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"37359 results found.
- GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
- GRB 260907A: SVOM/GRM observation
- GRB 260909A: CrAO and AbAO optical upper limits
- GRB 260909A: SVOM/ECLAIRs refined analysis
- GRB 260910B: GOTO tentative optical counterpart candidates
- GRB 260909A: Swift ToO observations
- GRB 260910B: Fermi GBM Final Real-time Localization
- 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
- GRB 260909A: EP-FXT follow-up observation
- GRB 260910A: Fermi GBM Final Real-time Localization
- GRB 260909A: SVOM/VT optical upper limits
- GRB 260909A: SVOM/GRM observation
- 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
- Fermi trigger No 810554827: Global MASTER-Net observations report
- GRB 260907A: Glowbug gamma-ray detection of a likely short burst
- GRB 260903A: Swift ToO observations
- Fermi GRB 260907B: Global MASTER-Net observations report
- GRB 260903A: SAO RAS optical upper limit
- GRB 260907B: Fermi GBM Final Real-time Localization
- Fermi GRB 260907A: Global MASTER-Net observations report
- GRB 260907A: Fermi GBM Final Real-time Localization
- 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
- GRB 260830A: GECAM-B detection of a burst
- GRB 260830A: Insight-HXMT/HE detection
- GRB 260903A: EP-FXT follow-up observation
- GRB 260903A: OHP/T193 optical afterglow detection
- GRB 260903A: NOT optical observations and afterglow fading
- GRB 260903A: LCO optical observations
- GRB 260903A: SVOM/VT optical candidate
- GRB 260903A: Retraction of optical counterpart of GCN 45501
- GRB 260831A: GECAM-B observation
- GRB 260903A: LCO optical counterpart detection
- 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
- GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
- GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
- SVOM trigger sb26083106 is not a GRB
- GRB 260829A: AstroSat CZTI detection
- GRB 260831B: EP-FXT follow-up observation
- GRB 260830A: NuSTAR detection of prompt emission
- GRB 260831B: LCO optical upper limits
- GRB 260827A: SVOM/GRM observation
- GRB 260831B: SVOM detection of a possible burst
- IPN triangulation of GRB 260829A
- GRB 260827A: Glowbug gamma-ray detection
- GRB 260831A: Fermi GBM Final Real-time Localization
- 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
- GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
- GRB 260829A: Fermi GBM Final Real-time Localization
- Fermi GBM trigger 809666623/260829141 is not a GRB
- GRB 260818B: Further EP-FXT observation
- GRB 260818B: VLT optical and nIR observations
- GRB 260818B: TNG NIR observations
- IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260827A: Fermi GBM Final Real-time Localization
- 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
- GRB 260807A: EP-FXT follow-up observations
- GRB 260822A: SVOM/ECLAIRs refined analysis
- GRB 260809A: SVOM/ECLAIRs refined analysis
- GRB 260822A: SVOM/VT optical upper limits
- GRB 260825A: Fermi GBM Final Real-time Localization
- IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260822A: EP/FXT follow-up observations
- GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
- GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
- GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
- GRB 260822A: GOTO optical counterpart detection
- GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
- GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- GRB 260822A: LCO optical upper limits
- GRB260822B: Fermi GBM Final Localization
- GRB 260822A: GROWTH-India Telescope Upper Limits
- GRB 260822A: GOTO optical upper limit
- GRB 260822A: SVOM detection of a short burst
- Fermi-LAT Gamma-ray Observations of IceCube-260821A
- Fermi-LAT Gamma-ray Observations of IceCube-260807A
- GRB 260818B: VLA radio observations
- GRB 260818B: SVOM/C-GFT optical upper limit