GRB 181110A
GCN Circular 23413
Subject
GRB 181110A: Swift detection of a burst with an optical counterpart
Date
2018-11-10T08:59:09Z (7 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
P. A. Evans (U Leicester), K. L. Page (U Leicester) and
T. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 08:43:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181110A (trigger=871316). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 302.342, -36.903 which is
RA(J2000) = 20h 09m 22s
Dec(J2000) = -36d 54' 08"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 150 sec. The peak count rate
was ~3870 counts/sec (15-350 keV), at ~10 sec after the trigger.
The XRT began observing the field at 08:44:35.2 UT, 64.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 302.31711, -36.89632 which
is equivalent to:
RA(J2000) = 20h 09m 16.11s
Dec(J2000) = -36d 53' 46.8"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 75 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density.
The initial flux in the 0.1 s image was 5.82e-08 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 72 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 20:09:16.28 = 302.31782
DEC(J2000) = -36:53:47.8 = -36.89661
with a 90%-confidence error radius of about 0.63 arc sec. This position is 3.3
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.39 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.07.
Burst Advocate for this burst is P. A. Evans (pae9 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 23414
Subject
GRB 181110A: Kanata 1.5m optical observation
Date
2018-11-10T10:26:30Z (7 years ago)
From
Koji Kawabata at HASC,Hiroshima U <kawabtkj@hiroshima-u.ac.jp>
M. Yamanaka, M. Kawabata, K. S. Kawabata (Hiroshima Univ.)
report on behalf of Kanata team:
We performed optical imaging polarimetry to the field of the
GRB 181110A (Evans et al. GCN 23413) from 2018-11-10 08:44:48 UT
(77 seconds after the trigger) with HOWPol attached to the 1.5-m
Kanata telescope at Higashi-Hiroshima Observatory, Japan. Although
the first frames were severely affected by bright twilight sky,
in later frames a possible bright optical counterpart of the GRB
appeared at the position consistent with the Swift-UVOT observation
(Evans et al. GCN 23413). The magnitude of the counterpart was
R~14 mag (USNO B1.0) at 940 seconds after the trigger, suggesting
it brightened by ~4 mag within ~15 minutes. It further brightened
slightly (by a few 0.1 mag) and then declined smoothly.
Further analysis is ongoing.
GCN Circular 23415
Subject
GRB 181110A: MITSuME Akeno optical observation
Date
2018-11-10T12:11:22Z (7 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, K. Iida, M. Oeda, M. Niwano, R. Adachi, Y. Yatsu, and N.
Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration
We searched for the optical counterpart of GRB 181110A (Evans et al., GCN
Circular #23413) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50 cm telescope of AkenoObservatory, Yamanashi,
Japan.
The observation for the position of the 1st GCN of this trigger (trigger
#871316) started on 08:44:56 UT which corresponds to 85 sec after the
trigger.
Here we report the result of the images after 08:55:15 UT.
We detected the point source at the position consistent with the Swift/UVOT
observation (Evans et al., GCN Circular #23413) and the Kanata observation
(Yamanaka et al., GCN Circular # 23414).
The measured magnitudes are listed as follows.
T0+[min] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
~12 09:00:58.3 420 ~14 ~14 ~14
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the AB system.
Further analysis is ongoing.
GCN Circular 23416
Subject
GRB 181110A: optical observations from iTelescope SSO
Date
2018-11-10T12:45:01Z (7 years ago)
From
Denis Denisenko at SAI MSU <d.v.denisenko@gmail.com>
D. Denisenko (SAI MSU), M. Gnetov, E. Guskov, M. Orlova, V. Smirnov,
I. Vodolazskiy, N. Zlobin, D. Fernandez Ortiz (Center on Donskaya,
Moscow) report:
GRB 181110A: optical observations from iTelescope SSO
The field of bright long GRB 181110A (Evans et al., GCN Circ. 23413)
was observed remotely from Siding Spring using iTelescope.Net T17
instrument (0.43-m f/6.8 reflector + FLI PL4710 CCD) on 09:49-09:55
UT. Four unfiltered 60-sec exposures were obtained, until the
telescope was occupied by the other scheduled user. The optical
transient is well detected on 4 images and slowly fading, in
accordance with Yamanaka et al., GCN Circ. 23414. The following
magnitudes were measured using the nearby star USNO-B1.0 0531-0876625
as a reference with R2=14.80 in USNO-B1.0:
TIME-OBS, JD T-T0,s Mag. Error
-------------------------------
2458432.9093 3952 15.60 0.02
2458432.9105 4055 15.64 0.01
2458432.9117 4156 15.68 0.01
2458432.9128 4257 15.77 0.02
-------------------------------
Comparison of T17 iTelescope.Net image and 1990-09-19 DSS Red plate is
uploaded to http://scan.sai.msu.ru/~denis/GRB/GRB181110A-T17-DSS-anim.gif
(FOV 5'x5', 2x zoom).
