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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"

42 results found.

  1. GRB 251013C: Kilonova-Catcher optical afterglow detection
  2. GRB 251002A: Kilonova-Catcher optical afterglow detection
  3. GRB 250502A: Montarrenti Observatory optical detection
  4. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  5. GRB 250403A: Montarrenti Observatory optical detection
  6. EP250302a: Montarrenti Observatory optical detection
  7. GRB 250129A: GRANDMA Continued Afterglow Detection
  8. GRB 250103A: Montarrenti Observatory optical detection
  9. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  10. GRB 241215A: Montarrenti Observatory optical upper limit
  11. GRB 241030B: Montarrenti Observatory optical upper limit
  12. GRB 240825A: Montarrenti Observatory optical follow-up observations
  13. GRB 240825A: Montarrenti Observatory optical observations
  14. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  15. EP240802a: Montarrenti Observatory optical upper limit
  16. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  17. EP240626a: Montarrenti Observatory optical upper limit
  18. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  19. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  20. GRB240204A: VIRT optical upper limit
  21. GRB 240204A: Montarrenti Observatory optical observations
  22. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  23. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  24. GRB 230812B: Montarrenti Observatory optical observations
  25. GRB 230723B: Montarrenti Observatory upper limit
  26. ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
  27. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  28. GRB221120A: Montarrenti Observatory Upper Limit
  29. GRB 221009A: GRANDMA/Kilonova-Catcher observations
  30. GRB 210610B: University of Siena Observatory optical photometry of the afterglow
  31. GRB 210420B: Montarrenti Observatory follow-up observations
  32. GRB 210420B: Montarrenti Observatory optical afterglow detection
  33. GRB 210419C: Montarrenti Observatory Upper Limit
  34. GRB 210402A: BOOTES-network early optical upper limit
  35. GRB 210402A: Montarrenti Observatory upper limit
  36. GRB 190627A: Montarrenti Observatory optical detection
  37. GRB 140311A: Montarrenti Observatory optical upper limit
  38. GRB 130831A: Montarrenti Observatory optical follow-up
  39. GRB 130831A: Montarrenti Observatory optical observations
  40. GRB130606A: Montarrenti Observatory afterglow detection
  41. GRB 120311A: C88 optical limits
  42. GRB 120311B: C88 optical limits

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