GRB 151118A
GCN Circular 18611
Subject
GRB 151118A: Swift detection of a burst
Date
2015-11-18T03:24:39Z (10 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
A. Amaral-Rogers (U Leicester), S. D. Barthelmy (GSFC),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of
the Swift Team:
At 03:06:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 151118A (trigger=664078). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 57.158, +65.869, which is
RA(J2000) = 03h 48m 38s
Dec(J2000) = +65d 52' 07"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a few peaks
with a duration of about 25 sec. The peak count rate
was ~2600 counts/sec (15-350 keV), at ~6 sec after the trigger.
The XRT began observing the field at 03:07:36.2 UT, 66.2 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 57.1719,
65.9012 which is equivalent to:
RA(J2000) = 03h 48m 41.25s
Dec(J2000) = +65d 54' 04.4"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 117 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 in excess of the Galactic value (4.54 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 5.9
(+4.29/-3.55) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 250 seconds with the U filter starting
281 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 none of the
XRT error circle. 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 18.0 mag. No correction has been made for the expected extinction
corresponding to E(B-V) of 1.10.
Burst Advocate for this burst is A. Amaral-Rogers (aar14 AT 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 18612
Subject
GRB 151118A: Optical observations from OSN
Date
2015-11-18T04:36:51Z (10 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), A. Sota (IAA-CSIC),
and C. Thoene (IAA-CSIC) report:
We observed the field of GRB 151118A (Amaral-Rogers et al. GCN 18611)
with the 1.5 m OSN telescope in Granada (Spain), starting at 03:17:55 UT
(11.42 min after the GRB onset). Observations consisted of 7x300 s
exposures in I-band. No new source is detected within the XRT error box.
The 3-sigma limiting magnitudes of the individual exposures, and the combined
frames are I(Vega) = 21.5 mag, and I(Vega) = 22.5 mag, respectively. The mean
time of the combined exposure is 03:37:49 (31.32 min after the burst). Photometry
was obtained by comparison with stars from the USNO-B1.0 catalogue.
GCN Circular 18613
Subject
GRB GRB 151118A: MASTER-NET optical observations
Date
2015-11-18T11:11:38Z (10 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E.Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa,
A.Kuznetsov, D. Vlasenko, D.Kuvshinov
Lomonosov Moscow State University, Sternberg Astronomical Institute
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik
Kislovodsk Solar Station of the Pulkovo Observatory
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Kislovodsk was pointed to the GRB151118.13 30 sec after notice
time and 44 sec after trigger time at 2015-11-18 03:07:17 UT. On our first
(10s exposure) set we haven`t found optical transient within SWIFT
error-box (ra=03 48 37 dec=+65 52 06 r=0.05).
The 5-sigma upper limit has been about 16.5 mag unfiltered.
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in IAC was pointed to the GRB151118A 24 sec after notice time
and 42 sec after trigger time at 2015-11-18 03:07:12 UT in two
polarizations. On our first (10s exposure) set we haven`t found optical
transient within SWIFT error-box (Amaral-Rogers et al GCN 18611).
Our early upper limits on single and coadd images given in a table below:
Table 1.
5 sigma limit.
T-Ts T-Tm Expt. P| P- coadd.
lim lim
----------------------------------------
42 47 10 16.7 16.8 1
42 90 50 17.9 18.0 3
42 508 790 19.9 20.0 12
86 96 20 17.3 17.4 1
117 127 20 17.3 17.4 1
147 218 120 18.7 18.8 3
299 420 220 19.2 19.3 3
551 762 400 19.6 19.7 3
---------------------------------------
T - is a trigger time [s].
Ts - image start time [s].
Tm - image middle time [s].
Expt - exposure time [s].
P| - image upper limit in polarizer orientated 90 deg. to RA axis [mag].
P- - image upper limit in polarizer orientated 0 deg. to RA axis [mag].
We do not see OT brighter 20 mag. There is marginal object (m~20) with 6"
W (RA) and 3"S (dec) offset from XRT error box center (Ra = 03h 48m
40.40s Dec= 65d 54m 01.3s Mag ~ 20.3 +- 0.7 ).
