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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"

36187 results found.

  1. GRB 240414A : MITSuME Akeno optical upper limits
  2. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  3. GRB 240414A : OHP/T193 redshift determination
  4. GRB 240414A : OHP/T193 optical counterpart detection
  5. GRB 240414A: Swift detection of a burst
  6. GRB 240411B: CrAO/ZTSh optical observations
  7. GRB 240411B: Kinder observations with Lulin observatory
  8. GRB 240411B: HiPERCAM/GTC observation
  9. GRB 240411B: Swift-BAT refined analysis
  10. GRB 240411B: Swift-XRT refined Analysis
  11. GRB 240411B: 1.3m DFOT Optical observations
  12. GRB 240411A: GRBAlpha detection
  13. GRB 240411B: OHP/T193 optical observations
  14. GRB 240405A: Glowbug gamma-ray detection
  15. GRB 240411B: Enhanced Swift-XRT position
  16. GRB 240411B: LCO optical afterglow detection
  17. GRB 240411B: Swift detection of a burst
  18. GRB 240408B: GRBAlpha detection
  19. GRB 240411A: Fermi GBM Final Real-time Localization
  20. EP240408a: Upper limits from GECAM-B Observation
  21. GRB 240405A: GRBAlpha detection
  22. GRB 240408B: AstroSat CZTI detection
  23. Fermi GRB 240408A: Global MASTER-Net observations report
  24. GRB 240408A: Fermi GBM Final Real-time Localization
  25. GRB 240407A: BALROG localization (Fermi Trigger 734144396 / GRB 240407042)
  26. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  27. Fermi GRB 240407A: Global MASTER-Net observations report
  28. GRB 240407A: Fermi GBM Final Real-time Localization
  29. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  30. Fermi GRB 240405B: Global MASTER-Net observations report
  31. GRB 240405B: Fermi GBM Final Real-time Localization
  32. GRB 240402C: Glowbug gamma-ray detection
  33. GRB 240405A: Fermi GBM Final Real-time Localization
  34. GRB 240402C: GRBAlpha detection
  35. GRB 240331A: GRBAlpha detection
  36. LXT 240402A/GRB 240402B: GECAM-C refined analysis
  37. GRB 240403B: Glowbug gamma-ray detection
  38. GRB 240403A: Glowbug gamma-ray detection
  39. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  40. Konus-Wind detection of LXT 240402A/GRB 240402B
  41. GRB/FXT 240402B: Kinder optical counterpart candidate
  42. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  43. GRB 240403A: Fermi GBM Detection
  44. LXT 240402A: EP-FXT detection of the X-ray afterglow
  45. Fermi GRB 240404A: Global MASTER-Net observations report
  46. GRB 240404A: Fermi GBM Final Real-time Localization
  47. GRB 240402B: GWAC-F50A optical upper limit
  48. GRB 240402B: GECAM-C detection
  49. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  50. Fermi GRB 240402A: Global MASTER-Net observations report
  51. GRB 240402A: Fermi GBM Final Real-time Localization
  52. IBAS Alert n.10651 not a GRB
  53. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  54. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 240329A: Glowbug gamma-ray detection
  56. GRB 240324A: AstroSat CZTI detection of a short burst
  57. GRB 240331A: AstroSat CZTI detection
  58. GRB 240329A: AstroSat CZTI detection
  59. GRB 240331A: Fermi GBM Final Real-time Localization
  60. GRB 240329A: GRBAlpha detection
  61. Fermi GRB 240329A: Global MASTER-Net observations report
  62. GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
  63. GRB 240329A: Fermi GBM Final Real-time Localization
  64. Fermi GRB 240328B: Global MASTER-Net observations report
  65. Fermi GRB 240328A: Global MASTER-Net observations report
  66. GRB 240328C: Glowbug gamma-ray detection
  67. GRB 240328B: Fermi GBM Final Real-time Localization
  68. GRB 240328A: Fermi GBM Final Real-time Localization
  69. X-ray transient EP 240315a: Second epoch Chandra observations
  70. GRB 240320A: Glowbug gamma-ray detection
  71. GRB 240318A: Fermi GBM Observation
  72. Fermi GRB 240320A: Global MASTER-Net observations report
  73. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  74. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  75. GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  76. GRB 240320A: Fermi GBM Final Real-time Localization
  77. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
  78. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  79. Fermi Gamma-ray Burst Monitor trigger 732299243/240316686 is not a GRB
  80. GRB 240318A: Glowbug gamma-ray detection
  81. GRB 240317C: Glowbug gamma-ray detection
  82. GRB 240318B: Glowbug gamma-ray detection
  83. GRB 240317B: Fermi GBM Observation
  84. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  85. Fermi GRB 240318A: Global MASTER-Net observations report
  86. GRB 240318A: Fermi GBM Final Real-time Localization
  87. GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
  88. GRB 240317A: AstroSat CZTI detection
  89. GRB 240315B: AstroSat CZTI detection
  90. X-ray transient EP240315a: Kitab observatory optical upper limitns
  91. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  92. Fermi GRB 240317B: Global MASTER-Net observations report
  93. Fermi GRB 240317A: Global MASTER-Net observations report
  94. GRB 240317B: Fermi GBM Final Real-time Localization
  95. GRB 240317A: Fermi GBM Final Real-time Localization
  96. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  97. GRID detection of GRB 240306A
  98. Changes to the Fermi-GBM Triggering Thresholds
  99. GRB 240315A: Fermi GBM Final Real-time Localization
  100. Fermi GRB 240314A: Global MASTER-Net observations report

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