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"2380 results found.
- GRB 260608A: Fermi GRB Observation
- GRB 260604C: AstroSat CZTI detection
- GRB 260604C: SVOM/ECLAIRs refined analysis
- GRB 260608A: SVOM/ECLAIRs refined analysis
- GRB 260604C: further SAO RAS optical observations
- GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
- GRB 260604C: SVOM/C-GFT upper limit
- GRB 260608A: SVOM detection of a burst
- GRB 260604C: GRANDMA further observations
- GRB 260604A: SVOM/GRM detection
- GRB 260604C: OPD1.6m - GRANDMA observations - detection
- GRB 260604C: GECAM-B observation
- GRB 260604C: 6 GHz VLA observations
- GRB 260604C: SAO RAS optical observations
- GRB 260604C: GRANDMA observations
- GRB 260604B: SVOM/GRM detection
- GRB 260605A: Insight-HXMT/HE detection
- GRB260603A: SVOM/ECLAIRs refined analysis
- GRB 260604C: LCO optical upper limit
- GRB 260604C: GOTO detections of the optical afterglow
- GRB 260604C: Kilonova-Catcher optical afterglow detection
- GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260604C: Jinshan optical observations
- GRB 260604C: Fermi GBM Observation
- GRB 260604C: LAST detection of optical counterpart candidate
- SVOM GRB260604.85: Global MASTER-Net observations report
- GRB 260604C: SVOM detection of a long burst
- GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
- GRB 260603A: NOT optical observations
- GRB 260601A: CALET Gamma-Ray Burst Monitor detection
- GRB 260603A: EP-FXT follow-up observation
- GRB 260603A: Kilonova-Catcher optical upper limit
- GRB 260603A: SVOM/VT optical observations
- GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
- EP260602a: SVOM/VT optical magnitudes correction
- GRB 260601A: SVOM/GRM observation of a short burst
- GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
- SVOM GRB260603.23: Global MASTER-Net observations report
- GRB 260603A: SVOM detection of a burst
- EP260602a: SVOM/VT optical candidate
- GRB 260601B/EP260601a: SVOM/VT optical observations
- GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
- GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
- GRB 260530B: SVOM/GRM detection of a possible bright short GRB
- EP260526a: SVOM/VT optical upper limits
- EP260527a: SVOM/VT optical observation
- GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
- GRB 260522B: NuSTAR detection of prompt emission
- GRB 260519C: SVOM/GRM observation
- GRB 260511A: iTelescope T-75 optical detection
- GRB 260520B: SVOM/GRM observation
- GRB 260411B: TERI Gamma-ray detection
- GRB 260225D: TERI Gamma-ray detection
- GRB 260428A: TERI Gamma-ray detection
- GRB 260509A: SVOM/ECLAIRs refined analysis
- GRB 260519C: NuSTAR detection of prompt emission
- GRB 260516D: SVOM/ECLAIRs refined analysis
- GRB 260515A: SVOM/ECLAIRs refined analysis
- GRB 260421B: radio detection with the VLA
- GRID detection of GRB 260511A
- GRB 260516D: EP-FXT follow-up observation
- GRB 260516D: GOTO optical counterpart detection
- GRB 260516D: LCO optical observations
- GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260516D: SVOM/VT optical bright candidate
- GRB 260516D: FRAM-ORM optical limit
- SVOM GRB260516D: Global MASTER-Net observations report
- GRB 260516D: SVOM possible detection of a burst
- 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: TRT optical counterpart candidate
- EP260514a: SVOM/VT optical candidate
- GRB 260515A: SVOM/VT optical observations
- GRB 260515A: OHP/T193 optical observations
- GRB 260515A: LCO optical observations
- SVOM GRB 260515A: Global MASTER-Net observations report
- GRB 260515A: NOT optical observations.
- SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
- GRB 260515A: SVOM/VT optical candidate from VHF data
- GRB 260515A: JinShan optical counterpart candidate
- GRB 260515A: SVOM detection of a burst
- GRB 260510C: Glowbug gamma-ray detection
- GRB 260511B: NOT optical observations
- GRB 260510C: CALET Gamma-Ray Burst Monitor detection
- GRB 260511B: Mephisto multi-band optical followup
- GRB 260511B: further SAO RAS optical observations
- GRB 260509A: SVOM/VT optical observations
- Konus-Wind detection of GRB 260511B
- GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
- GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
- GRB 260511A: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 260511A
- MASS-Cube (GRID 2.0) detection of GRB 260511A
- 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