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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. GRB 260530A: Fermi GBM Final Real-time Localization
  2. GRB 260527A / EP260527a: VLA radio detection
  3. GRB 260527A/EP260527a: Insight-HXMT detection
  4. GRB 260529A: Fermi GBM Final Real-time Localization
  5. EP260526a: SVOM/VT optical upper limits
  6. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  7. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  8. EP260527a/GRB 260527A: EP-FXT follow-up observation
  9. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  10. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  11. EP260526a: EP-FXT follow-up observation
  12. EP260527a: COLIBRÍ optical detection
  13. EP260527a: Einstein Probe detection of a fast X-ray transient
  14. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  15. EP260526a: LCO optical upper limits
  16. EP260526a: Einstein Probe detection of a fast X-ray transient
  17. GRB 260525A: AstroSat CZTI detection
  18. GRB 260526A: Fermi GBM Final Real-time Localization
  19. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  20. GRB 260525A: Fermi GBM Final Real-time Localization
  21. GRB 260523B: AstroSat CZTI detection
  22. GRB 260523B: Fermi GBM Final Real-time Localization
  23. GRB 260523A: Fermi GBM Final Real-time Localization
  24. GRB 260522B: NuSTAR detection of prompt emission
  25. GRB 260522B: Fermi GBM Final Real-time Localization
  26. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  27. GRB 260522A: Fermi-LAT detection
  28. GRB 260522A: Fermi GBM Final Real-time Localization
  29. GRB 260511A: iTelescope T-75 optical detection
  30. GRB 260411B: TERI Gamma-ray detection
  31. GRB 260407A: TERI Gamma-ray detection
  32. GRB 260307A: TERI Gamma-ray detection
  33. GRB 260225D: TERI Gamma-ray detection
  34. GRB 251118A: TERI Gamma-ray detection
  35. GRB 251113A: TERI Gamma-ray detection
  36. GRB 260428A: TERI Gamma-ray detection
  37. Konus-Wind detection of GRB 260519C
  38. GRB 260520B: Fermi GBM Final Localization
  39. GRB 260520A: Fermi GBM Final Localization
  40. GRB 260519D: Fermi GBM Final Localization Correction
  41. GRB 260519C: NuSTAR detection of prompt emission
  42. Konus-Wind detection of GRB 260518A
  43. GRB 260519B: Fermi GBM Final Localization
  44. GRB 260519A: Fermi GBM Final Localization
  45. GRB 260518A: AstroSat CZTI detection of a long burst
  46. GRB 260421B: radio detection with the VLA
  47. GRID detection of GRB 260511A
  48. GRB 260516D: GOTO optical counterpart detection
  49. GRB 260515A: further Liverpool Telescope observations
  50. GRB 260516D: GROWTH-India Telescope optical detection
  51. GRB 260516D: FRAM-ORM optical limit
  52. GRB 260515A: CrAO ZTSh BVRI optical observations
  53. GRB 260516D: SVOM possible detection of a burst
  54. GRB 260516C: Fermi GBM Final Real-time Localization
  55. Konus-Wind detection of GRB 260515A
  56. GRB 260515A: Liverpool Telescope optical detection
  57. GRB 260515A: LCO optical counterpart detection
  58. GRB 260515A: EP-FXT follow-up observation
  59. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  60. EP260514a: NOT optical counterpart confirmation
  61. EP260514a: TRT optical counterpart candidate
  62. GRB 260516B: Fermi GBM Final Real-time Localization
  63. GRB 260515A: SVOM/VT optical observations
  64. GRB 260515A: OHP/T193 optical observations
  65. GRB 260516A: Fermi GBM Final Real-time Localization
  66. GRID detection of GRB 260507A
  67. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  68. GRB 260515A: LCO optical observations
  69. GRB 260515A: NOT optical observations.
  70. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  71. GRB 260515A: SVOM/VT optical candidate from VHF data
  72. GRB 260515A: JinShan optical counterpart candidate
  73. GRB 260515A: SVOM detection of a burst
  74. GRB 260510C: Glowbug gamma-ray detection
  75. Konus-Wind detection of GRB 260512A
  76. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  77. EP260514a: Einstein Probe detection of a fast X-ray transient
  78. EP260512a: LCO optical upper limits
  79. IPN triangulation of GRB 260512A
  80. GRB 260512A: AstroSat CZTI detection
  81. EP260512a: EP-FXT follow-up observation
  82. EP260507a: Xinglong Schmidt optical counterpart detection
  83. GRB 260514A: Fermi GBM Final Real-time Localization
  84. GRB 260513A: Fermi GBM Final Real-time Localization
  85. Konus-Wind detection of GRB 260511B
  86. EP260512a: Einstein Probe detection of an X-ray transient
  87. GRB 260512A: NuSTAR detection of prompt emission
  88. GRB 260512A: Fermi GBM Final Real-time Localization
  89. GRB 260511A: Glowbug gamma-ray detection
  90. Konus-Wind detection of GRB 260511A
  91. MASS-Cube (GRID 2.0) detection of GRB 260511A
  92. MASS-Cube (GRID 2.0) detection of GRB 260507A
  93. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  94. GRB 260511B: FRAM-ORM optical detection
  95. GRB 260511B: LCO optical counterpart detection
  96. GRB 260511B: GOTO optical counterpart detection
  97. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  98. GRB 260511A: REM near-infrared detection
  99. GRB 260511B: AstroSat CZTI detection
  100. GRB 260506B: Glowbug gamma-ray detection

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