GRB 161108A
GCN Circular 20145
Subject
GRB 161108A: Swift detection of a burst
Date
2016-11-08T03:49:46Z (9 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:
At 03:32:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 161108A (trigger=721234). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 180.784, +24.869 which is
RA(J2000) = 12h 03m 08s
Dec(J2000) = +24d 52' 09"
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 30 sec. The peak count rate
was ~800 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 03:33:53.5 UT, 80.3 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 180.78748,
24.86801 which is equivalent to:
RA(J2000) = 12h 03m 09.00s
Dec(J2000) = +24d 52' 04.8"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 11 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.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.79
x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 8.63e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 90 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.02.
Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk).
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 20146
Subject
GRB 161108A: NOT candidate afterglow
Date
2016-11-08T06:08:47Z (9 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
D. Malesani (DARK/NBI and DTU Space), A. de Ugarte Postigo (IAA-CSIC and
DARK/NBI), A. Somero (UTU), E. Gafton (NOT, SU, OKC), S. Damsted (Univ.
Helsinki), G. Erfanianfar (MPE), A. Finoguenov (Univ. Helsinki), C.
Gibson (Univ. Helsinki), F. Kiefer (MPE), C. Kirkpatrick (Univ.
Helsinki), M. Lumme (Univ. Helsinki), V. Oja (Univ. Helsinki), J.
Rantakyla (Univ. Helsinki), I. Salmenpera (Univ. Helsinki), and M.
Seppala (Univ. Helsinki), report on behalf of a larger collaboration:
We observed the field of GRB 161108A (Beardmore et al., GCN 20145) with
the Nordic Optical Telescope (NOT) equipped with the AlFOSC imager and
spectrograph. Observations started on Nov 8.2132 UT (94.4 min after the
GRB trigger) and were carried out in the r and z filters.
Within the currently available XRT position (Beardmore et al., GCN
20145), we detect a single object, at coordinates (J2000):
RA = 12:03:09.11
Dec = +24:52:04.9
This source has a magnitude r = 20.82 +- 0.05 AB, calibrated against
nearby SDSS stars. The same object is visible in the SDSS archival
images, at a significantly fainter magnitude r = 22.69 +- 0.20. It is
classified as a galaxy with a photometric redshift of 0.50 +- 0.12. The
most likely interpretation is that the object seen in the NOT images is
the superposition of afterglow and host galaxy, so we consider the
association with GRB 161108A secure.
GCN Circular 20147
Subject
GRB 161108A: Enhanced Swift-XRT position
Date
2016-11-08T11:23:14Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 3332 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 161108A, 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 = 180.78794, +24.86815 which is equivalent
to:
RA (J2000): 12h 03m 9.11s
Dec (J2000): +24d 52' 05.3"
with an uncertainty of 1.6 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 20148
Subject
GRB 161108A: Swift-XRT refined Analysis
Date
2016-11-08T14:19:15Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
L.M. McCauley (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U.
Leicester), J.P. Osborne (U. Leicester), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and A.P. Beardmore report on behalf of the Swift-XRT
team:
We have analysed 6.5 ks of XRT data for GRB 161108A (Beardmore et al.
GCN Circ. 20145), from 73 s to 27.1 ks after the BAT trigger. The data
comprise 263 s in Windowed Timing (WT) mode (the first 6 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 20147).Considering only the late-time light curve
(from T0+4.5 ks), the source is fading with alpha >1.2.
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.20 (+/-0.04). The
best-fitting absorption column is 2.20 (+0.15, -0.14) x 10^21 cm^-2,
in excess of the Galactic value of 1.8 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.09 (+0.24, -0.22)
and a best-fitting absorption column of 1.5 (+0.7, -0.6) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.3 x 10^-11 (4.4 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.5 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 1.8 x 10^20 cm^-2
Excess significance: 3.7 sigma
Photon index: 2.09 (+0.24, -0.22)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00721234.
This circular is an official product of the Swift-XRT team.
