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"26042 results found.
- 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 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 221216A: Swift-BAT refined analysis
- ZTF23aabmzlp/AT2023azs: VLA radio detection
- ZTF23aaarlti/AT2023avj: AMI-LA radio detection
- ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
- GRB 221009A: radio afterglow detection with the EVN
- ZTF23aaarlti/AT2023avj: Assy continued optical observations
- AT2023avj: X-ray Detection with Swift/XRT
- ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
- ZTF23aaarlti/AT2023avj: VLA radio detection
- ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
- ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
- AT2023avj ZTF Candidate: Assy optical observations
- ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
- Swift-XRT observations of NuEm-230125A
- Trigger 1150965: Swift detection of LS V +44 17
- GRB 230124A: Fermi GBM Observation
- GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230123A: LCOGT Optical Upper Limits
- 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
- Trigger 1150107: Swift detection of LS V +44 17
- GRB 230116D: 3.6m DOT optical upper limit
- 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
- 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
- Swift GRB230116.88: Global MASTER-Net observations report
- GRB 230116C: Swift detection of a burst
- Trigger 1148770: Swift detection of Cyg X-1 due to Star Tracker loss of lock
- GRB 230102A: Fermi GBM Observation
- GRB 221231A: 3.6m DOT optical upper limit
- GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 221231A: Fermi GBM Observation
- GRB 221231A: Swift-XRT afterglow detection
- GRB 221231A: AKO Upper Limit
- GRB 221231A: Swift-XRT observations
- GRB 221231A: Swift ToO observations
- GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
- GRB 221226A: Fermi GBM detection
- IPN triangulation of GRB 221226A
- GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
- ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
- GRB 221226B: LCOGT Optical Upper Limits
- GRB 221226B Swift-BAT refined analysis
- GRB 221226B: Swift-UVOT Detection
- GRB 221226B: Fermi GBM Observation
- GRB 221226B: Swift-XRT refined Analysis
- GRB 221226B: VLT/X-shooter redshift and host galaxy
- GRB 221226B: Enhanced Swift-XRT position
- GRB 221226B: Swift detection of a burst
- Swift GRB221226.95: Global MASTER-Net observations report
- GRB 221218A: 3.6m DOT optical upper limit
- GRB 221218A: BOOTES-4/MET and OSN optical upper limits
- GRB 221218A: KAIT Optical Upper Limit
- GRB 221215A: Fermi GBM Detection
- GRB 221216A: Swift/UVOT Upper Limits
- GRB 221216A: Fermi GBM observation
- GRB 221216A: Swift-XRT refined Analysis
- GRB 221216A: AKO Upper Limit
- GRB 221215A: Swift-XRT observations
- GRB 221216A: Enhanced Swift-XRT position
- Swift GRB 221216A: Global MASTER-Net observations report
- GRB 221216A: Zadko observatory - Gingin optical observations
- GRB 221216A: Nanshan/NEXT optical upper limits
- GRB 221216A: Swift detection of a burst
- GRB 221215A: Swift ToO observations
- GRB 221215A: Swift/BAT-GUANO arcminute localization
- Swift GRB221215.15: Global MASTER-Net observations report