GRB 231118A
GCN Circular 35893
Subject
Konus-Wind detection of GRB 231118A
Date
2024-03-07T11:34:50Z (2 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
legacy email
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long-duration GRB 231118A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 35100;
Barra and Meegan, GCN Circ. 35131;
Swift-BAT detection: Laha et al., GCN Circ. 35101;
Moss et al., GCN Circ. 35141;
AstroSat-CZTI detection: Navaneeth et al., GCN Circ. 35116;
VZLUSAT-2 detection: Dafcikova et al., GCN Circ. 35143;
GRBAlpha detection: Dafcikova et al., GCN Circ. 35151)
triggered Konus-Wind at T0=62189.937 s UT (17:16:29.937).
The burst light curve shows the main multi-peaked emission episode
which starts at ~T0-2.7 s and has a total duration of ~6.7 s,
followed by a weaker emission seen up to ~70 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB231118_T62189/
As observed by Konus-Wind, the main episode
had a fluence of 9.65(-0.91,+1.13)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+2.864 s,
of 9.13(-1.69,+1.83)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The spectrum of the main episode
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.15(-0.17,+0.20)
and Ep = 321(-55,+84) keV (chi2 = 81/80 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.3
(chi2 = 81/79 dof).
Assuming the redshift z=0.8304 (Schneider et al., GCN Circ. 35123)
and a standard cosmology model with H_0 = 67.3 km/s/Mpc,
Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 1.86(-0.18,+0.22)x10^52 erg,
the peak luminosity L_iso is 3.22(-0.59,+0.64)x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i,z is 588(-101,+155) keV.
With the obtained estimates, GRB 231118A is inside 90% prediction band for the 'Amati' relation and inside 68% prediction band for the 'Yonetoku' relation derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB231118_T62189/GRB231118A_rest_frame.pdf
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 35167
Subject
GRB 231118A: REM optical afterglow detection
Date
2023-11-23T13:57:31Z (2 years ago)
From
Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com>
Via
legacy email
R. Brivio, M. Ferro, P. D'Avanzo, D. Fugazza, S. Covino (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 231118A (Fermi GBM Team., GCN 35100; Laha et al., GCN 35101) with the REM 60cm robotic telescope located at the ESO Observatory of La Silla (Chile). The observations were carried out in the g, r, i, z, J, H and K bands, starting on 2023 Nov 19 at 00:16:39 UT (i.e. about 7.00 hours after the GBM and Swift trigger) and lasted for about 1 hour.
The optical afterglow (Dutton et al., GCN 35103, Strausbaugh et al., GCN 35110, Shrestha et al., GCN 35113, de Wet et al., GCN 35126, Takahashi et al., GCN 35133), is detected in r, i bands coadded frames (t_exp = 20 min) . From preliminary photometry, we derive the following magnitudes and limits:
r = 19.66 +/- 0.08 (AB)
i = 19.19 +/- 0.11 (AB; calibrated against the the APASS catalogue)
at a mid time of t-t0 ~ 7.68 hours after the GRB trigger.
H > 17.7 (Vega; calibrated against the 2MASS catalogue)
at a mid time of t-t0 ~ 7.44 hours after the GRB trigger.
GCN Circular 35155
Subject
GRB 231118A: ATCA detection of radio counterpart
Date
2023-11-22T09:09:53Z (2 years ago)
From
Gemma Anderson at Curtin U <gemma.anderson@curtin.edu.au>
Via
Web form
S. Chastain (UNM), G. E. Anderson (Curtin), J. K. Leung (UofT/HUJI), S. D. Ryder (Macquarie), A. J. van der Horst (GWU), A. Gulati (USyd), and L. Rhodes (Oxford) on behalf of the ATCA PanRadio GRB collaboration
The Australia Telescope Compact Array (ATCA) observed the long GRB 231118A, first detected by the Fermi GRB Team (GCN 35100), as part of the ATCA "PanRadio GRB" Large Project C3542 (PI: G. Anderson) on 2023-11-20 at 14:30 UT for 3 hours (~2 days post-burst).
