GRB 170510A
GCN Circular 21110
Subject
GRB 170510A: LCO Siding Springs early observations
Date
2017-05-19T13:47:40Z (9 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc
(U. Nova Gorica), C.G. Mundell (U. Bath), A. Cucchiara, D. Morris, B.
Gendre (U. of Virgin Islands) on behalf of a large collaboration report:
We began observing Fermi GRB 170510A (Bissaldi et al. GCN 21081) on May
10, 12:14 UT (7.0 hours since the GRB) with a 1-m LCO unit with the SDSS
i filter. Within the Swift-XRT error circle (Cholden-Brown et al. GCN
21103) we clearly detect the optical afterglow candidate (Cucchiara et
al. GCN 21087; Lipunov et al. GCN 21091) at the following position:
RA(J2000) = 10:40:36.89
DEC(J2000)= -39:12:45.2
with an error radius of 1.0", with the following value:
Mid Time Exposure Filter Magnitude (AB)
(hours) (s)
-------------------------------------------------------
7.1 5x120 SDSS-I 18.60 +- 0.07
-------------------------------------------------------
as calibrated against nearby UCAC4 stars.
GCN Circular 21105
Subject
GRB 170510A CALET Gamma-Ray Burst Monitor detection
Date
2017-05-19T02:55:29Z (9 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
A. Tezuka, A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada, S. Matsukawa (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu,
T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:
The long-duration GRB 170510A (Roberts et al., GCN Circ. 21085;
Bissaldi et al., GCN Circ. 21080; Svinkin et al. GCN Circ. 21090;
Sharma et al. GCN Circ. 21093; INTEGRAL SPI-ACS trigger #7841)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:12:23.19 on
10 May 2017. The burst signal was seen by all CGBM instruments.
The light curve of the SGM shows multiple peaks. The emission
starts from T+5 sec, peaks at T+25 sec and ends at T+35 sec.
The T90 duration measured by the SGM data is 24.9 +- 1.0 sec (40-1000 keV).
The light curve is available at
http://cgbm.calet.jp/cgbm_trigger/flight/1178427921/
The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.
GCN Circular 21103
Subject
GRB 170510A: Swift-XRT afterglow detection
Date
2017-05-18T15:59:27Z (9 years ago)
From
Antonino D'Ai at IASF-PA <antonino.dai@ifc.inaf.it>
A. Cholden-Brown (PSU), S. J. LaPorte (PSU), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), V.
D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), J.A.
Kennea (PSU) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 170510A (Bissaldi et al. GCN Circ. 21080).
The observations now extend from T0+24.7 ks to T0+713.5 ks, and are
entirely in Photon Counting (PC) mode. The source previously reported
by Melandri et al. (GCN Circ. 21086), "Source 1", is fading with
3-sigma significance, and is therefore likely the GRB afterglow.
Using 1264 s of PC mode data and 4 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 = 160.15394, -39.21244 which is
equivalent to:
RA (J2000): 10h 40m 36.95s
Dec(J2000): -39d 12' 44.8"
with an uncertainty of 2.3 arcsec (radius, 90% confidence). This
position is 13.2 arcmin from the Fermi/LAT position. The source is
fading with alpha >0.9.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.8 (+0.8, -0.4). The
best-fitting absorption column is consistent with the Galactic value
of 6.1 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 3.2 x 10^-11 (3.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6 (+/-24) x 10^20 cm^-2
Galactic foreground: 6.1 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.8 (+0.8, -0.4)
The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/xrt_products/TILED_GRB00067/Source1.php.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00067.
Swift/UVOT observed "Source 1" at T0+696 ks. We did not find an optical
counterpart. We measured a 3 sigma upper limit >21 mag in the UVW1
filter, using an exposure of 1671 s.
This circular is an official product of the Swift-XRT and UVOT teams.
GCN Circular 21093
Subject
GRB 170510A: AstroSat CZTI(Veto) detection
Date
2017-05-14T18:59:22Z (9 years ago)
From
Vidushi Sharma at IUCAA <vidushi@iucaa.in>
V. Sharma (IUCAA), V. Bhalerao (IIT-B), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:
The bright long GRB170510A (Bissaldi E. et al., GCN Circ. 21080) was detected using the CsI veto detectors on Astrosat CZTI (Bhalerao et al., arXiv:1608.03408).
