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"11 results found.
- GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
- GRB 250407A: Mondy and AbAO Optical Observations
- IPN triangulation of GRB 250407A
- GRB 250407A: LCO detection of a fading optical counterpart
- Konus-Wind detection of GRB 250407A
- GRB 250407A: SVOM/GRM observation of a bright long burst
- GRB 250407A: EP-WXT afterglow detection
- GRB 250407A: KAIT Optical Afterglow Candidate
- GRB 250407A: Fermi GBM Detection
- Fermi GRB 250407A: Global MASTER-Net observations report
- GRB 250407A: Swift ToO observations