GRB 180314A
GCN Circular 22478
Subject
GRB 180314A: Swift detection of a burst with an optical counterpart
Date
2018-03-14T00:57:37Z (7 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
P. D'Avanzo (INAF-OAB), A. Deich (PSU), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (PSU),
M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 00:43:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180314A (trigger=814129). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 99.276, -24.491 which is
RA(J2000) = 06h 37m 06s
Dec(J2000) = -24d 29' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 40 sec. The peak count rate
was ~3000 counts/sec (15-350 keV), at ~4 sec after the trigger.
The XRT began observing the field at 00:46:10.6 UT, 159.3 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 99.26519, -24.49603 which
is equivalent to:
RA(J2000) = 06h 37m 03.65s
Dec(J2000) = -24d 29' 45.7"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 39 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 consistent with the Galactic value of 1.50
x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 1.58e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 166 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 06:37:03.68 = 99.26532
DEC(J2000) = -24:29:46.0 = -24.49612
with a 90%-confidence error radius of about 0.61 arc sec. This position is 2.8
arc sec. from the center of the XRT error circle. The estimated magnitude is
16.27 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.08.
Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.inaf.it).
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 22479
Subject
GRB180314A: GROND detection of the afterglow
Date
2018-03-14T01:17:19Z (7 years ago)
From
Jan Bolmer at MPE/Garching <jan@bolmer.de>
J. Bolmer (ESO/MPE) reports:
I observed the field of GRB 180314A (Swift trigger 814129; P. D'Avanzo et al.,
GCN 22478) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 00:47 UT on March 14, 2018, 4 minutes after
the GRB trigger. They were performed at an average seeing of 1".1 and at
an average airmass of 1.03.
We clearly detect the NIR/optical transient of GRB 180314A at
the position reported by P. D'Avanzo et al. (GCN 22478).
Based on total exposure of 200 seconds in g���r���i'z' at a midtime
of 00:50 UT, 7 minutes after the burst, we measure
the following preliminary magnitudes (AB magnitude
system):
g' = 17.87 +/- 0.01 mag,
r' = 17.57 +/- 0.02 mag,
i' = 17.36 +/- 0.03 mag,
z' = 17.25 +/- 0.03 mag
Magnitudes are calibrated against PanSTARRS field stars and are not
corrected for the Galactic foreground extinction corresponding to a
reddening of E_(B-V)= 0.07 mag in the direction of the burst (Schlegel et al. 1998).
Observations are continuing.
GCN Circular 22480
Subject
GRB 180314A: Enhanced Swift-XRT position
Date
2018-03-14T03:17:57Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1353 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180314A, 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 = 99.26522, -24.49627 which is equivalent
to:
RA (J2000): 06h 37m 3.65s
Dec (J2000): -24d 29' 46.6"
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 22481
Subject
GRB 180314A: MASTER-Net OT dtetction
Date
2018-03-14T08:04:37Z (7 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E.Gorbovskoy, N.Tyurina, V.Kornilov, D.Zimnukhov, V.Vladimirov,
A.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.Chazov, D. Kuvshinov
(Lomonosov Moscow State University, SAI),
R. Rebolo, M. Serra-Ricart
(The Instituto de Astrofisica de Canarias),
R.Podesta, C.Lopez, F. Podesta
(Observatorio Astronomico Felix Aguilar (OAFA),National University of San Juan, Argentina),
H. Levato, C. Saffe
(Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina),
D.Buckley, S. Potter
(South African Astronomical Observatory),
O.Gres, N.M.Budnev
(Irkutsk State University),
A. Tlatov, V.Senik, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory)
V.Yurkov, A.Gabovich, Yu.Sergienko
(Blagoveschensk Educational State University, Blagoveschensk),
MASTER-IAC and MASTER-OAFA automatically pointed to GRB 180314A (D'Avanzo et al. GCN 22478, Osborne et al. GCN 22480)
with optical transient detection by MASTER auto-detection system.
We confirm Swift and GROND OT (D'Avanzo et al. GCN 22478, Bolmer et al. GCN 22479).
There are also synchronous images from MASTER very wide field cameras (MASTER-VWFC).
MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru ,Lipunov et al. Advances in Astronomy, 2010, 30L)
located in Teyde observatory(Spain) was pointed to the GRB180314.03 7 sec after notice time
and 100 sec after trigger time at 2018-03-14 00:45:11 UT.
On our first (20s exposure) set we found 1 optical transient within SWIFT error-box
(ra=99.275 dec=-24.4908 r=0.05) :
T-Tmid Date Time Expt. Ra Dec Mag
---------|---------------------|-------|-----------------|-----------------|-------
110 2018-03-14 00:45:11 20 ( 6h 37m 03.7s , -24d 29m 45.8s) 15.36
The 5-sigma upper limit on the first 20s image is 17.2mag
The observations made on zenit distance = 83 degrees, galaxy latitude b = -13 degree.
