GRB 160509A
GCN Circular 19532
Subject
GRB 160509A: 15 GHz upper limits from AMI
Date
2016-06-14T16:18:03Z (9 years ago)
From
Kunal Mooley at Oxford U <kunal.mooley@physics.ox.ac.uk>
K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H.
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge),
K. Grainge, A. Scaife (Manchester)
We observed the Fermi/LAT GRB 160509A (Longo et al., GCN 19403) with the
AMI Large Array at 15 GHz on 2016 May 23.25 and May 26.21 (UT) as part
of the 4pisky program. We do not detect any source at the VLA location
(Alexander et al., GCN 19414), with 3sigma upper limits of 137 uJy and
152 uJy respectively.
We thank the AMI staff for scheduling these observations. The AMI-GRB
database is a log of all GRB follow up observations with the AMI, and is
available at http://4pisky.org/ami-grb/.
GCN Circular 19428
Subject
GRB 160509A: Further VLA Observations
Date
2016-05-13T15:48:05Z (9 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko (NASA GSFC), S. Vogel (U. Maryland), D. A. Perley (DARK), and A. Fruchter (STScI) report on behalf of a larger collaboration:
We have imaged the location of the radio afterglow (Alexander et al., GCN 19414) of GRB 160509A (Longo et al., GCN 19403; Roberts et al., GCN 19411; Ono et al, GCN 19405) with the Very Large Array beginning at 10:11 UT on 2016 May 11 (2.0 d after the Fermi-GBM trigger time) in both C and X bands. The radio counterpart has brightened significantly since the early observations reported in Alexander et al., GCN 19414. We measure a preliminary flux density of ~ 0.7 mJy in X-band (9.0 GHz) and ~ 0.5 mJy in C-band (6.0 GHz), corresponding to a spectral index beta ~ 0.8 (fnu ~ nu^beta).
Further observations are planned.
GCN Circular 19425
Subject
GRB 160509A MASTER-NET observations
Date
2016-05-12T10:27:08Z (9 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa,
A.Kuznetsov, D.Kuvshinov,
Lomonosov Moscow State University, Sternberg Astronomical Institute
D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik
Kislovodsk Solar Station of the Pulkovo Observatory
V.Krushinski, I.Zalozhnih, A. Popov
Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Blagoveschensk was pointed to the GRB160509A (Longo et al GCN
19403) 15306 sec after trigger time at 2016-05-09 13:14:10 UT directly
after sunset. On our first (180s exposure) set we not found optical
transient brighter then 18.5m on single (180 s) and 20.0m on coadd (total
exposure 1800 s) images at x-ray (Kennea et al GCN 19408) and optical
(Levan et al 19410, Alexander et al GCN 19414, Cenko et al GCN 19416,
Schmidl et al GCN 19421) position.
The message may be cited.
GCN Circular 19424
Subject
GRB 160509A: CALET Gamma-Ray Burst Monitor detection
Date
2016-05-12T06:41:12Z (9 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, Y. Yamada (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), 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), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:
The long-duration GRB 160509A (Longo et al., GCN circ. 19403; Ono et al.,
GCN circ. 19404; Roberts et al., GCN circ. 19411; Frederiks et al., GCN circ. 19417)
triggered the CALET Gamma-Ray Burst Monitor (CGBM) at 08:58:51.21 on 9 May 2016.
The burst signal was seen by all CGBM instruments. The angular separations between
the GRB position (Kennea et al., GCN 19408) and the boresignt of the HXM and
the SGM instrument at the trigger time were 108 deg. and 104 deg., respectively.
Therefore, the GRB was outside the field of view of the CAL instrument.
The light curve of the SGM shows multiple overlapping pulses with a broad structure
starting from T0-5 sec, peaking at T0+9 sec and ending at T0+30 sec. A hint of the
emission is seen at T0+~370 sec. The T90 duration measured by the SGM data is
14.6 +- 0.6 sec (40-1000 keV).
