Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

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').

45 results found.

  1. GRB 240123A: Mondy optical afterglow observations
  2. GRB 231117A: MeerKAT 1.3GHz detection
  3. GRB 231117A: Mondy optical observations
  4. GRB 231117A: Chandra afterglow detection
  5. GRB 231117A: Continued GTC Observations
  6. GRB 231117A: Swift/UVOT late time observations
  7. GRB 231117A: GTC Near-Infrared Observations
  8. GRB 231117A: Swift-BAT refined analysis
  9. GRB 231117A: AMI-LA radio observations
  10. GRB 231117A: LDT Confirmation of Optical Fading
  11. GRB 231117A: Wendelstein Confirmation of Fading of the Optical Afterglow
  12. GRB 231117A: CALET Gamma-Ray Burst Monitor detection
  13. GRB231117A: Swift-UVOT detection
  14. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  15. GRB 231117A: Swift-XRT refined Analysis
  16. GRB 231117A: OHP/T120 optical observations
  17. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  18. GRB 231117A: MAAO 0.7-m telescope optical upper limit
  19. GRB 231117A: AKO Follow-Up Observation
  20. GRB 231117A: GECAM-C detection
  21. GRB 231117A: 10 GHz VLA detection
  22. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  23. GRB 231117A: SOAR/Goodman imaging of the afterglow
  24. GRB 231117A: Lowell Discovery Telescope Observations
  25. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  26. GRB 231117A: ATCA detection of a radio counterpart
  27. GRB 231117A: GRBAlpha detection
  28. GRB 231117A: Keck spectroscopy of afterglow candidate
  29. GRB 231117A: GIT optical follow-up
  30. GRB 231117A: LT observations consistent with fading
  31. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  32. GRB 231117A: REM optical and NIR early-time observations
  33. GRB231117A: AGILE/MCAL analysis
  34. GRB 231117A: AKO Optical Upper Limit
  35. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  36. Swift GRB 231117A: Global MASTER-Net observations report
  37. GRB 231117A (short): Glowbug gamma-ray detection
  38. GRB 231117A: ATLAS non-detection of an optical counterpart
  39. Konus-Wind detection of GRB 231117A (short/hard)
  40. GRB 231117A : MITSuME Akeno optical upper limits
  41. GRB 231117A: AGILE detection of a bright short burst
  42. GRB 231117A: Enhanced Swift-XRT position
  43. GRB 231117A: GOTO optical upper limits
  44. GRB 231117A: AstroSat CZTI detection of a bright short burst
  45. GRB 231117A: Swift detection of a bright short burst


Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit