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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"

31 results found.

  1. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  2. The EP-WXT trigger 01709274014 is likely a flaring star
  3. GRB 260204A: Swift-XRT observations
  4. The EP-WXT trigger 01709248635 is likely a flaring star
  5. SVOM/sb25101004: SVOM detection of a stellar flare
  6. GRB 210708A: Swift/UVOT Upper Limits
  7. IceCube 201114A: Swift followup of Fermi J0703.5+0505
  8. IceCube-190221A: Swift-XRT Follow-up Observations
  9. GRB 180705A: OSN observations
  10. Trigger 809217: Swift trigger on RS CVn Star HD 8357
  11. IceCube-171106A: Swift Observations
  12. IceCube-170922A: Swift-XRT observations
  13. LIGO/Virgo G299232: Swift-XRT sources
  14. Global MASTER net follow up of IceCube-160731A
  15. Swift follow up of IceCube-160731A
  16. GRB 151122A: Swift/UVOT Observations
  17. GRB 151122A: Swift-XRT observations
  18. GRB 151107A: Further investigation of the source nature
  19. LIGO/Virgo G184098: Swift follow-up observations
  20. Swift observations of HD 305560
  21. Swift possible detection of the Be star HD 305560
  22. Swift-BAT trigger 582894 is HR 1099 (Flare star)
  23. GRB 120510A: Swift XRT and UVOT observations
  24. GRB 120212A: Swift/UVOT Detection
  25. GRB 100614A: Swift/UVOT Upper Limits
  26. GRB080506: Swift/UVOT observations
  27. GRB 051008 Tautenburg Supernova Search
  28. GRB051105B: Swift/XRT upper limit
  29. GRB 050713A: Swift/UVOT observation
  30. Possible GRB 040903 - further analysis
  31. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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