We detect a radio source with a flux density of ~0.4 mJy at 9 GHz. This source is consistent with the reported Swift/XRT enhanced position (Evans et al., GCN 35106).
Further observations are planned.
We thank the CSIRO Space and Astronomy staff for supporting these observations.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
GCN Circular 35151
Subject
GRB 231118A: GRBAlpha detection
Date
2023-11-21T14:46:20Z (2 years ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), yyT. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 231118A (Fermi/GBM detection: GCN 35100; Swift/BAT detection: GCN 35101; AstroSat detection: GCN 35116; VZLUSAT-2 detection: GCN 35143; Konus/WIND trigger at 2023-11-18 17:16:29.937 UT, INTEGRAL/SPI-ACS peak detection at 2023-11-18 ~17:16:33 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).
The detection was confirmed at the peak time 2023-11-18 17:16:33 UTC. The T90 duration measured by GRBAlpha is 4 s and the overall significance during T90 reaches 8.5 sigma in the 120-400 keV band.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB231118A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular 35143
Subject
GRB 231118A: VZLUSAT-2 detection
Date
2023-11-20T20:47:21Z (2 years ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long-duration GRB 231118A (Fermi/GBM detection: GCN 35100; Swift/BAT detection: GCN 35101; AstroSat detection: GCN 35116; Konus/WIND trigger at 2023-11-18 17:16:29.937 UT, INTEGRAL/SPI-ACS peak detection at 2023-11-18 ~17:16:33 UT) was detected by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector unit no. 1. The detection was confirmed at the peak time 2023-11-18 17:16:34 UTC. The T90 duration is 8 s and the significance during T90 reaches 5.6 sigma.
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB231118A_GCN_VZLUSAT2.pdf
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/
The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.
GCN Circular 35141
Subject
GRB 231118A: Swift-BAT refined analysis
Date
2023-11-20T20:35:03Z (2 years ago)
From
Mike Moss at NASA GSFC <mikejmoss3@gmail.com>
Via
Web form
M. J. Moss (GSFC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231118A (trigger #1197311)
(Laha, et al., GCN Circ. 35101). The BAT ground-calculated position is
RA, Dec = 4.840, -48.044 deg which is
RA(J2000) = 00h 19m 21.7s
Dec(J2000) = -48d 02' 37.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.
The light curve shows a single pulse with similar rise and fall times.
There is also a dim tail extending 30 seconds after the main pulse.
T90 (15-350 keV) is 37.63 +- 8.89 sec (estimated error including systematics).
The time-averaged spectrum from T-6.84 to T+55.21 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.40 +- 0.07. The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band
is 9.7 +- 0.5 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/1197311/BA/
GCN Circular 35131
Subject
GRB 231118A: Fermi GBM observation
Date
2023-11-20T03:17:28Z (2 years ago)
From
Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
Web form
C. de Barra (UCD) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 17:16:29.83 UT on 18 November 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 231118A (trigger 722020594 / 231118720),
which was also detected by Swift BAT (S. Laha et al. 2023, GCN 35101)
and Swift XRT (K.L. Page & P.A. Evens, 2023, GCN 35104).
The Fermi Final Localization was reported in GCN 35100 and is consistent
with the Swift BAT and XRT positions.
The angle from the Fermi LAT boresight at the GBM trigger time is 118 degrees.
