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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"15 results found.
- GRB 210820A: TSHAO optical upper limit
- GRB 210820A: CAHA 2.2m Optical Detection
- GRB 210820A: GROND observations
- GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
- GRB 210820A: Swift/UVOT Detection
- GRB 210820A: Swift-BAT refined analysis
- GRB 210820A: LT optical upper limit
- GRB 210820A: LCO Optical Upper Limit
- GRB 210820A: RATIR Optical Detections
- GRB 210820A: NOT optical upper limit
- GRB 210820A: Nanshan/NEXT optical upper limit
- GRB 210820A: Swift-XRT refined Analysis
- GRB 210820A: Enhanced Swift-XRT position
- Swift GRB 210820A: Global MASTER-Net observations report
- GRB 210820A: Swift detection of a burst with an optical counterpart