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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"

11102 results found.

  1. Fermi GRB 211204B: Global MASTER-Net observations report
  2. GRB 211204B: Fermi GBM Final Real-time Localization
  3. Fermi GRB 211204A: Global MASTER-Net observations report
  4. GRB 211204A: Fermi GBM Final Real-time Localization
  5. GRB 211124A: Fermi GBM Observation
  6. Fermi GBM Upper limits for GRB 211203A
  7. Konus-Wind detection of GRB 211130A
  8. IPN triangulation of GRB 211130A
  9. GRB 211201A: GECAM detection
  10. GRB 211201A: Swift/BAT-GUANO detection likely outside the coded FOV
  11. Fermi GRB 211201A: Global MASTER-Net observations report
  12. GRB 211201A: Fermi GBM Final Real-time Localization
  13. Fermi GRB 211130A: Global MASTER-Net observations report
  14. GRB 211130A: BALROG localization (Fermi Trigger 659978192 / GRB 211130636)
  15. GRB 211130A: Fermi GBM Final Real-time Localization
  16. GRB 211106A: GECAM detection
  17. GRB 211129A: Fermi GBM observation
  18. IPN triangulation of GRB 211118A
  19. GRB 211023A: Xinglong 2.16m optical observations
  20. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  21. GRB 211120548: Fermi GBM observation
  22. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 211118A: Fermi GBM detection
  24. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  25. IceCube-211123A: Upper limits from Fermi-GBM Observations
  26. IceCube-211117A: not observable by Fermi-GBM
  27. IceCube-211116A: not observable by Fermi-GBM
  28. IceCube-211023A: not observable by Fermi-GBM
  29. IPN triangulation of GRB 211124A (short)
  30. HAWC-211123A: not observable by Fermi-GBM
  31. GRB 211124A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  32. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  33. Fermi trigger No 659413798: Global MASTER-Net observations report
  34. Fermi trigger No 659183098: Global MASTER-Net observations report
  35. Fermi trigger No 659106591: Global MASTER-Net observations report
  36. GRB 211120B: Swift/BAT-GUANO detection outside the coded FOV
  37. GRB 211023A: optical observations and photometric evidence of supernova
  38. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  39. GRB211118A: Swift/BAT-GUANO detection outside the coded FOV
  40. Fermi trigger No 658971499: Global MASTER-Net observations report
  41. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  42. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  43. Fermi trigger No 658755664: Global MASTER-Net observations report
  44. Fermi trigger No 658764238: Global MASTER-Net observations report
  45. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  46. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  47. Fermi trigger No 658686687: Global MASTER-Net observations report
  48. GRB 211023A: classification and SPI-ACS/INTEGRAL registration
  49. Fermi GRB 211112A: Global MASTER-Net observations report
  50. GRB 211106A: Swift/UVOT upper limits
  51. IPN triangulation of GRB 211106A (short)
  52. GRB 211112A: Fermi GBM Final Real-time Localization
  53. Fermi trigger No 658214822: Global MASTER-Net observations report
  54. GRB 211107A: GECAM detection
  55. Fermi GRB 211109B: Global MASTER-Net observations report
  56. GRB 211023A: SAO RAS optical observations
  57. GRB 211109B: Fermi GBM Final Real-time Localization
  58. Fermi GRB 211109A: Global MASTER-Net observations report
  59. GRB 211109A: Fermi GBM Final Real-time Localization
  60. Fermi GBM Sub-Threshold Detection of GRB 211106A
  61. GRB 211107A: Fermi GBM Final Real-time Localization
  62. Fermi GBM trigger 657780594/211105201 is not a GRB
  63. GRB 211023A: optical detection by SBT in Ondrejov
  64. GRB 211023A: continued 1.3m DFOT Optical Observations and possible jet break
  65. Fermi trigger No 657742914: Global MASTER-Net observations report
  66. GRB 211104A: Fermi GBM Final Real-time Localization
  67. GRB 211024A: MITSuME Akeno optical observation
  68. GRB 211102B: GECAM detection
  69. Fermi GRB 211102A: Global MASTER-Net observations report
  70. GRB 211102B: BALROG localization (Fermi Trigger 657554740 / GRB 211102587)
  71. GRB 211102B: Fermi GBM Final Real-time Localization
  72. GRB 211102A: BALROG localization (Fermi Trigger 657533168 / GRB 211102338)
  73. GRB 211102A: Fermi GBM Final Real-time Localization
  74. GRB 211024A: 1.3m DFOT observations
  75. Fermi GRB 211031A: Global MASTER-Net observations report
  76. GRB 211031A: Fermi GBM Final Real-time Localization
  77. GRB 211023A: 1.3m DFOT Optical Observations
  78. Konus-Wind detection of GRB 211023A
  79. GRB 211023A: Terskol optical observations
  80. GRB 211023A: continued Mondy optical observations
  81. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  82. Fermi GRB 211027A: Global MASTER-Net observations report
  83. GRB 211024A: Possible afterglow candidate from GIT
  84. GRB 211027A: Fermi GBM Final Real-time Localization
  85. GRB 211024A: Fermi GBM detection
  86. GRB 211018A: Swift-XRT observations
  87. GRB211023A: optical afterglow detection from Konkoly Observatory
  88. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  89. GRB 211023A: Mondy optical observations
  90. Correction to GCN 30965: GRB 211023A: Fermi GBM detection
  91. IPN Triangulation of GRB 211019A
  92. GRB 211023A: 1.5m OSN optical observation
  93. GRB 211023A: OAJ Bright Afterglow Confirmation
  94. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  95. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  96. GRB 211024A: GECAM detection
  97. Fermi GRB 211023A: Global MASTER-Net observations report
  98. GRB 211023A: AGILE detection
  99. GRB 211023A: Fermi GBM detection
  100. Fermi GRB 211024A: Global MASTER-Net observations report

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