GRB 231117A
GCN Circular 35201
Subject
GRB 231117A: MeerKAT 1.3GHz detection
Date
2023-11-27T16:10:58Z (2 years ago)
From
Lauren Rhodes at Oxford <lauren.rhodes@physics.ox.ac.uk>
Via
Web form
L. Rhodes (Oxford), G. Schroeder (Northwestern), G. Anderson (Curtin), W. Fong (Northwestern), S. Chastain (UNM), A. Gulati (USyd), A. van der Horst(GWU), C. Kilpatrick (Northwestern), N. Klinger (NASA/GSFC), T. Laskar (Utah), J. K. Leung (UofT/HUJI), A. Nugent (Northwestern), J. Rastinejad (Northwestern), S. D. Ryder (Macquarie) on behalf of a larger collaboration.
We observed GRB 231117A (GCN 35071) with the MeerKAT radio telescope at 1.3GHz for a total of 2 hours starting on 26 November 2023 at 12:47 UTC. The observations used J1939-6342 and J2232+1143 as flux and phase calibrators, respectively. Using the SARAO SDP image we find an unresolved source at the position of the afterglow candidate (GCN 35083) with a flux density of ~100uJy/beam. The rms noise in the field is 7uJy/beam. We note that the measured flux density may have a substantial contribution from the host galaxy reported in GCN 35083 but said contribution cannot be quantified until the afterglow has faded.
We thank the staff at the South African Radio Astronomy Observatory for scheduling these observations.
GCN Circular 35172
Subject
GRB 231117A: Mondy optical observations
Date
2023-11-23T23:07:40Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
Via
legacy email
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We observed the field of GRB 231117A (Laha et al., GCN 35071; Navaneeth et al., GCN 35072; Beardmore et al., GCN3574; Cattaneo et al., GCN 35075; Svinkin et al., GCN 35079; Cheung et al., GCN 35081; Dafcikova et al., GCN 53095; Busman et al. GCN 35138; O'Connor et al., GCN 35139; Watson et al., GCN 35153, Kuin et al., GCN 35154; Dichiara et al., GCN 35160; Fong et al., GCN 35163) with AZT-33IK telescope of Mondy observatory in R-filter on 2023-11-17, 2023-11-18 and 2023-11-20. Using image subtraction and the image on 2023-11-20 as a template we obtained preliminary photometry of the optical transient
Date UT start t-T0 Exp. Filter OT Err.
(mid, days) (s)
2023-11-17 11:45:33 0.38349 30x120 R 21.00 0.16
2023-11-18 12:09:46 1.41142 46x120 R 21.59 0.16
The photometry is based on nearby USNO-B1.0 R2 stars. The index of power law (t-T0)^-alpha between the two epochs is alpha = 0.8 (+0.13 -0.2).
However, photometry may be biased due to the template contamination by a still decaying optical transient, so we caution against using this index for any physical assessments.
GCN Circular 35163
Subject
GRB 231117A: Chandra afterglow detection
Date
2023-11-23T03:12:50Z (2 years ago)
From
Wen-fai Fong at Northwestern University <wfong@northwestern.edu>
Via
Web form
W. Fong, T. Eftekhari, G. Schroeder (Northwestern), A. Rouco Escorial (ESA/ESAC) report:
"The Chandra X-ray Observatory observed the position of the short-duration GRB 231117A (Laha et al., GCN 35071, Navaneeth et al., GCN 35072, Cattaneo et al., GCN 35075, Svinkin et al., GCN 35079, Cheung et al., GCN 35081) starting on 2023 November 21 at 06:22:13 UT. We obtained an ACIS-S observation under Proposal 24400307 (PI: Fong), with an effective exposure time of ~27 ksec, for a mid-time of 4.3 days post-burst.
