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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 220107A: AstroSat CZTI detection
  2. GRB 220107B: Tiled Swift observations
  3. GRB 220107A: Fermi GBM observations
  4. Fermi trigger No 663274898: Global MASTER-Net observations report
  5. Fermi GRB 220107A: Global MASTER-Net observations report
  6. GRB 220107A: Swift/BAT-GUANO arcminute localization
  7. GRB 220107A: BALROG localization (Fermi Trigger 663259536 / GRB 220107615)
  8. GRB 220107A: Fermi GBM Final Real-time Localization
  9. GRB 220101A: Continued Mondy optical observations
  10. GECAM observation of a burst from SGR J1555.2-5402
  11. Fermi trigger No 663129379: Global MASTER-Net observations report
  12. GRB 220104A: Fermi GBM Observation
  13. GRB 220101A: Mondy optical observations
  14. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  15. GRB 220104A:GECAM detection
  16. Fermi GRB 220104A: Global MASTER-Net observations report
  17. GRB 220104A: Fermi GBM Final Real-time Localization
  18. GRB 211229B: Fermi GBM observation
  19. Fermi GRB 220103A: Global MASTER-Net observations report
  20. GRB 220103A: Fermi GBM Final Real-time Localization
  21. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  22. GRB 211231A: AstroSat CZTI detection
  23. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  24. Fermi trigger No 662768315: Global MASTER-Net observations report
  25. GRB 220101A: Fermi GBM Detection
  26. GRB 220101A: CAHA 2.2m/CAFOS detection
  27. GRB 220101A: AGILE detection
  28. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  29. GRB 220101A: Fermi-LAT detection
  30. IPN triangulation of GRB 211219A
  31. GRB 211231A: GECAM detection
  32. GRB 211229B: AGILE detection
  33. GRB 211231A: Fermi GBM Final Real-time Localization
  34. GRB 211229A: Swift-XRT and UVOT observations
  35. GRB 211229A: Fermi GBM observation
  36. GRB 211229B: GECAM detection
  37. Fermi GRB 211229B: Global MASTER-Net observations report
  38. GRB 211229B: Fermi GBM Final Real-time Localization
  39. GRB 211229A: Swift/BAT-GUANO arcminute localization
  40. GRB 211229A: GECAM detection
  41. Fermi GRB 211229A: Global MASTER-Net observations report
  42. GRB 211229A: Fermi GBM Final Real-time Localization
  43. Fermi trigger No 662216114: Global MASTER-Net observations report
  44. Fermi GRB 211225C: Global MASTER-Net observations report
  45. GRB 211225C: Fermi GBM Final Real-time Localization
  46. Fermi trigger No 662084433: Global MASTER-Net observations report
  47. GRB 211224A: Fermi GBM Final Real-time Localization
  48. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  49. Fermi trigger No 662010159: Global MASTER-Net observations report
  50. AGILE observations of a bright burst from SGR 1935+2154
  51. Fermi GRB 211223B: Global MASTER-Net observations report
  52. Fermi GBM Sub-Threshold Detection of GRB 211221A
  53. Fermi GBM Sub-Threshold Detection of GRB 211207A
  54. GRB 211223B: Fermi GBM Final Real-time Localization
  55. GRB 211223A: GECAM detection
  56. GRB 211219B: AstroSat CZTI detection
  57. GRB 211219A: AstroSat CZTI detection
  58. Fermi GRB 211222A: Global MASTER-Net observations report
  59. GRB 211222A: Fermi GBM Final Real-time Localization
  60. GRB 211219A: AGILE detection
  61. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  62. Fermi GRB 211219B: Global MASTER-Net observations report
  63. GRB 211219B: Fermi GBM Final Real-time Localization
  64. Fermi GRB 211219A: Global MASTER-Net observations report
  65. GRB 211219A: Fermi GBM Final Real-time Localization
  66. GRB 211216A: Fermi GBM observation
  67. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  68. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  69. IceCube-211216B: Upper limits from Fermi-GBM Observations
  70. IceCube-211216A: Upper limits from Fermi-GBM Observations
  71. Fermi trigger No 661417475: Global MASTER-Net observations report
  72. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  73. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  74. Fermi GRB 211216B: Global MASTER-Net observations report
  75. GRB 211216B: GECAM detection
  76. GRB 211216B: Fermi GBM Final Real-time Localization
  77. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  78. GRB 211216A: GECAM detection
  79. GRB 211216A: BALROG localization (Fermi Trigger 661329957 / GRB 211216282)
  80. Fermi GRB 211216A: Global MASTER-Net observations report
  81. GRB 211216A: Fermi GBM Final Real-time Localization
  82. GRB 211211A: Insight-HXMT/HE detection
  83. GRB 211211A: SAO RAS optical observations
  84. GRB 211211A: AbAO optical observations
  85. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  86. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  87. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  88. GRB 211211A: HCT and GIT optical follow up observations
  89. GRB 211211A: CALET Gamma-Ray Burst Monitor detection
  90. Fermi GRB 211212A: Global MASTER-Net observations report
  91. GRB 211211A: incorrect E_iso value in GCN 31221
  92. GRB 211211A: NOT optical spectroscopy
  93. GRB 211211B: GECAM detection
  94. Fermi GRB 211212B: Global MASTER-Net observations report
  95. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  96. GRB 211211A: MITSuME Akeno optical observation
  97. GRB 211212B: Fermi GBM Final Real-time Localization
  98. GRB 211211A: Nanshan/NEXT optical observations
  99. GRB 211212A: Fermi GBM Final Real-time Localization
  100. GRB 211211A: Fermi GBM observation

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