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; Cheung et al., GCN 35081;
Dafcikova et al., GCN 53095; Busman et al. GCN 35138; O'Connor et al.,
GCN 35139) with the EMIR instrument on the GTC telescope from
2023-11-19 19:33 to 19:57 UTC (64.5 to 64.9 hours after the trigger).
We obtained total integrations of 420 in J and 252 in Ks with a seeing
of about 0.8 arcsec.
From our preliminary analysis, the source is detected in all filters
with brightness J = 20.9 +/- 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, including Riccardo Scarpa and Antonio
Cabrera, for their help with these observations.
GCN Circular 35152
Subject
GRB 231117A: Swift-BAT refined analysis
Date
2023-11-21T19:58:25Z (2 years ago)
From
Tyler Parsotan at NASA GSFC <tyler.parsotan@nasa.gov>
Via
email
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), M. J. Moss (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-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231117A (trigger #1197027)
(Laha, et al., GCN Circ. 35071). The BAT ground-calculated position is
RA, Dec = 332.404, 13.516 deg which is
RA(J2000) = 22h 09m 37.0s
Dec(J2000) = +13d 30' 58.1"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.
The mask-weighted light curve shows a very strong fast rise exponential decay profile
with potential precursor emission prior to the main pulse.
T90 (15-350 keV) is 0.67 +- 0.07 sec (estimated error including systematics).
The time-averaged spectrum from T-0.42 to T+1.30 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.55 +- 0.04. The fluence in the 15-150 keV band is 2.3 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-0.05 sec in the 15-150 keV band
is 28.9 +- 0.7 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/1197027/BA/
GCN Circular 35142
Subject
GRB 231117A: AMI-LA radio observations
Date
2023-11-20T20:44:23Z (2 years ago)
From
Lauren Rhodes at Oxford <lauren.rhodes@physics.ox.ac.uk>
Via
Web form
Lauren Rhodes, Rob Fender (Oxford), Dave Green, Dave Titterington (Cambridge) report:
We observed the field of the afterglow candidate GRB 231117A (GCN 35071) with the Arcminute Microkelvin Imager Large-Array (AMI-LA) at 15.5 GHz beginning at UT 15:30:45 on 17-Nov-2023 for a total of 4 hours. The flux standard 3c286 was used to calibrate the bandpass response and flux scale of the AMI-LA and J2232+1143 was used as an interleaved complex gain calibrator.
We do not detect any radio emission at the position of the afterglow candidate as reported in GCN 35083 with a 3-sigma upper limit of 230uJy/beam.
We thank the staff at the Mullard Radio Astronomy Observatory for carrying out these observations and operating the AMI-LA.
GCN Circular 35139
Subject
GRB 231117A: LDT Confirmation of Optical Fading
Date
2023-11-20T17:19:39Z (2 years ago)
From
Brendan O'Connor at Carnegie Mellon University <boconno2@andrew.cmu.edu>
Via
Web form
B. O'Connor (CMU), I. Andreoni (JSI/UMD/NASA-GSFC), G. Srinivasaragavan (UMD), T. Ahumada (Caltech), S. B. Cenko (NASA-GSFC), J. Durbak (UMD), E. Hammerstein (UMD), N. Klingler (UMBC/NASA-GSFC), A. Kutyrev (NASA-GSFC), L. Singer (NASA-GSFC), S. Veilleux (UMD):
We performed additional observations 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) with the Large Monolithic Imager (LMI) mounted at the 4-m Lowell Discovery Telescope (LDT) located in Flagstaff, AZ, under program M01 (PI: Andreoni). The observations began on 2023-11-20 02:50:02 UT (~3 d after the GRB) under seeing of ~2.2". We performed observations in the riz bands with 750 s exposure in each band.
At the location of the optical afterglow (Yang et al., GCN 35083; Rastinejad et al., GCN 35087; Gompertz et al., GCN 35088; Kumar et al., GCN 35089, Ahumada et al., GCN 35093; Andreoni et al., GCN 35099; Kilpatrick et al., GCN 35102; Chen et al., GCN 35105; Odeh et al., GCN 35118; Takahashi et al., GCN 35133; Schneider et al., GCN 35124; Busmann et al., GCN 35138), we clearly detect a source.
Preliminary photometry (including some contribution from the host) suggests fading by ~0.85 magnitudes in i-band from our previous observations obtained 2.0 days before (Andreoni et al., GCN 35099). Our observations confirm the fading of the optical afterglow candidate, as first reported by Fulton et al. (GCN 35121) and later by Busmann et al. (GCN 35138).
We thank the staff of the Lowell Observatory for their support during the observations.