The GBM light curve consists of a single peak with a duration (T90)
of about 6 s (50-300 keV). The time-averaged spectrum from -4.1s to 6.1 s is best fit
with a Band function with Epeak = 217.7 +/- 22.6 keV, alpha = -0.77 +/- 0.07,
and beta = -2.17 +/- 0.13
The event fluence (10-1000 keV) in this time interval is (1.0 +/- 0.1)E-05 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+3.2 s in the 10-1000 keV band
is 18.0 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular 35127
Subject
GRB 231118A: Swift-XRT refined Analysis
Date
2023-11-19T19:16:02Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB),
S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans
report on behalf of the Swift-XRT team:
We have analysed 5.0 ks of XRT data for GRB 231118A, from 86 s to 81.5
ks after the BAT trigger. The data comprise 117 s in Windowed Timing
(WT) mode (the first 9 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode.
The light curve can be modelled with an initial power-law decay with an
index of alpha=0.84 (+/-0.05), followed by a break at T+8184 s to an
alpha of 1.6 (+0.4, -0.3).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.36 (+0.14, -0.13). The
best-fitting absorption column is 8.6 (+3.4, -2.8) x 10^21 cm^-2, at a
redshift of 0.8304, in addition to the Galactic value of 1.9 x 10^20
cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index
of 1.51 (+0.13, -0.12) and a best-fitting absorption column of 8.9
(+2.5, -2.2) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10
keV flux conversion factor deduced from this spectrum is 4.8 x 10^-11
(5.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 1.9 x 10^20 cm^-2
Intrinsic column: 8.9 (+2.5, -2.2) x 10^21 cm^-2 at z=0.8304
Photon index: 1.51 (+0.13, -0.12)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01197311.
This circular is an official product of the Swift-XRT team.
GCN Circular 35126
Subject
GRB 231118A: MeerLICHT afterglow detection
Date
2023-11-19T15:33:03Z (2 years ago)
From
Simon de Wet at University of Cape Town <simdewet@gmail.com>
Via
Web form
S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO) and P.M. Vreeswijk (Radboud) report on behalf of the MeerLICHT consortium:
The 0.6 m wide-field MeerLICHT optical telescope located in Sutherland, South Africa, obtained a repeated series of 60 s exposures in the q,u,g,r,i,z bands of GRB 231118A following the Swift detection (Laha et al., GCN 35101). Observations started at 18:58:24 UT on 2023 November 18 (1.7 hours post-trigger) and continued until 21:46:37 UT, following the filter sequence quqgqrqiqz.
We detect the optical afterglow first reported by Dutton et al. (GCN 35103) with the following AB magnitudes:
q = 17.65 +/- 0.05 at 18:58:56 UT
u = 18.39 +/- 0.20 at 19:00:35 UT
g = 18.03 +/- 0.09 at 19:04:08 UT
r = 17.40 +/- 0.12 at 19:07:43 UT
i = 17.24 +/- 0.11 at 19:28:53 UT
z = 17.72 +/- 0.17 at 19:50:19 UT
Our high cadence q-band observations show a power-law decline with temporal index of -1.63, consistent with the decay reported by Dutton et al. (GCN 35108).
MeerLICHT is built and run by a consortium consisting of Radboud University, the University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam.
GCN Circular 35123
Subject
GRB 231118A: VLT/X-shooter redshift
Date
2023-11-19T14:44:04Z (2 years ago)
From
Benjamin Schneider at MIT <bschn@mit.edu>
Via
Web form
B. Schneider (MIT), A. Saccardi (GEPI, Observatoire de Paris), L. Izzo (INAF-Naples & DARK/NBI), A. J. Levan (Radboud), D. B. Malesani (DAWN/NBI), N. R. Tanvir (Univ. Leicester), G. Pugliese (Amsterdam), report on behalf of the Stargate collaboration:
We observed the field of the Swift/Fermi GRB 231118A (Fermi GBM Team, GCN 35100; Laha et al., GCN 35101) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-21000 AA, and consist of
4 exposures of 600s each. The observation mid-time is 01:23:787 UT on Nov 19 2023 (8.1 hr after the Fermi trigger).
