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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"

23 results found.

  1. Swift GRB 251230A: Global MASTER-Net OT detection
  2. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  3. GRB 251230A / EP251230a: GECAM-B detection
  4. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  5. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  6. GRB 251230A: GRANDMA/TAROT Early Detection
  7. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  8. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  9. GRB 251230A: 1.3m DFOT optical upper limit
  10. GRB 251230A: Swift-XRT refined Analysis
  11. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  12. GRB 251230A: Swift/UVOT detection
  13. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  14. GRB 251230A: GOTO optical upper limit
  15. GRB 251230A / EP251230a: SVOM/VT optical observation
  16. GRB 251230A: Enhanced Swift-XRT position
  17. GRB 251230A: Early optical counterpart detection by LCO.
  18. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  19. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  20. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  21. Swift GRB 251230A: Global MASTER-Net observations report
  22. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  23. GRB 251230A: Swift detection of a burst with a bright optical counterpart

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Download all Circulars as a .tar.gz archive:
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