The CGBM data used in this analysis are provided by the Waseda CALET Operation Center
located at the Waseda University.
GCN Circular 19423
Subject
GRB 160509A: non-observation of VHE emission with HAWC
Date
2016-05-11T17:27:37Z (10 years ago)
From
Dirk Lennarz at HAWC <dirk.lennarz@gatech.edu>
D. Lennarz (Michigan State University), I. Taboada (Georgia Tech) report
on behalf of the HAWC collaboration
(http://www.hawc-observatory.org/collaboration/):
We used data from the HAWC detector to perform a search for VHE emission
in temporal coincidence with GRB 160509A (F.Longo et al., GCN 19403). At
the time of the LAT trigger, the elevation of the burst in HAWC's field
of view was only 27.98 degrees (it was rising, but culminated at an
elevation of 33 degrees). The sensitivity of HAWC at this elevation is
more than 2 orders of magnitude poorer than near the zenith.
Furthermore, the energy threshold towards the horizon is much higher.
Combined with the moderate redshift of z=1.17 (N. R. Tanvir et al., GCN
19419) it makes a detection by HAWC unlikely.
We used four search windows with respect to the LAT trigger time: one in
the range -5 s to 45 s, which covers the main GBM emission episode (O.J.
Roberts et al., GCN 19411) and appears to be correlated with the >100
MeV soft emission observed by the LAT (F.Longo et al., GCN 19413), a
window from -5 s to 375 s, which extends slightly beyond the T90
observed by GBM and a time window from 45 s to 375 s, where the LAT data
is fit with a power-law of index -2.0 +/- 0.1. We also searched -20 s to
20 s around the time of the highest-energy LAT photon (52 GeV) 77
seconds after the GBM trigger. A 2 degree angular bin is defined around
the position of the Swift-XRT afterglow position (J. A. Kennea et al.,
GCN 19408) and the number of background events is estimated using an
ON/OFF method. We find the counts in the search bin to deviate by 1.9 /
0.9 / 0.2 / -1.4 sigma from the background expectation. Our observations
are consistent with background only.
The search was conducted using the main data acquisition that
reconstructs the incident direction of showers. It uses data
reconstructed at the HAWC site, not applying gamma-hadron separation.
The implications of this non-detection with respect to the VHE fluence
of this GRB will be reported elsewhere.
HAWC is a very-high-energy gamma-ray observatory operating in Central
Mexico at a latitude of 19 deg north. HAWC has an instantaneous field of
view of 2 sr and surveys 2/3 of the sky every day. A detailed
description of the sensitivity of HAWC to GRBs can be found in A.U.
Abeysekara et al., Astroparticle Physics 35, 641-650 (2012).
GCN Circular 19421
Subject
GRB 160509A: TLS Tautenburg Afterglow Detection
Date
2016-05-10T21:32:49Z (10 years ago)
From
Sebastian Schmidl at TLS Tautenburg <schmidl@tls-tautenburg.de>
S. Schmidl, D. A. Kann, U. Laux (all TLS Tautenburg), S. Schulze (PUC), S.
Klose, and A. Nicuesa Guelbenzu (both TLS Tautenburg) report:
We observed the location of the afterglow of the bright Fermi LAT/GBM
(Longo et al., GCN 19403, Roberts et al., GCN 19411) GRB 160509A,
localized in the X-rays by Kennea (GCN 19407) and Kennea et al. (GCN
19408), in the optical/NIR by Levan et al. (GCN 19411) and Cenko et al.
(GCN 19416), as well as in the radio band by Alexander et al. (GCN 19414),
with the 1.34m Schmidt telescope of the Thueringer Landessternwarte
Tautenburg, in good conditions.
We obtained a total of 26 x 600 s images in the Rc band, starting at
20:46:04 UT, 11.78 hrs after the GRB. The total stack has an integration
time of 15600 s, centered 0.583 days after the GRB.
