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"20246 results found.
- GRB 260909A: CrAO and AbAO optical upper limits
- GRB 260909A: SVOM/ECLAIRs refined analysis
- GRB 260909A: KAIT optical upper limit
- GRB 260903A: Swift-XRT observations
- GRB 260909A: OHP/T193 z-band upper limit
- GRB 260909A: VLT optical and near-infrared upper limits
- EP260806a: NOEMA detection
- EP260623a: NOEMA detections
- GRB 260909A: Mondy optical observations and afterglow candidate
- GRB 260909A: Xinglong 2.16m optical upper limit
- GRB 260909A: SVOM/C-GFT optical upper limit
- GRB 260909A: SVOM detection of a burst
- GRB 260903A: SAO RAS optical upper limit
- GRB 260903A: J-band upper limit with WINTER
- GRB 260903A: SVOM/ECLAIRs refined analysis
- GRB260903A: Liverpool Telescope optical observations
- GRB 260903A: SAO RAS optical observations
- EP260903a: EP-WXT detection of a fast X-ray transient
- GRB 260903A: OHP/T193 optical afterglow detection
- NuSTAR Transient 260828: SOAR Optical Upper Limits
- GRB 260831A: GECAM-B observation
- GRB 260903A: LCO optical counterpart detection
- EP260901a: SVOM/VT optical upper limits
- EP260901a: EP-FXT follow-up observation
- Konus-Wind detection of GRB 260829A
- GRB 260829A: SVOM/GRM observation
- GRB 260818A: ATCA detection of a candidate radio counterpart
- GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
- NuSTAR Transient 260828: LCO Optical Upper Limits
- EP260901a: EP-WXT detection of a fast X-ray transient
- GRB 260831B: LCO optical upper limits
- EP260830a: EP-WXT detection of a fast X-ray transient
- GRB 260827A: SVOM/GRM observation
- GRB 260831B: SVOM detection of a possible burst
- EP260727a: ATCA 10 GHz detection
- GRB 260825A: SVOM/GRM observation of a long burst
- IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260818B: Further EP-FXT observation
- GRB 260818B: VLT optical and nIR observations
- GRB 260818B: TNG NIR observations
- GRB 260818B: 6 GHz VLA observations
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260808B: SAO RAS observations of the optical rebrightening
- GRB 260822A: SVOM/ECLAIRs refined analysis
- GRB 260809A: SVOM/ECLAIRs refined analysis
- IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
- 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
- IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260818B: SVOM/C-GFT optical upper limit
- EP260731a: SVOM/ECLAIRs detection through offline targeted search
- EP detected a brightening of LMXB 1ES 1735-26.9
- GRB 260818A: J-band observations with WINTER
- GRB 260818B: SVOM/ECLAIRs refined analysis
- GRB 260818A: SVOM/ECLAIRs refined analysis
- 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: SVOM/ECLAIRs detection through targeted search
- 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
- EP260812a: NOT and Liverpool Telescope upper limits:
- EP260812b: Liverpool Telescope observations
- 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 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 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
- GRB 260807A: SVOM/ECLAIRs refined analysis
- EP260806a: MAO/AZT-22 optical observations
- IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
- GRB260808B: MAO/AZT-22 optical observations
- GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
- GRB 260809A: J-band upper limit with WINTER
- EP260809a: VLT/X-shooter spectroscopic redshift z = 3.07