The moon (12 % bright part) below the horizon (The altitude of the Moon is -59 degree ).
The sun altitude is -63.5 degree.
MASTER-OAFA robotic telescope located in Argentina was pointed to the GRB180314A
17 sec after notice time and 110 sec after trigger time at 2018-03-14 00:45:21 UT.
On our first (20s exposure) set we found 1 optical transient within SWIFT error-box
(ra=99.275 dec=-24.4908 r=0.05)
T-Tmid Date Time Expt. Ra Dec Mag
---------|---------------------|-------|-----------------|-----------------|-------
120 2018-03-14 00:45:21 20 ( 6h 37m 03.7s , -24d 29m 45.8s) 15.60
The 5-sigma upper limit on first 20s image is 18.4 mag
The observations made on zenit distance = 15 degrees, galaxy latitude b = -13 degree.
The moon (12 % bright part) below the horizon (The altitude of the Moon is -37 degree ).
The sun altitude is -23.5 degree.
The message may be cited.
GCN Circular 22482
Subject
GRB 180314A: REM optical/NIR observations
Date
2018-03-14T09:49:07Z (7 years ago)
From
Andrea Melandri at INAF-OAB <andrea.melandri@brera.inaf.it>
A. Melandri, P. D'Avanzo, S. Covino, D. Fugazza (INAF/OAB) report on behalf of the REM team:
We observed the field of the GRB 180314A (D'Avanzo et al., GCN 22478) with the 60-cm robotic telescope REM located at the La Silla Observatory (Chile). The observations started at 00:45:38 UT, about 2 min after the burst, and were carried out for the first hour in the JHK bands. Then observations continued in the g, r, i, z, J, H and K bands.
A preliminary analysis shows that the optical counterpart (D'Avanzo et al., GCN 22478; Bolmer, GCN 22479; Lipunov et al., GCN 22481) is well detected and at a mid time of 165 seconds after the burst it was:
H = 12.9 +/- 0.1 (Vega)
Magnitude is calibrated against the 2MASS catalog.
GCN Circular 22483
Subject
GRB 180314A: Swift/UVOT Detection
Date
2018-03-14T11:49:54Z (7 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (U.Warwick) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180314A
167 s after the BAT trigger (D'Avanzo et al., GCN Circ. 22478).
A source consistent with the XRT position
(Osborne et al. GCN Circ. 22480)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 06:37:03.68 = 99.26535 (deg.)
Dec (J2000) = -24:29:46.0 = -24.49610 (deg.)
with an estimated uncertainty of 0.42 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
white(FC) 167 317 147 16.28 +/- 0.03
white 606 626 19 17.86 +/- 0.15
v 829 849 19 17.07 +/- 0.25
b 755 774 19 18.09 +/- 0.28
u 326 576 246 16.95 +/- 0.06
w1 705 1131 39 17.98 +/- 0.33
m2 680 1106 58 18.12 +/- 0.35
w2 631 1578 117 18.75 +/- 0.30
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).
---------------------------------------------
Dr Samantha Oates
Leverhulme Early Career Fellow
Department of Physics
University of Warwick
Coventry
CV4, UK
Tel: +44 (024) 765 23383
Email: s.oates@warwick.ac.uk<mailto:s.oates@warwick.ac.uk>
-----------------------------------------------
GCN Circular 22484
Subject
GRB 180314A: VLT/X-shooter redshift
Date
2018-03-14T12:27:27Z (7 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
B. Sbarufatti (INAF/Brera PSU), J. Bolmer (MPE), A. De Ugarte Postigo
(IAA/CSIC and DARK/NBI), J. P. U. Fynbo (DAWN/NBI), J. Selsing
(DARK/NBI), K. E. Heintz (Univ. Iceland and DAWN/NBI), D. Malesani
(DAWN/NBI and DARK/NBI), N. R. Tanvir (Univ. Leicester), A. J. Levan
(Univ. Warwick), A. Smette (ESO), K. Wiersema (Univ. Warwick), S. Covino
(INAF/Brera), report on behalf of the Stargate collaboration:
We observed the optical counterpart of GRB 180314A (D'Avanzo et al., GCN
22478; Bolmer, GCN 22479) with the ESO/VLT UT2 equipped with the
X-shooter spectrograph. Observations started on Mar 14.067 UT (53.3 min
after the GRB) and covered the wavelength range 3000-20000 AA. In our
acquisition image, we measure for the afterglow r = 18.87 +- 0.05 AB,
calibrated to the Pan-STARRS catalog. The afterglow position is RA =
06:37:03.66, Dec = -24:29:46.2, consistent with the UVOT position
(D'Avanzo et al., GCN 22478).
