with midpoint 23:02 UT on 8 May 2014.
We find absorption lines of Mg II and Fe II at a common redshift of z=1.027, though we
caution this redshift is based on archival wavelength calibrations. This is consistent with
the redshift reported by Malesani et al. (GCN 16229).
GCN Circular 16229
Subject
GRB 140508A: NOT photometry and spectroscopy
Date
2014-05-09T02:30:41Z (12 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
D. Malesani, D. Xu (DARK/NBI), P. D'Avanzo (INAF/OAB), E. Palazzi
(INAF/IASF Bologna), D. Perna (Obs. Paris) report on behalf of a larger
collaboration:
We observed the optical afterglow candidate of GRB 140508A (Yu &
Goldstein GCN 16224; Hurley et al., GCN 16225; Singer et al., GCN 16226)
with the Nordic Optical Telescope (NOT) equipped with ALFOSC. The
observation consisted of a 1800 s spectrum covering the wavelength range
between 3200 and 9100 AA, carried out at a mean time of 20.63 hr after
the GRB.
The afterglow is detected in the acquisition image (20.13 hr after the
GRB) with r = 19.07+-0.03 (AB) calibrated against SDSS stars. Compared
with the measurement by Singer et al. (GCN 16226), our measurement
yields a power-law decay slope alpha ~ 1, consistent with the value
reported by these authors.
We detect several absorption features which we intepret as due to Fe II
2600 and Mg II 2796, 2803 at a common redshift of z = 1.03. This can be
considered as a firm lower limit to the GRB redshift, and is consistent
with the constraint by Moskvitin et al. (GCN 16228).
GCN Circular 16228
Subject
GRB 140508A: SAO RAS and MASTER photometric and spectroscopic observations
Date
2014-05-09T01:15:15Z (12 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
A. S. Moskvitin, D. I. Makarov, A. F. Valeev, V. V. Sokolov (SAO-RAS,
Russia), A. J. Castro-Tirado, J. Gorosabel (IAA-CSIC, Spain),
E. S. Gorbovskoy, D. V. Denisenko, V. M.Lipunov (MASTER-team, Russia),
on behalf of a larger collaboration, report:
"Following the detection of GRB 140508A by Fermi (Yu et al. GCNC 16224) and
the IPN (Hurley et al. GCNC 16225), we have conducted BVRc imaging and
spectroscopy of the iPTF optical candidate (Singer et al. GCNC 16226) with
the 6m BTA telescope in Zelenchukskaia, starting at 19:47:56 UT (i.e. 16.7
hr after the trigger). The 20 minutes (noisy) spectrum, covering the range
3800-7200 A, displays no clear absorption features, i.e. a conservative
upper limit of z < 2.1 is derived.
The GRB OT magnitude was measured to have R = 18.7 +/- 0.05 during the BTA
observations spanning more than 1 hr. OT magnitudes calibrated against the
USNO-B1 star 1367-0290781 with R2 = 16.48.
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Kislovodsk also pointed to the GRB140508A (Yu et. al GCNC
16224, Hurley et. al. GCN 16224) ~17.5 h after trigger time at 2014-05-08
20:31:01.484 UT directly after sunset and weather conditions became
satisfactory. On the first (180s exposure) unfiltred image the iPTF
optical transient preliminary photometry is given below:
T_start T-T_trig FILTER Mag Err.Mag Exptime
2014-05-08 20:31:01 17h 28m C 18.7 0.3 180 s
2014-05-08 20:48:33 17h 45m R 18.7 0.3 180 s
2014-05-08 20:48:33 17h 45m V <19.0 0.3 180 s upper limit
2014-05-08 21:20:36 18h 17m R 18.9 0.3 540 s
2014-05-08 21:20:36 18h 17m V 19.9 0.4 540 s
"C" is unfiltred 0.8R+0.2B magnitude.
This message can be quoted."
GCN Circular 16227
Subject
GRB 140508A: 1.23m CAHA BVRI-band observations
Date
2014-05-08T23:02:30Z (12 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel (UPV-EHU/IAA-CSIC), A. Sanchez-Lavega (UPV/EHU), S. Perez-Hoyos (UPV/EHU), R. Hueso (UPV/EHU), J. Ugarte (UPV/EHU), I. Ordonez (UPV/EHU), E. Arandia (UPV/EHU), I. Perez de Nanclares (UPV/EHU), on behalf of the BEGIRA project:
"We observed the field of GRB140508A (GCN Cir. 16224,16225) starting on May 8.93559 UT. The optical transient detected by Singer et al. (GCN Cir. 16226) is clearly detected in our images with an approximate Vega magnitude of R=18.8 with respect to the USNO B1.0."