GCN Circular 35138
Subject
GRB 231117A: Wendelstein Confirmation of Fading of the Optical Afterglow
Date
2023-11-20T17:16:21Z (2 years ago)
From
m.busmann@physik.lmu.de
Via
Web form
Malte Busmann (LMU), Daniel Gruen (LMU), Brendan O’Connor (CMU), Antonella Palmese (CMU), Lei Hu (CMU), Arno Riffeser (LMU/MPE), Ananya Shankar (LMU) report:
We observed 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) with the 2m Fraunhofer telescope at Wendelstein Observatory, Germany. Observations were obtained using the 3kk imager in the r, i, and J bands simultaneously. The data were obtained starting at 2023-11-19 18:11:39 UT (~2.6 d after the GRB) under ~2” seeing.
At the location of the optical transient (Yang et al., GCN 35083; Rastinejad et al., GCN 35087; Gompertz et al., GCN 35088; Kumar et al., GCN 35089, Ahumada et al., GCN 35093; Andreoni et al., GCN 35099; Kilpatrick et al., GCN 35102; Chen et al., GCN 35105; Odeh et al., GCN 35118; Takahashi et al., GCN 35133; Schneider et al., GCN 35124) we measure an optical brightness of
r = 21.1 +/- 0.1 AB mag
i = 21.2 +/- 0.2 AB mag
Image subtraction has not yet been performed and these magnitudes encompass both the transient and host galaxy flux. These measurements are consistent with the archival host galaxy magnitudes, and confirm fading of the optical transient as reported by Fulton et al. (GCN 35121), solidifying the connection to the GRB.
The magnitudes are not corrected for Milky Way extinction and the photometry was calibrated against nearby stars in the PS1 catalog.
We thank the staff of the Wendelstein Observatory for obtaining these observations.
GCN Circular 35136
Subject
GRB 231117A: CALET Gamma-Ray Burst Monitor detection
Date
2023-11-20T14:39:59Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Nakahira (JAXA), Y. Asaoka (ICRR),
S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The short GRB 231117A (Swift detection: Laha et al., GCN Circ. 35071;
AstroSat CZTI detection: Navaneeth et al., GCN Circ. 35072; AGILE
detection: Cattaneo et al., GCN Circ. 35075; Konus-Wind detection:
Svinkin et al., GCN Circ. 35079; Glowbug gamma-ray detection:
Cheung et al., GCN Circ. 35081; AGILE/MCAL analysis: Casentini
et al., GCN Circ. 35085; GRBAlpha detection: Dafcikova et al., GCN
Circ. 35095; GECAM-C detection: Wang-Chen et al., GCN Circ. 35117)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 03:03:19.31
UTC on 17 November 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1384225326/).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a single pulse that starts
at T+0.35 sec, peaks at T+0.68 sec, and ends at T+1.02 sec.
The T90 and T50 durations measured by the SGM data are 0.45
+/- 0.08 sec and 0.15 +/- 0.02 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1384225326/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 35134
Subject
GRB231117A: Swift-UVOT detection
Date
2023-11-20T12:29:35Z (2 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Via
legacy email
N.P.M. Kuin (MSSL/UCL) and S. L. Laha (GSFC/UMBC) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 231117A
106 s after the BAT trigger (Laha et al., GCN Circ. 35071).
A source consistent with the XRT position (Beardmore et al.,
GCN Circ. 35074 is detected in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits 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 106 1713 392 21.21 +/- 0.27
v 648 1418 78 >18.8
b 574 1688 78 >19.3
u 318 741 265 >19.9
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 35133
Subject
GRB 231117A : MITSuME Akeno optical afterglow candidate detection
Date
2023-11-20T12:14:35Z (2 years ago)
From
Ichiro Takahashi at Tokyo Tech <itakahashi@hp.phys.titech.ac.jp>
Via
Web form
I. Takahashi, H. Takei, N. Higuchi, M. Sasada, M. Niwano, S. Sato, S. Hayatsu, H. Seki, Y. Yatsu and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
After our previous report (Takei et al., GCN 35076), we reanalyzed all of the GRB 231117A field data observed by the MITSuME 50 cm telescope Akeno on Nov. 17th, and the point source was presumably detected at the afterglow candidate position reported by Yang et al. (GCN 35083). Here we report the Rc-band magnitudes and the 3-sigma limits of the stacked images as follows.
