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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"

36149 results found.

  1. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  2. Konus-Wind detection of LXT 240402A/GRB 240402B
  3. GRB/FXT 240402B: Kinder optical counterpart candidate
  4. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  5. GRB 240403A: Fermi GBM Detection
  6. LXT 240402A: EP-FXT detection of the X-ray afterglow
  7. Fermi GRB 240404A: Global MASTER-Net observations report
  8. GRB 240404A: Fermi GBM Final Real-time Localization
  9. GRB 240402B: GWAC-F50A optical upper limit
  10. GRB 240402B: GECAM-C detection
  11. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  12. Fermi GRB 240402A: Global MASTER-Net observations report
  13. GRB 240402A: Fermi GBM Final Real-time Localization
  14. IBAS Alert n.10651 not a GRB
  15. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  16. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 240329A: Glowbug gamma-ray detection
  18. GRB 240324A: AstroSat CZTI detection of a short burst
  19. GRB 240331A: AstroSat CZTI detection
  20. GRB 240329A: AstroSat CZTI detection
  21. GRB 240331A: Fermi GBM Final Real-time Localization
  22. GRB 240329A: GRBAlpha detection
  23. Fermi GRB 240329A: Global MASTER-Net observations report
  24. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  25. GRB 240329A: Fermi GBM Final Real-time Localization
  26. Fermi GRB 240328B: Global MASTER-Net observations report
  27. Fermi GRB 240328A: Global MASTER-Net observations report
  28. GRB 240328C: Glowbug gamma-ray detection
  29. GRB 240328B: Fermi GBM Final Real-time Localization
  30. GRB 240328A: Fermi GBM Final Real-time Localization
  31. X-ray transient EP 240315a: Second epoch Chandra observations
  32. GRB 240320A: Glowbug gamma-ray detection
  33. GRB 240318A: Fermi GBM Observation
  34. Fermi GRB 240320A: Global MASTER-Net observations report
  35. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  36. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  37. GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  38. GRB 240320A: Fermi GBM Final Real-time Localization
  39. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
  40. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  41. Fermi Gamma-ray Burst Monitor trigger 732299243/240316686 is not a GRB
  42. GRB 240318A: Glowbug gamma-ray detection
  43. GRB 240317C: Glowbug gamma-ray detection
  44. GRB 240318B: Glowbug gamma-ray detection
  45. GRB 240317B: Fermi GBM Observation
  46. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  47. Fermi GRB 240318A: Global MASTER-Net observations report
  48. GRB 240318A: Fermi GBM Final Real-time Localization
  49. GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
  50. GRB 240317A: AstroSat CZTI detection
  51. GRB 240315B: AstroSat CZTI detection
  52. X-ray transient EP240315a: Kitab observatory optical upper limitns
  53. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  54. Fermi GRB 240317B: Global MASTER-Net observations report
  55. Fermi GRB 240317A: Global MASTER-Net observations report
  56. GRB 240317B: Fermi GBM Final Real-time Localization
  57. GRB 240317A: Fermi GBM Final Real-time Localization
  58. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  59. GRID detection of GRB 240306A
  60. Changes to the Fermi-GBM Triggering Thresholds
  61. GRB 240315A: Fermi GBM Final Real-time Localization
  62. Fermi GRB 240314A: Global MASTER-Net observations report
  63. GRB 240314A: Fermi GBM Final Real-time Localization
  64. GRB 240312A: Glowbug gamma-ray detection
  65. Swift Trigger 1219905 is not a GRB
  66. GRB 240312A: GECAM detection of a long burst
  67. GRB 240303C: VZLUSAT-2 detection
  68. GRB 240310A: MASTER OT J200702.72-263928.7 inside 3sigma
  69. GRB 240310B: Glowbug gamma-ray detection
  70. Fermi GRB 240310A: Global MASTER-Net observations report
  71. GRB 240310A: Fermi GBM Final Real-time Localization
  72. GRB 240309A: MAXI/GSC detection
  73. Swift Trigger 1219325 is not a GRB
  74. IceCube-240307A: Upper limits from a search for additional neutrino events in IceCube
  75. GRID detection of GRB 240229A (Updated Report)
  76. GRID detection of GRB 240229A
  77. GRB 240308A: Fermi GBM Final Localization
  78. GRB 231215A: further radio observations with the VLA
  79. GRB 240306A: Fermi GBM observation
  80. GRB 240229A: Glowbug gamma-ray detection
  81. GRB 240227A (short): Glowbug gamma-ray detection
  82. GRB 240229A: GRBAlpha detection
  83. Konus-Wind detection of GRB 231118A
  84. GRB 240306A: AstroSat CZTI detection
  85. Fermi GRB 240306A: Global MASTER-Net observations report
  86. Fermi GRB 240305A: Global MASTER-Net observations report
  87. GRB 240306A: Swift/BAT-GUANO detection of a burst
  88. GRB 240305A: Fermi GBM observation
  89. GRB 240305C: AstroSat CZTI detection of a short burst
  90. GRB 240306A: Fermi GBM Final Real-time Localization
  91. Fermi GRB 240305C: Global MASTER-Net observations report
  92. GRB 240305C: Fermi GBM Final Real-time Localization
  93. GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
  94. GRB 231028C: Glowbug gamma-ray confirmation of a prior burst
  95. GRB 240218A: ALMA detection
  96. GRB 240218A: Chandra Detection and Jet Break Confirmation
  97. GRB 240305B: Fermi GBM Final Localization
  98. Konus-Wind detection of GRB 240227A (short/hard)
  99. GRB 240303B: VZLUSAT-2 detection
  100. GRB 240229A: VZLUSAT-2 detection

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