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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"

27777 results found.

  1. Swift satellite in safe mode
  2. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  3. GRB 240318A: Fermi GBM Final Real-time Localization
  4. GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
  5. GRB 240317A: AstroSat CZTI detection
  6. GRB 240315B: AstroSat CZTI detection
  7. GRB 240317B: Fermi GBM Final Real-time Localization
  8. GRB 240317A: Fermi GBM Final Real-time Localization
  9. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  10. X-ray transient EP240315a: GROND J-band detection
  11. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  12. X-ray transient EP240315a: Nanshan/HMT optical upper limit
  13. AT2024eju: followup observations with Liverpool Telescope suggest a fading transient
  14. X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
  15. Einstein Probe detected of a fast X-ray transient EP240315a
  16. GRID detection of GRB 240306A
  17. Changes to the Fermi-GBM Triggering Thresholds
  18. Swift Triggers 1220155, 1220156, 1220157, 1220158, 1220160 and 1220161 were not astrophysical
  19. GRB 240315A: Fermi GBM Final Real-time Localization
  20. Swift Triggers 1220093, 1220094, 1220095 and 1220096 are not astrophysical
  21. Swift Triggers 1220090, 1220091 and 1220092 are not astrophysical
  22. GRB 240314A: Fermi GBM Final Real-time Localization
  23. GRB240204A: VIRT optical upper limit
  24. GRB 240312A: Glowbug gamma-ray detection
  25. Swift triggers 1219917, 1219917 and 1219922 were not astrophysical
  26. Swift Trigger 1219909 and 1219910 are not a astrophysical
  27. Swift Trigger 1219905 is not a GRB
  28. GRB 240312A: GECAM detection of a long burst
  29. Swift Trigger 1219874 is not astrophysical
  30. GRB 240303C: VZLUSAT-2 detection
  31. GRB 240310A: MASTER OT J200702.72-263928.7 inside 3sigma
  32. GRB 240310B: Glowbug gamma-ray detection
  33. Swift GRB240309.61: Global MASTER-Net observations report
  34. GRB 240310A: Fermi GBM Final Real-time Localization
  35. GRB 240309A: MAXI/GSC detection
  36. Swift Trigger 1219325 is not a GRB
  37. GRID detection of GRB 240229A (Updated Report)
  38. GRID detection of GRB 240229A
  39. GRB 240308A: Fermi GBM Final Localization
  40. GRB 240306A: Fermi GBM observation
  41. IceCube-240307A - IceCube observation of a high-energy neutrino candidate track-like event
  42. GRB 240229A: Glowbug gamma-ray detection
  43. GRB 240227A (short): Glowbug gamma-ray detection
  44. GRB 240229A: GRBAlpha detection
  45. Konus-Wind detection of GRB 231118A
  46. GRB 240306A: AstroSat CZTI detection
  47. GRB 240306A: Swift/BAT-GUANO detection of a burst
  48. GRB 240305A: Fermi GBM observation
  49. GRB 240305C: AstroSat CZTI detection of a short burst
  50. GRB 240306A: Fermi GBM Final Real-time Localization
  51. Swift GRB240305.18: Global MASTER-Net observations report
  52. Swift GRB240305.16: Global MASTER-Net observations report
  53. GRB 240305C: Fermi GBM Final Real-time Localization
  54. GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
  55. GRB 231028C: Glowbug gamma-ray confirmation of a prior burst
  56. GRB 240218A: ALMA detection
  57. GRB 240218A: Chandra Detection and Jet Break Confirmation
  58. GRB 240305B: Fermi GBM Final Localization
  59. Konus-Wind detection of GRB 240227A (short/hard)
  60. GRB 240303B: VZLUSAT-2 detection
  61. GRB 240229A: VZLUSAT-2 detection
  62. IPN triangulation of GRB 240229A
  63. GRB 240305A: Fermi GBM Final Real-time Localization
  64. Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
  65. Swift Trigger 1218696: Another trigger on Swift J151857.0-572147
  66. GRB240218A: ATCA observation of the radio counterpart
  67. Transient EPW20240219aa: Optical observations with LDT
  68. Konus-Wind detection of GRB 240303B
  69. Swift Trigger 1218645: Another detection of Swift J151857.0-572147
  70. IPN triangulation of GRB 240303B
  71. Swift J151857.0-572147: Swift-BAT refined analysis
  72. GRB 240303B: Fermi GBM Detection
  73. GRB 240225B: Swift-XRT afterglow detection
  74. Swift detection of Swift J151857.0-572147
  75. GRB 240303B: CALET Gamma-Ray Burst Monitor detection
  76. Swift GRB 240303A: Global MASTER-Net observations report
  77. Swift J151857.0-572147: Confirmation of a new galactic transient
  78. GRB 240215A: Swift-XRT afterglow detection
  79. GRB 240303B: Fermi GBM Final Localization
  80. GRB 240303A: Swift detection of a burst
  81. GRB 240225B: Glowbug gamma-ray detection
  82. GRB 240225C: Glowbug gamma-ray detection
  83. GRB 240225A (short): Glowbug gamma-ray detection
  84. GRB 240218A: NOEMA upper limit
  85. GRB 240229A: CALET Gamma-Ray Burst Monitor detection
  86. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  87. Swift BAT Triggers 1218081 and 1218082 are not astrophysical
  88. GRB 240225B: Swift ToO observations
  89. Konus-Wind detection of GRB 240225B (long)
  90. GRB 240229A: Fermi GBM Final Real-time Localization
  91. GRB 240225B: VLT/X-shooter redshift
  92. GRB 240225B : MITSuME Akeno optical afterglow candidate detection
  93. GRB 240225B: 3.6m DOT observation
  94. GRB 240226A: GRBAlpha detection
  95. GRB 240225B: Liverpool Telescope afterglow observations
  96. Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up
  97. Swift Trigger 1217799 is not a GRB
  98. IPN triangulation of GRB 240227A (short)
  99. Swift-BAT triggers 1217733 - 1217736 are not astrophysical events
  100. Swift-BAT triggers 1217729-1217732 are not astrophysical

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