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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"

11547 results found.

  1. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  2. Fermi GRB 211216B: Global MASTER-Net observations report
  3. GRB 211216B: GECAM detection
  4. GRB 211216B: Fermi GBM Final Real-time Localization
  5. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 211216A: GECAM detection
  7. GRB 211216A: BALROG localization (Fermi Trigger 661329957 / GRB 211216282)
  8. Fermi GRB 211216A: Global MASTER-Net observations report
  9. GRB 211216A: Fermi GBM Final Real-time Localization
  10. GRB 211211A: Insight-HXMT/HE detection
  11. GRB 211211A: SAO RAS optical observations
  12. GRB 211211A: AbAO optical observations
  13. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  14. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  15. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  16. GRB 211211A: HCT and GIT optical follow up observations
  17. GRB 211211A: CALET Gamma-Ray Burst Monitor detection
  18. Fermi GRB 211212A: Global MASTER-Net observations report
  19. GRB 211211A: incorrect E_iso value in GCN 31221
  20. GRB 211211A: NOT optical spectroscopy
  21. GRB 211211B: GECAM detection
  22. Fermi GRB 211212B: Global MASTER-Net observations report
  23. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  24. GRB 211211A: MITSuME Akeno optical observation
  25. GRB 211212B: Fermi GBM Final Real-time Localization
  26. GRB 211211A: Nanshan/NEXT optical observations
  27. GRB 211212A: Fermi GBM Final Real-time Localization
  28. GRB 211211A: Fermi GBM observation
  29. Fermi GRB 211211B: Global MASTER-Net observations report
  30. GRB 211211B: Fermi GBM Final Real-time Localization
  31. Fermi GRB 211211A: Global MASTER-Net observations report
  32. GRB 211211A: Fermi GBM Final Real-time Localization
  33. Fermi trigger No 660868196: Global MASTER-Net observations report
  34. Fermi trigger No 660736561: Global MASTER-Net observations report
  35. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  36. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  37. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  38. GRB 211204C: Fermi GBM detection
  39. GRB 211206A: Not observable by Fermi-GBM
  40. GRB 211204C: AstroSat CZTI detection
  41. IPN triangulation of GRB 211204C
  42. GRB 211204C: Swift/BAT-GUANO detection outside the coded FOV
  43. GRB 211204C: GECAM detection
  44. Fermi GRB 211204C: Global MASTER-Net observations report
  45. GRB 211204C: Fermi GBM Final Real-time Localization
  46. Fermi GRB 211204B: Global MASTER-Net observations report
  47. GRB 211204B: Fermi GBM Final Real-time Localization
  48. Fermi GRB 211204A: Global MASTER-Net observations report
  49. GRB 211204A: Fermi GBM Final Real-time Localization
  50. GRB 211124A: Fermi GBM Observation
  51. Fermi GBM Upper limits for GRB 211203A
  52. Konus-Wind detection of GRB 211130A
  53. IPN triangulation of GRB 211130A
  54. GRB 211201A: GECAM detection
  55. GRB 211201A: Swift/BAT-GUANO detection likely outside the coded FOV
  56. Fermi GRB 211201A: Global MASTER-Net observations report
  57. GRB 211201A: Fermi GBM Final Real-time Localization
  58. Fermi GRB 211130A: Global MASTER-Net observations report
  59. GRB 211130A: BALROG localization (Fermi Trigger 659978192 / GRB 211130636)
  60. GRB 211130A: Fermi GBM Final Real-time Localization
  61. GRB 211106A: GECAM detection
  62. GRB 211129A: Fermi GBM observation
  63. IPN triangulation of GRB 211118A
  64. GRB 211023A: Xinglong 2.16m optical observations
  65. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  66. GRB 211120548: Fermi GBM observation
  67. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  68. GRB 211118A: Fermi GBM detection
  69. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  70. IceCube-211123A: Upper limits from Fermi-GBM Observations
  71. IceCube-211117A: not observable by Fermi-GBM
  72. IceCube-211116A: not observable by Fermi-GBM
  73. IceCube-211023A: not observable by Fermi-GBM
  74. IPN triangulation of GRB 211124A (short)
  75. HAWC-211123A: not observable by Fermi-GBM
  76. GRB 211124A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  77. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  78. Fermi trigger No 659413798: Global MASTER-Net observations report
  79. Fermi trigger No 659183098: Global MASTER-Net observations report
  80. Fermi trigger No 659106591: Global MASTER-Net observations report
  81. GRB 211120B: Swift/BAT-GUANO detection outside the coded FOV
  82. GRB 211023A: optical observations and photometric evidence of supernova
  83. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  84. GRB211118A: Swift/BAT-GUANO detection outside the coded FOV
  85. Fermi trigger No 658971499: Global MASTER-Net observations report
  86. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  87. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  88. Fermi trigger No 658755664: Global MASTER-Net observations report
  89. Fermi trigger No 658764238: Global MASTER-Net observations report
  90. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  91. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  92. Fermi trigger No 658686687: Global MASTER-Net observations report
  93. GRB 211023A: classification and SPI-ACS/INTEGRAL registration
  94. Fermi GRB 211112A: Global MASTER-Net observations report
  95. GRB 211106A: Swift/UVOT upper limits
  96. IPN triangulation of GRB 211106A (short)
  97. GRB 211112A: Fermi GBM Final Real-time Localization
  98. Fermi trigger No 658214822: Global MASTER-Net observations report
  99. GRB 211107A: GECAM detection
  100. Fermi GRB 211109B: Global MASTER-Net observations report

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