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"

28068 results found.

  1. EP260602a: Einstein Probe detection of a fast X-ray transient
  2. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  3. EP260601a: Einstein Probe detection of an X-ray transient
  4. EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection
  5. GRB 260601A: Glowbug gamma-ray detection of a short burst
  6. GRB 260531B: Glowbug gamma-ray detection
  7. GRB 260516D: VLA radio detection
  8. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  9. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  10. GRB 260601A: Fermi GBM Final Real-time Localization
  11. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  12. GRB 260531C: Fermi GBM Final Localization Correction
  13. AT2026nik: EP-FXT X-ray counterpart
  14. GRB 260531B: Fermi GBM Final Real-time Localization
  15. GRB 260531A: MAXI/GSC detection
  16. AT 2026nuz: COLIBRÍ optical observations
  17. IPN triangulation of GRB 260527A / EP260527a
  18. GRB 260530B: SVOM/GRM detection of a possible bright short GRB
  19. GRB 260530A: Fermi GBM Final Real-time Localization
  20. GRB 260527A / EP260527a: VLA radio detection
  21. GRB 260529A: GOTO tentative optical afterglow candidate
  22. GRB 260527A/EP260527a: Insight-HXMT detection
  23. GRB 260529A: Fermi GBM Final Real-time Localization
  24. EP260526a: SVOM/VT optical upper limits
  25. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  26. EP260527a / GRB 260527A: NOT optical observations
  27. GRB 260527A/EP260527a: FTW optical and NIR observations
  28. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  29. EP260527a/GRB 260527A: EP-FXT follow-up observation
  30. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  31. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  32. EP260526a: EP-FXT follow-up observation
  33. EP260527a: COLIBRÍ optical detection
  34. EP260527a: Einstein Probe detection of a fast X-ray transient
  35. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  36. EP260526a: LCO optical upper limits
  37. EP260526a: Einstein Probe detection of a fast X-ray transient
  38. GRB 260525A: AstroSat CZTI detection
  39. GRB 260526A: Fermi GBM Final Real-time Localization
  40. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  41. GRB 260525A: Fermi GBM Final Real-time Localization
  42. GRB 260523B: AstroSat CZTI detection
  43. GRB 260523B: Fermi GBM Final Real-time Localization
  44. GRB 260523A: Fermi GBM Final Real-time Localization
  45. GRB 260522B: NuSTAR detection of prompt emission
  46. GRB 260522B: Fermi GBM Final Real-time Localization
  47. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  48. GRB 260522A: Fermi-LAT detection
  49. GRB 260522A: Fermi GBM Final Real-time Localization
  50. GRB 260511A: iTelescope T-75 optical detection
  51. GRB 260411B: TERI Gamma-ray detection
  52. GRB 260407A: TERI Gamma-ray detection
  53. GRB 260307A: TERI Gamma-ray detection
  54. GRB 260225D: TERI Gamma-ray detection
  55. GRB 251118A: TERI Gamma-ray detection
  56. GRB 251113A: TERI Gamma-ray detection
  57. GRB 260428A: TERI Gamma-ray detection
  58. Konus-Wind detection of GRB 260519C
  59. GRB 260520B: Fermi GBM Final Localization
  60. GRB 260520A: Fermi GBM Final Localization
  61. GRB 260519D: Fermi GBM Final Localization Correction
  62. GRB 260519C: NuSTAR detection of prompt emission
  63. Konus-Wind detection of GRB 260518A
  64. GRB 260519B: Fermi GBM Final Localization
  65. GRB 260519A: Fermi GBM Final Localization
  66. GRB 260518A: AstroSat CZTI detection of a long burst
  67. GRB 260421B: radio detection with the VLA
  68. GRID detection of GRB 260511A
  69. GRB 260516D: GOTO optical counterpart detection
  70. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  71. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  72. GRB 260516D: GROWTH-India Telescope optical detection
  73. GRB 260516D: FRAM-ORM optical limit
  74. GRB 260516D: SVOM possible detection of a burst
  75. GRB 260516C: Fermi GBM Final Real-time Localization
  76. Konus-Wind detection of GRB 260515A
  77. GRB 260515A: Liverpool Telescope optical detection
  78. GRB 260515A: LCO optical counterpart detection
  79. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  80. GRB 260516B: Fermi GBM Final Real-time Localization
  81. GRB 260516A: Fermi GBM Final Real-time Localization
  82. GRID detection of GRB 260507A
  83. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  84. GRB 260515A: LCO optical observations
  85. GRB 260515A: NOT optical observations.
  86. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  87. GRB 260515A: SVOM/VT optical candidate from VHF data
  88. GRB 260515A: SVOM detection of a burst
  89. GRB 260510C: Glowbug gamma-ray detection
  90. GRB 260511B: NOT optical observations
  91. Konus-Wind detection of GRB 260512A
  92. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  93. EP260514a: Einstein Probe detection of a fast X-ray transient
  94. EP260512a: LCO optical upper limits
  95. IPN triangulation of GRB 260512A
  96. GRB 260512A: AstroSat CZTI detection
  97. EP260512a: EP-FXT follow-up observation
  98. EP260507a: Xinglong Schmidt optical counterpart detection
  99. GRB 260514A: Fermi GBM Final Real-time Localization
  100. GRB 260513A: Fermi GBM Final Real-time Localization

Advanced

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