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"15247 results found.
- GRB 260903A: NOT optical observations and afterglow fading
- NuSTAR Transient 260828: SOAR Optical Upper Limits
- GRB 260903A: Retraction of optical counterpart of GCN 45501
- GRB 260831A: GECAM-B observation
- GRB 260827A: Insight-HXMT/HE detection
- GRB 260903A: SVOM detection of a soft faint burst
- Konus-Wind detection of GRB 260829A
- GRB 260829A: SVOM/GRM observation
- GRB 260818A: ATCA detection of a candidate radio counterpart
- IceCube-260827A: No transient candidates from the Zwicky Transient Facility
- GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
- SVOM trigger sb26083106 is not a GRB
- GRB 260829A: AstroSat CZTI detection
- GRB 260827A: SVOM/GRM observation
- NuSTAR 260828: a 1100s hard X-ray transient
- GRB 260831B: SVOM detection of a possible burst
- Fermi-LAT Gamma-ray Observations of IceCube-260827A
- Fermi-LAT Gamma-ray Observations of IceCube-260825A
- GRB 260829A: GECAM-B observation of a long burst
- GRB 260825A: SVOM/GRM observation of a long burst
- GRB 260825A: GECAM-B observation
- GRB 260829A: Fermi GBM Detection
- GRB 260825A: AstroSat CZTI detection
- 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: VLT optical and nIR observations
- IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260818B: 6 GHz VLA observations
- GRB 260818B: SVOM/VT optical upper limit and continuous observations
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260808B: SAO RAS observations of the optical rebrightening
- IceCube-260825A: No transient candidates from the Zwicky Transient Facility
- GRB 260809A: SVOM/ECLAIRs refined analysis
- IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
- GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
- GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
- GRB 260822A: GROWTH-India Telescope Upper Limits
- GRB 260822A: SVOM detection of a short burst
- Fermi-LAT Gamma-ray Observations of IceCube-260821A
- Fermi-LAT Gamma-ray Observations of IceCube-260807A
- 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
- GRB 260820A: Insight-HXMT/HE detection
- IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260818B: SVOM/GRM observation
- GRB 260818B: Insight-HXMT detection
- GRB 260818A: J-band observations with WINTER
- GRB 260818B: SVOM/ECLAIRs refined analysis
- GRB 260818A: SVOM/ECLAIRs refined analysis
- GRB 260810A: SVOM/GRM observation
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260818B: SVOM detection of a short burst
- GRB 260818A: LCO optical upper limits
- EP260812a: AbAO optical upper limit
- GRB 260810A: Insight-HXMT/HE detection
- GRB 260818A: SVOM possible detection of a long and faint GRB
- EP260806a: SVOM/ECLAIRs detection through targeted search
- EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
- 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: COLIBRÍ optical observations
- GRB 260808A: SVOM/GRM observation
- GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
- GRB 260810A: AstroSat CZTI detection of a long burst
- GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
- GRB 260806A: CALET Gamma-Ray Burst Monitor detection
- GRB 260808A: GECAM-B observation
- GRB 260807A: SVOM/ECLAIRs refined analysis
- 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 260808A: CALET Gamma-Ray Burst Monitor detection
- GRB 260805C: CALET Gamma-Ray Burst Monitor detection
- GRB 260804A: CALET Gamma-Ray Burst Monitor detection
- GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
- GRB260809A: MAO/AZT-22 optical observations
- IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260808B: SVOM/ECLAIRs refined analysis
- GRB 260809A: SVOM detection of a faint burst
- GRB 260808B: Liverpool Telescope optical observations
- GRB 260808B: SVOM detection of a faint burst
- IceCube-260805A: One candidate from the Zwicky Transient Facility
- GRB 260807A: SVOM possible detection of a faint burst
- IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
- EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260806a: SVOM/VT optical observation
- GRB 260715A: cubesat Avion detection
- GRB 260709A: cubesat Avion detection
- GRB 260708A: cubesat Avion detection
- SN 2026stf / GRB 260708A: ATLAS forced photometry
- IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event