At the afterglow position, we detect an extended source. Comparing to the
higher resolution DCT image (Cenko & Tanvir, priv. comm.), there is a
nearby source which is somewhat blended with the afterglow in our image.
Therefore, we use a small aperature to measure the afterglow magnitude.
Using four comparison stars in the surroundings, whose SDSS magnitudes
were transformed to the Rc band using the transformation equations of
Lupton (2005), we obtained a magnitude of:
Rc = 23.6 +/- 0.3 mag.
This is in good agreement with the detections derived by Levan et al. and
Cenko et al. after transforming their results from AB to Vega mags.
The magnitude is not corrected for the Galactic extinction along the line
of sight of E(B-V) = 0.25 mag (Schlafly & Finkbeiner 2011).
Using the prompt emission results of Konus-Wind (Frederiks et al., GCN
19417) and the redshift z = 1.17 (Tanvir et al., GCN 19419), we derive a
bolometric (1 keV - 10 MeV in the source frame) isotropic energy release
of (8.56 +/- 1.1)E53 erg, and a E_peak,rest = 625 keV. The isotropic
energy release is very similar to that of GRB 130427A, and we note the
light curve also shows similarities.
PS.: We also wish to point out that this GRB occurred on the 11th
anniversary of the first ever detected short-GRB X-ray afterglow, that of
GRB 050509B (Gehrels et al. 2005).
[GCN OPS NOTE(10may16): Per author's request, In the last paragraph,
"050509A" was corrected to "050509B".]
GCN Circular 19420
Subject
GRB 160509A: Further Swift/UVOT Observations
Date
2016-05-10T21:30:27Z (10 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and T.G.R. Roegiers (PSU) report on behalf of the Swift/UVOT team:
The afterglow of the LAT-triggered GRB 160509A (Longo et al., GCN Circ. 19403)
has been detected in the X-ray (Kennea et al., GCN Circ. 19408),
optical (Levan et al., GCN Circ. 19410; Cenko et al., GCN Circ. 19416),
near-IR (Tanvir et al., GCN Circ. 19419), and radio (Alexander et al. GCN Circ. 19414) bands.
No afterglow was seen in the initial UVOT observation in the u filter
(Marshall and Roegiers, GCN Circ. 19412). As detailed in the table below,
additional UVOT observations also show no detections.
All the upper limits are at 2-sigma confidence.
Filter T_start(s) T_stop(s) Exp(s) Mag
u 7259 19794 626 >21.6
u 24201 36310 1802 >22.2
v 25452 36990 1257 >21.4
white 24826 36919 1802 >23.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.31 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 19419
Subject
GRB 160509A Gemini North redshift
Date
2016-05-10T16:43:15Z (10 years ago)
From
Nial Tanvir at U.Leicester <nrt3@star.le.ac.uk>
N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick),
S. B. Cenko (NASA/GSFC), D. Perley (DARK), A. Cucchiara (GSFC/STScI),
K. Roth (Gemini), K. Wiersema (U. Leicester), A. Fruchter (STScI),
T. Laskar (NRAO/U.C. Berkeley) report on behalf of a larger collaboration:
We observed the optical counterpart of Fermi/LAT GRB 160509A
(Levan et al. GCN 19410) with the Gemini North telescope
on Mauna Kea, beginning at 2016-05-10 13:15 UT obtaining
both optical spectroscopy with GMOS-N and near-IR imaging
with NIRI.
Our spectroscopy covers a wavelength range of about 5900 AA
to 10100 AA, and reveals a single, well detected emission line
which we interpret as [OII] 3727 AA at a redshift of z=1.17
(provisional analysis). Alternative possible identifications for this
line are ruled out by the absence of other lines in the spectrum.
Our infrared imaging shows the source, presumably some
combination of host and afterglow, to be very red with
K(Vega)~16.6 and J(Vega)~19.7 calibrated via 2MASS stars
in the field. This would be consistent with a heavily dust
extinguished event. We also note that the source is apparently
unresolved in K-band seeing of 0.55 arcsec.
