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"

23410 results found.

  1. GRB 260718A : GRANDMA and KNC upper limits
  2. GRB 260718A: SVOM/VT optical upper limits
  3. GRB 260718A: SVOM/VT optical upper limits from VHF data
  4. GRB 260714B: SVOM/GRM observation
  5. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  6. GRB 260714B: COLIBRÍ optical counterpart candidate
  7. sb26071506: SVOM detection of a X-ray transient
  8. EP260703a: SVOM/ECLAIRs Upper Limit
  9. GRB 260709A: AstroSat CZTI detection
  10. GRB 260714B: AstroSat CZTI detection
  11. GRB 260714B: Fermi GBM Detection
  12. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  13. EP260713a: Einstein Probe detection of an X-ray transient
  14. EP260623a: KAIT optical observations
  15. EP260711a: EP-FXT follow-up observation
  16. GRB 260708A: GRANDMA Optical Observations
  17. GRB 260708A: LCO optical observations
  18. EP260711a: Einstein Probe detection of an X-ray transient
  19. GRB 260710A: Fermi GBM Detection
  20. GRB 260709A: SVOM/GRM detection
  21. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  22. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  23. GRB 260708A: Glowbug gamma-ray detection
  24. GRB 260706A : GRANDMA Upper limits
  25. GRB 260708A: Kilonova-Catcher optical afterglow detection
  26. IceCube-260708A: One candidate from the Zwicky Transient Facility
  27. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  28. GRB 260705B: SVOM/GRM observation
  29. GRB 260706A: Further EP-FXT follow-up observation
  30. EP260707a (by EP-FXT): NOT optical upper limit
  31. EP260707a is not a real source
  32. EP260707a: LCOGT Optical Upper Limit
  33. EP260707a: TRT optical upper limit
  34. EP260707a: Einstein Probe detection of an X-ray transient
  35. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  36. GRB 260705C: Glowbug gamma-ray detection of a short burst
  37. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  38. GRB 260706A: REM optical/NIR observations
  39. GRB 260706A: LCO optical upper limit
  40. IPN triangulation of GRB 260627A
  41. IceCube260704A: OHP/T193 optical observations
  42. GRB 260705A: LCO optical upper limits
  43. GRB 260704A: NOT optical upper limits
  44. GRB 260629A: SVOM/GRM observation of a short burst
  45. GRB 260704A: SVOM detection of a possible GRB
  46. EP260703a: EP-WXT detection of a fast X-ray transient
  47. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  48. GRB 260623A: Glowbug gamma-ray detection
  49. GRB 260614B: ATCA Radio Upper Limits
  50. EP260628a: EP-WXT detection of a fast X-ray transient
  51. EP260626a: further Liverpool Telescope optical upper limits
  52. EP260626a: COLIBRÍ optical upper limit
  53. EP260626a: Liverpool Telescope upper limits
  54. EP260626a: EP-WXT detection of a fast X-ray transient
  55. EP260623a: TNG NIR afterglow detection
  56. EP260623a: Liverpool Telescope optical observations
  57. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  58. EP260623a: WINTER J-band observations
  59. GRB 260617A: Glowbug gamma-ray detection of a short burst
  60. IPN triangulation of GRB 260605A
  61. EP260623a: Optical follow-up observations with Kinder
  62. EP260623a: SVOM/VT optical observations
  63. EP260623a: TRT optical observations
  64. EP260623a: REM optical/NIR afterglow detection
  65. EP 260623a: COLIBRÍ optical observations
  66. EP260623a: Las Cumbres discovery of the optical counterpart
  67. EP260623a: Einstein Probe detection of an X-ray transient
  68. EP260618a: Liverpool Telescope optical observations
  69. GRB 260618B: LCO optical observations
  70. EP260618a: JinShan optical observations
  71. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  72. GRB 260619A: TRT optical counterpart confirmation
  73. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  74. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  75. Konus-Wind detection of GRB 260617A
  76. GRB 260616B: AstroSat CZTI detection
  77. GRB 260616A: AstroSat CZTI detection
  78. GRB 260616A: SVOM/GRM observation
  79. EP260618a: OHP/T193 optical observations
  80. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  81. GRB 260619A: Kilonova-Catcher optical upper limit
  82. EP260618a: EP-FXT follow-up observation
  83. EP260618a: LCO optical counterpart confirmation
  84. EP260618a: COLIBRÍ optical counterpart candidate
  85. GRB 260619A: SVOM possible detection of a faint burst
  86. IPN triangulation of GRB 260617A (short)
  87. EP260618a: EP-WXT detection of an X-ray transient
  88. GRB 260610B: AbAO optical observations
  89. GRB 260506B: cubesat Avion detection
  90. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  91. GRB 260616A: GECAM-B observation
  92. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  93. GRB 260429A: cubesat Avion detection
  94. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  95. GRB 260614A: AstroSat CZTI detection
  96. EP260616a: EP-WXT detection of a fast X-ray transient
  97. GRB 260610B: Terskol optical observations
  98. GRB 260610B: SVOM/GRM observation
  99. GRB 260614B: SVOM/VT optical candidate from VHF data
  100. GRB 260614B: SVOM detection of a burst

Advanced

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