T0+[hour] | MID-UT | T-EXP[sec] | magnitudes of forced-photometry | 3-sigma limits
-----------------------------------------------------------------------------------------------
6.38 | 2023-11-17 09:25:57 | 5160 | Rc=20.7+/-0.3 | g'>20.5, Rc>20.4, Ic>19.8
7.59 | 2023-11-17 10:38:29 | 10320 | Rc=20.7+/-0.2 | g'>20.8, Rc>20.7, Ic>20.1
-----------------------------------------------------------------------------------------------
T0+ : Elapsed time after the trigger
T-EXP: Total Exposure time
These magnitudes include the contribution from the underlying host galaxy.
We used the PS1 catalog for flux calibration. The catalog magnitudes in PS1 g, r and i bands were converted to our g'-, Rc- and Ic-band magnitudes following Tonry et al. (2012), Table 6. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).
GCN Circular 35128
Subject
GRB 231117A: Swift-XRT refined Analysis
Date
2023-11-19T19:28:53Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto), D.N. Burrows (PSU), A.P. Beardmore (U.
Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB) and
P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 8.8 ks of XRT data for GRB 231117A, from 85 s to 223.3
ks after the BAT trigger. The data comprise 9 s in Windowed Timing
(WT) mode (taken while Swift was slewing), with the remainder in Photon
Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.65 (+0.07, -0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.81 (+0.17, -0.13). The
best-fitting absorption column is consistent with the Galactic value
of 6.1 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.6 x 10^-11 (4.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 6.1 (+/-3.8) x 10^20 cm^-2
Galactic foreground: 6.1 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.81 (+0.17, -0.13)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01197027.
This circular is an official product of the Swift-XRT team.
GCN Circular 35124
Subject
GRB 231117A: OHP/T120 optical observations
Date
2023-11-19T14:45:16Z (2 years ago)
From
Benjamin Schneider at MIT <bschn@mit.edu>
Via
Web form
B. Schneider (MIT), C. Adami (LAM/Pytheas/AMU), D. Turpin (CEA Paris-Saclay), S. Basa (Pytheas/OHP/LAM), Jean Balcaen (Pytheas/OHP), E. Le Floc'h, F. Schüssler (CEA Paris-Saclay), report on behalf of a larger collaboration:
We observed the field of the short 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) and its afterglow candidate (Yang et al. GCN 35083; Rastinejad et al., GCN 35087; Gompertz et al., GCN 35088; Kumar et al., GCN 35089; Ahumada et al., GCN 35093; Rhodes et al., GCN 35097; Andreoni et al., GCN 35099; Kilpatrick et al., GCN 35102) using the T120cm telescope at Observatoire de Haute-Provence (France). A total of 11 exposures of 900 seconds were obtained in the r band at 19:52:31.680 UT on 2023-11-17, ~16.82h after the trigger.
In the combined frame, we measured a flux excess at the position of SDSS J220933.34+133119.5 compared to archive values. After subtracting the SDSS J220933.34+133119.5 galaxy using the Legacy Survey image, we clearly detect a source consistent with the afterglow candidate reported by Yang et al., GCN 35083.
The preliminary magnitude derived for that source is
r = 21.0 ± 0.1 mag (AB)
The photometric calibration was performed using nearby stars from the PanSTARRS catalog and magnitudes are not corrected for Galactic extinction.
We acknowledge the Observatoire de Haute Provence staff for their excellent support.
GCN Circular 35121
Subject
GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
Date
2023-11-19T11:22:19Z (2 years ago)
From
shubhamsrivastav@gmail.com
Via
Web form
M. D. Fulton (QUB), S. Srivastav, S. J. Smartt (Oxford/QUB), J. H. Gillanders (Oxford), K. C. Chambers, M. E. Huber, A. S. B. Schultz (IfA, Hawaii), K. W. Smith, D. R. Young, M. Nicholl, M. McCollum, T. Moore, S. Sim, J. Weston, A. Aamer, C. R. Angus, X. Sheng (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), J. Sommer (LMU/QUB), H. Stevance, L. Rhodes, S. Ramaiya, A. Andersson (Oxford), T. de Boer, J. Herman, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, I. A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), T.-W. Chen (NCU), A. Rest (STScI), C. Stubbs (Harvard) report:
We observed the field of GRB 231117A (Laha et al., GCN 35071; Navaneeth et al., GCN 35072; Beardmore et al., GCN 35074; Cattaneo et al., GCN 35075; Svinkin et al., GCN 35079; Cheung et al., GCN 35081; Dafcikova et al., GCN 35095) with Pan-STARRS1 (Chambers et al., 2016) on two nights in the grizy filters, with the exposures beginning on MJDs 60266.255617 and 60267.271553.
We apply the Pan-STARRS1 reference frames for image subtraction and in all exposures, the afterglow candidate identified by Yang et al. (GCN 35083) as AT2023yba is well detected in griz and marginally in y. We confirm a clear and significant fading in all bands in a comparison between the two nights of:
delta-g = 1.5 +/- 0.2
delta-r = 1.3 +/- 0.2
delta-i = 1.2 +/- 0.2
delta-z = 1.1 +/- 0.2
The latest r-band magnitude at 60267.282458 is r = 22.0 +/- 0.2. This confirms the fast-fading nature of the optical transient AT2023yba, indicating this optical source, discovered by Yang et al. (GCN 35083), is very likely the afterglow of GRB 231117A.
Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the SSO Near-Earth Object Observations Program. Data are processed at Queen's University Belfast enabled through the STFC grants ST/P000312/1 and ST/T000198/1.
GCN Circular 35119
Subject
GRB 231117A: MAAO 0.7-m telescope optical upper limit
Date
2023-11-19T07:32:15Z (2 years ago)
From
Gu Lim at Pusan National University <lim9gu@gmail.com>
Via
Web form
Lim, Gu (PNU); Park, Junyeong (PNU); Kim, Dohyeong (PNU); Paek, Gregory S. H. (SNU); Im, Myungshin (SNU); Park, Keunhong (MAAO); Choi, Changmin (MAAO); and GECKO Collaboration
We searched for the optical afterglow of GRB 231117A (S. Laha et al., GCN 35071) with a 0.7m telescope at Miryang Arirang Astronomical Observatory (MAAO), one of the facilities of the GW EM-Counterpart Korean Observatory (GECKO). We started the observation at 2023-11-17 10:04:30 UT and obtained 30 images of each 120s with I-band after 6.9 hours after the Swift detection (GCN 35071). No significant source is found within the updated Swift-XRT position (Beardmore et al. GCN 35074). The photometry is performed using a 2xFWHM diameter aperture. The flux is calibrated using the PanStarrs DR1 photometric catalog (AB system) as a reference. The depth is the limiting magnitude for a point source without the galactic extinction correction.
T0 = 2023-11-17T03:03:19 UT (Laha et al., GCN 35071)
Filter Mean_Date-obs(UT) exptime(s) T-T0(d) FWHM(") Depth_3sigma(AB) Depth_5sigma(AB) zp zper
--------------------------------------------------------------------------------------------------------------------------------------------------
I 2023-11-17T10:38:14 120x30 +0.32 3.41 >20.34 >19.78 25.99 0.02
Our detection limit is deeper than the report from MITSuME (Takei et al., GCN 35076).
Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a network of 10+ 0.4m to 1m class telescopes worldwide.
GCN Circular 35118
Subject
GRB 231117A: AKO Follow-Up Observation
Date
2023-11-19T06:50:00Z (2 years ago)
From
Mohammad Odeh at Al Khatim Observatory M44 <mshodeh@gmail.com>
Via
legacy email
M. Odeh (Al-Khatim Observatory, AKO, operated by the International
Astronomical Center in Abu Dhabi, UAE) and N. Guessoum, D. Akl and I. Abdi
(American University of Sharjah, UAE) report:
As a follow-up to our first observation of GRB 231117A, performed on Nov.
17, 2023 (GCN 35084 <https://gcn.nasa.gov/circulars/35084>), we again
observed the field with our 0.36m f/7.7 robotic telescope, on Nov. 18,
starting at 15:50 UT using an (Ic) filter.
We again detected a faint object at the same location of the source SDSS
J220933.34+133119.5 (PS1 ID = 124223323889577032), which is listed in the
Pan-STARRS catalogue with imag = 21.5, and in the SDSS catalogue with imag
= 20.9. The coordinates of the detected object are: R.A. (2000) =
22:09:33.36, Dec. (2000) = +13:31:20.1, which is consistent with the
coordinates of the candidate optical source reported by Yang et al. (GCN
35083 <https://gcn.nasa.gov/circulars/35083>).
The following table summarizes the results of both nights using the Atlas
catalogue as a reference:
---------------------------------------------------------------------------
ObsTime (mid), T(Mid)–T(0), Exposure, Filter, Mag, RMS, Limiting Magnitude
---------------------------------------------------------------------------
2023-11-17 15:37:30Z, 12.6 h, 33x180s (stacked), Ic, 19.85, 0.20, 20.2
2023-11-18 15:50:06Z, 1.53 d, 40x180s (stacked), Ic, 19.78, 0.21, 20.4
---------------------------------------------------------------------------
The magnitudes are not corrected for galactic extinction.
GCN Circular 35117
Subject
GRB 231117A: GECAM-C detection
Date
2023-11-19T06:27:53Z (2 years ago)
From
Wang-Chen Xue <wcxuemail@gmail.com>
Via
Web form
Wang-Chen Xue, Shao-Lin Xiong and Chen-Wei Wang
report on behalf of the GECAM team:
GECAM-C was triggered on ground by a short burst, GRB 231117A at
2023-11-17T03:03:19.210 UTC (denoted as T0), which has been
detected by Swift (GCN 35071), AstroSat (GCN 35072), AGILE (GCN 35075),
Konus-Wind (GCN 35079), Glowbug (GCN 35081), and GRBalpha (GCN 35095).
According to the ground data of GECAM-C, this burst mainly consists
of a short pulse with a duration (T90) of 0.59 +/- 0.04 sec (15-4000 keV).
The GECAM-C localization is consistent with the Swift/BAT localization
(GCN 35074) within the error.
The time-averaged spectrum of GECAM-C data from T0 to T0+1.3 s could be
adequately fit by a cut-off power-law with photon index alpha of -1.52 (-0.07, +0.09),
and peak energy Ep of 437 (-174, +556) keV. The corresponding burst fluence is
8.40 (-1.64, +2.70) * 10^-6 erg/cm^2 in 15-4000 keV.
We note that these results are preliminary and refined analysis will be reported later.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor
(GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B)
launched in Dec. 2020. As the third member of GECAM constellation,
GECAM-C was launched onboard SATech-01 experimental satellite in July 2022.
GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN Circular 35114
Subject
GRB 231117A: 10 GHz VLA detection
Date
2023-11-19T03:49:13Z (2 years ago)
From
Genevieve Schroeder at Northwestern University <genevieveschroeder2023@u.northwestern.edu>
Via
legacy email
G. Schroeder (Northwestern), W. Fong, T. Laskar (Utah) report:
"We observed the position of the short 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) with the Karl G. Jansky Very Large
Array (VLA) under program 23A-296 (PI: Schroeder) beginning on 2023 Nov.
17.98 UT (0.85 days post-burst) for 0.75 hours at a mean frequency of 10
GHz.
We confirm the presence of a radio source consistent with the location of
the putative optical afterglow and host galaxy (Yang et al. GCN 35083,
Rastinejad et al., GCN 35087, Gompertz & Ackley, GCN 35088, Kumar et al.,
GCN 35089, Andreoni et al., GCN 35099, Kilpatrick et al., GCN 35102, Chen
et al. 35105). We measure a flux density of ~190 uJy, resulting in a radio
luminosity of ~4e29 erg/s/Hz, consistent with typical radio luminosities of
SGRB radio afterglows (Laskar et al. 2022).
Our measured flux density is somewhat fainter than the 9 GHz flux with ATCA
reported by Rhodes et al. (GCN 35097). While the ATCA observations occurred
at a slightly earlier mid-time of 0.54 days than our VLA observations, we
cannot make a strong statistically significant claim regarding fading
between the two observations at this time.
We thank the VLA staff for quickly approving and executing these
observations. Further observations are planned to assess the nature of the
radio source."
ReplyForward
GCN Circular 35105
Subject
GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
Date
2023-11-18T19:16:48Z (2 years ago)
From
Ting-Wan Chen at MPE <janet.chen@astro.su.se>
Via
legacy email
T.-W. Chen (NCUIA), S. Yang (HNAS), C.-S. Lin (NCUIA), S. Smartt (Oxford/QUB), M. Fraser (UCD), A.J. Levan (Radboud), M.-H. Lee, C.-C. Ngeow, Y.-C. Pan, H.-Y. Hsiao, W.-J. Hou, J.-K. Guo (NCUIA), Z.-N. Wang (HNAS), J. Gillanders (Oxford), M. Fulton, S. Srivastav, T. Moore, C. Angus, A. Aamer (QUB), and N. Tanvir (Leicester) report:
We observed the field of GRB 231117A (Laha et al., GCN 35071; Navaneeth et al., GCN 35072; Beardmore et al., GCN 35074; Cattaneo et al., GCN 35075; Svinkin et al., GCN 35079; Cheung et al., GCN 35081; Dafcikova et al. GCN 35095).
The afterglow candidate was initially identified in our previous report (Yang et al., GCN 35083) . Since it is a real astrophysical transient, but not yet confirmed as the afterglow, we registered it as AT2023yba (Chen et al., TNS 194096).
We used the 40cm SLT at Lulin Observatory, Taiwan to obtain r-band images of the field of GRB 231117A, as part of the Kinder collaboration (Chen et al., AstroNote 2021-92). The first SLT epoch of observations started at 10:51 UT on 18 of November 2023 (MJD = 60266.452), 1.32 days after the Swift trigger. The r-band images were combined from 21 frames with a 300-second exposure time for the r band, taken under seeing conditions of an average of 1".87 and at a median airmass of 1.16. Then we continuously conducted observations of i, g, and z-band images, commencing from MJD = 60266.552, under seeing conditions of an average of 1".94 and at a median airmass of 1.83.