In a 30s image taken with the acquisition camera on Nov 19 00:51:23 UT, we clearly detect the optical afterglow (Dutton et al., GCN 35103, GCN 35108; Lipunov et al., GCN 35109; Strausbaugh et al., GCN 35110; Shrestha et al, GCN 35113), for which we measure an AB magnitude r = 19.88 +/- 0.04 mag (calibrated against one nearby star from Legacy Survey).
In a preliminary reduction, we clearly detect a continuum over the entire wavelength range. From detection of multiple absorption features, which we interpret as being due to FeII, MnII, MgII, MgI and FeII*, ZnII, CrII, and CaII, we infer a common redshift of z = 0.8304. We conclude this is the redshift of the burst. We also detect multiple emission lines (Halpha, Hbeta, OIII doublet) at a consistent redshift, which we interpret as being due to the GRB host galaxy. We also note the presence of additional absorption features likely due to multiple intervening systems.
We acknowledge expert support from the ESO staff in Paranal, in particular Thomas Rivinius and Matias Jones.
GCN Circular 35116
Subject
GRB 231118A: AstroSat CZTI detection
Date
2023-11-19T05:42:15Z (2 years ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
P. K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 231118A which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35100), and Swift-BAT (Laha et al., GCN Circ. 35101).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2023-11-18 17:16:33.55 UTC. The measured peak count rate associated with the burst is 773 (+165, -131) counts/s above the background in the combined data of three quadrants (out of four), with a total of 885 (+229, -215) counts. The local mean background count rate was 237 (+5, -8) counts/s. Using cumulative rates, we measure a T90 of 3.9 (+1.6, -1.0) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-11-18 17:16:32.74 UTC. The measured peak count rate associated with the burst is 638 (+71, -77) counts/s above the background in the combined data of all quadrants, with a total of 1634 (+436, -460) counts. The local mean background count rate was 1222 (+9, -10) counts/s. We measure a T90 of 3.7 (+1.8, -1.3) s from the cumulative Veto light curve.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 35113
Subject
GRB 231118A: Las Cumbres optical detection
Date
2023-11-19T00:04:57Z (2 years ago)
From
Manisha Shrestha at University of Arizona <mshrestha1@arizona.edu>
Via
Web form
M. Shrestha (Univ. of Arizona), D. Sand (Univ. of Arizona), K. D. Alexander (Univ. of Arizona), J. Andrews (Gemini), J. Pearson (Univ. of Arizona), N. Smith (Univ. of Arizona), K. Bostroem (Univ. of Arizona) D. A. Howell (LCO/UCSB), C. McCully (LCO/UCSB), M. Newsome (LCO/UCSB), E Padilla Gonzalez (LCO/UCSB), C. Pellegrino (LCO/UCSB), G. Terreran (LCO/UCSB), J. Farah (LCO/UCSB) report on behalf of a wider Global Supernova Project collaboration:
We observed the field of GRB 231118A (Fermi GBM team GCN 34937, Swift GCN 34938) with the 1-m telescope, on 2023-11-18T22:30:11.370 UT (60266.937 MJD, ~5.3 hours after the trigger) using the Sinistro instrument in g, r, i bands. We detect the GRB with the following magnitude:
g = 19.81 +-0.09
r = 19.45 +-0.14
i = 19.44 +-0.19
Magnitudes were calculated with respect to ATLAS-REFCAT2 (Tonry et al. 2018, ApJ 867 105) catalog and are not corrected for galactic extinction. These values are consistent with other detections (Dutton et al., GCN 35103, Dutton et al., GCN 35108, Lipunov et al., GCN 35109, Strausbaugh et al., GCN 35110)
GCN Circular 35110
Subject
GRB 231118A: LCOGT Optical Observations
Date
2023-11-18T22:32:28Z (2 years ago)
From
Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>
Via
email
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the Swift/Fermi GRB 231118A field (Fermi GBM Team, GCN 35100; Laha et al., GCN 35101) with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on November 18, from 21:20 to 21:52 UT (corresponding to 4.07 to 4.60 hours from the GRB trigger time) with the Bessel R and I filters.
