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"32486 results found.
- IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260917A: Glowbug gamma-ray detection
- GRB 260915A: SVOM/ECLAIRs refined analysis
- GRB 260917B: WINTER J-band observations
- GRB 260917B: SVOM/VT optical observations
- GRB 260917B: LCO optical observation
- GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- GRB 260915A: J-band upper limit with WINTER
- IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260909A: NOEMA detection
- GRB 260914A: SVOM/GRM observation
- GRB 260914A: Mondy and TShAO optical observations
- GRB 260914A: SVOM/ECLAIRs refined analysis
- GRB 260909A: Swift-XRT observations
- GRB 260915A: Swift ToO 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: EP-FXT follow-up observation
- GRB 260915A: REM optical/NIR observations
- GRB 260914A: REM optical/NIR observations
- GRB 260914A: VLT/X-shooter observations and redshift confirmation
- GRB 260915A: SVOM/VT optical upper limits
- GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260914A: VLT/X-shooter spectroscopic redshift z = 0.778
- GRB 260915A: 10.4m GTC deep optical limits
- GRB 260915A: NOT optical upper limit
- GRB 260915A: SVOM/VT optical upper limits from VHF data
- Fermi GBM Sub-Threshold Detection of GRB 260915A
- GRB 260915A: LCO optical upper limits
- GRB 260914A: EP-FXT follow-up observation
- Fermi GBM Sub-Threshold Detection of GRB 260914A
- GRB 260914A: LCO optical observation
- GRB 260914A: SVOM/C-GFT optical observations
- GRB 260914A: SVOM/VT optical counterpart confirmation
- GRB 260914A: SVOM/VT optical observation from VHF data
- 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 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 260909A: KAIT optical upper limit
- GRB 260903A: Swift-XRT observations
- EP260806a: VLA+ALMA radio detections
- 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/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 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
- Fermi GRB 260907A: Global MASTER-Net observations report
- EP260903a: EP-FXT follow-up observation
- 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 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
- NuSTAR Transient 260828: SOAR Optical Upper Limits
- 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
- 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
- EP260901a: Global MASTER-Net observations report
- 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
- GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
- NuSTAR Transient 260828: LCO Optical Upper Limits
- 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