GCN Circular 23417
Subject
GRB 181110A: Enhanced Swift-XRT position
Date
2018-11-10T17:03:06Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2774 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 181110A, 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 = 302.31802, -36.89665 which is equivalent
to:
RA (J2000): 20h 09m 16.32s
Dec (J2000): -36d 53' 47.9"
with an uncertainty of 1.4 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 23418
Subject
GRB 181110A: Swift-XRT refined Analysis
Date
2018-11-10T18:09:21Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U.
Leicester), J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Tohuvavohu (PSU) and
P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 7.4 ks of XRT data for GRB 181110A (Evans et al. GCN
Circ. 23413), from 67 s to 24.8 ks after the BAT trigger. The data
comprise 260 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 23417).
The late-time light curve (from T0+5.2 ks) can be modelled with a
power-law decay with a decay index of alpha=2.10 (+/-0.14).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.88 (+/-0.04). The
best-fitting absorption column is 8.6 (+1.0, -0.9) x 10^20 cm^-2,
consistent with the Galactic value of 7.7 x 10^20 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 1.74 (+0.07,
-0.06) 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 3.8 x 10^-11 (4.3 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.7 (+1.5, -0.0) x 10^20 cm^-2
Galactic foreground: 7.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.74 (+0.07, -0.06)
If the light curve continues to decay with a power-law decay index of
2.10, the count rate at T+24 hours will be 2.2 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.3 x
10^-14 (9.3 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00871316.
This circular is an official product of the Swift-XRT team.
GCN Circular 23419
Subject
GRB 181110A: Swift/UVOT Detection
Date
2018-11-10T21:56:35Z (7 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 181110A
72 s after the BAT trigger (Evans et al., GCN Circ. 23413).
The GRB was detected in ground photometry (Yamanaka et al., GCN
Circ. 23414; Murata et al., GCN Circ. 23415; Denisenko et al.
GCN Circ. 23416). The UVOT detects a source consistent
with the XRT position (Goad et al. GCN Circ. 23417) in the initial
UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 20:09:16.27 = 302.31781 (deg.)
Dec (J2000) = -36:53:47.9 = -36.89664 (deg.)
with an estimated uncertainty of 0.46 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 72 222 147 18.52 +/- 0.07
v 614 634 19 16.09 +/- 0.13
b 540 559 20 16.98 +/- 0.11
u 284 534 246 16.66 +/- 0.04
w1 663 683 19 15.65 +/- 0.13
m2 1068 1088 20 14.66 +/- 0.11
w2 1018 1038 20 15.74 +/- 0.14
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).
The source showed a rebrightening with a late peak at around 1100s after
the trigger.
GCN Circular 23420
Subject
GRB 181110A, Swift-BAT refined analysis
Date
2018-11-11T01:33:53Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. A. Evans (U Leicester),
H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC),
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+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181110A (trigger #871316)
(Evans et al., GCN Circ. 23413). The BAT ground-calculated position is
RA, Dec = 302.330, -36.878 deg which is
RA(J2000) = 20h 09m 19.2s
Dec(J2000) = -36d 52' 41.4"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-110 s and ends at ~T+130 s. The main peak occurs at ~T+25 s.
T90 (15-350 keV) is 138.4 +- 10.9 sec (estimated error including systematics).
The time-averaged spectrum from T-109.3 to T+129.8 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.02 +- 0.05. The fluence in the 15-150 keV band is 9.9 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+25.03 sec in the 15-150 keV band
is 3.7 +- 0.3 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/871316/BA/
GCN Circular 23421
Subject
GRB 181110A: VLT/X-shooter redshift
Date
2018-11-11T12:05:33Z (7 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
D. A. Perley (LJMU), D. B. Malesani (DAWN/NBI and DARK/NBI), J. P. U.
Fynbo (DAWN/NBI and DAWN/DTU), K. E. Heintz (Univ. Iceland), D. A. Kann
(HETH/IAA-CSIC), V. D'Elia (SSDC), L. Izzo (HETH/IAA-CSIC), and N. R.
