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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').
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"

20 results found.

  1. GRB 250919A: TERI gamma-ray detection
  2. GRB 250919A / EP250919a: Global MASTER Net before, during and after trigger optical observations
  3. GRB 250919A / EP250919a: further LCO optical observation
  4. GRB 250919A / EP250919a: LCO optical observation
  5. Konus-Wind detection of GRB 250919A
  6. GRB 250919A / EP250919a: Insight-HXMT detection
  7. GRB 250919A/EP250919a: SVOM/VT optical observation
  8. GRB 250919A / EP250919a: MASTER bright afterglow detection 24h after GRB time
  9. GRB 250919A: Glowbug gamma-ray detection
  10. GRB 250919A: Fermi GBM Observation
  11. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  12. GRB 250919A/EP250919A: Swift/UVOT afterglow detection
  13. GRB 250919A: Swift-XRT afterglow detection
  14. GRB 250919A: Fermi-LAT detection
  15. EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
  16. GRB 250919A: SVOM/GRM observation of a very bright GRB
  17. GRB 250919A: BALROG localization (Fermi Trigger 779934537 / GRB 250919020)
  18. EP250919a: Einstein Probe detection of an X-ray transient
  19. Fermi GRB 250919A: Global MASTER-Net observations report
  20. GRB 250919A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive:
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