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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"

21 results found.

  1. GRB 250617B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  2. GRB 250615A/EP250615a: FTW optical and NIR observations
  3. GRB 250615A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  4. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  5. GRB 250430A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  6. GRB 250419A: Mondy Optical Observations
  7. GRB 250419A: Liverpool Telescope optical upper limit
  8. GRB250419A: VLA radio detection
  9. GRB 250419A: Mephisto Multi-band Optical Detection
  10. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  11. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  12. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  13. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  14. GRB 250205A: Leavitt Observatory optical upper limit
  15. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  16. GRB 250129A: Continued AbAO and Mondy optical observations
  17. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  18. GRB 240129A: further SAO RAS optical observations
  19. GRB 250129A: Skynet Continued Optical Observations
  20. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  21. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.

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