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"

41872 results found.

  1. GRB 260619A: Kilonova-Catcher optical upper limit
  2. EP260618a: EP-FXT follow-up observation
  3. EP260618a: LCO optical counterpart confirmation
  4. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  5. EP260618a: COLIBRÍ optical counterpart candidate
  6. GRB 260616A: NuSTAR detection of prompt emission
  7. GRB 260614B: NuSTAR detection of prompt emission
  8. GRB 260619A: SVOM possible detection of a faint burst
  9. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 260618B: Fermi-LAT detection
  11. GRB 260610B/AT 2026owq: FTW optical and NIR observations
  12. GRB 260616A: Insight-HXMT detection
  13. GRB 260618B: Fermi GBM Final Real-time Localization
  14. EP260618a: EP-WXT detection of an X-ray transient
  15. GRB 260610B: AbAO optical observations
  16. EP260616a/GRB 260616B: EP-FXT follow-up observation
  17. GRB 260506B: cubesat Avion detection
  18. GRB 260616C: GECAM-B observation of a burst
  19. GRB 260618A: Fermi GBM Final Real-time Localization
  20. GRB 260617A: Fermi GBM Detection
  21. GRB 260616A: Fermi GBM Observation
  22. GRB 260617A: Fermi GBM Final Real-time Localization
  23. Konus-Wind detection of GRB 260616B/EP260616a
  24. Konus-Wind detection of GRB 260616A
  25. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  26. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  27. GRB 260616A: GECAM-B observation
  28. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  29. GRB 260429A: cubesat Avion detection
  30. GRB260616C: MAXI/GSC detection
  31. GRB 260616A: Fermi-LAT detection
  32. GRB 260610B / AT 2026owq: Liverpool Telescope confirmation of continuing optical rebrightening
  33. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  34. GRB 260614A: AstroSat CZTI detection
  35. EP260616a: EP-WXT detection of a fast X-ray transient
  36. GRB 260610B / AT 2026owq: Possible re-brightening identified from Pan-STARRS observations
  37. The EP-WXT trigger 01709270148 is likely a flaring star
  38. GRB 260616B: Fermi GBM Detection
  39. GRB 260604C: GRANDMA late observations with CFHT/MegaCam
  40. GRB 260616B: BALROG localization (Fermi Trigger 803286321 / GRB 260616295)
  41. The EP-WXT trigger 01709269893 is likely a flaring star
  42. GRB 260616A: BALROG localization (Fermi Trigger 803272919 / GRB 260616140)
  43. GRB 260616A: Fermi GBM Final Real-time Localization
  44. GRB 260614B: SVOM/ECLAIRs refined analysis
  45. GRB 260610B: Terskol optical observations
  46. GRB 260614B: GECAM-B observation
  47. GRB 260610B: SVOM/GRM observation
  48. GRB 260614B: SVOM/VT optical afterglow confirmation
  49. GRB 260614B: Fermi GBM Observation
  50. GRB 260610B: ALMA detection
  51. GRB 260614A: GECAM-B observation
  52. GRB 260614B: SVOM/VT optical candidate from VHF data
  53. GRB 260614B: SVOM detection of a burst
  54. GRB 260614B: Fermi GBM Final Real-time Localization
  55. GRB 260611B: SVOM/GRM detection
  56. GRB 260614A: Fermi GBM Final Localization
  57. The EP-WXT trigger 01709269488 is likely a flaring star
  58. GRB 260603C: AstroSat CZTI detection
  59. GRB 260610B: further Liverpool Telescope optical observations
  60. GRB 260610B: Fermi GBM Observation
  61. GRB 260610B / AT2026owq: GRANDMA optical observations
  62. GRB 260610B / AT2026owq: further SAO RAS optical observations
  63. EP260605a: COLIBRÍ optical upper limits
  64. GRB 260610b: Liverpool Telescope optical observations
  65. IceCube-260610A: No candidates from the Zwicky Transient Facility
  66. IceCube-260610A: EP-FXT follow-up observation
  67. GRB 260611B: CALET Gamma-Ray Burst Monitor detection
  68. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  69. GRB 260610B / AT2026owq: SVOM/VT optical observations
  70. GRB 260610B / AT2026owq: OASDG optical observations
  71. GRB 260610B: IAC-80 Optical observations
  72. GRB 260610B / AT2026owq: SAO RAS optical observations
  73. GRB 260611B: Fermi GBM Final Real-time Localization
  74. EP260601a: VLT/X-shooter spectroscopic host galaxy redshift z = 1.068
  75. EP260610b: GTC likely spectroscopic redshift z = 1.10
  76. GRB 260610B: optical counterpart shows spectroscopic redshift of z=0.473
  77. The EP-WXT trigger 01709269176 is likely a flaring star
  78. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  79. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  80. GRB 260610B / AT2026owq: Early ATLAS observations
  81. GRB 260610B: TRT optical observation
  82. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  83. GRB 260611A: Fermi GBM Final Real-time Localization
  84. EP260610b: COLIBRÍ optical observations
  85. GRB 260610B: DDOTI optical observations
  86. EP260610b: MAO/AZT-22 optical observations
  87. GRB 260610B: GOTO optical counterpart candidate
  88. EP260610b: NOT optical observation
  89. GRB 260610B: Fermi GBM Final Localization
  90. EP260610b: SVOM/VT optical confirmation with blue color
  91. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  92. GRB 260515A: SOAR optical observations
  93. EP260610b: Gemini North optical counterpart candidate
  94. EP260610a: SVOM/VT optical upper limits
  95. EP260610b: Einstein Probe detection of an X-ray transient
  96. Konus-Wind detection of GRB 260601A
  97. GRB 260610A: Fermi GBM Final Real-time Localization
  98. EP260610a: COLIBRÍ optical upper limits
  99. EP260610a: Einstein Probe detection of a fast X-ray transient
  100. GRB 260609A: Fermi GBM Final Localization

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov