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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

36185 results found.

  1. GRB 211024A: Fermi GBM detection
  2. GRB 211018A: Swift-XRT observations
  3. GRB 211025A: Optical Afterglow Detection
  4. GRB 211024A: Swift ToO observations
  5. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  6. GRB 211024B: Swift/UVOT detection
  7. GRB 211023A: Mondy optical observations
  8. GRB 211023B: Mondy optical afterglow confirmation
  9. GRB 211023B: Gemini-North Optical Observations
  10. Swift GRB 211025A: Global MASTER-Net observations report
  11. GRB 211023B: LDT Optical Afterglow Detection
  12. Correction to GCN 30965: GRB 211023A: Fermi GBM detection
  13. GRB 211025A: Swift-BAT refined analysis
  14. GRB 211025A: Swift-XRT refined Analysis
  15. GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
  16. GRB 211024B: Swift-XRT refined Analysis
  17. IPN Triangulation of GRB 211019A
  18. Possible Short GRB 211023B: CAHA 2.2m Detection
  19. GRB 211025A: Swift/UVOT Detection
  20. GRB 211023A: 1.5m OSN optical observation
  21. GRB 211024B: Swift-BAT refined analysis
  22. GRB 210610B: Sintesz-Newton/CrAO optical observations
  23. GRB 211025A: Enhanced Swift-XRT position
  24. GRB 211025A: Swift detection of a burst
  25. GRB 211024B: Nanshan/NEXT optical afterglow detection
  26. GRB 210919A: FORS2/VLT observations
  27. GRB 211023A: OAJ Bright Afterglow Confirmation
  28. Swift GRB 211024B: Global MASTER-Net observations report
  29. GRB 211024B: Swift detection of a burst
  30. GRB 211023B: Swift-BAT refined analysis
  31. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  32. GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
  33. GRB 211023B: Swift/UVOT Detection
  34. GRB 211024A: GECAM detection
  35. GRB 211023B: RATIR Optical and NIR Upper Limits
  36. GRB 211023B: TSHAO optical observation
  37. Fermi GRB 211023A: Global MASTER-Net observations report
  38. GRB 211023A: AGILE detection
  39. GRB 211022A: AstroSat CZTI detection
  40. GRB 211023B: Swift-XRT refined Analysis
  41. GRB 211023B: Enhanced Swift-XRT position
  42. GRB 211023A: Fermi GBM detection
  43. Swift GRB 211023B: Global MASTER-Net observations report
  44. Fermi GRB 211024A: Global MASTER-Net observations report
  45. GRB 211024A: Fermi GBM Final Real-time Localization
  46. GRB 211023A: Fermi-LAT detection
  47. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  48. GRB 211023A: Fermi GBM Final Real-time Localization
  49. IPN Triangulation of GRB 210927B
  50. GRB 211022A: GECAM detection
  51. GRB 211018A: Swift ToO observations
  52. GRB 211021A: BALROG localization (Fermi Trigger 656506979 / GRB 211021460)
  53. BepiColombo MGNS joins the IPN
  54. GRB 211018A: Fermi GBM observation
  55. GRB 211019A: Detection by GRBAlpha
  56. GRB 211018A: Detection by GRBAlpha
  57. Fermi GRB 211019A: Global MASTER-Net observations report
  58. GRB 211018A: Fermi-LAT detection
  59. GRB 211019A: BALROG localization (Fermi Trigger 656315976 / GRB 211019250)
  60. GRB 211019A: Fermi GBM Final Real-time Localization
  61. GRB 210919A: LDT optical observations and candidate host galaxies
  62. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  63. Swift Trigger 1078701 is probably not a GRB
  64. Fermi Gamma-ray Burst Monitor trigger 211008665/655401471 is not a GRB
  65. GRB 211008A: BALROG localization (Fermi Trigger 655401471 / GRB 211008665)
  66. GRB 210928A: MeerKAT detection
  67. Konus-Wind detection of GRB 210928A
  68. Correction to GCN 30915: GRB 210928A: Swift-XRT analysis
  69. GRB 210928A: Kinder SLT-40cm optical limits
  70. GRB 210930A: Swift-BAT refined analysis
  71. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  72. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  73. GRB 210928A: Swift-XRT refined Analysis
  74. GRB 210928A: Fermi GBM observation
  75. GRB 210928A: Fermi-LAT detection
  76. GRB 210927B: GECAM detection
  77. GRB 210930A: CAHA 2.2m telescope optical limit
  78. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  79. Swift Trigger 1076121 is not a GRB
  80. GRB 210930A: Swift/UVOT Upper Limits
  81. GRB 210930A: Swift-XRT refined Analysis
  82. Swift GRB 210930A: Global MASTER-Net observations report
  83. GRB 210930A: Enhanced Swift-XRT position
  84. Fermi GRB 210929B: Global MASTER-Net observations report
  85. GRB 210930A: Swift detection of a burst
  86. GRB 210929B: Fermi GBM Final Real-time Localization
  87. GRB 210929A: Fermi GBM Final Real-time Localization
  88. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  89. GRB 210925B: AstroSat CZTI detection
  90. IPN triangulation of GRB 210925B
  91. GRB 210926A: AstroSat CZTI detection
  92. GRB 210919A: iTelescope T-11 upper limits
  93. GRB 210926A: GECAM detection
  94. GRB 210927A: Fermi GBM Final Real-time Localization
  95. GRB 210919A OSN 1.5m Source Confirmation
  96. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  97. GRB 210925A: GECAM detection
  98. GRB 210925A: Fermi GBM Final Real-time Localization
  99. GRB 210919A: Chandra rapid ToO upper limit
  100. GRB 210924A: Fermi GBM Final Real-time Localization

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