GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- GRB 260512A: NuSTAR detection of prompt emission
- GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
- GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
- EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
- GRB 260512A: Fermi GBM Final Real-time Localization
- GRB 260511A: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 260511A
- MASS-Cube (GRID 2.0) detection of GRB 260511A
- MASS-Cube (GRID 2.0) detection of GRB 260507A
- GRB 260511B: SAO RAS optical observations
- GRB 260510D: Glowbug gamma-ray detection of a likely short burst
- GRB 260511B: FRAM-ORM optical detection
- GRB 260511A: EP-FXT follow-up observation
- GRB 260511B: EP-FXT follow-up observation
- GRB 260511B: LCO optical counterpart detection
- GRB260511B: MAO/AZT-22 optical observations
- GRB 260511A: SVOM/VT optical observations
- GRB 260511B: LCO optical observations
- GRB 260511B: OHP/T193 spectroscopic observations
- GRB 260511B: GOTO optical counterpart detection
- GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
- GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
- GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
- GRB 260511B: SVOM/VT optical observations
- GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260510B: EP-FXT follow-up observation
- GRB 260511B: OSIRIS+/GTC redshift z=2.006
- GRB 260510C: Fermi GBM Observation
- GRB 260509A: SAO RAS optical observations
- GRB 260511A: REM near-infrared detection
- GRB 260511B: GROWTH-India Telescope optical observations
- GRB 260511B: AstroSat CZTI detection
- GRB 260506B: Glowbug gamma-ray detection
- GRB 260506A: Glowbug gamma-ray detection of a short burst
- GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
- GRB 260511B: NuSTAR detection of prompt emission
- GRB 260511A: NuSTAR detection of prompt emission
- GRB 260511B: Fermi GBM Detection
- GRB 260511C: Fermi GBM Final Real-time Localization
- GRB 260511B: SVOM/VT optical observation with VHF data
- GRB 260511B: TRT optical observation
- GRB 260510B: SVOM/ECLAIRs refined analysis
- GRB 260511B : MITSuME Akeno optical afterglow candidate detection
- GRB 260511A: Fermi GBM Detection
- GRB 260511B SVOM/C-GFT optical counterpart detection
- EP260509a: LCO optical upper limits
- GRB 260511A: UTGO H50 optical afterglow observation
- GRB 260510C: AstroSat CZTI detection
- GRB 260511B: SVOM detection of a burst
- GRB 260511B: Fermi GBM Final Real-time Localization
- GRB 260510C: EP-FXT follow-up observation
- GRB 260510C: SVOM/VT optical counterpart confirmation
- EP260509a: EP-FXT non-detection and upper limit
- GRB 260511A: SVOM/VT optical observation with VHF data
- Fermi GRB 260511A: Global MASTER-Net observations report
- GRB 260511A: KAIT optical afterglow observations
- GRB 260511A: LCO optical afterglow detection
- GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
- GRB 260511A: TRT optical counterpart detection
- GRB 260511A: SVOM detection of a bright burst
- GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
- GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260511A: Fermi GBM Final Real-time Localization
- GRB 260510B: SVOM/VT optical upper limits
- GRB 260510C: SVOM/VT optical upper limits
- GRB 260510C: MAXI/GSC detection
- EP260509a: Global MASTER-Net observations report
- Fermi GBM Sub-Threshold Detection of GRB 260510B
- GRB 260510D: Fermi GBM Final Real-time Localization
- GRB 260510B: GOTO early upper limit
- GRB 260510C: SVOM detection of a burst
- GRB 260510C: Fermi GBM Final Real-time Localization
- GRB 260510A: GECAM-B observation
- GRB 260510B: LCO optical upper limits
- EP260509a: Einstein Probe detection of an X-ray transient
- GRB 260509A: Liverpool Telescope optical observations
- GRB 260510B: SVOM detection of a burst
- GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
- GRB 260509A: LCO optical observations
- SVOM GRB 260509A: MASTER-OAFA optical observation
- Fermi GRB 260510A: Global MASTER-Net observations report
- GRB 260509A: KAIT optical observations
- GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
- GRB 260510A: Fermi GBM Final Real-time Localization
- GRB 260509A: SVOM/VT optical candidate with VHF data
- GRB 260509A: LCO optical counterpart detection
- GRB 260509A: GOTO optical counterpart candidate
- GRB 260509A: SVOM detection of a burst
- GRB 260506B: AstroSat CZTI detection
- IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
- EP260507a: REM optical/NIR observations
- EP260507a: refined analysis of the EP-WXT and EP-FXT observations
- GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
- EP260507a: COLIBRÍ optical observations
- EP260507a: SVOM/VT optical observations
- EP260507a: NOT optical observations
- EP260507a: further Liverpool Telescope observations
- EP260507a: Liverpool Telescope optical upper limits
- GRB 260507A: Fermi GBM Final Real-time Localization
- EP260507a: GOTO optical counterpart detection