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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"

36 results found.

  1. GRB 250617B: Kilonova-Catcher optical afterglow detection
  2. GRB 250617B: NUTTelA-TAO early time optical observations
  3. GRB 250430A: NUTTelA-TAO Early Measurements
  4. GRB 250402A: NUTTelA-TAO Early Optical Limits
  5. EP250302a: NUTTelA-TAO Early Measurments
  6. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits
  7. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  8. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  9. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  10. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  11. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  12. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  13. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  14. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  15. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  16. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  17. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  18. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  19. GRB 231111A NUTTelA-TAO / BSTI Early Measurements
  20. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  21. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  22. GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
  23. GRB 221028A: GRANDMA observations
  24. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  25. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  26. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  27. GRB 220403B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  28. GRB 220118A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  29. GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  30. GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  31. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  32. GRB 201015A NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  33. GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  34. LIGO/Virgo S190728q: ZTF19abjethn TShAO and NUTTelA-TAO optical observations / classification
  35. GRB 190627A: NUTTelA-TAO optical counterpart observations
  36. GRB 190627A: NUTTelA-TAO optical observations

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