The message may be cited.
GCN Circular 18614
Subject
GRB 151118A: Enhanced Swift-XRT position
Date
2015-11-18T11:22:15Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 4427 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 151118A, 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 = 57.17172, +65.90168 which is equivalent
to:
RA (J2000): 03h 48m 41.21s
Dec (J2000): +65d 54' 06.1"
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 18615
Subject
GRB 151118A: Swift/UVOT Upper Limits
Date
2015-11-18T12:31:35Z (10 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and Amaral-Rogers (U Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151118A
70 s after the BAT trigger (Amaral-Rogers et al., GCN Circ. 18611).
No optical afterglow consistent with the XRT position
(Amaral-Rogers et al. GCN Circ. 18611)
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 first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 70 220 148 >20.6
u (fc) 282 532 246 >20.0
white 70 754 186 >20.8
v 612 631 19 >18.3
b 537 730 39 >19.3
u 282 705 265 >19.9
w1 661 680 19 >18.2
w2 587 607 19 >17.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.10 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 18617
Subject
GRB 151118A: Swift-XRT refined Analysis
Date
2015-11-18T12:44:51Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A.
Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
D.N. Burrows (PSU) and A. Amaral-Rogers report on behalf of the
Swift-XRT team:
We have analysed 7.4 ks of XRT data for GRB 151118A (Amaral-Rogers et
al. GCN Circ. 18611), from 52 s to 22.7 ks after the BAT trigger. The
data comprise 22 s in Windowed Timing (WT) mode (the first 7 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 Evans
et al. (GCN Circ. 18614).
The late-time light curve (from T0+4.9 ks) can be modelled with a
power-law decay with a decay index of alpha=1.07 (+/-0.26).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.93 (+0.23, -0.22). The
best-fitting absorption column is 1.07 (+0.25, -0.21) x 10^22 cm^-2,
in excess of the Galactic value of 4.5 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 5.1 x 10^-11 (9.2 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.07 (+0.25, -0.21) x 10^22 cm^-2
Galactic foreground: 4.5 x 10^21 cm^-2
Excess significance: 4.7 sigma
Photon index: 1.93 (+0.23, -0.22)
If the light curve continues to decay with a power-law decay index of
1.07, the count rate at T+24 hours will be 4.6 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x
10^-13 (4.2 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/00664078.
This circular is an official product of the Swift-XRT team.
GCN Circular 18618
Subject
GRB 151118A: ISON-NM early optical limit
Date
2015-11-18T14:44:20Z (10 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
L. Elenin (KIAM), A. Volnova (IKI), E. Mazaeva (IKI), I. Molotov
(KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the field of the Swift GRB 151118A (Amaral-Rogers et al.,
GCN 18611) with 0.4-m telescope of ISON-NM observatory in robotic mode
starting on Nov., 18 (UT) 03:08:32 i.e. 122 seconds after burst
trigger. We obtained 6 unfiltered images of 30 s exposure under
unfavorable weather conditions. We do not detect any source within
enhanced XRT error circle (Evans et al., GCN 18614):
Date UT start t-T0 Filter Exp. UL(3 sigma)
(mid, days) (s)
2015-11-28 03:08:32 0.00158 None 1*30 17.4
2015-11-28 03:08:32 0.00265 None 5*30 18.0
The photometry is based on nearby USNO-B1.0 stars:
USNO-B1.0 id R2
1559-0079254 15.66
1558-0078601 16.03
1558-0078636 14.62
GCN Circular 18619
Subject
GRB 151118A: Early optical limit from pt5m, La Palma
Date
2015-11-18T17:56:51Z (10 years ago)
From
Liam K Hardy at U of Shffield <liam.hardy@sheffield.ac.u>
L. K. Hardy (Sheffield), V. S. Dhillon (Sheffield, IAC),
S. P. Littlefair (Sheffield), T. Butterley (Durham) and
R. W. Wilson (Durham) report:
Our automated robotic telescope 'pt5m' (Hardy et al. 2015, MNRAS 454,
4316) on La Palma observed the field of
GRB 151118A (Amaral-Rogers et al., GCN 18611) starting
at 03:16:27 UT on Nov 18, 10 min after the GRB detection.
