Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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').
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"

26303 results found.

  1. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  2. GRB 260706A: SVOM/GRM observation
  3. GRB 260706A: REM optical/NIR observations
  4. IceCube-260704A: No candidates from the Zwicky Transient Facility
  5. GRB 260706A: LCO optical upper limit
  6. GRB 260706A: EP-FXT follow-up observation
  7. GRB 260706A: Fermi GBM Observation
  8. IPN triangulation of GRB 260627A
  9. GRB 260705A: SVOM/ECLAIRs refined analysis
  10. GRB 260706A: SVOM detection of a burst
  11. IceCube260704A: OHP/T193 optical observations
  12. GRB 260705A: LCO optical upper limits
  13. GRB 260704A: NOT optical upper limits
  14. Fermi GBM Sub-Threshold Detection of GRB 260705A
  15. GRB 260705A: SVOM detection of a burst
  16. GRB 260704A: EP-FXT follow-up observation
  17. GRB 260629A: SVOM/GRM observation of a short burst
  18. GRB 260629A: GECAM-A observation of a short burst
  19. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  20. GRB 260629A: AstroSat CZTI detection
  21. GRB 260704A: SVOM detection of a possible GRB
  22. EP260703a: EP-WXT detection of a fast X-ray transient
  23. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  24. GRB 260623A: Glowbug gamma-ray detection
  25. GRB 260614B: ATCA Radio Upper Limits
  26. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  27. EP260628a: EP-WXT detection of a fast X-ray transient
  28. EP260626a: further Liverpool Telescope optical upper limits
  29. EP260626a: COLIBRÍ optical upper limit
  30. EP260626a: EP-WXT detection of a fast X-ray transient
  31. Konus-Wind detection of GRB 260623B / EP260623a
  32. EP260623a: TNG NIR afterglow detection
  33. GRB 260618A: Fermi GBM Observation
  34. MASS-Cube (GRID 2.0) detection of GRB 260616B
  35. GRB 260619A: SVOM/ECLAIRs refined analysis
  36. EP260623a: Liverpool Telescope optical observations
  37. Konus-Wind detection of GRB 260618B
  38. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  39. EP260623a: WINTER J-band observations
  40. GRB 260617A: Glowbug gamma-ray detection of a short burst
  41. IPN triangulation of GRB 260605A
  42. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  43. EP260623a: SVOM/VT optical observations
  44. EP260623a: TRT optical observations
  45. EP260623a: REM optical/NIR afterglow detection
  46. EP 260623a: COLIBRÍ optical observations
  47. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  48. EP260623a: Las Cumbres discovery of the optical counterpart
  49. EP260623a: Einstein Probe detection of an X-ray transient
  50. GRB 260614B: EP-FXT follow-up observation
  51. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  52. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  53. EP260618a: Liverpool Telescope optical observations
  54. GRB 260619A: NOT optical observations
  55. GRB 260618B: LCO optical observations
  56. EP260618a: JinShan optical observations
  57. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  58. GRB 260618B: Fermi GBM Observation
  59. GRB 260619A: TRT optical counterpart confirmation
  60. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  61. GRB 260604B: 239Alferov CubeSat detection
  62. GRB 260604A: 239Alferov CubeSat detection
  63. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  64. GRB 260619A: SVOM/VT optical counterpart confirmation
  65. GRB 260618B: SVOM/VT optical candidate
  66. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  67. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  68. Konus-Wind detection of GRB 260617A
  69. GRB 260616B: AstroSat CZTI detection
  70. GRB 260616A: AstroSat CZTI detection
  71. GRB 260616A: SVOM/GRM observation
  72. EP260618a: OHP/T193 optical observations
  73. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  74. GRB 260619A: Kilonova-Catcher optical upper limit
  75. EP260618a: LCO optical counterpart confirmation
  76. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  77. EP260618a: COLIBRÍ optical counterpart candidate
  78. GRB 260616A: NuSTAR detection of prompt emission
  79. GRB 260614B: NuSTAR detection of prompt emission
  80. GRB 260619A: SVOM possible detection of a faint burst
  81. GRB 260618B: Fermi-LAT detection
  82. IPN triangulation of GRB 260617A (short)
  83. GRB 260616A: Insight-HXMT detection
  84. EP260618a: EP-WXT detection of an X-ray transient
  85. GRB 260506B: cubesat Avion detection
  86. GRB 260616C: GECAM-B observation of a burst
  87. GRB 260617A: Fermi GBM Detection
  88. GRB 260616A: Fermi GBM Observation
  89. Konus-Wind detection of GRB 260616B/EP260616a
  90. Konus-Wind detection of GRB 260616A
  91. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  92. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  93. GRB 260616A: GECAM-B observation
  94. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  95. GRB 260429A: cubesat Avion detection
  96. GRB 260616A: Fermi-LAT detection
  97. GRB 260610B / AT 2026owq: Liverpool Telescope confirmation of continuing optical rebrightening
  98. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  99. GRB 260614A: AstroSat CZTI detection
  100. EP260616a: EP-WXT detection of a fast X-ray transient

Advanced

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