GRB 231017A
GCN Circular 34822
Subject
GRB231017A: Fermi GBM Final Localization
Date
2023-10-17T14:51:29Z (2 years ago)
From
Joe Mangan at IJCLab <joseph.mangan@ijclab.in2p3.fr>
Via
Web form
The Fermi GBM team reports the detection of a likely Long GRB.
At 08:05:03.30 UT on 17 October 2023, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB231017A (trigger 719222708 / 231017337).
The on-ground calculated location, using the GBM trigger data, is RA = 88.8, DEC = 57.2 (J2000 degrees, equivalent to 5h 55m, 57d 09'), with a statistical uncertainty of 5.7 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
The angle from the Fermi LAT boresight at the GBM trigger time is 58 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231017337/quicklook/glg_skymap_all_bn231017337.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/bn231017337/quicklook/glg_healpix_all_bn231017337.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231017337/quicklook/glg_lc_medres34_bn231017337.gif
GCN Circular 34824
Subject
GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
Date
2023-10-17T15:30:08Z (2 years ago)
From
Jimmy DeLaunay at University of Alabama <delauj2@gmail.com>
Via
Web form
James DeLaunay (U Alabama, PSU), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 231017A onboard (T0: 2023-10-17T08:05:03.30 UTC, Fermi/GBM GCN 34822, Trigger 719222708).
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 15 in a 2.048 s analysis time bin, starting at T0 - 0.512 s.
A candidate arcminute localization is found with DeltaLLHOut of 17 and a DeltaLLHPeak of 6.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
The BAT position is
RA, Dec = 86.191, +56.666 deg which is
RA(J2000) = 05 44m 45.84s
Dec(J2000) = +56d 39′ 57.6″
with an estimated uncertainty of 6 arcmin radius.
XRT and UVOT follow-up has been requested.
Results of follow-up observations will be reported in future circulars.
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/
GCN Circular 34825
Subject
GRB 231017A: Swift ToO observations
Date
2023-10-17T17:27:04Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Swift/BAT-GUANO GRB 231017A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021623
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Swift/BAT-GUANO event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 34829
Subject
GRB 231017A: Swift-XRT observations
Date
2023-10-18T15:56:18Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi
(INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR),
A. Tohuvavohu (U. Toronto) and P.A. Evans (U. Leicester) reports on
behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Swift/BAT-GUANO-detected burst GRB 231017A (GCN Circ. 34824, DeLaunay
et al.), collecting 4.2 ks of Photon Counting (PC) mode data between
T0+32.7 ks and T0+101.7 ks.
One uncatalogued X-ray source has been detected consistent with being
within 493 arcsec of the Swift/BAT-GUANO position, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:
Source 2:
RA (J2000.0): 86.1666 = 05:44:39.99
Dec (J2000.0): +56.7487 = +56:44:55.3
Error: 8.4 arcsec (radius, 90% conf.)
Count-rate: (2.09 [+1.11, -0.84])e-3 ct s^-1
Distance: 301 arcsec from Swift/BAT-GUANO position.
Flux: (3.3 [+1.8, -1.3])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Two uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021623.
This circular is an official product of the Swift-XRT team.
GCN Circular 34830
Subject
GRB 231017A: Fermi GBM Detection
Date
2023-10-18T16:19:02Z (2 years ago)
From
Joe Mangan at IJCLab <joseph.mangan@ijclab.in2p3.fr>
Via
Web form
J.Mangan (CNRS/IJCLab), E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 08:05:03.30 UT on 17 October 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231017A (trigger 719222708/231017337), which was also
detected by the Swift/BAT-GUANO (DeLaunay et al. 2023, GCN 34824).
The Fermi GBM Final Real-time Localization is reported in GCN 34822.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 4.8 s (50-300 keV). The time-averaged spectrum
from T0-3.5 to T0+4.7 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.1 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 270 +/- 82 keV.
A Band function fits the spectrum equally well
with Epeak= 175 +/- 92 keV, alpha = -0.9 +/- 0.3 and beta = -1.9 +/- 0.3.