We used the Kinder pipeline (Yang et al. A&A 646, A22) to measure the PSF photometry of AT 2023yba after template subtraction using the SDSS images. We obtained the following magnitudes and a 3-sigma detection limit (in the AB system):
r = 20.86 +/- 0.13 mag (exposure time of 300sec*21),
i = 20.94 +/- 0.17 mag (300sec*6),
g = 21.37 +/- 0.13 mag (300sec*6) and
z > 20.02 mag (300sec*6).
The given magnitudes derived based on calibrating against SDSS field stars and is not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.06 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
Since the various GCNs on this source have heterogeneous methods, we focus on comparing our own nightly template subtracted measurements. By comparing these data with measurements on MJD = 60265.435 (at the epoch of 7.39 hours after the Swift trigger), we found AT 2023yba has faded by more than 0.4 mag in g and i bands in one day, but no fading in the r band. No fading in r band was also noticed in Kumar et al. (GCN 35089) at the epoch of 10.56 hours. The redshift of the host galaxy, SDSS J220933.34+133119.5, has been spectroscopically confirmed at z = 0.257 (Ahumada et al., GCN 35093; Gonzalez-Bañuelos et al., GCN 35098), placing this transient at absolute magnitude M_r = -19.6 mag.
GCN Circular 35102
Subject
GRB 231117A: SOAR/Goodman imaging of the afterglow
Date
2023-11-18T18:06:31Z (2 years ago)
From
Charles Kilpatrick at Northwestern U <ckilpatrick@northwestern.edu>
Via
Web form
C. D. Kilpatrick (Northwestern), L. Santana (CBPF), R. Salinas (ULS), C. Briceño (NOIRLab/CTIO), C. Fuentes (PUC), C. Bom, A. Santos (CBPF) report on behalf of a larger collaboration:
“We observed the putative host galaxy of GRB 231117A (Laha et al., GCN 30571, Navaneeth et al., GCN 35072, Cattaneo et al., GCN 35075, Svinkin et al., GCN 35079, Cheung et al., GCN 35081, Odeh et al., GCN 35084, D'Avanzo et al., GCN 35086, Rastinejad et al., GCN 35087, Gompertz et al., GCN 35088) with the Goodman High-Throughput Spectrograph mounted on the SOAR 4m telescope on Cerro Pachon, Chile. We obtained 5x200s of imaging in r-band starting at 2023 Nov 18.03.
We detect a r=20.4+/-0.1 mag counterpart at the location of SDSS J220933.34+133119.5, consistent with the reported afterglow position reported by Yang et al. (GCN 35083) and subsequent detections of the putative afterglow (Rastinejad et al., GCN 35087, Gompertz & Ackley, GCN 35088, Kumar et al., GCN 35089, Andreoni et al., GCN 35099). These data are on the AB magnitude system and not corrected for Galactic extinction, however we caution that these data are preliminary and there is uncertain contribution from the host galaxy in our aperture. Additional SOAR follow up is planned.”
GCN Circular 35099
Subject
GRB 231117A: Lowell Discovery Telescope Observations
Date
2023-11-18T17:18:44Z (2 years ago)
From
Brendan O'Connor at Carnegie Mellon University <boconno2@andrew.cmu.edu>
Via
Web form
I. Andreoni (JSI/UMD/NASA-GSFC), G. Srinivasaragavan (UMD), B. O'Connor (CMU), T. Ahumada (Caltech), S. B. Cenko (NASA-GSFC), J. Durbak (UMD), E. Hammerstein (UMD), N. Klingler (UMBC/NASA-GSFC), A. Kutyrev (NASA-GSFC), L. Singer (NASA-GSFC), S. Veilleux (UMD):
We report target of opportunity follow-up observations 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) with the Large Monolithic Imager (LMI) mounted at the Lowell Discovery Telescope (LDT) located in Flagstaff, AZ, under program M01 (PI: Andreoni).
Observations started on 2023-11-18 at 01:46 UT (~22.7 hr after the GRB trigger). We obtained sets of 4x150s exposures for each g-r-i-z filter. The candidate afterglow identified by Yang et al.; GCN 35083 (also detected by Rastinejad et al., GCN 35087; Gompertz et al., GCN 35088; Kumar et al., GCN 35089, Ahumada et al., GCN 35093; Rhodes et al., GCN 35097) is well detected. Preliminary photometry of the images, with contribution from the host galaxy included and not corrected for Galactic extinction, was measured as follows in the AB magnitude system:
g = 20.55 +/- 0.04 mag
r = 20.20 +/- 0.04 mag
i = 20.05 +/- 0.04 mag
z = 19.98 +/- 0.03 mag
We thank Ben Shafransky and the Lowell Observatory staff for their support.
