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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"

11528 results found.

  1. GRB 211211A: NOT optical spectroscopy
  2. GRB 211211B: GECAM detection
  3. Fermi GRB 211212B: Global MASTER-Net observations report
  4. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  5. GRB 211211A: MITSuME Akeno optical observation
  6. GRB 211212B: Fermi GBM Final Real-time Localization
  7. GRB 211211A: Nanshan/NEXT optical observations
  8. GRB 211212A: Fermi GBM Final Real-time Localization
  9. GRB 211211A: Fermi GBM observation
  10. Fermi GRB 211211B: Global MASTER-Net observations report
  11. GRB 211211B: Fermi GBM Final Real-time Localization
  12. Fermi GRB 211211A: Global MASTER-Net observations report
  13. GRB 211211A: Fermi GBM Final Real-time Localization
  14. Fermi trigger No 660868196: Global MASTER-Net observations report
  15. Fermi trigger No 660736561: Global MASTER-Net observations report
  16. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  17. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  18. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 211204C: Fermi GBM detection
  20. GRB 211206A: Not observable by Fermi-GBM
  21. GRB 211204C: AstroSat CZTI detection
  22. IPN triangulation of GRB 211204C
  23. GRB 211204C: Swift/BAT-GUANO detection outside the coded FOV
  24. GRB 211204C: GECAM detection
  25. Fermi GRB 211204C: Global MASTER-Net observations report
  26. GRB 211204C: Fermi GBM Final Real-time Localization
  27. Fermi GRB 211204B: Global MASTER-Net observations report
  28. GRB 211204B: Fermi GBM Final Real-time Localization
  29. Fermi GRB 211204A: Global MASTER-Net observations report
  30. GRB 211204A: Fermi GBM Final Real-time Localization
  31. GRB 211124A: Fermi GBM Observation
  32. Fermi GBM Upper limits for GRB 211203A
  33. Konus-Wind detection of GRB 211130A
  34. IPN triangulation of GRB 211130A
  35. GRB 211201A: GECAM detection
  36. GRB 211201A: Swift/BAT-GUANO detection likely outside the coded FOV
  37. Fermi GRB 211201A: Global MASTER-Net observations report
  38. GRB 211201A: Fermi GBM Final Real-time Localization
  39. Fermi GRB 211130A: Global MASTER-Net observations report
  40. GRB 211130A: BALROG localization (Fermi Trigger 659978192 / GRB 211130636)
  41. GRB 211130A: Fermi GBM Final Real-time Localization
  42. GRB 211106A: GECAM detection
  43. GRB 211129A: Fermi GBM observation
  44. IPN triangulation of GRB 211118A
  45. GRB 211023A: Xinglong 2.16m optical observations
  46. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  47. GRB 211120548: Fermi GBM observation
  48. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  49. GRB 211118A: Fermi GBM detection
  50. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  51. IceCube-211123A: Upper limits from Fermi-GBM Observations
  52. IceCube-211117A: not observable by Fermi-GBM
  53. IceCube-211116A: not observable by Fermi-GBM
  54. IceCube-211023A: not observable by Fermi-GBM
  55. IPN triangulation of GRB 211124A (short)
  56. HAWC-211123A: not observable by Fermi-GBM
  57. GRB 211124A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  58. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  59. Fermi trigger No 659413798: Global MASTER-Net observations report
  60. Fermi trigger No 659183098: Global MASTER-Net observations report
  61. Fermi trigger No 659106591: Global MASTER-Net observations report
  62. GRB 211120B: Swift/BAT-GUANO detection outside the coded FOV
  63. GRB 211023A: optical observations and photometric evidence of supernova
  64. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  65. GRB211118A: Swift/BAT-GUANO detection outside the coded FOV
  66. Fermi trigger No 658971499: Global MASTER-Net observations report
  67. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  68. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  69. Fermi trigger No 658755664: Global MASTER-Net observations report
  70. Fermi trigger No 658764238: Global MASTER-Net observations report
  71. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  72. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  73. Fermi trigger No 658686687: Global MASTER-Net observations report
  74. GRB 211023A: classification and SPI-ACS/INTEGRAL registration
  75. Fermi GRB 211112A: Global MASTER-Net observations report
  76. GRB 211106A: Swift/UVOT upper limits
  77. IPN triangulation of GRB 211106A (short)
  78. GRB 211112A: Fermi GBM Final Real-time Localization
  79. Fermi trigger No 658214822: Global MASTER-Net observations report
  80. GRB 211107A: GECAM detection
  81. Fermi GRB 211109B: Global MASTER-Net observations report
  82. GRB 211023A: SAO RAS optical observations
  83. GRB 211109B: Fermi GBM Final Real-time Localization
  84. Fermi GRB 211109A: Global MASTER-Net observations report
  85. GRB 211109A: Fermi GBM Final Real-time Localization
  86. Fermi GBM Sub-Threshold Detection of GRB 211106A
  87. GRB 211107A: Fermi GBM Final Real-time Localization
  88. Fermi GBM trigger 657780594/211105201 is not a GRB
  89. GRB 211023A: optical detection by SBT in Ondrejov
  90. GRB 211023A: continued 1.3m DFOT Optical Observations and possible jet break
  91. Fermi trigger No 657742914: Global MASTER-Net observations report
  92. GRB 211104A: Fermi GBM Final Real-time Localization
  93. GRB 211024A: MITSuME Akeno optical observation
  94. GRB 211102B: GECAM detection
  95. Fermi GRB 211102A: Global MASTER-Net observations report
  96. GRB 211102B: BALROG localization (Fermi Trigger 657554740 / GRB 211102587)
  97. GRB 211102B: Fermi GBM Final Real-time Localization
  98. GRB 211102A: BALROG localization (Fermi Trigger 657533168 / GRB 211102338)
  99. GRB 211102A: Fermi GBM Final Real-time Localization
  100. GRB 211024A: 1.3m DFOT observations

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