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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"

11122 results found.

  1. Fermi GRB 240702A: Global MASTER-Net observations report
  2. GRB 240702A: Fermi GBM Final Real-time Localization
  3. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  4. Fermi trigger No 741448122: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  6. Fermi trigger No 741356809: Global MASTER-Net observations report
  7. Fermi GRB 240629A: Global MASTER-Net observations report
  8. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  9. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  10. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  11. GRB 240629A: Fermi GBM Final Real-time Localization
  12. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  13. Fermi trigger No 741296200: Global MASTER-Net observations report
  14. Fermi trigger No 741251380: Global MASTER-Net observations report
  15. IPN triangulation of GRB 240619C
  16. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  17. GRB 240615A: SAI CMO J- band observations
  18. Fermi trigger No 741211696: Global MASTER-Net observations report
  19. Konus-Wind detection of GRB 240619A
  20. Fermi GRB 240625B: Global MASTER-Net observations report
  21. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  22. GRB 240625B: Fermi GBM Final Real-time Localization
  23. GRB 240625A: Fermi GBM Observation
  24. GRB 240624B: GRBAlpha detection
  25. GRB 240625A: Fermi GBM Final Real-time Localization
  26. GRB240624A: Fermi GBM Observation
  27. GRB240615A: Gemini-North observations of the BAT and XRT positions
  28. Fermi GRB 240624A: Global MASTER-Net observations report
  29. GRB 240624B: Fermi GBM Final Real-time Localization
  30. Fermi trigger No 740949590: Global MASTER-Net observations report
  31. GRB240615A: Gemini-North observations of the BAT and XRT positions
  32. GRB 240624A: Fermi GBM Final Real-time Localization
  33. GRB 240619A: J-band detection with WINTER
  34. Fermi trigger No 740744838: Global MASTER-Net observations report
  35. IPN triangulation of GRB 240615A (short)
  36. X-ray transient EP240618a: Fermi/GBM non-detection
  37. GRB 240619A: GRBAlpha detection
  38. EP240617a: tentative Swift/XRT detection of the afterglow
  39. GRB 240619A: Swift-XRT probable afterglow detection
  40. GRB 240619A: Swift ToO observations
  41. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  42. GRB 240619C: NuSTAR automated detection of the GRB
  43. GRB 240619A: Fermi GBM Observation
  44. Fermi GBM Sub-Threshold Detection of GRB 240619C
  45. GRB 240619A: GOTO candidate optical afterglow
  46. GRB 240615A: NOT optical observations
  47. Fermi trigger No 740474239: Global MASTER-Net observations report
  48. Fermi GRB 240619A: Global MASTER-Net observations report
  49. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  50. GRB 240619B: Fermi GBM Final Real-time Localization
  51. Fermi trigger No 740430582: Global MASTER-Net observations report
  52. GRB240615A: 1.3m DFOT optical upper limit
  53. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  54. GRB 240619A: Fermi GBM Final Real-time Localization
  55. EP240617a is likely a GRB event
  56. GRB 240615A: Fermi GBM Observation
  57. GRB 240615A: GECAM detection
  58. GRB 240615A: FLWO-1.2m optical upper limits
  59. Fermi trigger No 740221779: Global MASTER-Net observations report
  60. Fermi GRB 240616A: Global MASTER-Net observations report
  61. Konus-Wind detection of GRB 240615A (short/hard)
  62. GRB 240615A: GOTO optical upper limits
  63. Fermi trigger No 740166710: Global MASTER-Net observations report
  64. GRB 240616A: Fermi GBM Final Real-time Localization
  65. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  66. GRB 240615A: Fermi GBM Final Real-time Localization
  67. GRB 240603A: VZLUSAT-2 detection
  68. GRB 240612A: GRBAlpha detection
  69. GRB 240613A: Fermi GBM Final Real-time Localization
  70. Fermi GRB 240612B: Global MASTER-Net observations report
  71. Fermi GRB 240612A: Global MASTER-Net observations report
  72. GRB 240612B: Fermi GBM Final Real-time Localization
  73. GRB 240612A: Fermi GBM Final Real-time Localization
  74. GRB 240607A: GECAM detection of a bright long burst
  75. Fermi GRB 240611A: Global MASTER-Net observations report
  76. Konus-Wind detection of GRB 240607A
  77. GRB 240611A: Fermi GBM Final Real-time Localization
  78. Fermi GRB 240610A: Global MASTER-Net observations report
  79. GRB 240610A: Fermi GBM Final Real-time Localization
  80. IPN triangulation of GRB 240607A
  81. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  82. Fermi trigger No 739632045: Global MASTER-Net observations report
  83. Fermi GRB 240608A: Global MASTER-Net observations report
  84. Konus-Wind detection of GRB 240606B
  85. Fermi trigger No 739506569: Global MASTER-Net observations report
  86. GRB 240608A: Fermi GBM Final Real-time Localization
  87. Fermi GRB 240607A: Global MASTER-Net observations report
  88. GRB 240607A: Fermi GBM Observation
  89. GRB 240606B: Fermi GBM Observation
  90. GRB 240607A: AstroSat CZTI detection of bright long burst
  91. GRB 240607A: Fermi GBM detection of a very bright burst
  92. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  93. GRB 240607A: Fermi GBM Final Real-time Localization
  94. Fermi trigger No 739373591: Global MASTER-Net observations report
  95. Konus-Wind detection of GRB 240603A
  96. Fermi GRB 240604A: Global MASTER-Net observations report
  97. Fermi GRB 240605A: Global MASTER-Net observations report
  98. Fermi GRB 240605C: Global MASTER-Net observations report
  99. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  100. GRB 240605C: Fermi GBM Final Real-time Localization

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