GCN Circular 35098
Subject
GRB 231117A: ePESSTO+ host galaxy redshift confirmation
Date
2023-11-18T13:08:05Z (2 years ago)
From
Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>
Via
Web form
M. Gonzalez-Bañuelos, M. Kopsacheili (ICE), P. D'Avanzo (INAF-OAB), D. B. Malesani (DAWN/NBI and Radboud univ.), L. Galbany, T. Müller-Bravo (ICE), C. Gutierrez (IEEC/ICE-CSIC), M. Dennefeld (IAP), A. Gkini (Stockholm), N. Ihanec (Warsaw and ING), J. Anderson (ESO), T.-W. Chen (NCU), M. Gromadzki (Warsaw), C. Inserra (Cardiff), E. Kankare (Turku), M. Nicholl (QUB), O. Yaron (Weizmann), D. Young (QUB), report on behalf of the ePESSTO+ collaboration:
We observed the candidate counterpart of the short GRB 231117A (Laha et al., GCN Circ. 35071; Navaneeth et al., GCN Circ. 35072; Cattaneo et al., GCN Circ. 35075; Svinkin et al., Gin Circ. 35079; Cheung et al. GCN Circ. 35081; Dafcikova et al. GCN Circ. 35095) under the advanced Public ESO Spectroscopic Survey for Transient Objects (ePESSTO+; see Smartt et al. 2015, A&A, 579, 40; http://www.pessto.org). The observations were performed with the ESO New Technology Telescope (NTT) at La Silla equipped with the EFOSC2 instrument in spectroscopic mode, starting on 2023 Nov 18 at 00:22:34 UT (i.e. 21.3 hr after the burst) and using grism 13 (covering the wavelength range 3985-9315 AA).
The 1.5" slit was oriented in order to cover both the optical afterglow and the host galaxy candidate positions (Yang et al., GCN Circ. 35083; Rastinejad et al., GCN 35087; Gompertz & Ackley, GCN 35088). However, the observations were carried out under poor seeing conditions (1.7") and in the acquisition image the two objects cannot be distinguished.
The spectrum shows prominebt emission features, which we identify as [O II], [O III] and Halpha at a common redshift z = 0.257, in agreement with the findings of Ahumada et al. (GCN Circ. 35093). No clear absorption features are detected.
GCN Circular 35097
Subject
GRB 231117A: ATCA detection of a radio counterpart
Date
2023-11-18T10:44:18Z (2 years ago)
From
Lauren Rhodes at Oxford <lauren.rhodes@physics.ox.ac.uk>
Via
email
L. Rhodes (Oxford), G. E. Anderson (Curtin), A. J. van der Horst (GWU),J. K. Leung (UofT/HUJI), S. D. Ryder (Macquarie), A. Gulati (USyd), S. Chastain (UNM) on behalf of the PanRadio GRB collaboration
The Australia Telescope Compact Array (ATCA) observed short GRB 231117A (Laha et al., GCN 35071) as part of the Large ATCA "PanRadio GRB" follow-up programme C3542 (PI. Anderson) starting at 2023-11-17 04:00UT for 11hours.
We detect a radio source with a flux density of ~210uJy/beam at 9GHz at coordinates consistent with both those given by the XRT and the Lulin Observatory (A.P. Beardmore et al., GCN 35074; S. Yang et al., GCN 35083).
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 35095
Subject
GRB 231117A: GRBAlpha detection
Date
2023-11-18T09:27:43Z (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, 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 short-duration GRB 231106B (Swift/BAT detection: GCN 35071; AstroSat detection: GCN 35072; AGILE/MCAL detection: GCN 35075; Konus/Wind detection: GCN 35079; Glowbug detection: GCN 35081; CALET/CGBM detection: trigger no. 1384225326) 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 2023-11-17 03:03:19 UTC. The T90 duration measured by GRBAlpha is 1 s and the overall significance during T90 reaches 14 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB231117A_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 35093
Subject
GRB 231117A: Keck spectroscopy of afterglow candidate
Date
2023-11-18T06:10:57Z (2 years ago)
From
Tomas Ahumada Mena at Caltech <tahumada@caltech.edu>
Via
Web form
Tomas Ahumada, Yashvi Sharma(Caltech) on behalf of a larger collaboration:
We report optical spectroscopic observations of the candidate counterpart of the short GRB 231117A (GCN 35083, 35071) with the Low Resolution Imaging Spectrometer (LRIS, Oke et al. 95) at the Keck I Observatory (C358, PI: Kasliwal). Observations started 2023-11-18 05:19:00 (~1.1 days after the burst), and consisted of 2x900 exposures with the 400/3400 grism and 400/8500 grating.