The event fluence (10-1000 keV) in this time interval is
(1.7 +/- 0.2)E-06 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.77 s in the 10-1000 keV band is 7.8 +/- 1.6 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 34833
Subject
GRB231017A: GROWTH-India upper limits on the optical afterglow
Date
2023-10-18T20:23:19Z (2 years ago)
From
Anirudh Salgundi <salgundi.anirudh@gmail.com>
Via
Web form
R. Kumar, A. Salgundi, R. Sharma, Y. Wagh, V. Swain, V. Bhalerao (IIT Bombay), S. Barway, G. C. Anupama (IIA), K. Angail (IAO)
We observed the field of GRB 231017A detected by Fermi (Fermi GBM team GCN 34822) with 0.7m GROWTH-India Telescope (GIT). GIT was triggered at 2023-10-18 15:49:46.29 UT, i.e., 1.32 days after the Fermi trigger, as a response to the Swift/GUANO trigger (J DeLaunay et al., GCN 34824). We obtained multiple frames in the g' and r' bands, covering the localisation reported by Swift/XRT (P. A. Evans et al., GCN 34825). We searched individual images and the stacked image for an afterglow, but do not detect any. Our upper limits on the magnitude of the afterglow are:
JD (mid) | t_mid-t0 (days)| Filter | Exposure (s) | Limiting Magnitude (5 sigma) |
2460236.187750 | 1.351 | g' | 3 x 300 | 19.27 |
2460236.171885 | 1.335 | r' | 6 x 300 | 21.08 |
2460236.250104 | 1.413 | g' | 2 x 400 | 19.98 |
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 34834
Subject
GRB 231017A: LCOGT Optical Upper Limits
Date
2023-10-18T20:47:26Z (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 Fermi GRB 231017A field (Fermi GBM team, GCN 34822) with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on October 18, from 01:01 to 01:34 UT (corresponding to 15.93 to 16.48 hours from the GRB trigger time) with the SDSS r and i filters.
We performed a series of 3x300s exposures in each band. We do not detect a source within the Swift-XRT error region around the candidate X-ray source (Dichiara et al., GCN 34829) in either band.
The following upper limits are calculated using the PanSTARRS catalog as reference:
r > 23.0
i > 22.6
These magnitudes are not corrected for galactic extinction.
GCN Circular 34836
Subject
GRB 231017A: Las Cumbres optical upper limit
Date
2023-10-18T23:23:48Z (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 231017A (Fermi GBM team GCN 34822, Trigger 719222708) localized by Swift/BAT-GUANO (DeLaunay et al. GCN 34824) with the 1-m telescope, on 2023-10-18T02:56:38.021 UT (60235.12 MJD, ~0.8 days after the trigger) using the Sinistro instrument in V, g, r, i bands. We do not detect any new optical counterpart within the error region of BAT-GUANO with upper limit of:
g> 22.5
r> 21.2
i> 20.9
These values were calculated with respect to ATLAS-REFCAT2 (Tonry et al. 2018, ApJ 867 105) catalog are not corrected for galactic extinction. This non-detection is in agreement with Strausbaugh et al., GCN 34834 and Kumar et al., GCN 34833.
GCN Circular 34840
Subject
GRB 231017A: JinShan optical upper limit
Date
2023-10-19T13:18:13Z (2 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
email
D. Xu, X. Liu, S.Q. Jiang, Z.P. Zhu, S.Y. Fu, J. An, T.H. Lu (NAOC), J.Z. Liu (XAO) report on behalf of a large collaboration:
We observed the field of GRB 231017A detected by Fermi/GBM (Fermi GBM team, GCN 34822) and Swift/BAT-GUANO (DeLaunay et al. GCN 34824) using the No.2 50cm telescope (50B) located at Altay, Xinjiang, China. We obtained 20x180 s frames in the Sloan r-band, starting at 15:41:21 UT on 2023-10-17, i.e. 7.6 hr after the trigger.
No optical transient is detected in our stacked image within the error region of the Swift/BAT-GUANO, with the Swift-XRT Source 2 candidate inside the error region (Dichiara et al. GCN 34829), down to a limiting magnitude of r>20.5, calibrated with the nearby PanSTARRS field.
Altay Astronomical Time-Domain Project (JinShan Project for short) is located on the southern side of the Altay mountains in Xinjiang, China. It has geographical Longitude 88 43 35 E, Latitude +47 35 24 N, and Altitude 1025 meters. Altay and JinShan have the same meaning of Gold Mountain. The project consists of four 50cm telescopes with FOV of 1.7x1.7 deg^2 for each (50A, 50B, 50C, and 50D), two 100cm telescopes with FOV of 1.4x1.4 deg^2 for each (100A and 100B), and one 100cm telescope with FOV of 14x14 arcmin^2 (100C). Each telescope has different filters. JinShan is now at its early commissioning stage.