GCN Circular 16226
Subject
GRB 140508A: iPTF optical transient candidate
Date
2014-05-08T19:30:09Z (12 years ago)
From
Leo Singer at CIT/PTF <lsinger@caltech.edu>
L. P. Singer (Caltech), S. B. Cenko (NASA/GSFC), M. M. Kasliwal
(Carnegie Observatories/Princeton), Christoffer Fremling (Stockholm
University), and Yifat Dzigan (Weizmann) report on behalf of the
intermediate Palomar Transient Factory (iPTF) collaboration:
We have searched for an optical counterpart of GRB 140508A (Yu and
Goldstein, GCN 16224), Fermi/GBM trigger 421211037 (2014-05-08
03:03:54.60), using the Palomar 48-inch Oschin telescope (P48). Based
on the final Fermi GBM localization, we observed 10 fields covering
73 deg2, with an estimated 67% chance of containing the true location
of the event. Due to weather at Palomar early in the night,
observations started at 09:48 UTC, 6.7 hours after the trigger.
Also detected by Konus-Wind, INTEGRAL, Swift BAT (outside FoV), and
MESSENGER, the IPN error box (Hurley et al., GCN 16225) was mostly
contained within two CCDs in one of our fields.
Sifting through candidate variable sources using image subtraction
and standard iPTF vetting procedures, we detected several optical
transients. Only is located within the IPN error box:
iPTF14aue, at the coordinates:
RA(J2000) = 17h 01m 51.95s (255.466450 deg)
Dec(J2000) = +46d 46' 49.5" (+46.780417 deg)
The source was detected at r = 17.89 +/- 0.01 mag and appeared to
fade. A power-law fit to the first two observations, relative to the
time of the GBM trigger, gives a decay index of alpha = 1.12 +/- 0.1.
There is no source coincident with this location in our reference
images or in SDSS DR10.
This position is also consistent with the IPN triangulation
(Hurley et al., GCN 16225), and is 7' from the center of the error
box.
Given the spatial coincidence with the IPN localization, the lack of
archival detections, and the source fading, iPTF14aue is likely
associated with the GRB. We are submitting a Swift XRT target of
opportunity. Further observations are encouraged to confirm the
association and the nature of the candidate.
The diagram
http://www.its.caltech.edu/~lsinger/iptf/Fermi421211037.pdf shows the
ten P48 fields in relation to the Fermi GBM 1- and 2-sigma
statistical+systematic contours, and the IPN error box.
We thank the Fermi-GBM and IPN teams for sharing their localizations
with us.
GCN Circular 16225
Subject
IPN triangulation of GRB 140508A
Date
2014-05-08T19:05:02Z (12 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and
T. Cline, on behalf of the Konus-Wind team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, on behalf of
the Fermi GBM team, and
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on
behalf of the Swift-BAT team, report:
The long-duration, very intense GRB 140508A (Yu and Goldstein, GCN Circ.
16224) has been observed by Fermi (GBM), Konus-Wind, INTEGRAL (SPI-ACS),
Swift (BAT), and MESSENGER (GRNS) so far, at about 11035 s UT
(03:03:55). 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
---------------------------------------------
Center:
255.631 (17h 02m 31s) +46.747 (+46d 44' 51")
Corners:
254.602 (16h 58m 24s) +47.063 (+47d 03' 48")
256.275 (17h 05m 06s) +46.717 (+46d 43' 00")
256.649 (17h 06m 36s) +46.418 (+46d 25' 06")
254.988 (16h 59m 57s) +46.773 (+46d 46' 23")
---------------------------------------------
The error box area is 882 sq. arcmin, and its maximum dimension is 1.5
deg (the minimum one is 12 arcmin). The Sun distance was about 110 deg.
This box can be improved.
A triangulation map will be posted at
ssl.berkeley.edu/ipn3/140508/140508.png
Details of the K-W observation will be given in a forthcoming GCN Circular
GCN Circular 16224
Subject
GRB 140508A: Fermi GBM detection
Date
2014-05-08T14:51:43Z (12 years ago)
From
Hoi-Fung Yu at MPE <sptfung@mpe.mpg.de>
Hoi-Fung Yu (MPE) and Adam Goldstein (ORAU/NASA MSFC)
report on behalf of the Fermi GBM Team:
"At 03:03:54.60 UT on 08 May 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140508A (trigger 421211037 / 140508128).
The trigger resulted in an Autonomous Repoint Request (ARR) that was
accepted and the spacecraft slewed to the GBM in-flight location.
The on-ground calculated location, using the GBM trigger data,
is RA = 250.1, Dec = 44.4 (J2000 degrees, equivalent to 16h 40m, 44d 24'),
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 initial angle from the Fermi LAT boresight is 112 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of several pulses with decaying peak flux
with a duration (T90) of about 44.3 s (50-300 keV). The time-averaged
spectrum from T0-0.512 s to T0+51.712 s is well fit by a Band function
with Epeak = 256.2 +/- 11.8 keV, alpha = -1.07 +/- 0.02, and
beta = -2.38 +/- 0.09.
The event fluence (10-1000 keV) in this time interval is
(6.24 +/- 0.07)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+4.480 s in the 10-1000 keV band is 66.8 +/- 1.0 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."