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"35947 results found.
- GRB 230204B: Fermi GBM detection
- GRB 230205A: LCOGT Optical Upper Limits
- GRB 230204B: Swift-XRT afterglow detection
- GRB 230204B: 3.6m DOT optical observation
- GRB 230205A: SVOM/C-GFT optical upper limit
- GRB 230205A: OHP/T193 optical observations
- GRB 230204B: VLT/X-shooter redshift
- GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s)
- GRB 230204A: Swift-BAT refined analysis
- GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
- GRB 230205A: Swift-XRT refined Analysis
- GRB 230204B: Swift ToO observations
- GRB 230205A: Enhanced Swift-XRT position
- GRB 230205A: BOOTES-5/JGT early optical upper limit
- GRB 230204B: Detection by GRBAlpha
- GRB 230204B: AGILE detection
- GRB 230205A: Swift detection of a burst
- GRB 230204B: GIT discovery of the likely optical afterglow
- GRB 230204B: AstroSat CZTI detection
- GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230204A: Swift/UVOT Upper Limits
- GRB 230204B: MAXI/GSC detection
- GRB 230204A: Swift-XRT refined Analysis
- GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
- GRB 230204A: Enhanced Swift-XRT position
- GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
- GRB 230201B: TURBO Optical Upper Limits
- Fermi Gamma-ray Burst Monitor trigger 230203275 / 697098930 is not a GRB
- GRB 221216A: Swift-BAT refined analysis
- Fermi GRB 230201B: Global MASTER-Net observations report
- GRB 230201B: Fermi GBM Final Real-time Localization
- GRB 230126A: Detection by VZLUSAT-2
- Fermi GRB 230201A: Global MASTER-Net observations report
- GRB 221009A: radio afterglow detection with the EVN
- GRB 230201A: Fermi GBM Final Real-time Localization
- ZTF23aaarlti/AT2023avj: Assy continued optical observations
- ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
- AT2023avj: X-ray Detection with Swift/XRT
- GRB 230129A: AstroSat CZTI detection
- GRB 230128A: AstroSat CZTI detection
- GRB 230130A: Fermi GBM Final Real-time Localization
- GRB 230129A: Fermi GBM Final Real-time Localization
- GRB 230128A: Fermi GBM Final Real-time Localization
- AT2023avj ZTF Candidate: Assy optical observations
- GRB 230126A: Fermi GBM Final Real-time Localization
- GRB 230124A: Fermi GBM Observation
- GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230114B: Detection by VZLUSAT-2
- GRB 230123A: LCOGT Optical Upper Limits
- Fermi GRB 230124A: Global MASTER-Net observations report
- GRB 230124A: Fermi GBM Final Real-time Localization
- GRB 230123A: Swift-BAT refined analysis
- GRB 230122A: Swift/BAT-GUANO detection
- GRB 230123A: Swift/UVOT Upper Limits
- GRB 230123A: Swift-XRT refined Analysis
- GRB 230123A: Enhanced Swift-XRT position
- GRB 230123A: Zadko observatory - Gingin optical observations
- GRB 230116C: Swift-XRT observations
- GRB 230123A: Swift detection of a burst
- GRB 230116B: Fermi GBM observation
- GRB 230120A: AstroSat CZTI detection
- IPN triangulation of GRB 230116B (short)
- GRB 230119A: CALET Gamma-Ray Burst Monitor detection
- GRB 230116D: 3.6m DOT optical upper limit
- GRB 230119A: Fermi GBM Final Real-time Localization
- Fermi GRB 230118A: Global MASTER-Net observations report
- GRB 230118A: Fermi GBM Final Real-time Localization
- GRB 230116D: Swift-BAT refined analysis
- GRB 230116C: Swift-BAT refined analysis
- GRB 230116D: SAO RAS further observations
- GRB 230116D: SAO RAS photometry
- GRB 230116D: KGO RC-25 optical observations
- GRB 230116D: Sintez-Newton/CrAO optical observations
- GRB 230116D: LCOGT Optical Upper Limit
- GRB 230116D: SAO RAS redshift
- GRB 230116D: Swift-XRT refined Analysis
- Fermi GRB 230117A: Global MASTER-Net observations report
- GRB 230117A: Fermi GBM Final Real-time Localization
- GRB 230116D: GIT optical follow-up
- GRB 230116D: GIT optical follow-up
- GRB 230116D: Enhanced Swift-XRT position
- GRB 230116D: SAO RAS observations of OT brightening
- GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
- GRB 230116D: Nanshan/NEXT optical afterglow detection
- GRB 230116D: Swift detection of a burst
- GRB 230116C: Swift detection of a burst
- GRB 230116B: Fermi GBM Final Real-time Localization
- GRB 230116A: Fermi GBM Final Real-time Localization
- GRB 230114A: Detection by VZLUSAT-2
- GRB 230114A: Fermi GBM Final Real-time Localization
- GRB 230111A: Fermi GBM Observation
- Fermi GRB 230112A: Global MASTER-Net observations report
- GRB 230112A: Fermi GBM Final Real-time Localization
- GRB 230111A: MAXI/GSC detection
- GRB 230111A: Fermi GBM Final Real-time Localization
- GRB 230106: AstroSat LAXPC detection
- GRB 230102A: Fermi GBM Observation
- Fermi Gamma-ray Burst Monitor trigger 694043024/221229905 is not a GRB
- GRB 221231A: 3.6m DOT optical upper limit
- GRB 230104A: AGILE/MCAL detection of a burst