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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 230307A: soft X-ray detection with LEIA
  2. GRB 230307A: Swift-XRT afterglow detection
  3. Further improved IPN localization for GRB 230307A
  4. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  5. GRB 230308A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 230310A: AstroSat CZTI detection
  7. GRB 230307A: GECKO optical observations and detections of the afterglow
  8. GRB 230307A: MAXI/GSC upper limit
  9. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  10. Fermi GRB 230310A: Global MASTER-Net observations report
  11. GRB 230310A: Fermi GBM Final Real-time Localization
  12. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  13. GRB 230308A: Fermi GBM detection
  14. GRB 230307A: Possible optical afterglow
  15. GRB 230307A: ASO-S/HXI detection
  16. GRB 230308A: AGILE/MCAL detection
  17. GRB 230307A: optical upper limit
  18. GRB 230307A: Upper limits from a neutrino search with IceCube
  19. GRB 230307A: Swift-XRT observations
  20. Fermi GRB 230307A: Global MASTER-Net observations report
  21. Konus-Wind detection of GRB 230307A
  22. Improved IPN localization for GRB 230307A
  23. GRB 230307A: VZLUSAT-2 detection
  24. GRB 230304B: CALET Gamma-Ray Burst Monitor detection
  25. Fermi GRB 230308A: Global MASTER-Net observations report
  26. GRB 230308A: BALROG localization (Fermi Trigger 699975152 / GRB 230308564)
  27. GRB 230308A: Fermi GBM Final Real-time Localization
  28. GRB 230307A: Tiled Swift observations
  29. GRB 230307A: Detection by GRBAlpha
  30. GRB 230305A: Detection by GRBAlpha
  31. GRB 230307A: BALROG localization (Fermi Trigger 699896651/ GRB 230307656)
  32. GRB 230307A: AstroSat CZTI detection
  33. GRB 230307A: possibly the second highest GRB energy fluence ever identified
  34. IPN triangulation of GRB 230307A (long/very bright)
  35. GRB 230307A: AGILE/MCAL detection
  36. GRB 230307A: Fermi GBM Observation of a very bright burst
  37. Fermi-LAT gamma-ray observations of IceCube-230306A
  38. GRB 230307A: Fermi GBM detection of a very bright GRB
  39. GRB 230307A: GECAM detection of an extremely bright burst
  40. GRB 230307A: Fermi GBM Final Real-time Localization
  41. Fermi trigger No 699811746: Global MASTER-Net observations report
  42. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  43. GRB 230304C: AstroSat CZTI detection
  44. GRB 230304B: AstroSat CZTI detection
  45. GRB 230304A: AstroSat CZTI detection
  46. GRB 230304B: Detection by GRBAlpha
  47. GRB 230304C: Fermi GBM Final Real-time Localization
  48. GRB 230304B: Fermi GBM Final Real-time Localization
  49. GRB 230304A: Fermi GBM Final Real-time Localization
  50. Fermi GRB 230301B: Global MASTER-Net observations report
  51. GRB 230301B: Fermi GBM Final Real-time Localization
  52. GRB 230228A: Fermi GBM Observation
  53. Fermi trigger No 699294715: Global MASTER-Net observations report
  54. Fermi trigger No 699311646: Global MASTER-Net observations report
  55. GRB 230301A: Fermi GBM Final Real-time Localization
  56. Fermi GRB 230227A: Global MASTER-Net observations report
  57. GRB 230227A: Fermi GBM Final Real-time Localization
  58. Fermi trigger No 699029364: Global MASTER-Net observations report
  59. GRB 230222A: Fermi GBM Final Real-time Localization
  60. Fermi-LAT gamma-ray observations of IceCube-230220A
  61. Fermi GRB 230220B: Global MASTER-Net observations report
  62. GRB 230217A: AstroSat CZTI detection
  63. GRB 230220B: Fermi GBM Final Real-time Localization
  64. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  65. GRB 230217A: Fermi GBM observation
  66. IceCube-230217A: BOOTES-4/MET Optical Observations
  67. Fermi-LAT gamma-ray observations of IceCube-230217A
  68. Konus-Wind detection of GRB 230217A
  69. Fermi trigger No 698427992: Global MASTER-Net observations report
  70. GRB 230218A is not a GRB
  71. GRB 230218A: Fermi GBM Final Real-time Localization
  72. GRB 230217A: AGILE/MCAL detection
  73. GRB 230216B: AstroSat CZTI detection
  74. GRB 230217A: Fermi GBM Final Real-time Localization
  75. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  76. Fermi GRB 230215A: Global MASTER-Net observations report
  77. GRB 230215A: Fermi GBM Final Real-time Localization
  78. GRB 230209B: AGILE detection
  79. GRB 230209B: Fermi GBM Observation
  80. IPN triangulation of GRB 230209B
  81. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  82. Outburst from LS V +44 17 / RX J0440.9+4431: Transient detection by GRBAlpha
  83. Fermi trigger No 697926015: Global MASTER-Net observations report
  84. Fermi trigger No 697904388: Global MASTER-Net observations report
  85. 230211A is not a GRB
  86. GRB 230211A: Fermi GBM Final Real-time Localization
  87. GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
  88. Fermi trigger No 697678542: Global MASTER-Net observations report
  89. GRB 230210A: Fermi GBM Final Real-time Localization
  90. Fermi GRB 230209B: Global MASTER-Net observations report
  91. GRB 230209B: Fermi GBM Final Real-time Localization
  92. GRB 230209A is not a GRB
  93. GRB 230209A: Fermi GBM Final Real-time Localization
  94. GRB 221009A: Continued Swift Observations
  95. Fermi Gamma-ray Burst Monitor trigger 230208382/697540213 is not a GRB
  96. GRB 230208A: Fermi GBM Final Real-time Localization
  97. Fermi Gamma-ray Burst Monitor triggers 230206723/697396830 and 230206797/697403223 are not GRBs
  98. Fermi GRB 230207A: Global MASTER-Net observations report
  99. GRB 230207A: Fermi GBM Final Real-time Localization
  100. Fermi trigger No 697403223: Global MASTER-Net observations report

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