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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. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  2. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  3. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  4. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  5. GRB 230430A: A short GRB from a neutron star merger
  6. GRB 221009A: Determination of the black holes mass and spin
  7. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  8. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  9. GRB 221009A: A type I BdHN of exceptional energetics
  10. GRB 220527A: A BdHN I with a clear UPE phase
  11. GRB 220101A: The first example of a Petanova
  12. GRB 220101A: The most powerful GRB and BDHN I in 26 years
  13. GRB 211023A: A BdHN of type I
  14. GRB 210411C: A very significant early X-ray afterglow
  15. GRB 210410A: A twin of short GRB 090510 with complementary observations
  16. GRB 210210A as a BdHN II
  17. GRB 190114C: A type 1 BdHN with TeV emission
  18. GRB 180728A: A long GRB of the X-ray flash (XRF) subclass, expecting supernova appearance
  19. GRB 180720B: Testing the universality of the newly born neutron star in BdHNe
  20. GRB 160303A: LCOGT-FTN optical observations
  21. GRB 160104A: LCOGT-FTN afterglow candidate
  22. GRB 151114A: LCOGT-FTS afterglow observations
  23. GRB 151111A: LCOGT-FTS afterglow observations
  24. GRB 151029A: LCOGT-FTS afterglow observations
  25. GRB 151027B: LCOGT FTN afterglow observations
  26. GRB 151027A: LCOGT-McDonald afterglow observations
  27. GRB 131024C: ICSP discovery of a burst in X-rays by balloon borne study
  28. GRB 130702A in the Ep,i - Eiso plane
  29. Redshift of GRB 110402A theoretically estimated (revised)
  30. Redshift of GRB 110402A theoretically estimated
  31. Request for Supernova related data for GRB 101023A

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