We acknowledge the excellent support of the Gemini staff,
in particular Michael Hoenig, and kind cooperation of the
visiting observers, in expediting these observations. We also
thank Gemini Head of Science, Nancy Levenson, for approving
this request.
GCN Circular 19417
Subject
Konus-Wind observation of GRB 160509A
Date
2016-05-10T12:44:04Z (10 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:
The very bright, long-duration GRB 160509A
(Fermi-LAT detection: Longo et al., GCN 19403;
MAXI/GSC detection: Ono et al., GCNs 19404;
Fermi-GBM detection: Roberts, Fitzpatrick & Veres, GCN 19411)
triggered Konus-Wind at T0=32326.696 s UT (08:58:46.696).
The light curve shows a broad, multi-peaked pulse in the interval
from ~T0-10 s to ~T0+30 s, followed by several weaker emission
episodes until ~T0+380 s.
The emission is seen up to ~15 MeV.
As observed by Konus-Wind, the burst had a fluence
of 2.90(-0.35,+0.35)x10^-4 erg/cm2, and a 64-ms peak flux,
measured from T0+12.096 s, of 2.8(-0.2,+0.2)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+370.944 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 = -0.99 (-0.08,+0.10),
the high energy photon index beta = -2.08 (-0.17,+0.12),
the peak energy Ep = 288 (-45,+48) keV,
chi2 = 51.3/97 dof.
The spectrum near the peak count rate (measured from T0+11.264
to T0+12.800 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 = -0.71 (-0.07,+0.07),
the high energy photon index beta = -2.27 (-0.14,+0.11),
the peak energy Ep = 311 (-32,+35) keV,
chi2 = 96.7/77 dof.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160509_T32326/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 19416
Subject
GRB 160509A: DCT Imaging / Afterglow Confirmation
Date
2016-05-10T12:17:04Z (10 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko (NASA GSFC), E. Troja (NASA GSFC), and S. Tegler (NAU) report on behalf of a larger collaboration:
We imaged the location of the Fermi GBM (Roberts et al., GCN 19411), Fermi LAT (Longo et al., GCN 19403), and MAXI GSC (Ono et al, GCN 19405) GRB160509A with the Large Monolithic Imager on the 4.3 m Discovery Channel Telescope in Happy Jack, AZ. Observations were obtained in the g�, r�, i�, and z� filters beginning at 9:40 UT on 10 May 2016 (~ 1.03 d after the trigger).
At the location of the candidate optical afterglow (Levan et al., GCN 19410), we detect a source in all four filters. We report the following preliminary photometry (using nearby point sources from SDSS for calibration):
g� = 25.03 +/- 0.15
r� = 24.05 +/- 0.14
The source has faded since the Gemini observations reported by Levan et al. (GCN 19410), indicating that it is indeed the afterglow of GRB160509A. However, the detection in g� limits the host redshift to be z <~ 3.5, requiring significant dust extinction along the line of sight.
GCN Circular 19415
Subject
GRB 160509A: MAXI/GSC refined analysis
Date
2016-05-10T04:13:32Z (10 years ago)
From
H. Negoro at Nihon U. <negoro@phys.cst.nihon-u.ac.jp>
H. Negoro (Nihon U.), S. Nakahira (JAXA), T. Mihara (RIKEN),
S. Ueno, H. Tomida, M. Ishikawa, Y. E. Nakagawa, Y. Sugawara (JAXA),
M. Sugizaki, M. Serino, W. Iwakiri, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN),
N. Kawai, N. Isobe, S. Sugita, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka (AGU),
H. Tsunemi, R.Imatani (Osaka U.), M. Nakajima, K. Tanaka, T. Masumitsu,
T. Kawase (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.),
Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.), M. Yamauchi, K. Furuya (Miyazaki U.),
K. Yamaoka (Nagoya U.) report on behalf of the MAXI team:
We reexamined the localization of GRB 160509A (Longo et al. GCN 19403;
Ono et al. GCN 19404,19405) only using the GSC camera 7 (Bcam1), and
not using an uncalibrated GSC camera 0 (Acam0) which was also used in
the previous analysis (GCN 19404, 19405).