The X-ray afterglow is clearly detected at high significance. The source is spatially coincident with the optical (e.g., Yang et al., GCN 35083, Rastinejad et al., GCN 35087, Gompertz et al., GCN 35088) and radio (Rhodes et al., GCN 35097, Schroeder et al., GCN 35114) afterglows at the position:
RA (J2000) = 22:09:33.37
Dec (J2000) = 13:31:20.0
We note that, similar to the reported optical positions, the Chandra source is just outside the 90% confidence region of the latest XRT position. We measure a 0.3-10 keV flux for the Chandra afterglow of FX ~ 2e-13 erg/s/cm^2. We find that the XRT light curve beyond ~300 seconds post-burst can be modeled with a single power-law with FX ~ t^-0.6, and that the Chandra observation is fully consistent with this power law.
We thank the Chandra staff for rapid approval and planning of these observations."
GCN Circular 35160
Subject
GRB 231117A: Continued GTC Observations
Date
2023-11-22T20:56:27Z (2 years ago)
From
Simone Dichiara at Pennsylvania State University <sbd5667@psu.edu>
Via
Web form
Simone Dichiara (PSU), Alan M. Watson (UNAM), Nathaniel R. Butler (ASU), Eleonora Troja (Università di Roma Tor Vergata), Brendan O’Connor (CMU), Rosa L. Becerra (UNAM), Nissim Fraija (UNAM), William Lee (UNAM), Kin López (UNAM), and Margarita Pereyra (UNAM) report:
We observed the field of GRB 231117A (Laha et al., GCN 35071; Navaneeth et al., GCN 35072; Beardmore et al., GCN3574; Cattaneo et al., GCN 35075; Svinkin et al., GCN 35079; Cheung et al., GCN 35081; Dafcikova et al., GCN 53095; Busman et al. GCN 35138; O'Connor et al., GCN 35139; Watson et al., GCN 35153, Kuin et al., GCN 35154) with the OSIRIS instrument on the GTC telescope from 2023-11-21 20:34 to 21:16 UTC (113.5 to 114.2 hours after the trigger). We obtained total integrations of 480 s in r and 960 s in z with a seeing of about 0.9 arcsec.
We detect the source in both bands but, even with our good seeing, reliable photometry will require image subtraction. We measure r = 21.8 +/- 0.1 AB, with an uncertain contribution from the host galaxy. This value is not corrected for Galactic extinction.
Further observations are planned.
We thank the staff of the GTC, especially David García Álvarez and Antonio Cabrera, for their help with these observations.
GCN Circular 35154
Subject
GRB 231117A: Swift/UVOT late time observations
Date
2023-11-21T22:05:33Z (2 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Via
email
N.P.M. Kuin (MSSL/UCL) and S. L. Laha (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The initial Swift/UVOT observations of the field of GRB 231117A
(Laha et al., GCN Circ. 35071) have been reported by Kuin and
Laha (GCN Circ. 35134) based on the enhanced XRT position (Beardmore
et al. GCN Circ. 35074). A refined position was published by
Yang et al. (GCN Circ. 35083) which we use for the current
circular.
We report here exposures taken over the specified period and summed for
better S/N. We also report here in AB magnitudes (Breeveld et al. 2011,
AIP Conf. Proc. 1358, 373):
Filter T_start(s) T_stop(s) Exp(s) AB-Mag
white 106 1713 392 22.3 +/- 0.5
u 5863 18,406 917 20.9 +/- 0.2
white 67,725 68,529 675 21.7 +/- 0.2
white 210,209 223,742 4848 22.4 +/- 0.4
Considering that these are AB magnitudes, we can compare the white and u
values to see a likely peak around the time of the u magnitude with a
subsequent decay.
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.071 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 35153
Subject
GRB 231117A: GTC Near-Infrared Observations
Date
2023-11-21T21:05:30Z (2 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
Via
legacy email
Alan M. Watson (UNAM), Simone Dichiara (PSU), Eleonora Troja
(Università di Roma Tor Vergata), Brendan O’Connor (CMU), Rosa L.
Becerra (UNAM), Nathaniel R. Butler (ASU), Nissim Fraija (UNAM),
William Lee (UNAM), Océlotl López (UNAM), and Margarita Pereyra (UNAM)
report:
We observed the field of GRB 231117A (Laha et al., GCN 35071;
Navaneeth et al., GCN 35072; Beardmore et al., GCN3574; Cattaneo et
al., GCN 35075; Svinkin et al., GCN 35079