GRB231220A

This page lists all entries on GRB231220A in GRBweb

Summary Fermi GBM IPN GCN 35407 GCN 35409 GCN 35410 GCN 35411 GCN 35477

Summary table
Variable Value Source
GRB_name_Fermi GRB231220674
T0 16:10:16.636 UTC Fermi_GBM
ra 27.3208° IPN
decl 77.9000° IPN
pos_error 8.33e-02° IPN
T90 5.12 s Fermi_GBM
T90_error 0.81 s Fermi_GBM
T90_start 16:10:16.636 UTC Fermi_GBM
fluence 2.07e-06 erg/cm² Fermi_GBM
fluence_error 4.17e-08 erg/cm² Fermi_GBM
T100 5.12 s
GBM_located False
mjd 60298.67380365741 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB231220674
trigger_name bn231220674
ra 73.3700°
decl 82.2900°
pos_error 3.90e+00°
datum 2023-12-20
t_trigger 16:10:17.404 UTC
T90 5.12 s
T90_error 0.81 s
T90_start 16:10:16.636 UTC
fluence 2.07e-06 erg/cm²
fluence_error 4.17e-08 erg/cm²
flux_1024 3.21e+00 erg/cm²/s
flux_1024_error 3.84e-01 erg/cm²/s
flux_1024_time 1.60e+00 erg/cm²/s
flux_64 6.69e+00 erg/cm²/s
flux_64_error 1.77e+00 erg/cm²/s
IPN table
GRB_name GRB231220A
ra 27.3208°
decl 77.9000°
pos_error 8.33e-02°
GCN 35407 table
GRB_name GRB231220A
GCN_number 35407
Detection_method Fermi GBM final loc
t_trigger 16:10:17 UTC
ra 73.4000°
decl 82.3000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 35407 SUBJECT: GRB 231220A: Fermi GBM Final Real-time Localization DATE: 23/12/20 16:20:38 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 16:10:17 UT on 20 Dec 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231220A (trigger 724781422.403544 / 231220674). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 73.4, Dec = 82.3 (J2000 degrees, equivalent to J2000 04h 53m, 82d 17'), with a statistical uncertainty of 5.0 degrees. The angle from the Fermi LAT boresight is 136.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231220674/quicklook/glg_skymap_all_bn231220674.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/bn231220674/quicklook/glg_healpix_all_bn231220674.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231220674/quicklook/glg_lc_medres34_bn231220674.gif
GCN 35409 table
GRB_name GRB231220A
GCN_number 35409
Detection_method Swift Other
ra 27.3210°
decl 77.8970°
Circular_text TITLE: GCN CIRCULAR NUMBER: 35409 SUBJECT: GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst DATE: 23/12/20 22:09:23 GMT FROM: Samuele Ronchini at PSU Samuele Ronchini (PSU), James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 231220A onboard (T0: 2023-12-20T16:10:17.4 UTC, Fermi/GBM GCN 35407). 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), detects the burst in a 4.096 s analysis time bin with a sqrt(TS) of 28.32, starting at T0 - 1.02 s. An arcminute localization is found with DeltaLLHOut of 48.29 and a DeltaLLHPeak of 49.13. 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 = 27.321, 77.897 deg which is RA(J2000) = 01h 49m 17.04s Dec(J2000) = +77d 53′ 49.2″ with an estimated uncertainty of 5 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 35410 table
GRB_name GRB231220A
GCN_number 35410
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 35410 SUBJECT: GRB 231220A: Swift ToO observations DATE: 23/12/20 23:38:36 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the GUANO GRB 231220A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021638 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 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 35411 table
GRB_name GRB231220A
GCN_number 35411
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 35411 SUBJECT: GRB 231220A: Swift-XRT follow-up observations DATE: 23/12/21 15:25:45 GMT FROM: Phil Evans at U of Leicester C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), R. Brivio (INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the GUANO-detected burst GRB 231220A, collecting 3.6 ks of Photon Counting (PC) mode data between T0+27.0 ks and T0+39.5 ks. No candidate counterpart was detected, with an upper limit of 2.2×10-3 ct s-1 at the best BAT position (GCN 35409). One uncatalogued X-ray source was flagged as spurious after manual inspection. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021638. This circular is an official product of the Swift-XRT team.
GCN 35477 table
GRB_name GRB231220A
GCN_number 35477
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 35477 SUBJECT: GRB 231220A: Swift-UVOT upper limit DATE: 24/01/04 03:26:25 GMT FROM: noelklin@umbc.edu N. Klingler (UMBC/NASA-GSFC/CRESST II) reports on behalf of the Swift-UVOT team: Swift-UVOT has performed follow-up observations of the Swift-BAT/GUANO-detected and Fermi-GBM-detected GRB 231220A, collecting 2.6 ks of data between T0+35.2 ks and T0+47.8 ks. No candidate counterpart was detected. The 3 sigma limiting (AB) magnitude in the White filter near the center of the BAT/GUANO localization (GCN 35409) is >23.20.