GCN Circular 34841
Subject
GRB 231017A: GOTO optical upper limits
Date
2023-10-19T16:24:59Z (2 years ago)
From
Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>
Via
email
S. Belkin; K. Ackley; A. Kumar; B. P. Gompertz; B. Godson; R. Starling; M. J. Dyer; J. Lyman; K. Ulaczyk; F. Jimenez-Ibarra; D. O'Neill; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; G. Ramsay; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 231017A (Fermi GBM team, GCN 34822). Targeted observations were performed between 00:20:50 UT on 2023-10-18 and 02:37:04 UT on 2023-10-18 (starting ~16.25 hours after trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
We identify no candidate optical counterparts within the Swift/BAT-GUANO localisation region (DeLaunay et al., GCN 34824) or at the positions of the 9 sources identified in XRT pointed observations (Evans et al., GCN 34825; Dichiara et al., GCN 34829). The mean 5-sigma limiting magnitude was L > 20.2 mag. This result is consistent with other observations (Kumar et al., GCN 34833; Strausbaugh et al., GCN 34834; Shrestha et al., GCN 34836; Xu et al., GCN 34840).
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
GOTO (https://goto-observatory.org<https://goto-observatory.org/>) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 34844
Subject
GRB 231017A: Swift/UVOT Upper Limit
Date
2023-10-19T18:34:36Z (2 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
Via
email
A. A. Breeveld (UCL-MSSL) and T. Parsotan (GSFC/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 231017A 73640 s after the GBM trigger (Mangan et al., GCN Circ. 34822).
No new sources are seen in the UVOT data.
A preliminary 3-sigma upper limit using the UVOT photometric system, (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) at the position of the XRT candidate (Source 2) given by Dichiara et al. (GCN Circ. 34829) is:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 73640 101690 4839 >21.0
The magnitude in the table is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.252 in the direction of the burst (Schlegel et al. 1998).
GCN Circular 34853
Subject
GRB 231017A: 1.3m DFOT Optical upper limit
Date
2023-10-20T17:12:08Z (2 years ago)
From
Amit Kumar Ror at ARIES <mitturor77894@gmail.com>
Via
email
Amit K. Ror, Rahul Gupta, Amar Aryan, Shashi B. Pandey, Rishi C., and
Neelam Panwar (ARIES) report:
We observed the field of Fermi, and Swift detected GRB 231017A (Fermi GCM
Team GCN 34822; Mangan et al. 2023, GCN 34830; DeLaunay et al. 2023, GCN
34824; and Swift team GCN 34825) with the 1.3m Devasthal Fast Optical
Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta
Research Institute of Observational Sciences (ARIES), India. The
observations were started on 2023-10-18 at 22:19:07 UT, i.e., ~ 1.6 days
after the GBM trigger. We have taken multiple frames with an exposure time
of 100 s in the R filter. We stacked the images after the alignment. We did
not detect any optical afterglow in our stacked image within the error box
of Swift-XRT observation (Dichiara et al., 2023, GCN 34829). We obtain the
following preliminary 3-sigma upper limit in the stacked image:
Date Start_UT T_start-T0 (days) Filter Exp time (s) Limiting magnitude
=========================================================
2023-10-18 22:19:07 1.6 R 100*36 > 21.6
Our non-detection is consistent with Kumar et al. 2023, GCN 34833;
Strausbaugh et al. 2023, GCN 34834; Shrestha et al. 2023, GCN 34836; Xu et
al. 2023, GCN 34840; and Belkin et al. 2023, GCN 34841.
The magnitude is not corrected for the Galactic extinction in the direction
of the burst. Photometric calibration is performed using the standard stars
from the USNO-B1.0 catalog. This circular may be cited.
GCN Circular 34867
Subject
GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
Date
2023-10-21T11:22:19Z (2 years ago)
From
XXXX at IKI <alex@cgrsmx.iki.rssi.ru>
Via
legacy email
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) report on behalf of GRB IKI FuN:
We observed the field of GBM/Fermi and Swift/BAT-GUANO candidate of GRB 231017A (Fermi GCM Team GCN 34822; Mangan et al. 2023, GCN 34830; DeLaunay et al. 2023, GCN 34824; GCN 34825) with AZT-33IK telescope of Mondy observatory in R-filter on 2023-10-20 starting (UT) 18:02:43. We detect only one object within Swift-XRT X2 candidate error circle (Dichiara et al. GCN 34829) at coordinates of (J2000) 05:44:40.6245 +56:44:54.767. The object position is 5.3 arcsec apart from Swift-XRT center of the XRT X2 error circle. However, at the moment we cannot say about the variability of the object.
We may propose the object as a candidate for an afterglow or host galaxy of GRB 230420A.
Preliminary photometry of the object is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s)
2023-10-20 18:02:43 3.43519 29x120 R 22.98 0.20 23.5
The photometry is based on nearby USNO-B1.0 R2 stars
USNO-B1.0
RA DEC R2
05:44:36.1893600 +56:44:30.523200 15.96
05:44:49.0394400 +56:45:26.060400 16.24
05:44:55.8448800 +56:45:12.002400 16.30
05:44:44.9767200 +56:47:48.480000 16.48