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"18 results found.
- GRB 250617B: Nickel telescope optical observations
- GRB 250617B: Assy AZT-20 Optical Observations
- GRB 250617B: Swift/UVOT Detection
- GRB 250617B: Kilonova-Catcher optical afterglow detection
- GRB 250617B: VLT/X-shooter spectroscopic redshift z = 1.396
- GRB 250617B: COLIBRÍ optical observations
- GRB 250617B: NOT NIR observations of the afterglow
- GRB 250617B: Swift-XRT refined Analysis
- GRB 250617B: SVOM/VT optical observation
- GRB 250617B: NUTTelA-TAO early time optical observations
- Swift GRB 250617B: Global MASTER-Net observations report
- GRB 250617B: GOTO optical upper limit
- GRB 250617B: Enhanced Swift-XRT position
- GRB 250617B: Fermi GBM Observation
- GRB 250617B: Fermi GBM Final Localization
- GRB 250617B: Ondrejov D50 optical afterglow detection
- GRB 250617B: SAO RAS optical observations
- GRB 250617B: Swift detection of a burst with an optical counterpart