A high-S/N continuum is detected in all arms (reaching ~3100 AA in the
blue end). We identify several absorption features, including Mg II, Zn
II, Al II, Al III, Cr II, Fe II at a common redshift z = 1.445. We also
detect at least one Fe II* fine-structure line at the same redshift,
thus confirming the association of this system with GRB 180314A.
We acknowledge excellent support from the observing staff in Paranal, in
particular Boris Haeussler and Zahed Wahhaj.
GCN Circular 22485
Subject
GRB 180314A: Fermi GBM observation
Date
2018-03-14T12:58:13Z (7 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
E. Bissaldi (Politecnico & INFN Bari) and O. Roberts (USRA)
report on behalf of the Fermi GBM Team:
"At 00:43:19.90 UT on 14 March 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180314A (trigger 542681004 / 180314030),
which was also detected by the Swift/BAT
(D'Avanzo et al. 2018, GCN 22478).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight
at the GBM trigger time is 99 degrees.
The GBM light curve consists of single emission episode
with a duration (T90) of about 28 s (50-300 keV).
The time-averaged spectrum from T0-1 s to T0+30 s is
well fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.36 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 104 +/- 3 keV.
The event fluence (10-1000 keV) in this time interval is
(1.52 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+15.3 s in the 10-1000 keV band
is 10.5 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 22486
Subject
GRB 180314A: Swift-XRT refined Analysis
Date
2018-03-14T14:45:07Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
S. J. LaPorte (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester),
P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU) and
P. D'Avanzo report on behalf of the Swift-XRT team:
We have analysed 8.7 ks of XRT data for GRB 180314A (D'Avanzo et al.
GCN Circ. 22478), from 165 s to 37.0 ks after the BAT trigger. The
data comprise 181 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Osborne et al. (GCN Circ. 22480).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.60 (+0.04, -0.17). At T+328 s the decay
steepens to an alpha of 5.8 (+2.2, -1.0) before breaking again at T+401
s to a final decay with index alpha=0.94 (+/-0.03).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.34 (+0.08, -0.04). The
best-fitting absorption column is consistent with the Galactic value
of 1.5 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.77 (+/-0.07) 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 3.9 x
10^-11 (4.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 1.5 x 10^21 cm^-2
Intrinsic column: 1.5 (+0.8, -0.0) x 10^21 cm^-2 at z=1.445
Photon index: 1.77 (+/-0.07)
If the light curve continues to decay with a power-law decay index of
0.94, the count rate at T+24 hours will be 0.014 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.7 x
10^-13 (6.9 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/00814129.
This circular is an official product of the Swift-XRT team.
GCN Circular 22487
Subject
GRB 180314A: LCO Siding Springs observations
Date
2018-03-14T17:03:19Z (7 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a
large collaboration report:
We observed the field of Swift GRB180314A (D'Avanzo et al. GCN 22478) on
March 14, from 10:00 to 10:25 UT (mid time of 0.39 days post burst) with
1-m and 2-m unit LCO telescopes in Siding Springs in the SDSS gri
filters. We detect the optical afterglow (D'Avanzo et al.; Bolmer GCN
22479; Lipunov et al. GCN 22481; Melandri et al. GCN 22482; Sbarufatti
et al. GCN 22484) with the following magnitudes:
Mid time since GRB���� Exp������� Filter�������� Magnitude
(days)���������������� (s)
-------------------------------------------------------------
0.39������������������ 5x120����� SDSS-R�������� 21.5 +- 0.15
0.40������������������ 5x120����� SDSS-I�������� 21.4 +- 0.2
-------------------------------------------------------------
as calibrated against nearby Pan-STARRS stars.
GCN Circular 22488
Subject
GRB 180314A: TAROT La Silla observatory optical observations
Date
2018-03-14T17:56:36Z (7 years ago)
From
Alain Klotz at IRAP-CNRS-OMP <Alain.Klotz@free.fr>
Klotz A., Noysena K., Atteia J.L. (CNRS-OMP-IRAP),
Boer M., Eymar L. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:
We imaged the field of GRB 180314A detected by SWIFT
(trigger 814129) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.
The observations started 172.7s after the GRB trigger
(83.1s after the notice). The elevation of the field decreased from
77 degrees above horizon and weather conditions were good.
We detected the candidate couterpart mentioned by D'Avanzo et al.
(GCNC 22478), Bolmer (GCNC 22479), Lipunov et al. (GCNC 22481),
Melandri et al. (GCNC 22482) Sbarufatti et al. (GCNC 22484),
Guidorzi et al. (GCNC 22487). TAROT photometry is:
t1(h) t2(h) r(AB) 1sig
0.048 0.056 15.64 0.05
0.059 0.067 16.00 0.05
0.070 0.079 16.34 0.05
0.081 0.090 16.64 0.06
0.093 0.101 16.92 0.07
0.104 0.129 17.26 0.10
0.132 0.182 17.68 0.13
0.227 0.276 18.18 0.19
0.282 0.332 18.32 0.24
0.343 0.443 18.62 0.30
It shows clearly a decay -1.8 until 8 minutes after the trigger
and then a decay -0.92 later. So we suspect a strong reverse shock
during the 8 first minutes.
Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.
GCN Circular 22490
Subject
GRB 180314A: Swift-BAT refined analysis
Date
2018-03-14T21:28:51Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. D'Avanzo (INAF-OAB),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
(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 180314A (trigger #814129)
(D'Avanzo et al., GCN Circ. 22478). The BAT ground-calculated position is
RA, Dec = 99.208, -24.530 deg which is
RA(J2000) = 06h 36m 50.0s
Dec(J2000) = -24d 31' 47.7"
with an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 24%.
The mask-weighted light curve shows a few overlapping pulses that starts
at ~ T-12 s and ends at ~T+110 s. The main peak occurs at ~T+4 s. Note that
the burst location came in to the BAT FOV at ~T-32 s, and thus the burst
emission might start before it is in the BAT FOV. T90 (15-350 keV) is
51.2 +- 22.3 sec (estimated error including systematics).
The time-averaged spectrum from T-11.80 to T+109.75 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.83 +- 0.25,
and Epeak of 94.9 +- 17.8 keV (chi squared 47.72 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.1 +- 0.04 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+3.05 sec in the 15-150 keV band is
7.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.50 +- 0.05 (chi squared 72.57 for 57 d.o.f.). 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/814129/BA/
GCN Circular 22505
Subject
GRB 180314A: MITSuME Okayama optical upper limits
Date
2018-03-16T11:29:04Z (7 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
K. Shiraishi, R. Itoh, K. L. Murata, T. Yoshii, Y. Tachibana, S. Harita, K.
Morita, T. Ozawa, H. Mamiya, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 180314A (P. D'Avanzo et
al., GCN Circular #22478) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Okayama Astrophysical
Observatory, Japan.
The observation started on 10:32:06 UT. We did not find any new point
source within enhanced XRT circle (J.P. Osborne et al., GCN Circular
#22480) in all three bands.
We obtained following limits for the magnitudes.
T0+[hour] MID-UT T-EXP[sec] g' Rc Ic
------------------------------------------------------------
-------------------------------------------
9.99 12:03:20 7240 >19.3 >18.8 >18.6
------------------------------------------------------------
-------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 22513
Subject
Konus-Wind observation of GRB 180314A
Date
2018-03-16T22:19:52Z (7 years ago)
From
Anastasia Tsvetkova at Ioffe Institute <tsvetkova@mail.ioffe.ru>
A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 180314A
(Swift-BAT detection: D'Avanzo�� et al., GCN 22478;
Ukwatta et al., GCN 22490;
Fermi GBM observation: Bissaldi & Roberts, GCN 22485)
triggered Konus-Wind at T0=2601.957 s UT (00:43:21.957).
The burst light curve shows a single emission episode with a total
duration of ~22 s.
The emission is seen up to ~1.5 MeV.
As observed by Konus-Wind, the burst
had a fluence of 1.47(-0.06,+0.06)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+0.490 s,
of 2.61(-1.05,+1.21)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+33.024 s)
is best fit in the 20 keV - 1.5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with�� alpha = -0.61(-0.16,+0.17),
and Ep = 111(-6,+6) keV (chi2 = 45/60 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -3.08 (chi2 = 45/59 dof).
The spectrum near the peak count rate
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 1.5 MeV range
by a power law with exponential cutoff model
with�� alpha = -0.34(-0.57,+0.84),
and Ep = 303(-89,+161) keV (chi2 = 14/15 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.26 (chi2 = 14/14 dof).
Assuming the redshift z=1.445 (Sbarufatti et al., GCN 22484)
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 8.18(-0.34,+0.36)x10^52 erg,
the peak luminosity L_iso is 3.55(-1.42,+1.64)x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is 272(-14,+15) keV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180314_T02601/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 22515
Subject
GRB 180314A: AstroSat CZTI detection
Date
2018-03-17T21:15:29Z (7 years ago)
From
Vidushi Sharma at IUCAA <vidushi@iucaa.in>
V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data showed the detection of a bright GRB 180314A, which was also detected by Swift (D'Avanzo P. et al., GCN 22478) and Fermi-GBM (Bissaldi E. et al., GCN 22485).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 00:43:20.5 UT. The measured peak count rate is 339.5 cts/s above the background in combined data of four quadrants, with a total of 5127 cts. The local mean background count rate was 586.5 cts/s. Using cumulative rates, we measure a T90 of 37.3 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.