The spectrum shows narrow galaxy lines at redshift of z = 0.257 (H, [O II], [O III], N II). We also see narrow absorption lines consistent with MgII(2796,2803) doublet at this redshift. We note the spectrum shows a blue continuum.
We thank Michael Lundquist and the Keck team for their support during this Target of Opportunity trigger.
The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
GCN Circular 35089
Subject
GRB 231117A: GIT optical follow-up
Date
2023-11-18T01:51:44Z (2 years ago)
From
Vishwajeet Swain at IIT Bombay <vishwajeet.s@iitb.ac.in>
Via
Web form
R. Kumar, A. Salgundi, V. Swain, V. Bhalerao (IIT Bombay), G. C. Anupama, S. Barway (IIA), R. Norboo (IAO)
We observed the field of GRB 231117A detected by Swift (S. Laha et al., GCN 35071) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2023-11-17 13:36:59 UT, i.e., 10.56 hours after the Swift trigger. We obtained the multiple images of 300s each in the r' and g' band. We did not detect any source within the uncertainty radius of Swift-XRT position reported by A.P. Beardmore et al., GCN 35074 upto a limiting magnitude of 22.38 in r' band. We do detect the candidate optical afterglow in our subtracted image at the position reported by Yang et al. (GCN 35083). The photometry values are given below:
------------------------------------------------------------------------
| JD (mid) | t-t0 (days) | Filter | Exposure (s) | Magnitude (5 sigma) |
------------------------------------------------------------------------
| 2460266.072780335 | 0.445 | r' | 3 x 300 | 20.80 +/- 0.06 |
| 2460266.087725621 | 0.460 | r' | 3 x 300 | 21.18 +/- 0.08 |
| 2460266.098941961 | 0.471 | r' | 3 x 300 | 20.88 +/- 0.07 |
| 2460266.203419748 | 0.576 | r' | 3 x 300 | 20.84 +/- 0.07 |
| 2460266.253062681 | 0.625 | g' | 2 x 300 | 20.88 +/- 0.07 |
------------------------------------------------------------------------
Our data shows slight variability in the source, but no clear decay. The results are comparable to the values reported by B. P. Gompertz et al., GCN 35088; J. C. Rastinejad et al., GCN 35087; Yang et al., GCN 35083; and consistent with the upper limits given by M.Ferro et al., GCN 35086; M. Odeh et al., GCN 35084; J. H. Gillanders et al., GCN 35080; H. Takei., GCN 35076; B. Godson et al., GCN 35073. Based on these measurements, we conclude that this source is unlikely to be the afterglow. The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular 35088
Subject
GRB 231117A: LT observations consistent with fading
Date
2023-11-17T22:43:55Z (2 years ago)
From
Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>
Via
email
B. P. Gompertz (U. Birmingham) and K. Ackley (U. Warwick) report:
We observed the field of the short 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) with the IO:O camera on the 2m robotic Liverpool Telescope. Observations began at 19:18:59 UT on 2023-11-17, ~16.3 hours after trigger, and consisted of 20x120s exposures in each of the SDSS r and i filters.
At the position of the optical counterpart reported by Yang et al. (GCN 35083) we detect a source with preliminary AB magnitudes of:
i = 20.10 +/- 0.03
r = 20.24 +/- 0.02
While these magnitudes include the contribution from the underlying galaxy, a comparison to the Keck observations taken ~14 hours prior (Rastinejad et al., GCN 35087) indicates fading at around the 3-sigma level. Combined with the significant excess above archival magnitudes, this supports the presence of the optical afterglow of GRB 231117A.
Analysis is ongoing. Reported magnitudes are not corrected for Galactic foreground extinction.
GCN Circular 35087
Subject
GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
Date
2023-11-17T21:56:10Z (2 years ago)
From
Jillian Rastinejad at Northwestern Univ. <jillianrastinejad2024@u.northwestern.edu>
Via
Web form
J. C. Rastinejad, W. Fong, H. Sears (Northwestern), R. Chornock, W. Jacobson-Galan (UC Berkeley), C. D. Kilpatrick (Northwestern), R. Margutti (UC Berkeley), G. Schroeder (Northwestern) et al. report:
''We observed the location of the bright 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