We obtain the source position for a constant flux source at
(R.A., Dec) = (311.521 deg, 76.057 deg) = (20 46 05, +76 03 24) (J2000)
with a 90% C.L. statistical error of 0.12 deg and an additional systematic
uncertainty of 0.1 deg (90% containment radius),
and a rectangular error box for a variable flux source with the following corners:
(R.A., Dec) = (310.806 deg, 76.105 deg) = (20 43 13, +76 06 16) (J2000)
(R.A., Dec) = (311.249 deg, 75.892 deg) = (20 44 59, +75 53 32) (J2000)
(R.A., Dec) = (312.671 deg, 76.056 deg) = (20 50 41, +76 03 21) (J2000)
(R.A., Dec) = (312.242 deg, 76.270 deg) = (20 48 57, +76 16 13) (J2000)
The Swift/XRT source position (Kennea et al. GCN 19408; Levan et al. GCN 19410;
Alexander et al. GCN 19414) is 0.076 arc-degree from the refined best position,
and also within the rectangular region.
A GSC spectrum is roughly represented by an absorbed power-law
with a photon spectral index of 1.26 +/- 0.16, and the resultant 2-10 keV flux
is 2.78e-08 ergs/cm^2/s. The absorption column is fixed to 4.6 x 10^21 cm^-2
in the fit (Kennea et al. GCN 19408).
We also note that there was no significant excess flux in the next transit at
10:37 UT on 2016 May 9 with an upper limit of 20 mCrab.
~
GCN Circular 19414
Subject
GRB 160509A: VLA Detection
Date
2016-05-09T22:29:25Z (10 years ago)
From
Kate Alexander at Harvard <kalexander@cfa.harvard.edu>
K. D. Alexander (Harvard), T. Laskar (NRAO / UC Berkeley), and E. Berger
(Harvard) report on behalf of a larger collaboration:
We observed the Fermi/LAT GRB 160509A (Longo et al. GCN 19403) at multiple
frequencies with the Karl G. Jansky Very Large Array (VLA) beginning 2016
May 9.72 UT (8.33 hours after the burst). At a mean frequency of 6.0 GHz,
we detect a radio source with a preliminary flux density of ~80 uJy at
RA (J2000) = 20:47:00.89 +/- 0.11
Dec (J2000) = +76:06:28.92 +/- 1.2
consistent with the position of the candidate optical afterglow reported by
Levan et al. (GCN 19410) and the refined Swift/XRT position (Kennea et al.
GCN 19408). Follow-up observations are planned.
We thank the VLA staff for rapidly executing these observations.
GCN Circular 19413
Subject
GRB 160509A: Fermi-LAT refined analysis
Date
2016-05-09T18:09:47Z (10 years ago)
From
Elisabetta Bissaldi at U.Innsbruk/IAPP <Elisabetta.Bissaldi@uibk.ac.at>
F. Longo (University and INFN, Trieste), E. Bissaldi (Politecnico and INFN, Bari),
G. Vianello (Stanford U.), E. Moretti (MPI, Munich), N. Omodei (Stanford U.),
J. Bregeon (CNRS/IN2P3/LUPM), F. Dirirsa (Johannesburg U.), M. Yassine (LUPM, Montpellier),
D. Kocevski, J. Racusin, J. McEnery (all NASA/GSFC), M. Ohno (Hiroshima U.) and
S. Zhu (AEI Potsdam-Golm / AEI Hannover) report on behalf of the Fermi-LAT Team:
Using LAT source class events >100 MeV from 0 until 2660 seconds after the LAT trigger,
we find a LAT localization of
RA, Dec = 311.3, 76.1 (J2000 deg)
with a 90% containment radius of 0.12 degrees (statistical only).
