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"18333 results found.
- EP01709266106 (EP260526a?): Liverpool Telescope upper limits
- EP-WXT 01709266106: NOT optical upper limits
- Fermi trigger No 801135305: Global MASTER-Net observations report
- EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
- GRB 260511A: iTelescope T-75 optical detection
- GRB 260520B: SVOM/GRM observation
- Konus-Wind detection of GRB 260518A
- GRB 260518A: AstroSat CZTI detection of a long burst
- GRB 260421B: radio detection with the VLA
- GRB 260509A: CrAO ZTSh optical upper limit
- GRB 260516D: EP-FXT follow-up observation
- GRB 260516D: GOTO optical counterpart detection
- GRB 260516D: LCO optical observations
- GRB 260515A: further Liverpool Telescope observations
- GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260516D: GROWTH-India Telescope optical detection
- GRB 260516D: SVOM/VT optical bright candidate
- GRB 260515A: CrAO ZTSh BVRI optical observations
- Konus-Wind detection of GRB 260515A
- GRB 260515A: LCO optical counterpart detection
- GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260515A: EP-FXT follow-up observation
- EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
- EP260514a: NOT optical counterpart confirmation
- EP260514a: TRT optical counterpart candidate
- EP260514a: SVOM/VT optical candidate
- GRB 260515A: OHP/T193 optical observations
- EP260514a: COLIBRÍ optical upper limits
- GRB 260515A: LCO optical observations
- GRB 260515A: SVOM/VT optical candidate from VHF data
- GRB 260515A: JinShan optical counterpart candidate
- GRB 260515A: SVOM detection of a burst
- EP260514a: GROWTH-India Telescope optical upper limit
- GRB 260511B: GMG Optical Upper Limit
- EP260514a: Einstein Probe detection of a fast X-ray transient
- EP260512a: LCO optical upper limits
- GRB 260511B: Mephisto multi-band optical followup
- The EP-WXT trigger 01709262077 is likely a flaring star
- EP260512a: EP-FXT follow-up observation
- EP260507a: Xinglong Schmidt optical counterpart detection
- GRB 260511B: further SAO RAS optical observations
- The EP-WXT trigger 01709262036 is likely a flaring star
- EP260512a: COLIBRÍ optical upper limits
- EP260512a: Einstein Probe detection of an X-ray transient
- GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
- GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
- 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 260511B: SAO RAS optical observations
- 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 260511B: LCO optical observations
- GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
- GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260510B: EP-FXT follow-up observation
- GRB 260509A: SAO RAS optical observations
- GRB 260511A: REM near-infrared detection
- GRB 260511B: GROWTH-India Telescope optical observations
- GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
- GRB 260511B: SVOM/VT optical observation with VHF data
- GRB 260511B: TRT optical observation
- 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 260511B: SVOM detection of a burst
- 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
- 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 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260510C: SVOM detection of a burst
- 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: LCO optical observations
- GRB 260509A: KAIT optical observations
- GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
- GRB 260509A: SVOM/VT optical candidate with VHF data
- GRB 260509A: LCO optical counterpart detection
- GRB 260509A: SVOM detection of a burst
- EP260507a: REM optical/NIR observations
- EP260507a: refined analysis of the EP-WXT and EP-FXT observations
- EP260507a: COLIBRÍ optical observations
- EP260507a: NOT optical observations
- EP260507a: further Liverpool Telescope observations
- EP260507a: Liverpool Telescope optical upper limits
- EP260507a: TRT optical counterpart detection
- EP260507a: Kinder optical counterpart candidate