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"27770 results found.
- EP260610a: SVOM/VT optical upper limits
- EP260610b: Einstein Probe detection of an X-ray transient
- Konus-Wind detection of GRB 260601A
- IPN triangulation of GRB 260601A (short/hard)
- GRB 260610A: Fermi GBM Final Real-time Localization
- EP260610a: Einstein Probe detection of a fast X-ray transient
- GRB 260609A: Fermi GBM Final Localization
- Konus-Wind detection of GRB 260604C
- GRB 260604C: AstroSat CZTI detection
- IPN triangulation of GRB 260601B / EP260601a
- GRB 260604C: SVOM/ECLAIRs refined analysis
- Konus-Wind detection of GRB 260607B
- GRB 260608C: Fermi GBM Final Real-time Localization
- GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
- GRB 260608B: Fermi GBM Final Localization
- GRB 260607B: AstroSat CZTI detection
- GRB 260608A: SVOM detection of a burst
- GRB 260608A: Fermi GBM Final Real-time Localization
- EP260605a: EP-FXT follow-up observation
- GRB 260604A: SVOM/GRM detection
- GRB 260607B: Fermi-LAT detection
- GRB 260607B: Fermi GBM Final Localization Correction
- GRB 260604C: OPD1.6m - GRANDMA observations - detection
- GRB 260607A: Fermi GBM Final Real-time Localization
- GRB 260604B: SVOM/GRM detection
- GRB 260605A: Insight-HXMT/HE detection
- EP260605a: Einstein Probe detection of a fast X-ray transient
- GRB 260604A: Glowbug gamma-ray detection
- GRB 260604C: Liverpool Telescope optical detection
- EP260602d: EP-FXT follow-up observation
- EP260602c: EP-FXT follow-up observation
- GRB 260601B / EP260601a: AstroSat CZTI detection
- GRB 260527A/EP260527a: 6 GHz VLA observations
- GRB 260604C: Correction to GCN 44828
- GRB 260604C: Kilonova-Catcher optical afterglow detection
- GRB 260604C: LAST detection of optical counterpart candidate
- GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery
- GRB 260604C: SVOM detection of a long burst
- GRB 260604C: Fermi GBM Final Real-time Localization
- GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
- GRB 260604B: Fermi GBM Final Real-time Localization
- GRB 260601A: CALET Gamma-Ray Burst Monitor detection
- EP260602a: EP-FXT follow-up observation
- EP260603a: Einstein Probe detection of a fast X-ray transient
- EP260602d: Optical Upper limits with kinder observations
- GRB 260604A: Fermi GBM Final Real-time Localization
- EP260602b: Liverpool Telescope observations
- GRB 260603B: Fermi GBM Final Localization
- Konus-Wind detection of GRB 260601B/EP260601a
- EP260602b: EP-FXT follow-up observation
- GRB 260601B/EP260601a: Glowbug gamma-ray detection
- EP260602d: Einstein Probe detection of a fast X-ray transient
- EP260602c: Einstein Probe detection of a fast X-ray transient
- EP260602a: COLIBRÍ optical observations
- GRB 260603A: SVOM detection of a burst
- EP260602b: Einstein Probe detection of a fast X-ray transient
- GRB 260601B/EP260601a: Insight-HXMT detection
- EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
- GRB 260602B: Fermi GBM Final Localization
- GRB 260602A: Fermi GBM Final Real-time Localization
- GRB 260601B: CALET Gamma-Ray Burst Monitor detection
- EP260602a: Optical upper limits with Kinder observations
- GRB 260601B / EP260601a: NuSTAR detection of prompt emission
- EP260602a: Einstein Probe detection of a fast X-ray transient
- GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
- EP260601a: Einstein Probe detection of an X-ray transient
- EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection
- GRB 260601A: Glowbug gamma-ray detection of a short burst
- GRB 260531B: Glowbug gamma-ray detection
- GRB 260516D: VLA radio detection
- GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
- GRB 260527A/EP260527a: Glowbug gamma-ray detection
- GRB 260601A: Fermi GBM Final Real-time Localization
- GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
- GRB 260531C: Fermi GBM Final Localization Correction
- AT2026nik: EP-FXT X-ray counterpart
- GRB 260531B: Fermi GBM Final Real-time Localization
- GRB 260531A: MAXI/GSC detection
- IPN triangulation of GRB 260527A / EP260527a
- GRB 260530B: SVOM/GRM detection of a possible bright short GRB
- GRB 260530A: Fermi GBM Final Real-time Localization
- GRB 260527A / EP260527a: VLA radio detection
- GRB 260527A/EP260527a: Insight-HXMT detection
- GRB 260529A: Fermi GBM Final Real-time Localization
- EP260526a: SVOM/VT optical upper limits
- EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
- GRB 260527A: CALET Gamma-Ray Burst Monitor detection
- EP260527a/GRB 260527A: EP-FXT follow-up observation
- GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
- Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
- EP260526a: EP-FXT follow-up observation
- EP260527a: COLIBRÍ optical detection
- EP260527a: Einstein Probe detection of a fast X-ray transient
- GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
- EP260526a: LCO optical upper limits
- EP260526a: Einstein Probe detection of a fast X-ray transient
- GRB 260525A: AstroSat CZTI detection
- GRB 260526A: Fermi GBM Final Real-time Localization
- EP01709266106 (EP260526a?): Liverpool Telescope upper limits
- GRB 260525A: Fermi GBM Final Real-time Localization