GCN Circular 20149
Subject
GRB 161108A: RATIR Afterglow Confirmation
Date
2016-11-08T14:29:23Z (9 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), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), 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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 161108A (Beardmore, et al., GCN 20145) 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 2016/11 8.48 to 2016/11 8.54 UTC (7.87 to
9.34 hours after the BAT trigger), obtaining a total of 1.03 hours exposure
in the r and i bands and 0.40 hours exposure in the Z, Y, J, and H bands.
The afterglow candidate reported by Malesani et al. (GCN 20146) is well
detected. In comparison with the SDSS DR9 and 2MASS catalogs, we obtain
the following detections and upper limits (3-sigma):
r = 21.97 +/- 0.12
i = 21.36 +/- 0.06
Z = 20.88 +/- 0.11
Y = 20.57 +/- 0.14
J = 20.05 +/- 0.27
H > 18.12
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The source appears to have faded
in r by about 1 magnitude as compared to Malesani et al. (GCN 20146).
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 20150
Subject
GRB 161108A: NOT redshift
Date
2016-11-08T15:00:18Z (9 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC and DARK/NBI), D. Malesani (DARK/NBI
and DTU Space), D.A. Perley (DARK/NBI), J.P.U. Fynbo (DARK/NBI),
K.E. Heintz (Univ. of Iceland and DARK/NBI), A. Somero (UTU), E. Gafton
(NOT, SU, OKC), S. Damsted (Univ. Helsinki), G. Erfanianfar (MPE),
A. Finoguenov (Univ. Helsinki), C. Gibson (Univ. Helsinki), F. Kiefer (MPE),
C. Kirkpatrick (Univ. Helsinki), M. Lumme (Univ. Helsinki), V. Oja (Univ.
Helsinki), J. Rantakyla (Univ. Helsinki), I. Salmenpera (Univ. Helsinki), and
M. Seppala (Univ. Helsinki), report on behalf of a larger collaboration:
Continuing with the observations of GRB 161108A (Beardmore et al.,
GCN 20145) reported by Malesani et al. (GCN 20146) we performed
spectroscopy of the afterglow (see also Butler et al. GCN 20149) and host
galaxy using the Nordic Optical Telescope (NOT) equipped with AlFOSC.
The observation consisted of 2x1200s+1x600s exposures using grism 4,
starting at 5:47 UT (2.25 hr after the burst).
The spectrum shows continuum from 3900 to 9300 AA, with a single
emission line at 8048 AA, consistent with being due to the [O II] doublet
at z=1.159. Additionally we detect low SNR absorption features consistent
with Mg II, Mg I, and Fe II at the same redshift, which we identify as the
redshift of the GRB.
GCN Circular 20151
Subject
GRB 161108A, Swift-BAT refined analysis
Date
2016-11-08T22:14:28Z (9 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 161108A (trigger #721234)
(Beardmore, et al., GCN Circ. 20145). The BAT ground-calculated position is
RA, Dec = 180.776, 24.905 deg which is
RA(J2000) = 12h 03m 06.1s
Dec(J2000) = +24d 54' 19.4"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 95%.
The mask-weighted light curve shows a multi-peaked structure that starts
at ~ T-5 s and ends at ~ T+ 130 s. The main peak occurs at ~T0.
T90 (15-350 keV) is 105.1 +- 11.9 sec (estimated error including systematics).
The time-averaged spectrum from T-1.9 to T+126.8 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.85 +- 0.17. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-1.80 sec in the 15-150 keV band
is 0.6 +- 0.1 ph/cm2/sec. 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/721234/BA/
GCN Circular 20153
Subject
GRB 161108A: TAROT Calern observatory optical observations
Date
2016-11-08T22:57:10Z (9 years ago)
From
Alain Klotz at IRAP-CNRS-OMP <Alain.Klotz@free.fr>
Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:
We imaged the field of GRB 161108A detected by SWIFT
(trigger 721234) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
The observations started 449s after the GRB trigger
The elevation of the field increased from 28 degrees
above horizon and weather conditions were good.
We co-added a series of exposures but we did not detect the
afterglow candidate of Malesani et al. (GCNC 20146).
