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.
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"23618 results found.
- GRB 260228A: SVOM/ECLAIRs refined analysis
- GRB 260225A: SVOM/ECLAIRs refined analysis
- EP260302a: LCO observations
- EP260302a: BOOTES-7 optical counterpart detection at early times
- GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 251130B: TERI Gamma-ray detection
- GRB 260208A: TERI Gamma-ray detection
- GRB 260228A: CAHA 2.2m telescope optical upper limit
- GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- EP260227a: Mephisto optical detection
- GRB 260228A: SVOM/VT optical upper limits
- GRB 260228A: SVOM detection of a burst
- EP260227a: COLIBRÍ optical observations
- EP260227a: NOT optical observations
- EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
- Konus-Wind detection of GRB 260226A
- GRB 260225A: WINTER J-band upper limit
- GRB 260226A: CALET Gamma-Ray Burst Monitor detection
- GRB 260226A: COLIBRÍ optical upper limits
- GRB 260225D: Glowbug gamma-ray detection of a likely short burst
- GRB 260226A: Glowbug gamma-ray detection
- GRB 260226A : GROWTH-India Telescope optical observations
- GRB 260226A: LAST optical upper limit
- GRB 260226A: AstroSat CZTI detection of bright long burst
- EP260214a: VLA 6 GHz detection
- GRB260225A: SVOM/ECLAIRs refined position
- GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
- GRB 260223A: Fermi GBM Observation
- EP260126a: VLA 6 GHz detection
- GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
- EP 260225.148: COLIBRÍ Confirmation of flaring star
- EP260223a: Xinglong optical upper limit
- GRB 260223A: Glowbug gamma-ray detection
- EP260213a: Mephisto optical upper limits
- GRB 260223A: COLIBRÍ optical afterglow decay confirmation
- EP260223a: COLIBRÍ optical upper limits
- GRB 260223A: COLIBRÍ further optical observations and a brightening
- EP260221a: Optical upper limit with Kinder observations
- GRB 260223A: COLIBRÍ optical observations
- GRB 260223A: DDOTI Optical Candidate
- EP260221a: COLIBRÍ optical counterpart candidate
- EP260221a: EP-FXT follow-up observation
- EP-WXT01709258519: Xinglong optical upper limit
- EP260221a: Xinglong optical upper limit
- ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
- EP260221a: GOTO optical upper limit
- EP260221a: COLIBRÍ optical upper limit
- SVOM alert sb26021801: LCO optical upper limit
- EP260221a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709258519 is likely caused by Mrk 421
- GRB 260219A: AstroSat CZTI detection
- SVOM alert sb26021801: LAST optical upper limit
- sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
- EP-WXT 01709258455: NOT optical upper limits
- Konus-Wind detection of GRB 260212A
- IPN triangulation of GRB 260212A
- GRB 260206A: probable hard X-ray burst from 4U 0513-40
- EP260214b: Optical upper limit with Kinder observations
- EP260214a: Optical upper limits with Kinder observations
- EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
- EP260214b: DDOTI Optical Detection
- EP260214a: NOT optical upper limits
- EP260214a: COLIBRÍ optical upper limits
- EP260214b: OHP/T120 optical observations
- EP260214b: LCO optical counterpart detection
- EP260214b: COLIBRÍ optical observations
- EP260214b: NOT optical counterpart detection
- EP260214b: Einstein Probe detection of a fast X-ray transient
- GRB 260212A: AstroSat CZTI detection
- EP260213a: COLIBRÍ optical upper limits
- EP260213a: Optical upper limits with Kinder observations
- EP260213a: NUTTelA-TAO Early Optical Limits
- EP260213a: SVOM/C-GFT upper limit
- GRB 260212A: SVOM/GRM observation of a long burst
- GRB 260211A - SVOM/ECLAIRs refined analysis
- GRB 260204A: SVOM/ECLAIRs refined analysis
- GRB 260211A: EP-FXT follow-up observation
- GRB 260211A: SVOM/VT optical observation
- GRB 260212A: Glowbug gamma-ray detection
- GRB 260211A: GOTO optical upper limit
- GRB 260211A: LAST optical upper limit
- Konus-Wind detection of GRB 260207B
- GRB 260128B: SVOM/ECLAIRs refined analysis
- GRB 260211A: LCO optical upper limits
- GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
- Konus-Wind detection of GRB 260209B
- Konus-Wind detection of GRB 260127B
- EP260209a: COLIBRÍ optical upper limit
- GRB 260208A: LCO detection of the optical counterpart
- EP260210a: Optical upper limits with Kinder observations
- IPN triangulation of GRB 260207B (short/hard with EE)
- GRB 260210A: Glowbug gamma-ray detection
- GRB 260210A: AstroSat CZTI detection
- GRB 260208C: AstroSat CZTI detection
- EP260210a: COLIBRÍ optical upper limit
- GRB 260207B: AstroSat CZTI detection
- GRB 260204A: Swift-XRT afterglow detection
- GRB 260208B: AstroSat CZTI detection of a bright long burst
- GRB 260208A: Glowbug gamma-ray detection