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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"

11528 results found.

  1. GRB 230313A: AstroSat CZTI detection
  2. IPN triangulation of GRB 230308A (short/bright)
  3. Fermi GRB 230314A: Global MASTER-Net observations report
  4. GRB 230307A: ATCA radio detection
  5. GRB 230314A: Fermi GBM Final Real-time Localization
  6. GRB 230307A: Swift/UVOT detection
  7. GRB 230313A: BALROG localization (Fermi Trigger 700400328 / GRB 230313485)
  8. Fermi GRB 230313A: Global MASTER-Net observations report
  9. GRB 230313A: Fermi GBM Final Real-time Localization
  10. GRB 230307A: soft X-ray detection with LEIA
  11. GRB 230307A: Swift-XRT afterglow detection
  12. Further improved IPN localization for GRB 230307A
  13. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  14. GRB 230308A: CALET Gamma-Ray Burst Monitor detection
  15. GRB 230310A: AstroSat CZTI detection
  16. GRB 230307A: GECKO optical observations and detections of the afterglow
  17. GRB 230307A: MAXI/GSC upper limit
  18. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  19. Fermi GRB 230310A: Global MASTER-Net observations report
  20. GRB 230310A: Fermi GBM Final Real-time Localization
  21. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  22. GRB 230308A: Fermi GBM detection
  23. GRB 230307A: Possible optical afterglow
  24. GRB 230307A: ASO-S/HXI detection
  25. GRB 230308A: AGILE/MCAL detection
  26. GRB 230307A: optical upper limit
  27. GRB 230307A: Upper limits from a neutrino search with IceCube
  28. GRB 230307A: Swift-XRT observations
  29. Fermi GRB 230307A: Global MASTER-Net observations report
  30. Konus-Wind detection of GRB 230307A
  31. Improved IPN localization for GRB 230307A
  32. GRB 230307A: VZLUSAT-2 detection
  33. GRB 230304B: CALET Gamma-Ray Burst Monitor detection
  34. Fermi GRB 230308A: Global MASTER-Net observations report
  35. GRB 230308A: BALROG localization (Fermi Trigger 699975152 / GRB 230308564)
  36. GRB 230308A: Fermi GBM Final Real-time Localization
  37. GRB 230307A: Tiled Swift observations
  38. GRB 230307A: Detection by GRBAlpha
  39. GRB 230305A: Detection by GRBAlpha
  40. GRB 230307A: BALROG localization (Fermi Trigger 699896651/ GRB 230307656)
  41. GRB 230307A: AstroSat CZTI detection
  42. GRB 230307A: possibly the second highest GRB energy fluence ever identified
  43. IPN triangulation of GRB 230307A (long/very bright)
  44. GRB 230307A: AGILE/MCAL detection
  45. GRB 230307A: Fermi GBM Observation of a very bright burst
  46. Fermi-LAT gamma-ray observations of IceCube-230306A
  47. GRB 230307A: Fermi GBM detection of a very bright GRB
  48. GRB 230307A: GECAM detection of an extremely bright burst
  49. GRB 230307A: Fermi GBM Final Real-time Localization
  50. Fermi trigger No 699811746: Global MASTER-Net observations report
  51. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  52. GRB 230304C: AstroSat CZTI detection
  53. GRB 230304B: AstroSat CZTI detection
  54. GRB 230304A: AstroSat CZTI detection
  55. GRB 230304B: Detection by GRBAlpha
  56. GRB 230304C: Fermi GBM Final Real-time Localization
  57. GRB 230304B: Fermi GBM Final Real-time Localization
  58. GRB 230304A: Fermi GBM Final Real-time Localization
  59. Fermi GRB 230301B: Global MASTER-Net observations report
  60. GRB 230301B: Fermi GBM Final Real-time Localization
  61. GRB 230228A: Fermi GBM Observation
  62. Fermi trigger No 699294715: Global MASTER-Net observations report
  63. Fermi trigger No 699311646: Global MASTER-Net observations report
  64. GRB 230301A: Fermi GBM Final Real-time Localization
  65. Fermi GRB 230227A: Global MASTER-Net observations report
  66. GRB 230227A: Fermi GBM Final Real-time Localization
  67. Fermi trigger No 699029364: Global MASTER-Net observations report
  68. GRB 230222A: Fermi GBM Final Real-time Localization
  69. Fermi-LAT gamma-ray observations of IceCube-230220A
  70. Fermi GRB 230220B: Global MASTER-Net observations report
  71. GRB 230217A: AstroSat CZTI detection
  72. GRB 230220B: Fermi GBM Final Real-time Localization
  73. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  74. GRB 230217A: Fermi GBM observation
  75. IceCube-230217A: BOOTES-4/MET Optical Observations
  76. Fermi-LAT gamma-ray observations of IceCube-230217A
  77. Konus-Wind detection of GRB 230217A
  78. Fermi trigger No 698427992: Global MASTER-Net observations report
  79. GRB 230218A is not a GRB
  80. GRB 230218A: Fermi GBM Final Real-time Localization
  81. GRB 230217A: AGILE/MCAL detection
  82. GRB 230216B: AstroSat CZTI detection
  83. GRB 230217A: Fermi GBM Final Real-time Localization
  84. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  85. Fermi GRB 230215A: Global MASTER-Net observations report
  86. GRB 230215A: Fermi GBM Final Real-time Localization
  87. GRB 230209B: AGILE detection
  88. GRB 230209B: Fermi GBM Observation
  89. IPN triangulation of GRB 230209B
  90. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  91. Outburst from LS V +44 17 / RX J0440.9+4431: Transient detection by GRBAlpha
  92. Fermi trigger No 697926015: Global MASTER-Net observations report
  93. Fermi trigger No 697904388: Global MASTER-Net observations report
  94. 230211A is not a GRB
  95. GRB 230211A: Fermi GBM Final Real-time Localization
  96. GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
  97. Fermi trigger No 697678542: Global MASTER-Net observations report
  98. GRB 230210A: Fermi GBM Final Real-time Localization
  99. Fermi GRB 230209B: Global MASTER-Net observations report
  100. GRB 230209B: Fermi GBM Final Real-time Localization

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