The source was clearly detected in the 125-250 keV energy range. The light curve shows a multiple peak structure. The peak count rate in the CsI detectors was 940.2 counts/sec above the background (four quadrants summed together), with a total of 699536 counts. The local mean background count rate was 1365.7 counts/sec. Using cumulative rates, we measure a T90 of 67.8 secs.
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.
GCN Circular 21091
Subject
GRB 170510A: Global MASTER Net possible OT observations
Date
2017-05-12T14:36:50Z (9 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut
D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory
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
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova
Irkutsk State University
V.Yurkov, Yu.Sergienko
Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) located
in SAAO was starting survey on the LAT GRB170510.22 error-box (Bissaldi et
al., GCN #21080) 22480 sec after notice time and 41530 sec after trigger time
at 2017-05-10 16:44:36 UT. The 5-sigma upper limit on our first (180s exposure)
set is about 18.9 mag
We marginaly see optical candidate (Cucchiara et al. GCN 21087) at XRT
(Evans et al. GCN #21082, Melandri et al. GCN #21086) position with
unfiltered mag ~ 19 m .
Ra, Dec = 10 40 36.76 -39 12 43.8 (+/-1 arcsec)
We did not see object 2.5 hours late with limit 19.5 .
So X-ray Source 1 (Melandri et al. GCN #21086) is possible OT.
The message may be cited.
GCN Circular 21090
Subject
Konus-Wind observation of GRB 170510A
Date
2017-05-12T14:07:37Z (9 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, A. Tsvetkova, A. Lysenko, A.Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 170510A
(Fermi-LAT detection: Bissaldi, et al., GCN Circ. 21080;
Fermi-GBM detection: Roberts, et al., GCN Circ. 21085)
triggered Konus-Wind at T0=18750.788 s UT (05:12:30.788).
The burst light curve shows a multipeaked structure
which starts at ~T0-2 s and has a total duration of ~141 s.
The emission is seen up to ~18 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170510_T18750/
As observed by Konus-Wind, the burst
had a fluence of 5.70(-0.70,+1.51)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+20.688 s,
of 5.60(-1.12,+1.63)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+137.216 s)
is best fit in the 20 keV - 18 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.84(-0.14,+0.17),
the high energy photon index beta = -3.12(-6.88,+0.73),
the peak energy Ep = 261(-36,+42) keV
(chi2 = 76/96 dof).
The spectrum near the maximum count rate
(measured from T0+16.640 to T0+22.528 s)
is best fit in the 20 keV - 18 MeV range
by a power law with exponential cutoff model (CPL):
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.72(-0.09,+0.10)
and Ep = 331(-25,+29) keV (chi2 = 89/92 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.56
(chi2 = 88/91 dof).
In this (and only this) time interval, a prominent count excess
over the Band (and CPL) function is seen in the ~2-18 MeV range,
suggesting a presence of a hard spectral component.
Fitting this spectrum by a CPL + power law (PL) model
yields alpha = -0.48(-0.31,+0.44),
Ep = 301(-31,+50) keV, and
PL photon index of about -1.6 (chi2 = 85/90 dof),
with the component energy flux ratio (PL to CPL) of ~ 0.6
(20 keV - 10 MeV).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 21087
Subject
GRB 170510A: LCO possible counterpart
Date
2017-05-11T04:14:49Z (9 years ago)
From
Bruce Gendre at UVI <bruce.gendre@gmail.com>
A. Cucchiara, D. Morris (U. of Virgin Islands),
C. Guidorzi (U. Ferrara), B. Gendre (U. of
Virgin Islands), reports on behalf of a larger
collaboration:
"On May 10 at 16:46 UT (T_0 +11.4h) we began observing the center
of the field of LAT GRB 170510A (Bissaldi et al. GCN #21080)
using the Las Cumbres Observatory 1m Sutherland facility.
We covered 50% of the LAT error region and we obtained a series
of 5x120s observations in R band, for a total of 10 minutes on sky.
We identified a possible optical counterpart of GRB170510A located
at the same position of candidate #1 from the Swift-XRT tiled
observations (Evans et al. GCN #21082, Melandri et al. GCN #21086).
Our preliminary photometry for this source is:
R = 19.6 +/- 0.2 mag
At the moment we cannot establish the temporal variability of this source.
