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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"

11519 results found.

  1. GRB 211027A: Fermi GBM Final Real-time Localization
  2. GRB 211024A: Fermi GBM detection
  3. GRB 211018A: Swift-XRT observations
  4. GRB211023A: optical afterglow detection from Konkoly Observatory
  5. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  6. GRB 211023A: Mondy optical observations
  7. Correction to GCN 30965: GRB 211023A: Fermi GBM detection
  8. IPN Triangulation of GRB 211019A
  9. GRB 211023A: 1.5m OSN optical observation
  10. GRB 211023A: OAJ Bright Afterglow Confirmation
  11. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  12. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  13. GRB 211024A: GECAM detection
  14. Fermi GRB 211023A: Global MASTER-Net observations report
  15. GRB 211023A: AGILE detection
  16. GRB 211023A: Fermi GBM detection
  17. Fermi GRB 211024A: Global MASTER-Net observations report
  18. GRB 211024A: Fermi GBM Final Real-time Localization
  19. GRB 211023A: Fermi-LAT detection
  20. GRB 211023A: Fermi GBM Final Real-time Localization
  21. IPN Triangulation of GRB 210927B
  22. GRB 211018A: Swift ToO observations
  23. GRB 211021A: BALROG localization (Fermi Trigger 656506979 / GRB 211021460)
  24. Fermi trigger No 656506979: Global MASTER-Net observations report
  25. Fermi trigger No 656268212: Global MASTER-Net observations report
  26. GRB 211018A: Fermi GBM observation
  27. GRB 211019A: Detection by GRBAlpha
  28. GRB 211018A: Detection by GRBAlpha
  29. Fermi GRB 211019A: Global MASTER-Net observations report
  30. GRB 211018A: Fermi-LAT detection
  31. GRB 211019A: BALROG localization (Fermi Trigger 656315976 / GRB 211019250)
  32. GRB 211019A: Fermi GBM Final Real-time Localization
  33. Fermi trigger No 656288898: Global MASTER-Net observations report
  34. Fermi trigger No 655673024: Global MASTER-Net observations report
  35. Fermi trigger No 655646385: Global MASTER-Net observations report
  36. Fermi Gamma-ray Burst Monitor trigger 211008665/655401471 is not a GRB
  37. GRB 211008A: BALROG localization (Fermi Trigger 655401471 / GRB 211008665)
  38. Fermi trigger No 655401471: Global MASTER-Net observations report
  39. GRB 210928A: MeerKAT detection
  40. GECAM observation of a burst from SGR J1555.2-5402
  41. Konus-Wind detection of GRB 210928A
  42. Fermi trigger No 654854799: Global MASTER-Net observations report
  43. GRB 210928A: Kinder SLT-40cm optical limits
  44. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  45. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  46. GRB 210928A: Fermi GBM observation
  47. GRB 210928A: Fermi-LAT detection
  48. GRB 210927B: GECAM detection
  49. Fermi trigger No 654739449: Global MASTER-Net observations report
  50. Fermi trigger No 654658271: Global MASTER-Net observations report
  51. Fermi GRB 210929B: Global MASTER-Net observations report
  52. GRB 210929B: Fermi GBM Final Real-time Localization
  53. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  54. GRB 210929A: Fermi GBM Final Real-time Localization
  55. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  56. IPN triangulation of GRB 210925B
  57. GRB 210926A: GECAM detection
  58. GRB 210927A: Fermi GBM Final Real-time Localization
  59. GRB 210925A: GECAM detection
  60. GRB 210925A: Fermi GBM Final Real-time Localization
  61. GRB 210924A: Fermi GBM Final Real-time Localization
  62. Retraction of Fermi GBM GRB 210923A: the trigger is not a GRB
  63. IceCube-210922A: Upper limits from Fermi-GBM Observations
  64. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  65. GRB 210923A: Fermi GBM Final Real-time Localization
  66. IceCube-210922A - IceCube observation of a high-energy neutrino candidate track-like event
  67. GRB 210919B: Fermi GBM Final Real-time Localization
  68. GRB 210917A: Fermi GBM Final Real-time Localization
  69. GRB 210812A is not a compelling example of a lensed GRB
  70. GRB 210909A: Detection by GRBAlpha
  71. AGILE observations of two bright bursts from SGR 1935+2154
  72. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  73. Fermi trigger No 653151835: Global MASTER-Net observations report
  74. Fermi trigger No 653124492: Global MASTER-Net observations report
  75. Fermi trigger No 653122278: Global MASTER-Net observations report
  76. GRB 210912B: Fermi GBM Final Real-time Localization
  77. Fermi trigger No 653093506: Global MASTER-Net observations report
  78. Fermi trigger No 653066776: Global MASTER-Net observations report
  79. Fermi trigger No 653084584: Global MASTER-Net observations report
  80. Fermi trigger No 653083551: Global MASTER-Net observations report
  81. Fermi trigger No 653079281: Global MASTER-Net observations report
  82. Fermi trigger No 653066130: Global MASTER-Net observations report
  83. Fermi trigger No 653072474: Global MASTER-Net observations report
  84. Fermi trigger No 653071808: Global MASTER-Net observations report
  85. Fermi trigger No 653054042: Global MASTER-Net observations report
  86. Fermi trigger No 653049776: Global MASTER-Net observations report
  87. Fermi trigger No 653022153: Global MASTER-Net observations report
  88. Fermi trigger No 653031163: Global MASTER-Net observations report
  89. Fermi GBM observation of a bright flare in the direction of SGR 1935+2154
  90. Fermi trigger No 653010039: Global MASTER-Net observations report
  91. IPN triangulation of a bright burst from SGR 1935+2154
  92. Fermi trigger No 652957973: Global MASTER-Net observations report
  93. Fermi trigger No 652944960: Global MASTER-Net observations report
  94. Fermi trigger No 652981861: Global MASTER-Net observations report
  95. Fermi trigger No 652934203: Global MASTER-Net observations report
  96. Fermi trigger No 652927551: Global MASTER-Net observations report
  97. Fermi trigger No 652911693: Global MASTER-Net observations report
  98. Fermi trigger No 652906639: Global MASTER-Net observations report
  99. Fermi GRB 210909A: Global MASTER-Net observations report
  100. GECAM observation of a burst from SGR J1555.2-5402

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