Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

1145 results found.

  1. EP240416a: EP-WXT detection of a fast X-ray transient
  2. EP240414a: EP-FXT follow-up observation
  3. EP 240414a: NOT optical counterpart confirmation
  4. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  5. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  6. EP240414a: EP-WXT detection of a fast X-ray transient
  7. EP240413a: EP-WXT detection of a fast X-ray transient
  8. EP240408a: GSP optical upper limit
  9. EP240408a: Swift follow-up observation
  10. EP240408a: BOOTES-6/DPRT optical upper limit
  11. EP240408a: EP-WXT detection of a fast X-ray transient
  12. X-ray transient LXT 240402A: WFST optical upper limits​
  13. GRB/FXT 240402B: Kinder optical counterpart candidate
  14. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  15. X-ray transient LXT240402A: AST3-3 optical upper limits
  16. LXT 240402A: EP-FXT detection of the X-ray afterglow
  17. X-ray transient LXT 240402A: LEIA detection
  18. X-ray transient EP240331a: Kinder optical upper limits
  19. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  20. X-ray transient EP20240331a: MeerLICHT optical upper limits
  21. X-ray transient EP240315a: Ondrejov D50 optical limit
  22. Transient EPW20240219aa: REM optical/NIR further observations
  23. X-ray transient EP240315a: GTC/HiPERCAM photometry
  24. X-ray transient EP240315a: GTC/OSIRIS spectroscopic redshift confirmation
  25. X-ray transient EP240315a: PRIME near infrared detection
  26. X-ray transient EP240315a: 3.6 m TNG NIR detection
  27. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  28. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  29. X-ray transient EP240315a: Kitab observatory optical upper limitns
  30. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  31. X-ray transient EP240315a: orphan FXT?
  32. X-ray transient EP240315a: GROND J-band detection
  33. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  34. X-ray transient EP240315a: Nanshan/HMT optical upper limit
  35. X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
  36. Einstein Probe detected of a fast X-ray transient EP240315a
  37. Transient EPW20240219aa: REM optical/NIR upper limits
  38. Transient EPW20240219aa: GECKO: LOAO Optical Upper Limits
  39. Transient EPW20240219aa: 7DT Optical Upper Limits
  40. VLA X-band observation of EPW20240219aa
  41. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  42. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  43. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  44. GRB 230307A: soft X-ray detection with LEIA
  45. GRB 221009A: LEIA X-ray Afterglow Detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov