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"27777 results found.
- GRB 260302A: Fermi GBM Final Real-time Localization
- GRB 260228A: CAHA 2.2m telescope optical upper limit
- EP260227a: Mephisto optical detection
- GRID detection of GRB 260225D
- EP260227A: 3.6m DOT optical afterglow detection
- GRB 260228A: SVOM detection of a burst
- GRB 260226A: Asiago r-band upper limit
- EP260227a: Liverpool Telescope observations
- GRID detection of GRB 260223A
- EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
- IceCube cascade alert 142200_1517143 retraction
- GRB 260226A: Insight-HXMT/HE detection of the very bright burst
- Konus-Wind detection of GRB 260226A
- GRB 260223A: 7DT detection and Medium-band SED of Afterglow
- GRB 260226A: CALET Gamma-Ray Burst Monitor detection
- GRB 260225D: Glowbug gamma-ray detection of a likely short burst
- GRB 260226A: Glowbug gamma-ray detection
- GRB 260226A: NuSTAR detection of bright prompt emission
- GRB 260226A: AstroSat CZTI detection of bright long burst
- EP260214a: VLA 6 GHz detection
- GRB 260226A: Fermi-LAT detection of a bright burst
- GRB 260226A: Fermi GBM Final Real-time Localization
- GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
- GRB 260225C: Fermi GBM Final Real-time Localization
- GRB 260225A: SVOM/VT optical upper limits
- GRB 260225B: Fermi GBM Final Real-time Localization
- EP260126a: VLA 6 GHz detection
- EP260223a: Liverpool Telescope upper limits
- GRB 260225A: SVOM detection of a burst
- EP260224a: Einstein Probe detection of an X-ray transient
- EP260223a: Xinglong optical upper limit
- GRB 260223A: Glowbug gamma-ray detection
- EP260213a: Mephisto optical upper limits
- EP260223a: EP-FXT follow-up observation
- sb26021801: SVOM/VT optical upper limits
- EP260223a: Einstein Probe detection of an X-ray transient
- EP260221a: Optical upper limit with Kinder observations
- GRB 260223A: Fermi GBM Final Real-time Localization
- EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
- EP260221a: COLIBRÍ optical counterpart candidate
- EP260221a: Gemini South z-band upper limit
- GRB 260222A: Fermi GBM Final Real-time Localization
- GRB 260221B: Fermi GBM Final Real-time Localization
- EP-WXT01709258519: Xinglong optical upper limit
- EP260221a: Xinglong optical upper limit
- GRB 260221A: Fermi GBM Final Real-time Localization
- EP260221a: Einstein Probe detection of an X-ray transient
- GRB 260219A: AstroSat CZTI detection
- GRB 260219A: Fermi GBM Final Real-time Localization
- GRB 260217A: Fermi GBM Final Localization
- GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
- sb26021801: SVOM detection of a long faint X-ray transient
- EP260214b: 1.3m DFOT optical upper limit
- Konus-Wind detection of GRB 260212A
- IPN triangulation of GRB 260212A
- IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260216A: Fermi GBM Final Real-time Localization
- 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
- EP260214b: EP-FXT follow-up observation
- EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
- EP260214b: DDOTI Optical Detection
- EP260214b: LCO optical counterpart detection
- EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
- EP260214b: NOT optical counterpart detection
- EP260214b: Einstein Probe detection of a fast X-ray transient
- EP260214a: Einstein Probe detection of an X-ray transient
- GRB 260212A: AstroSat CZTI detection
- EP260213a: Liverpool Telescope optical upper limits
- EP260213a: Optical upper limits with Kinder observations
- EP260213a: Einstein Probe detection of a fast X-ray transient
- GRB 260213B: Fermi GBM Final Localization
- GRB 260204A: SVOM/ECLAIRs refined analysis
- GRB 260213A: Fermi GBM Final Localization
- GRB 260212A: Glowbug gamma-ray detection
- GRB 260212A: Fermi GBM Final Real-time Localization
- Fermi GBM Sub-Threshold Detection of GRB 260211A
- Konus-Wind detection of GRB 260207B
- GRID detection of GRB 260207B
- GRB260131A/B: 3.6m DOT Optical Observations
- GRB 260211A: SVOM detection of a burst
- Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
- Konus-Wind detection of GRB 260209B
- GRB 260208A: Swift UVOT detection
- Konus-Wind detection of GRB 260127B
- GRB 260208A: LCO detection of the optical counterpart
- EP260209a: Einstein Probe detection of a fast X-ray transient
- IPN triangulation of GRB 260207B (short/hard with EE)
- GRB 260210C: Fermi GBM Final Real-time Localization
- GRB 260210A: Glowbug gamma-ray detection
- GRB 260210B: Fermi GBM Final Real-time Localization
- GRB 260210A: AstroSat CZTI detection
- GRB 260208C: AstroSat CZTI detection
- GRB 260208B: refined analysis of the EP-FXT observation
- EP260210a: Einstein Probe detection of an X-ray transient
- 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