This magnitude is calibrated against nearby USNO-B1 sources,
and is not corrected for Galactic Extinction."
GCN Circular 21086
Subject
GRB 170510A: Swift-XRT observations
Date
2017-05-10T22:22:51Z (9 years ago)
From
Antonino D'Ai at IASF-PA <antonino.dai@ifc.inaf.it>
A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows
(PSU), A. Cholden-Brown (PSU), S.L. Gibson (U. Leicester), J.P. Osborne
(U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and P.A. Evans
(U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 170510A (Bissaldi et al. GCN Circ. 21080)
in a series of observations tiled on the sky. The total exposure time
is 4.7 ks, distributed over 7 tiles; the maximum exposure at a single
sky location was 1.4 ks. The data were collected between T0+24.3 ks and
T0+36.2 ks, and are entirely in Photon Counting (PC) mode.
One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:
Source 1:
RA (J2000.0): 160.15394 = 10:40:36.95
Dec (J2000.0): -39.21244 = -39:12:44.8
Error: 2.3 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: 0.0630 [+0.0091, -0.0090] ct s^-1
Distance: 794 arcsec from Fermi/LAT position.
Flux: (1.76 [+0.26, -0.25])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Two catalogued sources were also detected.
The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00067.
This circular is an official product of the Swift-XRT team.
GCN Circular 21085
Subject
GRB 170510A: Fermi GBM observation
Date
2017-05-10T17:47:13Z (9 years ago)
From
Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>
O.J. Roberts (USRA/NASA), E. Bissaldi (Politecnico & INFN Bari)
and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 05:12:25.73 UT on 10 May 2017, the Fermi Gamma-Ray Burst
Monitor triggered and located GRB 170510A
(trigger 516085950 / 170510217), which was also detected by the
Fermi/LAT (Bissaldi et al. 2017, GCN 21081).
The GBM on-ground location is consistent with the LAT position.
The trigger resulted in an Autonomous Repoint Request (ARR) by
the GBM Flight Software owing to the high peak flux of the GRB.
This ARR was accepted and the spacecraft slewed to the GBM
in-flight location.
The angle from the Fermi LAT boresight is 67 degrees.
The GBM light curve consists of multiple peaks with a
duration (T90) of about 128 s (50-300 keV). The time-averaged
spectrum from T0+2.0 s to T0+130.0 s is best fit by a power law
function with an exponential high-energy cutoff. The power law
index is -0.82 +/- 0.03 and the cutoff energy, parameterized as
Epeak, is 302 +/- 13 keV.
A Band function fits the spectrum equally well with
Epeak= 264 +/- 17 keV, alpha = -0.77 +/- 0.04 and
beta = -2.33 +/- 0.16.
The event fluence (10-1000 keV) in this time interval is
(4.78 +/- 0.11)E-05 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+21.8 s in the 10-1000 keV band
is 17.0 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 21082
Subject
GRB 170510A: Tiled Swift observations
Date
2017-05-10T11:58:15Z (9 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/LAT GRB 170510A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00067
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/LAT 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; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 21080
Subject
GRB 170510A: Fermi-LAT detection
Date
2017-05-10T10:55:57Z (9 years ago)
From
Elisabetta Bissaldi at U.Innsbruk/IAPP <Elisabetta.Bissaldi@uibk.ac.at>
E. Bissaldi (Politecnico & INFN Bari), M. Axelsson (Stockholm Univ. & KTH),
and F. Longo (University & INFN, Trieste) report on behalf of the Fermi-LAT team:
At 05:12:25.73 UT on May 10, 2017 Fermi-LAT detected high-energy emission
from GRB 170510A, which was also detected by Fermi-GBM (trigger 516085950/170510217).
The best LAT on-ground location is found to be
RA, Dec = 159.91, -39.32 (J2000)
with an error radius of 0.34 deg (90 % containment, statistical error only).
This was ~67 deg from the LAT boresight at the time of the trigger
and triggered an autonomous repoint of the spacecraft.
The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the trigger with high significance.
The highest-energy photon is a 1.8 GeV event which is observed 410 seconds
after the GBM trigger.
A total of 15 photons were detected in the first 500 seconds after the trigger,
after which time the spacecraft entered the SAA.
A Swift ToO has been approved for this burst.
The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.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.