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"26484 results found.
- GRB 260914A: SVOM/ECLAIRs refined analysis
- GRB 260909A: Swift-XRT observations
- GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
- GRB 260915A: SVOM/C-GFT optical upper limits
- GRB 260915A: EP-FXT follow-up observation
- GRB 260915A: SVOM/VT refined early optical upper limits
- GRB 260915A: REM optical/NIR observations
- GRB 260914A: REM optical/NIR observations
- GRB 260914A: VLT/X-shooter observations and redshift confirmation
- GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260915A: NOT optical upper limit
- GRB 260915A: SVOM/VT optical upper limits from VHF data
- GRB 260915A: LCO optical upper limits
- GRB 260914A: EP-FXT follow-up observation
- GRB 260915A: SVOM detection of a burst
- GRB 260914A: LCO optical observation
- GRB 260914A: SVOM/C-GFT optical observations
- GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- GRB 260914A: SVOM detection of a burst
- GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
- GRB 260818A: Continued ATCA observations
- GRB 260913A: SVOM/C-GFT optical upper limit
- GRB 260913A: SVOM detection of a faint burst
- 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: 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
- EP260806a: NOEMA detection
- EP260623a: NOEMA detections
- 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
- The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
- GRB 260907A: Glowbug gamma-ray detection of a likely short burst
- GRB 260903A: SAO RAS optical upper limit
- The EP-WXT trigger 01709305715 is likely a flaring star
- EP260903a: EP-FXT follow-up observation
- The EP-WXT trigger 01709302592 is likely a flaring star
- 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
- EP260903a: EP-WXT detection of a fast X-ray transient
- GRB 260903A: EP-FXT follow-up observation
- GRB 260903A: OHP/T193 optical afterglow detection
- NuSTAR Transient 260828: SOAR Optical Upper Limits
- 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 260903A: SVOM detection of a soft faint burst
- 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
- EP260830a: EP-FXT follow-up observation
- 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 260829A: AstroSat CZTI detection
- GRB 260831B: EP-FXT follow-up observation
- GRB 260831B: LCO optical upper limits
- EP260830a: EP-WXT detection of a fast X-ray transient
- GRB 260827A: SVOM/GRM observation
- NuSTAR 260828: a 1100s hard X-ray transient
- GRB 260831B: SVOM detection of a possible burst
- GRB 260827A: Glowbug gamma-ray detection
- 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 260829A: Fermi GBM Detection
- GRB 260825A: AstroSat CZTI detection
- GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
- 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
- The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
- GRB 260818B: 6 GHz VLA observations
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260808B: SAO RAS observations of the optical rebrightening
- EP Alert 260820.31: Global MASTER-Net observations report
- GRB 260807A: EP-FXT follow-up observations
- 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