GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"23249 results found.
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
- EP260822a: EP-FXT non-detection and upper limit
- GRB 260822A: GOTO optical counterpart detection
- GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- EP260822a: Einstein Probe detection of a fast X-ray transient
- GRB 260822A: LCO optical upper limits
- GRB 260822A: GROWTH-India Telescope Upper Limits
- GRB 260818B: VLA radio observations
- GRB 260818B: SVOM/C-GFT optical upper limit
- EP detected a brightening of LMXB 1ES 1735-26.9
- GRB 260818A: J-band observations with WINTER
- GRB 260818B: NOT optical upper limits
- GRB 260810A: SVOM/GRM observation
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260818B: LCO optical upper limits
- EP260806a: SAO RAS multicolor optical observations
- GRB 260818A: LCO optical upper limits
- EP260812a: AbAO optical upper limit
- GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- EP260806a: NUTTELA-TAO optical observations
- EP260812a: AZT-22 optical upper limit
- EP260806a: WFST optical observations
- EP260812b: Optical upper limit with Kinder
- GRB 260805D: SVOM/GRM detection of a possible magnetar burst
- GRB 260808B: Liverpool Telescope further optical observations
- GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
- EP260812a: NOT and Liverpool Telescope upper limits:
- EP260812b: Liverpool Telescope observations
- EP260812b: GOTO detection of the optical counterpart
- EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
- EP260812a: SVOM/C-GFT optical upper limit
- EP260812b: COLIBRÍ optical observations
- EP260812b: SVOM/VT optical observation
- GRB 260808A: SVOM/GRM observation
- EP260812b: Einstein Probe detection of an X-ray transient
- EP trigger #01709278129 (EP260812b?): NOT optical counterpart
- GRB 260810A: Glowbug gamma-ray detection
- GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
- GRB 260810A: AstroSat CZTI detection of a long burst
- EP260812a: Einstein Probe detection of an X-ray transient
- GRB 260809A: SAO RAS optical observations
- GRB 260808B: SAO RAS optical observations
- GRB 260808B: SVOM/VT optical re-brightening at day 3
- EP260806a: MAO/AZT-22 optical observations
- GRB260808B: MAO/AZT-22 optical observations
- GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
- GRB 260809A: J-band upper limit with WINTER
- GRB 260806A: Glowbug gamma-ray detection
- GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
- GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
- GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
- GRB 260809A: NOT optical observations
- GRB260809A: MAO/AZT-22 optical observations
- GRB260809A: OHP/T193 optical observations
- EP260809a: J-band upper limit with WINTER
- GRB 260808B: J-band upper limit with WINTER
- EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
- GRB 260809A: SVOM detection of a faint burst
- GRB 260808B: Liverpool Telescope optical observations
- GRB 260808B: NOT optical observations
- GRB 260808B: LCO optical observations
- EP260809a: COLIBRÍ optical observations
- EP260809a: LCO optical observation
- EP260809a: OHP/T193 optical observations
- GRB260808B: OHP/T193 optical observations
- EP260809a: Einstein Probe detection of an X-ray transient
- GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
- GRB 260808B: SVOM/VT optical candidate from VHF data
- GRB 260808B: SVOM detection of a faint burst
- GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- EP260806a: COLIBRÍ optical observations
- EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260806a: SVOM/VT optical observation
- EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
- EP260806a: OSIRIS+/GTC redshift z=0.089
- EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260806a: LCO likely optical counterpart
- EP260806a: Einstein Probe detection of an X-ray transient
- GRB 260715A: cubesat Avion detection
- GRB 260709A: cubesat Avion detection
- GRB 260708A: cubesat Avion detection
- GRB 260730B: Glowbug gamma-ray detection
- GRB 260805C: Glowbug gamma-ray detection
- GRB 260805B: Glowbug gamma-ray detection
- GRB 260804A: Glowbug gamma-ray detection
- GRB 260803A: Fermi GBM Final Real-time Localization
- GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
- GRB 260802A: SVOM/VT optical upper limits from VHF data
- GRB 260802A: LCO optical upper limits
- GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
- GRB 260731A: AstroSat CZTI detection of a long burst
- GRB 260730B: AstroSat CZTI detection
- EP260731a: COLIBRÍ optical upper limit
- EP260731a: NOT optical upper limit
- EP260731a: Einstein Probe detection of an X-ray transient
- GRB 260727A: SVOM/ECLAIRs refined analysis
- EP260728a: COLIBRÍ optical upper limit
- EP 260729a: Ondrejov D50 optical detection supports stellar flare origin