The LAT executed an autonomous repoint 2 minutes after the trigger to follow
the burst for 2.5 hours. A Fermi ToO for the next 36 hours has been issued.
Following our detection, Swift followed the GRB and detected the X-ray afterglow
with the Swift/XRT (Kennea et al. GCN 19408).
The highest-energy photon is a 52 GeV event, which is observed
77 seconds after the GBM trigger.
The LAT Low Energy (LLE) emission consists of two bright structured
peaks (around T0+12 and T0+18 s), in coincidence with the main GBM emission episode.
The >100 MeV emission spectrum during the main GBM emission episode
(from T0 to T0+40 s, see Roberts et al. GCN 19411) is fit by a
soft power-law with index -3.4 +/- 0.2,
resulting in a flux of (0.56 +/- 0.06)E-4 ph cm^-2 s^-1.
The >100 MeV emission spectrum after 40 s and up to the currently
available data (up to 2660 s) is fit by a power-law with index -2.0 +/- 0.1.
The Fermi LAT point of contact for this burst is
Francesco Longo (francesco.longo@ts.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.
GCN Circular 19412
Subject
GRB 160509A: Swift/UVOT Upper Limit
Date
2016-05-09T17:54:45Z (10 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and T.G.R. Roegiers (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the Swift-XRT afterglow
(Kennea et al., GCN Circ. 19408) 7259 s after the LAT trigger
(Longo et al., GCN Circ. 19403). No UVOT source consistent with the position
of Swift-XRT afterglow or the position of the optical afterglow
candidate (Levan et al., GCN Circ. 19410) is found in the initial exposure.
The preliminary upper limit using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) is:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 7259 7531 268 >20.5
The magnitude in the table is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.31 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 19411
Subject
GRB 160509A: Fermi GBM Detection
Date
2016-05-09T17:47:13Z (10 years ago)
From
Oliver Roberts at UCD/Fermi <oliver.roberts@ucd.ie>
O.J. Roberts (UCD), G. Fitzpatrick (UCD) and
P. Veres (UAH) report on behalf of the Fermi GBM Team:
"At 08:59:04.36 UT on 09 May 2016, the Fermi Gamma-Ray
Burst Monitor triggered and located GRB 160509A
(trigger 484477148/160509374). 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 GRB was also detected by the
LAT (F. Longo et al. 2016, GCN 19403), MAXI/GSC
(Y. Ono et al. 2016, GCN 19404) and Swift XRT
(J.A. Kennea et al. 2016, GCN 19408). The GBM on-ground
location is consistent with these positions.
The angle from the Fermi LAT boresight at the GBM
trigger time using the LAT position, is 32 degrees.
The GBM light curve consists of multiple peaks
with a duration (T90) of about 371 s (50-300 keV).
The time-averaged spectrum from T0-1.5 s to T0+39.4 s is
best fit by a BAND function, with Epeak = 370 +/- 7 keV,
alpha = -0.89 +/- 0.01, and beta = -2.11 +/- 0.02.
The event fluence (10-1000 keV) in this time interval is
(1.51 +/- 0.01)E-04 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+16.6 s in the 8-1000 keV band
is 75.5 +/- 0.6 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 19410
Subject
GRB 160509A Gemini North candidate afterglow
Date
2016-05-09T17:08:50Z (10 years ago)
From
Nial Tanvir at U.Leicester <nrt3@star.le.ac.uk>
A. J. Levan (U. Warwick), N. R. Tanvir (U. Leicester),
S. B. Cenko (NASA/GSFC), D. Perley (DARK) report on behalf
of a larger collaboration:
We observed the field of Fermi/LAT GRB 160509A
(Longo et al. GCN 19403) with the Gemini North telescope
on Mauna Kea, beginning at 14:45 UT during morning twilight,
approximately 5.75 hr post-burst. Consistent with the
refined X-ray afterglow position reported by Kennea et al.
