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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"

27763 results found.

  1. GRB 230506A: Fermi GBM Final Real-time Localization
  2. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  3. GRB 230427A: Swift-BAT refined analysis
  4. GRB 230503A: Fermi GBM Final Real-time Localization
  5. Konus-Wind detection of GRB 230430A
  6. IPN triangulation of GRB 230430A (short)
  7. GRB 230420A: AROMA-N Optical Upper Limit
  8. GRB 230430B: Fermi GBM Final Localization
  9. GRB 230430A: AstroSat CZTI detection
  10. GRB 230430A: Fermi GBM Final Real-time Localization
  11. GRB 230427A: NOT optical upper limit
  12. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  13. GRB 230427A: Swift/UVOT Detection
  14. GRB 230427A: Gaoyazi/GOT optical upper limit
  15. GRB 230427A: Nanshan/HMT optical upper limit
  16. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  17. GRB 230427A: Swift-XRT refined Analysis
  18. GRB 230426A: VZLUSAT-2 detection
  19. GRB 230428A: Fermi GBM Final Real-time Localization
  20. GRB 230427A: GIT optical upper limit
  21. GRB 230427A: Bassano Bresciano Observatory upper limit
  22. GRB 230427A: BOOTES-5/JGT afterglow detection
  23. GRB 230423A(trigger #1165354): Swift-BAT refined analysis
  24. GRB 230427A: AKO Upper Limit
  25. Swift GRB230427.44: Global MASTER-Net observations report
  26. GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery
  27. GRB 230427A: MITSuME Akeno optical upper limits
  28. GRB 230426A: Fermi GBM Detection
  29. GRB 230427A: Enhanced Swift-XRT position
  30. GRB 230427A: Swift detection of a burst with an optical counterpart
  31. GRB 230426A: AstroSat CZTI detection
  32. GRB 230426A: Fermi GBM Final Real-time Localization
  33. GRB 230423A: Swift/UVOT Upper Limits
  34. GRB 230425A: Fermi GBM Final Real-time Localization
  35. GRB 230423A: Swift-XRT refined Analysis
  36. GRB 230420A: Lowell Discovery Telescope Optical Detection
  37. GRB 230423A: Swift-XRT afterglow detection
  38. Swift Trigger 1165354 is probably not a GRB
  39. GRB 221009A: Late-time JWST Observations and Detection of Supernova Emission
  40. GRB 230421A: Fermi GBM observation
  41. Konus-Wind detection of GRB 230418A
  42. GRB 230420A: Swift/UVOT Upper Limits
  43. GRB 230421: Swift/BAT-GUANO arcminute localization
  44. GRB 230420A: Swift-BAT refined analysis
  45. GRB 230421A: Fermi GBM Final Real-time Localization
  46. GRB 230420A: Swift-XRT refined Analysis
  47. GRB 230420A: MITSuME Akeno optical observation
  48. GRB 230420A: NOT optical afterglow confirmation
  49. GRB 230420A: Gaoyazi/GOT optical upper limit
  50. GRB 230420A: BOOTES-5/JGT optical afterglow detection
  51. GRB 230420A: LCOGT Optical Upper Limit
  52. GRB 230420A: Enhanced Swift-XRT position
  53. IPN triangulation of GRB 230418A (short)
  54. GRB 230420A: Swift detection of a burst
  55. GRB 230418A: AstroSat CZTI detection
  56. GRB 230418A: AGILE detection
  57. GRB 230402A: Fermi GBM detection
  58. GRB 230419A: Fermi GBM Final Real-time Localization
  59. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  60. GRB 230402A: Fermi-LAT detection
  61. GRB 230414B Swift-BAT refined analysis
  62. GRB 230415A: Fermi GBM detection
  63. GRB 230414B: Swift/UVOT Detection
  64. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  65. GRB 230415A: Swift/BAT-GUANO detection
  66. VIRT optical transient detection
  67. GRB 230307A: iTelescope optical upper limit (likely)
  68. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  69. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  70. GRB 230414B: Lulin 40cm-SLT optical limit
  71. GRB 230414B: Bassano Bresciano Observatory optical observations
  72. GRB 230414B: AbAO optical observations
  73. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  74. GRB 230414B: Swift-XRT refined Analysis
  75. GRB 230414B: Dabancheng/GHOST optical observations
  76. GRB 230414B: SAO RAS optical observations
  77. GRB 230414B: Enhanced Swift-XRT position
  78. GRB 230414B: 1.3m DFOT Optical observations
  79. GRB 230414B: GROWTH India Telescope afterglow confirmation
  80. GRB 230414B: Nanshan/HMT optical afterglow detection
  81. GRB 230414A: Mondy optical afterglow candidate
  82. Swift GRB 230414B: Global MASTER-Net observations report
  83. GRB 230414B: Prompt enhanced Swift-XRT position
  84. GRB 230414B: Swift detection of a burst
  85. GRB 230414A: Fermi GBM Final Real-time Localization
  86. GRB 230328B: redshift lower limit estimating
  87. GRB 230409B: Mondy optical upper limit
  88. GRB 230410B: VZLUSAT-2 detection
  89. GRB 230409D: VZLUSAT-2 detection
  90. GRB 230410B: AGILE detection of a burst
  91. GRB 230410A: Fermi GBM Final Real-time Localization
  92. GRB 230409C: Fermi GBM Final Real-time Localization
  93. GRB 230409B: Swift-XRT refined Analysis
  94. GRB 230409B: Swift-BAT refined analysis
  95. Swift GRB 230409B: Global MASTER-Net observations report
  96. GRB 230409B: Swift/UVOT Detection
  97. GRB 230409B: Enhanced Swift-XRT position
  98. GRB 230409B: Swift detection of a burst
  99. GRB 230409A: Fermi GBM Final Real-time Localization
  100. GRB 230405B: VZLUSAT-2 detection

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