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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"

2921 results found.

  1. GRB 220305A: Swift-BAT refined analysis
  2. GRB 220305A: Swift detection of a burst
  3. IceCube Alert 220304.74: Global MASTER-Net observations report
  4. Fermi GRB 220304A: Global MASTER-Net observations report
  5. GRB 220304A: Fermi GBM Final Real-time Localization
  6. IPN triangulation of GRB 220222A
  7. GCN Circ.draft on GRB 220222A
  8. Fermi GRB 220223A: Global MASTER-Net observations report
  9. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  10. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  11. Fermi GRB 220222B: Global MASTER-Net observations report
  12. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  13. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  14. IceCube Alert 220220.60: Global MASTER-Net observations report
  15. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  16. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  17. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  18. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  19. IceCube Alert 220202.49: Global MASTER-Net observations report
  20. GRB 220128A: AstroSat CZTI detection
  21. IPN triangulation of GRB 220128A (long)
  22. GRB 220124A: AstroSat CZTI detection of a bright long GRB
  23. GRB 220117B: TARGET optical upper limit
  24. GRB 220101A: TSHAO optical observation, Terskol, AbAO upper limits
  25. GECAM observations of a series of bursts from SGR J1935+2154
  26. Fermi-GBM Observations of Recent Bursting Activity from SGR J1935+2154
  27. GECAM observations of a series of bursts from SGR J1935+2154
  28. GRB 220111A: AstroSat CZTI detection
  29. Fermi GRB 220111A: Global MASTER-Net observations report
  30. Fermi trigger No 663406755: Global MASTER-Net observations report
  31. GRB 220107A: AbAO and Terskol optical observations
  32. GRB 220107B: AstroSat CZTI detection
  33. GRB 220107A: AstroSat CZTI detection
  34. Fermi GRB 220107A: Global MASTER-Net observations report
  35. Fermi GRB 220104A: Global MASTER-Net observations report
  36. GRB 211231A: AstroSat CZTI detection
  37. Konus-Wind detection of the intermediate flare from SGR 1935+2154
  38. GRB 211227A: BOOTES-2/TELMA optical upper limit
  39. GRB 211227A: Swift detection of a burst
  40. GRB 211225A: MITSuME Akeno optical upper limits
  41. Fermi trigger No 662084433: Global MASTER-Net observations report
  42. AGILE observations of a bright burst from SGR 1935+2154
  43. Swift GRB 211223C: Global MASTER-Net observations report
  44. GRB 211219B: AstroSat CZTI detection
  45. GRB 211219A: AstroSat CZTI detection
  46. GRB 211218A: MITSuME Akeno optical upper limits
  47. Fermi GRB 211219B: Global MASTER-Net observations report
  48. Fermi GRB 211211B: Global MASTER-Net observations report
  49. GRB 211211B: Fermi GBM Final Real-time Localization
  50. Fermi trigger No 660868196: Global MASTER-Net observations report
  51. Fermi trigger No 660736561: Global MASTER-Net observations report
  52. GRB 211206A: AstroSat CZTI detection
  53. GRB 211206B: AstroSat CZTI detection
  54. GRB 211204C: AstroSat CZTI detection
  55. Fermi GRB 211204C: Global MASTER-Net observations report
  56. Fermi GRB 211204B: Global MASTER-Net observations report
  57. GRB 211201A: Swift/BAT-GUANO detection likely outside the coded FOV
  58. GRB 211201A: Fermi GBM Final Real-time Localization
  59. IceCube Alert 211125.27: Global MASTER-Net observations report
  60. GRB 211120A: AstroSat CZTI detection
  61. GRB 211118A: AstroSat CZTI detection
  62. Fermi trigger No 658971499: Global MASTER-Net observations report
  63. Fermi trigger No 658755664: Global MASTER-Net observations report
  64. GRB 211115A: MAXI/GSC detection
  65. Fermi GRB 211112A: Global MASTER-Net observations report
  66. GRB 211110A: AstroSat CZTI detection
  67. Fermi trigger No 658214822: Global MASTER-Net observations report
  68. GRB 211109B: Fermi GBM Final Real-time Localization
  69. GRB 211023A: A BdHN of type I
  70. GRB 211024A: MITSuME Akeno optical observation
  71. Fermi GRB 211031A: Global MASTER-Net observations report
  72. GRB 211023B: LDT Optical Afterglow Detection
  73. GRB 211022A: AstroSat CZTI detection
  74. Fermi GRB 211024A: Global MASTER-Net observations report
  75. Fermi trigger No 656506979: Global MASTER-Net observations report
  76. Fermi GRB 211019A: Global MASTER-Net observations report
  77. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  78. Swift Trigger 1078701 is probably not a GRB
  79. Fermi trigger No 654658271: Global MASTER-Net observations report
  80. Fermi GRB 210929B: Global MASTER-Net observations report
  81. GRB 210929B: Fermi GBM Final Real-time Localization
  82. GRB 210925B: AstroSat CZTI detection
  83. GRB 210926A: AstroSat CZTI detection
  84. GRB 210919A: LOAO and LSGT optical upper limits
  85. Konus-Wind observation of the recent SGR 1935+2154 activity
  86. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  87. Fermi trigger No 653022153: Global MASTER-Net observations report
  88. Fermi trigger No 653010039: Global MASTER-Net observations report
  89. GECAM observations of a series of bursts from SGR J1935+2154
  90. Fermi trigger No 652911693: Global MASTER-Net observations report
  91. Fermi trigger No 652906639: Global MASTER-Net observations report
  92. Fermi GRB 210909A: Global MASTER-Net observations report
  93. GRB 210905A: AstroSat CZTI detection
  94. Fermi trigger No 652585475: Global MASTER-Net observations report
  95. GRB 210610A: Maidanak and AbAO optical observations
  96. Fermi GRB 210904A: Global MASTER-Net observations report
  97. Fermi GRB 210903B: Global MASTER-Net observations report
  98. GRB 210827A: Fermi GBM Observation
  99. Fermi GRB 210827A: Global MASTER-Net observations report
  100. Fermi GRB 210827B: Global MASTER-Net observations report

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