(GCN 19408) we detect a faint source with preliminary
magnitudes of r=23.52+/-0.15, z=21.35+/-0.30 (calibrated
via SDSS stars in the field). We cannot make any statement
about the variability of this source at the present time.
The position of the source is 20:47:00.93 +76:06:29.2 (J2000),
accurate to about 0.5" in each coordinate.
The fairly red r-z colour could be explained if the burst
was at a high redshift of z=5-6, or alternatively at a
more moderate redshift with some extinction in the host
galaxy.
We acknowledge the rapid response of the Gemini staff, in
obtaining these observations.
GCN Circular 19409
Subject
GRB 160509A: optical observations
Date
2016-05-09T16:52:26Z (10 years ago)
From
Luca Izzo at IAA-CSIC <izzo@iaa.es>
L.Izzo (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C. Thoene
(IAA-CSIC) report:
We observed the field of GRB 160509A (Longo et al., GCN 19403; Ono et al.,
GCN 19404) with the iTelescope.Net <http://itelescope.net> (
http://www.itelescope.net)
T11 (Planewave CDK 0.51m) telescope located at the Mayhill observatory
(NM).
A single image of 300 s was obtained in the R filter, starting at 10:32:32
UT, 1.56 hr
after the GRB trigger. We do not detect any optical afterglow candidate at
the refined Swift-XRT position (Kennea et al. GCN 19408). We estimate an
upper limit magnitude of R = 19.5 mag (3-sigma), using the USNO-B1 catalog
as reference. We note that our image covers also the complete error box of
the MAXI (Ono et al., GCN 19404). Data are available on request.
An image of the field of view can be seen at http://goo.gl/dKTki3
[GCN OPS NOTE(09may16): Per author's request, The affiiation and reply-to
email address of LI was changed.]
GCN Circular 19408
Subject
GRB 160509A: Swift-XRT afterglow detection
Date
2016-05-09T15:04:24Z (10 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@swift.psu.edu>
J. A. Kennea (PSU), T.G.R. Roegiers (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), L.M. McCauley (PSU),
C. Pagani (U. Leicester) 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 160509A (Longo et al. GCN Circ. 19403) in
a series of observations tiled on the sky. The total exposure time is
1.7 ks, distributed over 7 tiles; the maximum exposure at a single sky
location was 560 s. The data were collected between T0+7.3 ks and
T0+7.5 ks, and are entirely in Photon Counting (PC) mode.
Using 250 s of XRT Photon Counting mode data and 1 UVOT images, 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 = 311.75375, 76.10837 which is equivalent to:
RA (J2000): 20 47 00.90
Dec (J2000): +76 06 30.1
with an uncertainty of 2.3 arcsec (radius, 90% confidence). This
position is 24.8 arcmin from the Fermi/LAT position, and 11 arcseconds
from the preliminary XRT position (GCN 19407). The light curve is
consistent with a constant source of mean count rate 1.4 ct/sec. We
cannot determine fading at this time.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.7 (+/-0.3). The
best-fitting absorption column is 4.6 (+2.3, -1.8) x 10^21 cm^-2, in
excess of the Galactic value of 2.1 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 4.9 x 10^-11 (6.6 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.6 (+2.3, -1.8) x 10^21 cm^-2
Galactic foreground: 2.1 x 10^21 cm^-2
Excess significance: 2.2 sigma
Photon index: 1.7 (+/-0.3)
The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/xrt_products/TILED_GRB00054/index_2.php.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00054.
This circular is an official product of the Swift-XRT team.