We performed a series of 3x300s exposures in each band. We detect an uncataloged source consistent with the Skynet afterglow candidate (Dutton et al., GCN 35103) in both bands. This result is consistent with fading detected in continued Skynet observations (Dutton et al., GCN 35108) and MASTER observations (Lipunov, et al., GCN 35109)
The following magnitudes are calculated using the USNO-B1.0 catalog as reference:
R = 19.08 +/- 0.04
I = 18.67 +/- 0.03
These magnitudes are not corrected for galactic extinction.
GCN Circular 35109
Subject
GRB 231118A: MASTER OT observation
Date
2023-11-18T22:10:51Z (2 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V.Lipunov (Lomonosov MSU), D.Buckley (SAAO),
A.Kuznetsov, D.Vlasenko, P.Balanutsa, K.Zhirkov, E.Gorbovskoy, Ya.Kechin, Yu.Tselik,
N.Tiurina, I.Gorbunov, V.Vladimirov, D.Zimnukhov, V.Senik, V.Topolev, A.Yudin,
A.Chasovnikov, D.Cheryasov, A.Sosnovskij, A.Pozdnyakov, M.Gulyaev (Lomonosov MSU,SAI,PhysicsDepartment),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
MASTER Global robotic net (MASTER-Net:http://observ.pereplet.ru Lipunov etal.,2010,Advances in Astronomy,2010,30L)
started Fermi (GCN 35100) and
Swift (Evans et al. GCN 35101, GCN 35104, GCN 35106) GRB 231118A error box observation at 2023-11-18 20:19:50 UT by MASTER-SAAO (Lipunov et al. GCN 35107).
There is optical counterpart MASTER OT J001919.45-480224.7
with m_OT=19.2m+-0.2m at 2023-11-18 20:26:40 and next 5 expositions (automatic, unfiltered, mlim=19.5), at Skynet position (discovered by Dutton et al. GCN 35103, GCN 35108)
Observations started at 70deg.altitude.
Observation and reduction will be continued.
GCN Circular 35108
Subject
GRB 231118A: Continued Skynet Observations
Date
2023-11-18T21:49:27Z (2 years ago)
From
Dylan Dutton at UNC Chapel Hill <ddutton59@gmail.com>
Via
Web form
Dylan Dutton, Megan Dubay, Ruide Fu, Donovan Schlekat, Logan Selph, Daniel Reichart, Joshua Haislip, Vladimir Kouprianov, Daryl Janzen, Arie Verveer, and John Kennewell report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill.
We continued to observe the afterglow of GRB 231118A located at RA=00:19:19.3583, Dec=-48:02:24.923 (GCN 35103, Dutton et al.) with our 0.4m robotic telecope located in Meckering, Australia. The observation began at 17:19:11 UTC on Nov 18 2023, approximately 3 minutes after the trigger, and continued for approximately 100 minutes, until 18:54:53 UTC. We obtained multiple expsoures in the B, V, R, and I filters.
During the first approximately 40 minutes of the observation, the afterglow faded very slowly, and irregularly, with an approximate temporal index between -0.2 and -0.1.
After 40 minutes, the afterglow faded much more quickly with an approximate temporal index between -2 and -1.5, which could be consistent with the non-detection from Global MASTER-Net (GCN 35107, Lipunov et al.).
Throughout the entire observation, the afterglow is very red, with an approximate spectral index between -2 and -1.5. This is likely due to source-frame dust.
We report the photometry of our most recent images below.
ExpLen | Filter | Mag | MagErr | Date | UTC
-----------------------------------------------------------
110.95s | R | 17.02 | 0.04 | Nov 18, 2023 | 18:52:55
89.47s | I | 16.65 | 0.07 | Nov 18, 2023 | 18:54:53
Our images have been calibrated using stars from the APASS catalog.
