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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"

11531 results found.

  1. GRB 220107A: SAO RAS optical observations
  2. GRB 220101A: SAO RAS optical observations
  3. GRB 220107A: AbAO and Terskol optical observations
  4. GRB 220107B: MITSuME Akeno optical upper limits
  5. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  6. GRB 220107A: Nanshan/NEXT optical observations
  7. GRB 220107A: Swift/UVOT Detection
  8. GRB 220107B: Fermi GBM observations
  9. GRB 220107A: MITSuME Akeno optical observation
  10. GRB 220107B: AstroSat CZTI detection
  11. GRB 220107B: Swift-XRT afterglow detection
  12. GRB 220107B: Fermi-LAT detection
  13. GRB 220107A: AstroSat CZTI detection
  14. GRB 220107B: Tiled Swift observations
  15. GRB 220107A: Fermi GBM observations
  16. Fermi trigger No 663274898: Global MASTER-Net observations report
  17. Fermi GRB 220107A: Global MASTER-Net observations report
  18. GRB 220107A: Swift/BAT-GUANO arcminute localization
  19. GRB 220107A: BALROG localization (Fermi Trigger 663259536 / GRB 220107615)
  20. GRB 220107A: Fermi GBM Final Real-time Localization
  21. GRB 220101A: Continued Mondy optical observations
  22. GECAM observation of a burst from SGR J1555.2-5402
  23. Fermi trigger No 663129379: Global MASTER-Net observations report
  24. GRB 220104A: Fermi GBM Observation
  25. GRB 220101A: Mondy optical observations
  26. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  27. GRB 220104A:GECAM detection
  28. Fermi GRB 220104A: Global MASTER-Net observations report
  29. GRB 220104A: Fermi GBM Final Real-time Localization
  30. GRB 211229B: Fermi GBM observation
  31. Fermi GRB 220103A: Global MASTER-Net observations report
  32. GRB 220103A: Fermi GBM Final Real-time Localization
  33. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  34. GRB 211231A: AstroSat CZTI detection
  35. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  36. Fermi trigger No 662768315: Global MASTER-Net observations report
  37. GRB 220101A: Fermi GBM Detection
  38. GRB 220101A: CAHA 2.2m/CAFOS detection
  39. GRB 220101A: AGILE detection
  40. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  41. GRB 220101A: Fermi-LAT detection
  42. IPN triangulation of GRB 211219A
  43. GRB 211231A: GECAM detection
  44. GRB 211229B: AGILE detection
  45. GRB 211231A: Fermi GBM Final Real-time Localization
  46. GRB 211229A: Swift-XRT and UVOT observations
  47. GRB 211229A: Fermi GBM observation
  48. GRB 211229B: GECAM detection
  49. Fermi GRB 211229B: Global MASTER-Net observations report
  50. GRB 211229B: Fermi GBM Final Real-time Localization
  51. GRB 211229A: Swift/BAT-GUANO arcminute localization
  52. GRB 211229A: GECAM detection
  53. Fermi GRB 211229A: Global MASTER-Net observations report
  54. GRB 211229A: Fermi GBM Final Real-time Localization
  55. Fermi trigger No 662216114: Global MASTER-Net observations report
  56. Fermi GRB 211225C: Global MASTER-Net observations report
  57. GRB 211225C: Fermi GBM Final Real-time Localization
  58. Fermi trigger No 662084433: Global MASTER-Net observations report
  59. GRB 211224A: Fermi GBM Final Real-time Localization
  60. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  61. Fermi trigger No 662010159: Global MASTER-Net observations report
  62. AGILE observations of a bright burst from SGR 1935+2154
  63. Fermi GRB 211223B: Global MASTER-Net observations report
  64. Fermi GBM Sub-Threshold Detection of GRB 211221A
  65. Fermi GBM Sub-Threshold Detection of GRB 211207A
  66. GRB 211223B: Fermi GBM Final Real-time Localization
  67. GRB 211223A: GECAM detection
  68. GRB 211219B: AstroSat CZTI detection
  69. GRB 211219A: AstroSat CZTI detection
  70. Fermi GRB 211222A: Global MASTER-Net observations report
  71. GRB 211222A: Fermi GBM Final Real-time Localization
  72. GRB 211219A: AGILE detection
  73. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  74. Fermi GRB 211219B: Global MASTER-Net observations report
  75. GRB 211219B: Fermi GBM Final Real-time Localization
  76. Fermi GRB 211219A: Global MASTER-Net observations report
  77. GRB 211219A: Fermi GBM Final Real-time Localization
  78. GRB 211216A: Fermi GBM observation
  79. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  80. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  81. IceCube-211216B: Upper limits from Fermi-GBM Observations
  82. IceCube-211216A: Upper limits from Fermi-GBM Observations
  83. Fermi trigger No 661417475: Global MASTER-Net observations report
  84. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  85. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  86. Fermi GRB 211216B: Global MASTER-Net observations report
  87. GRB 211216B: GECAM detection
  88. GRB 211216B: Fermi GBM Final Real-time Localization
  89. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  90. GRB 211216A: GECAM detection
  91. GRB 211216A: BALROG localization (Fermi Trigger 661329957 / GRB 211216282)
  92. Fermi GRB 211216A: Global MASTER-Net observations report
  93. GRB 211216A: Fermi GBM Final Real-time Localization
  94. GRB 211211A: Insight-HXMT/HE detection
  95. GRB 211211A: SAO RAS optical observations
  96. GRB 211211A: AbAO optical observations
  97. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  98. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  99. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  100. GRB 211211A: HCT and GIT optical follow up observations

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