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"23407 results found.
- 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
- EP260729a: Einstein Probe detection of an X-ray transient
- EP260727a: SAO RAS optical observations
- GRB 260727A: AbAO and SAO RAS optical observations
- EP260728a: Einstein Probe detection of a fast X-ray transient
- GRB 260727A: SVOM/GRM observation
- EP260727a:refined analysis of the EP-WXT and EP-FXT observation
- EP260727a: OHP/T193 optical observations
- Konus-Wind detection of GRB 260727A
- GRB 260726A: Liverpool Telescope optical observations
- GRB 260727A: Liverpool Telescope optical upper limits
- EP260727a: Liverpool Telescope confirmation of optical counterpart
- EP260727a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
- GRB 260727A: Glowbug gamma-ray detection
- GRB 260726A: J-band upper limit with WINTER
- GRB 260727A: J-band upper limit with WINTER
- GRB 260726A: SVOM/VT optical candidate
- GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
- EP260723a: SVOM/ECLAIRs Upper Limit
- GRB 260727A: AstroSat CZTI detection
- GRB 260727A: Kilonova-Catcher optical upper limit
- GRB 260727A: LCO optical upper limits
- GRB 260726A: SVOM detection of a burst
- EP260725a: EP-WXT detection of an X-ray transient
- GRB 260616A: cubesat Avion detection
- EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
- GRB 260602B: cubesat Avion detection
- GRB 260601A: cubesat Avion detection
- IPN triangulation of GRB 260706B
- EP260723a: SVOM/VT optical observation
- EP260723a: COLIBRÍ optical observations
- EP260723a: NOT optical conterpart confirmation
- EP260723a: Liverpool Telescope likely optical counterpart
- EP260723a: EP-WXT detection of a fast X-ray transient
- IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
- SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
- GRB 260718A: LCO optical upper limits
- GRB 260710A: SVOM/GRM observation
- GRB 260718A: Fermi GBM Observation
- GRB 260718A : GRANDMA and KNC upper limits
- GRB 260718A: SVOM/VT optical upper limits
- GRB 260718A: SVOM/VT optical upper limits from VHF data