GCN Circular 35106
Subject
GRB 231118A: Enhanced Swift-XRT position
Date
2023-11-18T20:12:11Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 539 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 231118A, 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 = 4.83131, -48.03940 which is equivalent
to:
RA (J2000): 00h 19m 19.51s
Dec (J2000): -48d 02' 21.8"
with an uncertainty of 2.2 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 35104
Subject
GRB 231118A: Swift-XRT position
Date
2023-11-18T18:45:21Z (2 years ago)
From
K.L. Page at U Leicester <klp5@leicester.ac.uk>
Via
email
K.L. Page and P.A. Evens (U. Leicester) report on behalf of the Swift-XRT
team:
Using promptly downlinked data we find an uncatalogued X-ray source
located at RA,Dec = 4.8314, -48.0390 which is equivalent to:
RA (J2000.0) = 00 19 19.65
DEC (J2000.0) = -48 02 20.8
with an uncertainty of 3.50 arcsec (radius, 90% containment).
This location is 31.4 arcsec from the BAT position, inside the BAT
error circle.
This circular is an official product of the Swift-XRT team.
GCN Circular 35103
Subject
GRB 231118A: Skynet Optical Afterglow Discovery
Date
2023-11-18T18:45:17Z (2 years ago)
From
Dylan Dutton at UNC Chapel Hill <ddutton59@gmail.com>
Via
Web form
Dylan Dutton, Megan Dubay, Donovan Schlekat, Logan Selph, Daniel Reichart, Joshua Haislip, Vladimir Kouprianov, Daryl Janzen, Arie Verveer, John Kennewell, and Ruide Fu report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill.
We observed the field of GRB 231118A with our 0.4m robotic telecope located in Meckering, Australia. The observation began at 17:19:11 UTC on Nov 18 2023, approximately 3 minutes after the trigger.
We obtained multiple expsoures in the B, V, R, and I filters. Exposure lengths were calculated using our automated exposure length scaling model.
We detected a bright object within the uncertainty radius of the Swift localization, at:
R.A. (J2000): 00:19:19.3583
Dec. (J2000): -48:02:24.923
We report the discovery photometry below.
ExpLen | Filter | Mag | Date | UTC
-----------------------------------------
3.034s | R | 14.8 | Nov 18, 2023 | 17:19:30
Our images have been calibrated using stars from the APASS catalog.
GCN Circular 35101
Subject
GRB 231118A: Swift detection of a burst
Date
2023-11-18T17:31:56Z (2 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
Via
email
S. Laha (GSFC/UMBC), M. Ferro (INAF-OAB), C. Gronwall (PSU),
M. J. Moss (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL),
T. M. Parsotan (GSFC/UMBC/CRESSTII), T. Sbarrato (INAF-OAB),
M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 17:16:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 231118A (trigger=1197311). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 4.843, -48.035 which is
RA(J2000) = 00h 19m 22s
Dec(J2000) = -48d 02' 07"
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 15 sec. The peak count rate
was ~11,000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to a telemetry outage, XRT and UVOT data are not
immediately available and will be reported later.
Burst Advocate for this burst is S. Laha (sib.laha AT gmail.com).
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/)
GCN Circular 35100
Subject
GRB 231118A: Fermi GBM Final Real-time Localization
Date
2023-11-18T17:27:02Z (2 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 17:16:29 UT on 18 Nov 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231118A (trigger 722020594.832338 / 231118720).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 4.0, Dec = -48.2 (J2000 degrees, equivalent to J2000 00h 16m, -48d 12'), with a statistical uncertainty of 1.4 degrees.
The angle from the Fermi LAT boresight is 118.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231118720/quicklook/glg_skymap_all_bn231118720.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231118720/quicklook/glg_healpix_all_bn231118720.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231118720/quicklook/glg_lc_medres34_bn231118720.gif