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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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

20 results found.

  1. GRB 241209A: ATCA radio follow-up observations
  2. GRB 241209A: Chandra X-ray Detection
  3. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  4. GRB 241209A: Swift-XRT refined Analysis
  5. GRB 241209A: EP-FXT follow-up observations
  6. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  7. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  8. GRB 241209A: COLIBRÍ Optical Upper Limit
  9. GRB 241209A: Fermi GBM Observation
  10. GRB 241209A: GRANDMA/TAROT upper limit
  11. GRB 241209A: REM optical/NIR observations
  12. GRB 241209A: VLT/X-shooter spectroscopy
  13. GRB 241209A: Enhanced Swift-XRT position
  14. GRB 241209A: VLT optical observations
  15. Fermi GRB 241209A: Global MASTER-Net observations report
  16. GRB 241209A: GOTO optical upper limits
  17. GRB 241209A: Prompt enhanced Swift-XRT position
  18. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  19. GRB 241209A: Swift detection of a short burst
  20. GRB 241209A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive:
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