Observations comprised of 46 x 60-second exposures in
the R-band. We detect no new source within the XRT error box (Evans et
al., GCN 18614). The 3-sigma limiting magnitude of
a combined image is R = 22.1 mag. The mean time of the
combined exposure is 03:42 UT (36 mins after the burst).
We obtained photometry using the nearest comparison star,
USNOB1.0:1559-0079286, R=15.6.
GCN Circular 18622
Subject
GRB 151118A, Swift-BAT refined analysis
Date
2015-11-20T00:36:34Z (10 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), A. Amaral-Rogers (U Leicester), S. D. Barthelmy (GSFC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), 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+941 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 151118A (trigger #664078)
(Amaral-Rogers, et al., GCN Circ. 18611). The BAT ground-calculated position is
RA, Dec = 57.169, 65.889 deg which is
RA(J2000) = 03h 48m 40.6s
Dec(J2000) = +65d 53' 22.0"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.
The mask-weighted light curve shows a multi-peaked structure that
starts at ~ T0 and ends at ~T+30 s. The structure contains roughly two main
pulses that peak at ~ T0 and ~T+7 s, respectively. T90 (15-350 keV) is
23.4 +- 10.5 sec (estimated error including systematics).
The time-averaged spectrum from T+0.0 to T+30.8 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.80 +- 0.20. The fluence in the 15-150 keV band is 4.5 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+6.41 sec in the 15-150 keV band
is 1.2 +- 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/664078/BA/
GCN Circular 18627
Subject
GRB 151118A: AAO optical upper limit
Date
2015-11-20T15:09:39Z (10 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), R. Inasaridze (AAO), V. Ayvazian (AAO), A. Volnova
(IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger
GRB follow-up collaboration:
We observed the field of the Swift GRB 151118A (Amaral-Rogers et al.,
GCN 18611) with AS-32 (0.7m) telescope of Abastumani Observatory
starting on Nov. 18 (UT) 18:08:09. We do not detect any source within
enhanced XRT error circle (Evans et al., GCN 18614):
Date UT start t-T0 Filter Exp. UL(3 sigam)
(mid, days) (s)
2015-11-18 18:08:09 0.65922 None 35*120 22.1
The photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id R2
1559-0079254 15.66
1559-0079234 16.18
1559-0079286 15.60
1559-0079243 16.15
1558-0078596 14.88
GCN Circular 18630
Subject
GRB 151118A: MITSuME Akeno optical upper limits
Date
2015-11-21T08:27:02Z (10 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
Y.Yano, T.Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana,
Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 151118A (A. Amaral���Rogers et al., GCN Circular #18611) with the
optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2015-11-18 19:14:09 UT (~16.1 h after the burst).
We did not find any new point source within XRT circle in all three bands.
We obtained following limits for the magnitudes.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------
58059 19:44:17 2520 > 20.3 > 19.6 > 18.4
-------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 18642
Subject
GRB 151118A iTelescope observation
Date
2015-11-26T10:03:41Z (10 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
Y. Kitaoka, T. Sakamoto, A. Yoshida (AGU)
We observed the field of GRB 151118A detected by Swift (trigger #664078;
Amaral-Rogers et al., GCN Circ. 18611) with the iTelescope.Net (http://www.itelescope.net)
T7 (17" Plane Wave) telescope located at the AstroCamp Observatory (Nerpio, Spain).
20 images of 60 sec exposures were taken in the R filter starting from November 18 03:45:22 (UT)
about 38.8 minutes after the trigger and stopped on November 18 04:23:04 (UT).
We do not detect the optical afterglow both in the individual images and the stacked image
at the enhanced X-ray afterglow position (Evans et al., GCN Circ. 18614). The estimated
five sigma upper limit of the combined image (total exposure of 1200 sec) is ~18.3 using
the USNO-B1 catalog.