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"

14824 results found.

  1. EP260806a: OSIRIS+/GTC redshift z=0.089
  2. EP260806a: LCO likely optical counterpart
  3. EP260806a: Einstein Probe detection of an X-ray transient
  4. GRB 260715A: cubesat Avion detection
  5. GRB 260709A: cubesat Avion detection
  6. GRB 260708A: cubesat Avion detection
  7. SN 2026stf / GRB 260708A: ATLAS forced photometry
  8. IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 260730B: Glowbug gamma-ray detection
  10. GRB 260805C: Glowbug gamma-ray detection
  11. GRB 260805B: Glowbug gamma-ray detection
  12. GRB 260805B: Fermi GBM Final Localization
  13. GRB 260804A: Glowbug gamma-ray detection
  14. GRB 260805A: Fermi GBM Final Localization
  15. AT 2026wki: EP/FXT follow-up observations
  16. GRB 260730B: CALET Gamma-Ray Burst Monitor detection
  17. GRB 260804A: Fermi GBM Final Real-time Localization
  18. GRB 260803A: Fermi GBM Final Real-time Localization
  19. GRB 260802B: Fermi GBM Final Localization
  20. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  21. GRB 260731A: AstroSat CZTI detection of a long burst
  22. GRB 260730B: AstroSat CZTI detection
  23. EP260731a: NOT optical upper limit
  24. GRB 260730B: NuSTAR detection of prompt emission
  25. EP260731a: Einstein Probe detection of an X-ray transient
  26. GRB260730A: Fermi GBM Final Localization
  27. EP260727a: VLT/X-shooter spectroscopic redshift z = 2.817
  28. EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
  29. EP260729a: Einstein Probe detection of an X-ray transient
  30. EP260727a: SAO RAS optical observations
  31. EP260728a: Einstein Probe detection of a fast X-ray transient
  32. EP260727a: 1.5m OSN optical counterpart detection
  33. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  34. EP260727a: OHP/T193 optical observations
  35. Konus-Wind detection of GRB 260727A
  36. GRB 260726A: Liverpool Telescope optical observations
  37. EP260727a: Liverpool Telescope confirmation of optical counterpart
  38. EP260727a: NUTTELA-TAO Early Optical Limits
  39. GRB 260728A: Fermi GBM Final Localization
  40. EP260727a: Einstein Probe detection of an X-ray transient
  41. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  42. GRB 260727A: Glowbug gamma-ray detection
  43. GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart
  44. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  45. GRB 260727A: AstroSat CZTI detection
  46. GRB 260727B: Fermi GBM Final Real-time Localization
  47. GRB 260727A: SVOM detection of a bright long burst
  48. GRB 260726A: SVOM detection of a burst
  49. GRB 260726A: Fermi GBM Final Real-time Localization
  50. EP260723a: further EP-FXT follow-up observation
  51. EP260725a: EP-FXT follow-up observation and association with a bright flaring star
  52. EP260725a: EP-WXT detection of an X-ray transient
  53. GRB 260616A: cubesat Avion detection
  54. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  55. GRB 260602B: cubesat Avion detection
  56. GRB 260601A: cubesat Avion detection
  57. EP260723a: EP-FXT follow-up observation
  58. EP260723a: SVOM/VT optical observation
  59. EP260723a: COLIBRÍ optical observations
  60. EP260723a: NOT optical conterpart confirmation
  61. EP260723a: Liverpool Telescope likely optical counterpart
  62. EP260723a: EP-WXT detection of a fast X-ray transient
  63. GRB 260723A: Fermi GBM Final Localization
  64. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  65. Konus-Wind detection of GRB 260721A
  66. GRB 260722A: Fermi GBM Final Real-time Localization
  67. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  68. GRB 260721A: NuSTAR detection of prompt emission
  69. Konus-Wind detection of GRB 260714B
  70. GRB 260705A: Retraction of optical counterpart
  71. GRB 260714B: Insight-HXMT/HE detection
  72. GRB 260718A: SVOM/VT optical upper limits
  73. GRB 260718A: SVOM/VT optical upper limits from VHF data
  74. GRB 260718A: SVOM detection of a burst
  75. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  76. sb26071506: SVOM detection of a X-ray transient
  77. GRB 260715A: Fermi GBM Final Real-time Localization
  78. GRB 260710A: AstroSat CZTI detection
  79. GRB 260709A: AstroSat CZTI detection
  80. GRB 260714B: AstroSat CZTI detection
  81. GRB 260714B: Fermi-LAT detection
  82. GRB 260714B: Fermi GBM Detection
  83. GRB 260714B: Fermi GBM Final Real-time Localization
  84. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  85. GRB 260706A: ATCA detection of possible radio counterpart
  86. GRB 260714A: Fermi GBM Final Real-time Localization
  87. EP260713a: Einstein Probe detection of an X-ray transient
  88. GRB 260619A: SVOM/VT continuous optical observations
  89. EP260711a: EP-FXT follow-up observation
  90. GRB 260710A: Insight-HXMT/HE detection
  91. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  92. EP260711a: Einstein Probe detection of an X-ray transient
  93. GRB 260710A: Fermi GBM Detection
  94. GRB 260709A: SVOM/GRM detection
  95. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  96. GRB 260705C: AstroSat CZTI detection
  97. GRB 260710A: Fermi GBM Final Real-time Localization
  98. GRB 260708A: Glowbug gamma-ray detection
  99. GRB 260708A: Kilonova-Catcher optical afterglow detection
  100. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart 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