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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"

11099 results found.

  1. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  2. GRB 211231A: AstroSat CZTI detection
  3. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  4. Fermi trigger No 662768315: Global MASTER-Net observations report
  5. GRB 220101A: Fermi GBM Detection
  6. GRB 220101A: CAHA 2.2m/CAFOS detection
  7. GRB 220101A: AGILE detection
  8. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  9. GRB 220101A: Fermi-LAT detection
  10. IPN triangulation of GRB 211219A
  11. GRB 211231A: GECAM detection
  12. GRB 211229B: AGILE detection
  13. GRB 211231A: Fermi GBM Final Real-time Localization
  14. GRB 211229A: Swift-XRT and UVOT observations
  15. GRB 211229A: Fermi GBM observation
  16. GRB 211229B: GECAM detection
  17. Fermi GRB 211229B: Global MASTER-Net observations report
  18. GRB 211229B: Fermi GBM Final Real-time Localization
  19. GRB 211229A: Swift/BAT-GUANO arcminute localization
  20. GRB 211229A: GECAM detection
  21. Fermi GRB 211229A: Global MASTER-Net observations report
  22. GRB 211229A: Fermi GBM Final Real-time Localization
  23. Fermi trigger No 662216114: Global MASTER-Net observations report
  24. Fermi GRB 211225C: Global MASTER-Net observations report
  25. GRB 211225C: Fermi GBM Final Real-time Localization
  26. Fermi trigger No 662084433: Global MASTER-Net observations report
  27. GRB 211224A: Fermi GBM Final Real-time Localization
  28. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  29. Fermi trigger No 662010159: Global MASTER-Net observations report
  30. AGILE observations of a bright burst from SGR 1935+2154
  31. Fermi GRB 211223B: Global MASTER-Net observations report
  32. Fermi GBM Sub-Threshold Detection of GRB 211221A
  33. Fermi GBM Sub-Threshold Detection of GRB 211207A
  34. GRB 211223B: Fermi GBM Final Real-time Localization
  35. GRB 211223A: GECAM detection
  36. GRB 211219B: AstroSat CZTI detection
  37. GRB 211219A: AstroSat CZTI detection
  38. Fermi GRB 211222A: Global MASTER-Net observations report
  39. GRB 211222A: Fermi GBM Final Real-time Localization
  40. GRB 211219A: AGILE detection
  41. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  42. Fermi GRB 211219B: Global MASTER-Net observations report
  43. GRB 211219B: Fermi GBM Final Real-time Localization
  44. Fermi GRB 211219A: Global MASTER-Net observations report
  45. GRB 211219A: Fermi GBM Final Real-time Localization
  46. GRB 211216A: Fermi GBM observation
  47. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  48. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  49. IceCube-211216B: Upper limits from Fermi-GBM Observations
  50. IceCube-211216A: Upper limits from Fermi-GBM Observations
  51. Fermi trigger No 661417475: Global MASTER-Net observations report
  52. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  53. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  54. Fermi GRB 211216B: Global MASTER-Net observations report
  55. GRB 211216B: GECAM detection
  56. GRB 211216B: Fermi GBM Final Real-time Localization
  57. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  58. GRB 211216A: GECAM detection
  59. GRB 211216A: BALROG localization (Fermi Trigger 661329957 / GRB 211216282)
  60. Fermi GRB 211216A: Global MASTER-Net observations report
  61. GRB 211216A: Fermi GBM Final Real-time Localization
  62. GRB 211211A: Insight-HXMT/HE detection
  63. GRB 211211A: SAO RAS optical observations
  64. GRB 211211A: AbAO optical observations
  65. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  66. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  67. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  68. GRB 211211A: HCT and GIT optical follow up observations
  69. GRB 211211A: CALET Gamma-Ray Burst Monitor detection
  70. Fermi GRB 211212A: Global MASTER-Net observations report
  71. GRB 211211A: incorrect E_iso value in GCN 31221
  72. GRB 211211A: NOT optical spectroscopy
  73. GRB 211211B: GECAM detection
  74. Fermi GRB 211212B: Global MASTER-Net observations report
  75. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  76. GRB 211211A: MITSuME Akeno optical observation
  77. GRB 211212B: Fermi GBM Final Real-time Localization
  78. GRB 211211A: Nanshan/NEXT optical observations
  79. GRB 211212A: Fermi GBM Final Real-time Localization
  80. GRB 211211A: Fermi GBM observation
  81. Fermi GRB 211211B: Global MASTER-Net observations report
  82. GRB 211211B: Fermi GBM Final Real-time Localization
  83. Fermi GRB 211211A: Global MASTER-Net observations report
  84. GRB 211211A: Fermi GBM Final Real-time Localization
  85. Fermi trigger No 660868196: Global MASTER-Net observations report
  86. Fermi trigger No 660736561: Global MASTER-Net observations report
  87. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  88. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  89. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  90. GRB 211204C: Fermi GBM detection
  91. GRB 211206A: Not observable by Fermi-GBM
  92. GRB 211204C: AstroSat CZTI detection
  93. IPN triangulation of GRB 211204C
  94. GRB 211204C: Swift/BAT-GUANO detection outside the coded FOV
  95. GRB 211204C: GECAM detection
  96. Fermi GRB 211204C: Global MASTER-Net observations report
  97. GRB 211204C: Fermi GBM Final Real-time Localization
  98. Fermi GRB 211204B: Global MASTER-Net observations report
  99. GRB 211204B: Fermi GBM Final Real-time Localization
  100. Fermi GRB 211204A: Global MASTER-Net observations report

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