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"15247 results found.
- GRB 260604A: SVOM/GRM detection
- GRB 260607B: Fermi GBM Observation
- GRB 260607B: Fermi-LAT detection
- GRB 260604C: GECAM-B observation
- GRB 260604C: GRANDMA observations
- GRB 260604B: SVOM/GRM detection
- GRB 260605A: Insight-HXMT/HE detection
- GRB260603A: SVOM/ECLAIRs refined analysis
- EP260605a: Einstein Probe detection of a fast X-ray transient
- The EP-WXT trigger 01709267001 is likely a flaring star
- GRB 260601B / EP260601a: AstroSat CZTI detection
- GRB 260527A/EP260527a: 6 GHz VLA observations
- GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
- The EP-WXT trigger 01709266798 is likely a flaring star
- GRB 260604C: Jinshan optical observations
- GRB 260604C: Fermi GBM Observation
- GRB 260604C: LAST detection of optical counterpart candidate
- GRB 260604C: SVOM detection of a long burst
- GRB 260601A: CALET Gamma-Ray Burst Monitor detection
- Konus-Wind detection of GRB 260601B/EP260601a
- EP260601a/GRB 260601B: EP-FXT follow-up observation
- GRB 260601B / EP260601a: Mondy optical upper limit
- GRB 260603A: Kilonova-Catcher optical upper limit
- EP260602a: NOT NIR J-band observations
- GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
- GRB 260601A: SVOM/GRM observation of a short burst
- EP260602a: COLIBRÍ optical observations
- GRB260601B/EP260601a: NOT near-infrared observations
- GRB 260603A: SVOM detection of a burst
- EP260602b: Einstein Probe detection of a fast X-ray transient
- GRB 260601B/EP260601a: Insight-HXMT detection
- GRB 260601A: GECAM-B observation of a short burst
- GRB 260601B: CALET Gamma-Ray Burst Monitor detection
- GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
- GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
- EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
- GRB 260601A: Fermi GBM Observation
- EP260530a/AT 2026nwl: COLIBRÍ optical observations
- GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
- GRB 260531B: GECAM-B observation
- GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
- AT2026nik: EP-FXT X-ray counterpart
- AT 2026nuz: COLIBRÍ optical observations
- GRB 260530B: SVOM/GRM detection of a possible bright short GRB
- EP260527a/GRB 260527A: optical upper limit with Kinder observations
- GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
- GRB 260527A/EP260527a: Insight-HXMT detection
- EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
- EP260527a / GRB 260527A: NOT optical observations
- GRB 260527A/EP260527a: FTW optical and NIR observations
- GRB 260527A: CALET Gamma-Ray Burst Monitor detection
- GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
- GRB 260526A: GECAM-B observation
- Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
- EP260527a: COLIBRÍ optical detection
- The EP-WXT trigger 01709266172 is likely a flaring star
- GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
- EP260526a: LCO optical upper limits
- GRB 260525A: AstroSat CZTI detection
- EP260526.405: COLIBRÍ optical upper limits
- GRB 260523B: AstroSat CZTI detection
- GRB 260523B: GECAM-B observation
- GRB 260522A: Fermi GBM Observation
- GRB 260522A: Fermi-LAT detection
- GRB 260519C: SVOM/GRM observation
- GRB 260520B: SVOM/GRM observation
- GRB 260411B: TERI Gamma-ray detection
- GRB 260407A: TERI Gamma-ray detection
- GRB 260307A: TERI Gamma-ray detection
- GRB 260225D: TERI Gamma-ray detection
- GRB 251118A: TERI Gamma-ray detection
- GRB 251113A: TERI Gamma-ray detection
- GRB 260428A: TERI Gamma-ray detection
- Konus-Wind detection of GRB 260519C
- GRB 260509A: SVOM/ECLAIRs refined analysis
- Konus-Wind detection of GRB 260518A
- GRB 260518A: AstroSat CZTI detection of a long burst
- GRB 260516D: SVOM/ECLAIRs refined analysis
- GRB 260515A: SVOM/ECLAIRs refined analysis
- GRB 260516D: GOTO optical counterpart detection
- GRB 260515A: further Liverpool Telescope observations
- GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260516D: GROWTH-India Telescope optical detection
- GRB 260516D: SVOM possible detection of a burst
- Konus-Wind detection of GRB 260515A
- GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
- EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
- EP260514a: TRT optical counterpart candidate
- EP260514a: COLIBRÍ optical upper limits
- GRB 260515A: SVOM/VT optical candidate from VHF data
- GRB 260515A: SVOM detection of a burst
- IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
- Konus-Wind detection of GRB 260512A
- GRB 260510C: CALET Gamma-Ray Burst Monitor detection
- GRB 260511B: Mephisto multi-band optical followup
- GRB 260512A: AstroSat CZTI detection
- The EP-WXT trigger 01709262077 is likely a flaring star
- EP260507a: Xinglong Schmidt optical counterpart detection
- Konus-Wind detection of GRB 260511B
- EP260512a: COLIBRÍ optical upper limits