Tanvir (Univ. Leicester) report:
We observed the optical counterpart of GRB 181110A (Evans et al. GCN
23413; Yamanaka et al., GCN 23414; Murata et al. GCN 23415) with the
ESO-VLT UT2 equipped with the X-shooter spectrograph. We acquired four
600 second spectra on UT 2018-11-11 between 00:36 and 01:21,
approximately 16 hours after the GRB. The optical afterglow was R~20.4
at this time.
Continuum is detected in the reduced spectrum across the entire spectral
range of the instrument (blue limit of 3000 Angstroms). Several weak
absorption features are also detected: in particular, we identify Mg II
and Fe II at a common redshift of z=1.505, identifying this as the most
likely redshift of the GRB. An additional intervening system is also
identified from (probable) Mg II absorption at z=0.28.
We acknowledge the ESO observing staff at Paranal, including Stephane
Brillant and Eleonora Sani.
GCN Circular 23422
Subject
GROND observations of GRB181110A
Date
2018-11-11T13:17:04Z (7 years ago)
From
Jan Bolmer at MPE/Garching <jan@bolmer.de>
J. Bolmer (MPE, Garching) and P. Schady (Univ. of Bath) report:
We observed the field of GRB 181110A (Swift trigger 871316; Evans et al., GCN #23413)
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 00:01 UT, 15.5 hrs after the GRB trigger, and were performed
under poor seeing conditions, 4.1���, and at an average airmass of 1.2.
We detect a source at a position consistent with the X-ray and optical afterglow
(Evans et al., GCN #23413; Kuin et al., GCN #23419). Based on the first 17 min of
total exposures in g'r'i'z' and 20 min in JHK, we measure the following preliminary
AB magnitudes:
g' = 21.25 +/- 0.06 mag
r' = 20.58 +/- 0.05 mag
i' = 19.91 +/- 0.08 mag
z' = 20.08 +/- 0.09 mag
J = 20.16 +/- 0.20 mag
H = 19.76 +/- 0.18 mag
K = 19.27 +/- 0.18 mag
Given magnitudes are calibrated against USNO and 2MASS field stars and are not corrected
for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.06
in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular 23423
Subject
GRB 181110A: optical observations in Chilescope observatory
Date
2018-11-11T18:27:48Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI)
report on behalf of IKI-FuN follow-up collaboration:
We observed the field of GRB 181110A (Evans et al., GCN 23413) with
RC-1000 telescopes of CHILESCOPE observatory. Observation started on
Nov. 11 (UT) 01:02:08 in r'-filter and were performed under moderate
seeing conditions of 1.5''. We detect optical afterglow (Evans et al.,
GCN 2341; Yamanaka et al., GCN 23414; Murata et al., GCN 23415;
Denisenko et al., GCN 23416; Perley et al., GCN 23421; Bolmer et
al., GCN 23422).
Preliminary photometry in AB is following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-11-11 01:02:08 0.69979 r' 10*300 20.53 0.10 22.8
The photometry is based on several nearby stars, magnitudes taken from
NOMAD catalog and Jester et al. (2005) transformations.
GCN Circular 23424
Subject
Konus-Wind observation of GRB 181110A
Date
2018-11-12T14:38:18Z (7 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov,
and T. Cline, on behalf of the Konus-Wind team, report:
The long GRB 181110A (Swift-BAT trigger #871316: (Evans et al.,
GCN 23413; Lien et al., GCN 23420; T0(BAT)= 08:43:31.320 UT)
was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data in
the 22-380 keV band reveals a count rate increase in the interval
from ~T0(BAT)-42 s to ~T0(BAT)+98 s.
No statistically significant emission has been detected above
380 keV.
The KW light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB181110A/
Modeling the KW 3-channel spectrum (from T0(BAT)-36 s to T0(BAT)+32 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.63(-0.26,+0.34) and Ep = 48(-27,+14) keV.
The total burst fluence in the 15-1500 keV band
is (1.1 �� 0.2)x10^-5 erg/cm^2.
Assuming z = 1.505 (Perley et al., GCN 23421) and a standard cosmology
model with H_0 = 70 km/s/Mpc, Omega_M = 0.30, and Omega_Lambda = 0.70,
the burst isotropic energy release E_iso is ~1.1x10^53 erg (1-10000 keV,
rest frame), and the rest-frame peak energy is ~120 keV.
All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.