TAROT limiting magnitudes are:
t0+ 449s to t0+ 539s : Rlim = 18.5
t0+1271s to t0+1941s : Rlim = 19.5
t0+1952s to t0+3694s : Rlim = 19.5
t0+3705s to t0+6041s : Rlim = 19.5
Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.
GCN Circular 20159
Subject
GRB 161108A: Swift/UVOT Upper Limits
Date
2016-11-09T18:46:33Z (9 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and A. P. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 161108A
90 s after the BAT trigger (Beardmore et al., GCN Circ. 20131).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 20147) or the NOT position (Malesani et al.,
GCN Cir., 20146) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 90 239 147 >20.08
white 90 5617 344 >20.62
v 578 6029 235 >18.61
b 5212 5412 196 >19.76
u 248 498 245 >19.24
u 248 10794 652 >19.88
uvw1 628 6439 412 >19.66
uvm2 603 6234 412 >19.89
uvw2 554 5823 235 >19.59
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 20160
Subject
GRB 161108A: TSHAO optical observations
Date
2016-11-09T21:29:59Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I.
Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 161108A (Beardmore et al., GCN 20145)
with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical
Observatory. We obtained several images in R filter starting on Nov. 08
(UT) 23:06:16. Within enhanced XRT position (Beardmore et al., GCN
20147) we detected a source coinciding with the afterglow of GRB 161014A
(Malesani et al., GCN 20146; Butler et al., GCN 20149). Preliminary
photometry of the source is following
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2016-11-08 23:06:16 0.83869 R 28*120 21.8 0.20 22.0
Our photometry of the afterglow might be affected by nearby galaxy
mentioned in GCN 20149 (Malesani et al.)
Photometry is based on nearby SDSS-DR9 stars (Lupton transformations):
SDSS-DR9_id R(Lupton)
J120315.88+245217.4 18.37
J120326.17+245228.7 18.71
J120318.05+245356.7 18.52
J120250.21+245354.3 18.35
J120258.81+245024.2 16.90
J120314.67+244944.0 17.06
J120321.43+244829.2 16.79
GCN Circular 20163
Subject
GRB 161108A: MITSuME Okayama upper limits
Date
2016-11-10T01:15:17Z (9 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of MITSuME and OISTER collaboration:
We observed the field of GRB 161108A (Beardmore et al., GCNC 20145)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2016-11-08 17:48:36 UT (~14.3 h after
the burst). We could not detect the previously reported afterglow
(Malesani et al., GCNC 20146; Butler et al., GCNC 20149)
in all the three bands.
Three sigma upper limits of the OT are listed below.
We used SDSS-DR8 catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Ic
-----------------------------------------------------
0.63016 18:39:58 5940.0 >19.9 >19.6 >19.2
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 20167
Subject
GRB 161108A: continued TSHAO optical observations
Date
2016-11-10T20:53:57Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I.
Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 161108A (Beardmore et al., GCN 20145) with
Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory.
We obtained several images in R filter starting on Nov. 09 (UT)
22:52:14. Within enhanced XRT position (Beardmore et al., GCN 20147) we
detected the afterglow of GRB 161014A (Malesani et al., GCN 20146;
Butler et al., GCN 20149). Preliminary photometry of the afterglow is
following
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2016-11-09 22:52:14 1.83762 R 41*120 22.0 0.24 22.2
The photometry of the afterglow might be affected by nearby galaxy
mentioned in GCN 20149 (Malesani et al.)
Photometry is based on nearby SDSS-DR9 stars (Mazaeva et al., GCN 20160).
GCN Circular 20200
Subject
GRB 161108A: 15 GHz upper limits from AMI
Date
2016-11-21T18:19:57Z (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), D. Titterington, S. H. Carey, J.
Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K.
Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for GRB
161108A (Beardmore et al., GCN 20145) as part of the 4pisky program, and
subsequent follow up observations were obtained up to 10 days
post-burst. Our observations at 15 GHz on 2016 Nov 08.19, Nov 09.40, Nov
12.35 and Nov 15.36 (UT) do not reveal any radio source at the XRT
location (Beardmore et al., GCN 20147), with 3sigma upper limits of 378
uJy, 284 uJy, 190 uJy and 93 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/.