GCN Circular 19407
Subject
GRB 160509A: Preliminary XRT positon
Date
2016-05-09T14:20:01Z (10 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@swift.psu.edu>
J. A. Kennea (PSU) reports on behalf of the Swift team:
Swift performed a target of opportunity observation of the Fermi/LAT
detected GRB 160509A (GCN 19403). In rapid analysis of XRT downlinked data
we find a bright uncatalogued point source at the following location:
RA/Dec (J2000) = 311.74406, 76.10634, which is equivalent to:
RA(J2000) = 20h 46m 58.6s
Dec(J2000) = +76d 06m 22.8s
with an estimated uncertainty of 8 arcseconds (90% confidence). This
position lies 24.6' away from the LAT onboard position, and 8 arcminutes
from a LAT ground refined position (Racusin, private communication), so
we suggest this is likely the afterglow of GRB 160509A. A refined position
will be issued soon. Swift observations of this burst are on-going.
GCN Circular 19406
Subject
GRB 160509A: Tiled Swift observations
Date
2016-05-09T10:55:20Z (10 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 160509A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00054
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 19405
Subject
Correction to GCN 19404; GRB 160509A: MAXI/GSC detection
Date
2016-05-09T10:20:07Z (10 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
Y.Ono (Tokyo Tech), S. Ueno, H. Tomida, S. Nakahira, M. Ishikawa, Y. E. Nakagawa, Y. Sugawara (JAXA),
T. Mihara, M. Sugizaki, M. Serino, W. Iwakiri, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN),
N. Kawai, N.Isobe, S.Sugita, T. Yoshii, Y. Tachibana, T. Fujiwara (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka (AGU),
H. Tsunemi, R.Imatani (Osaka U.),
H. Negoro, M. Nakajima, K. Tanaka, T. Masumitsu, T. Kawase (Nihon U.),
Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.),
Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.),
M. Yamauchi, K. Furuya (Miyazaki U.),
K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at UT 2016-05-09T09:04:16.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (312.131 deg, 75.810 deg) = (20 48 31, +75 48 36) (J2000)
with a 90% C.L. statistical error of 0.06 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 1307 +- 69 mCrab
(4-10keV, 1 sigma error).
Without assumptions on the source constancy,we obtain a rectangular error
box for the transient source with the following corners:
(310.897 deg, 75.728 deg) = (20 43 35, +75 43 40) (J2000)
(311.105 deg, 75.626 deg) = (20 44 25, +75 37 34) (J2000)
(313.379 deg, 75.887 deg) = (20 53 30, +75 53 14) (J2000)
(313.181 deg, 75.991 deg) = (20 52 43, +75 59 27) (J2000)
There was no significant excess flux in the previous transit at UT 2016-0509T07:32
with an upper limit of 20 mCrab.
GCN Circular 19403
Subject
GRB 160509A: Fermi-LAT prompt detection of a very bright burst
Date
2016-05-09T09:42:59Z (10 years ago)
From
Elisabetta Bissaldi at U.Innsbruk/IAPP <Elisabetta.Bissaldi@uibk.ac.at>
F.Longo (University and INFN, Trieste), E.Bissaldi (Politecnico and INFN, Bari),
J. Bregeon (CNRS/IN2P3/LUPM), J. McEnery (NASA/GSFC), M. Ohno (Hiroshima U),
S. Zhu (AEI Potsdam-Golm/AEI Hannover) report on behalf of the Fermi-LAT team:
At 08:59:04.36 UTC on May 09, 2016, Fermi-LAT triggered on
high-energy emission from GRB 160509A,
also detected by GBM (trigger 484477130/160509374).
The onboard location is
RA, Dec 310.1, 76.0 (J2000)
with an estimated error radius of 0.50 deg
(90% containment, systematic error only).
This was 31.8 deg from the LAT boresight at the time of the trigger.
We anticipate providing a refined location within the next 12 hours
when the LAT science data for this burst is downlinked and processed.
We note that this is an extraordinarily bright GRB,
and strongly encourage additional observations.
The Fermi-LAT point of contact for this burst
is Francesco Longo (francesco.longo@ts.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.