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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"

19613 results found.

  1. GRB 220521A: Enhanced Swift-XRT position
  2. GRB 220521A: Prompt enhanced Swift-XRT position
  3. GRB 220521A: Swift detection of a burst
  4. Swift GRB220521.97: Global MASTER-Net observations report
  5. Swift BAT Trigger 1107209 is not an astrophysical event
  6. GRB 220518A: Swift-BAT refined analysis
  7. Swift GRB220519.84: Global MASTER-Net observations report
  8. GRB 220518A: Swift-XRT refined Analysis
  9. GRB 220518A: Swift/UVOT Detection
  10. GRB 220518A: Enhanced Swift-XRT position
  11. Swift GRB 220518A: Global MASTER-Net observations report
  12. GRB 220518A: Swift detection of a burst
  13. GRB 220514B: Swift-XRT observations
  14. GRB 220511A: Swift-XRT afterglow detection
  15. GRB 220514B: Tiled Swift observations
  16. GRB 220427A: MeerLICHT afterglow observations
  17. GRB 220511A: Fermi GBM observation
  18. GRB 220511A: Swift-XRT observations
  19. GRB 220511A: AstroSat CZTI detection
  20. GRB 220511A: BOOTES-2/TELMA optical upper limit
  21. GRB 220511A: Swift ToO observations
  22. GRB 220511A: Swift/BAT-GUANO arcminute localization
  23. GRB 220506A: GIT optical upper limit.
  24. GRB 220506A: BOOTES-5/JGT optical upper limit
  25. GRB 220506A: Swift-XRT afterglow detection
  26. GRB 220506A: Tiled Swift observations
  27. Swift-BAT triggers 1105560-1 are not GRBs
  28. Swift GRB220506.51: Global MASTER-Net observations report
  29. GRB 220430A: Nanshan/NEXT optical upper limit
  30. GRB 220430A: Nanshan/HMT optical upper limit
  31. GRB 220430A: GIT optical upper limits
  32. IPN triangulation of GRB 220423A
  33. GRB 220427A: LCO Optical Observations
  34. GRB 220501A: Swift-BAT refined analysis
  35. GRB 220427A: GRANDMA Early Optical Afterglow Detection
  36. GRB 220501A: BOOTES-1 optical upper limit
  37. GRB 220501A: Fermi GBM observation
  38. GRB 220430A: AstroSat CZTI detection
  39. GRB 220501A: Swift detection of a burst
  40. GRB 220430A: Swift-BAT refined analysis
  41. GRB 220430A: CAHA 2.2m telescope optical limit
  42. GRB 220430A: Swift-XRT refined Analysis
  43. Swift GRB 220430A: Global MASTER-Net observations report
  44. GRB 220430A: GRANDMA observations
  45. GRB 220430A: Mondy and AbAO optical upper limits
  46. GRB 220430A: AGILE detection
  47. GRB 220430A: MeerLICHT optical upper limits
  48. GRB 220430A: Enhanced Swift-XRT position
  49. GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
  50. GRB 220427A: Swift-BAT refined analysis
  51. GRB 220426A: Swift-XRT and UVOT observations
  52. GRB 220423A: Detection by VZLUSAT-2
  53. Konus-Wind detection of GRB 220427A
  54. GRB 220427A: Swift-XRT refined Analysis
  55. GRB 220427A: Enhanced Swift-XRT position
  56. GRB 220426A: Tiled Swift observations
  57. GRB 220427A: Swift detection of a burst with an optical counterpart
  58. Konus-Wind detection of GRB 220426A
  59. IPN triangulation of GRB 220426A
  60. GRB 220426C: Swift/BAT-GUANO detection outside the coded FOV (short)
  61. GRB 220426A: Swift/BAT-GUANO detection outside the coded FOV
  62. GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
  63. GRB 220421A: Fermi GBM observation
  64. GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
  65. GRB 220418B: Swift-XRT observations
  66. GRB 220418B Fermi GBM observation
  67. GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
  68. GRB 220403C: Further Swift-XRT observations
  69. GRB 220418B: Swift ToO observations
  70. GRB 220417A: Fermi GBM detection
  71. GRB 220418B: Swift/BAT-GUANO refined location of a short burst
  72. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  73. GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
  74. GRB 220412B: Swift/UVOT Upper Limits
  75. GRB 220412B: Swift-BAT refined analysis
  76. Konus-Wind detection of GRB 220412B
  77. GRB 220412B: Fermi GBM observation
  78. Konus-Wind detection of GRB 220403C
  79. GRB 220412A: GRANDMA observations
  80. GRB 220412A: BOOTES-network optical upper limits
  81. GRB 220412B: BOOTES-1 optical upper limit
  82. GRB 220412A: Swift-BAT refined analysis
  83. GRB 220412B: Swift-XRT observations
  84. IPN triangulation of short/soft GRB 220406A
  85. Swift GRB 220412B: Global MASTER-Net observations report
  86. GRB 220408A: HCT optical upper limit
  87. GRB 220412B: GIT optical upper limit
  88. GRB 220412A: MITSuME Akeno optical upper limits
  89. Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
  90. GRB 220412B: MITSuME Akeno optical upper limits
  91. GRB 220412A: Swift-XRT refined Analysis
  92. GRB 220412A: Enhanced Swift-XRT position
  93. GRB 220412B: Swift detection of a short burst
  94. GRB 220412A: Swift/UVOT Upper Limits
  95. GRB 220408A: GRANDMA observations
  96. GRB 220412A: RATIR Afterglow Candidate
  97. GRB 220412A: Swift detection of a burst
  98. Swift GRB220412.28: Global MASTER-Net observations report
  99. IPN triangulation of GRB 220403C
  100. GRB 220403B: Swift/UVOT Detection

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