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"36130 results found.
- GRB 260925A: Swift/UVOT Upper Limits
- Konus-Wind detection of GRB 260924A
- GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
- GRB 260923A: Glowbug gamma-ray detection
- GRB 260924A: Optical follow-up observations with Kinder
- GRB 260922A: Glowbug gamma-ray detection
- GRB 260925A: Enhanced Swift-XRT position
- GRB 260925A: COLIBRÍ optical upper limits
- GRB 260925A: FRAM-Auger optical limit
- GRB 260924A: Ondrejov D50 optical afterglow detection
- GRB 260924A: SVOM/GRM observation
- GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
- GRB 260925A: Swift detection of a burst
- GRB 260923A: Insight-HXMT/HE detection
- GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
- GRB 260924A: Swift/UVOT Detection
- GRB 260924A: GROWTH-India Telescope optical observations
- GRB 260924A: Swift-BAT refined analysis
- GRB 260924A: NuSTAR detection of prompt emission
- GRB 260924A: Swift/UVOT Upper Limits
- GRB 260924A: Swift-XRT refined Analysis
- Konus-Wind detection of GRB 260922A
- GRB 260922A: NuSTAR detection of prompt emission
- GRB 260921A: NuSTAR detection of prompt emission
- Konus-Wind detection of GRB 260921A (correction to GCN 45722)
- GRB 260921A: SVOM/GRM observation
- GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
- GRB 260924A: Fermi GRB Observation
- Konus-Wind detection of GRB 260921A (possible merger-origin)
- GRB 260924A: Fermi-LAT detection of a bright burst
- GRB 260924A: AstroSat CZTI detection
- GRB 260920A: SVOM/GRM observation
- GRB 260924A: NOT optical counterpart confirmation
- GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
- GRB 260922A: CALET Gamma-Ray Burst Monitor detection
- GRB 260924A: Enhanced Swift-XRT position
- GRB 260924A: Swift detection of a burst
- GRB 260924A: Fermi GBM Final Real-time Localization
- Fermi GRB 260923A: Global MASTER-Net observations report
- GRB 260923A: Fermi GBM Final Real-time Localization
- GRB 260922A: Ondrejov D50 optical limit
- ATCA observations of GRB 260909A
- GRB 260922A: Swift-BAT refined analysis
- GRB 260922A: J-band upper limit with WINTER
- GRB 260922A: Swift/UVOT Upper Limits
- GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
- GRB 260922A: COLIBRÍ optical upper limits
- GRB 260922A: Swift-XRT refined Analysis
- GRB 260922A: Enhanced Swift-XRT position
- Konus-Wind detection of GRB 260810A
- GRB 260920A: Glowbug gamma-ray detection
- GRB 260918A: SVOM/ECLAIRs refined analysis
- GRB 260922A: SVOM/C-GFT optical upper limit
- GRB 260922A: Swift detection of a burst
- GRB 260917C: AstroSat CZTI detection
- GRB 260920B/EP260920b: GECAM-B detection of a burst
- GRB 260921A: AstroSat CZTI detection
- GRB 260921A: Swift-BAT refined analysis
- GRB 260921B: Fermi GBM Final Localization
- GRB 260921A: Fermi GBM Observation
- GRB 260917B:: SVOM/ECLAIRs refined analysis
- Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
- Swift GRB 260921A: Global MASTER-Net observations report
- GRB 260921A: Swift detection of a burst
- GRB 260921A: Fermi GBM Final Real-time Localization
- GRB 260920A: AstroSat CZTI detection
- IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260920A: Fermi GBM Final Real-time Localization
- GRB 260915A: VLT optical and near-infrared upper limits
- IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260918A: SVOM/C-GFT optical upper limits
- Fermi GBM Sub-Threshold Detection of GRB 260918A
- Konus-Wind detection of GRB 260916B (short/hard)
- GRB 260918A: SVOM/VT optical upper limits
- GRB 260916B: Glowbug gamma-ray detection of a short burst
- GRB 260918A: EP-FXT follow-up observation
- GRB 260917B: Mondy optical upper limit
- IPN triangulation of GRB 260916B (short)
- IPN triangulation of GRB 260810A
- GRB 260917B: EP-FXT follow-up observation
- GRB 260915A: Swift-XRT afterglow detection
- GRB 260918A: LCO optical upper limits
- GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
- GRB 260918A: SVOM detection of a burst
- GRB 260917C: Fermi GBM Final Real-time Localization
- GRB 260917B: FRAM-Auger optical limits
- GRB 260916B: Fermi GBM Detection
- IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260916B: Fermi GBM Final Localization
- GRB 260917A: Glowbug gamma-ray detection
- GRB 260915A: SVOM/ECLAIRs refined analysis
- GRB 260917B: WINTER J-band observations
- GRB 260917B: SVOM/VT optical observations
- GRB 260917B: LCO optical observation
- GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260917B: SVOM detection of a faint burst
- GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
- GRB 260917A: Fermi GBM Final Real-time Localization
- GRB 260915A: J-band upper limit with WINTER