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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"

27225 results found.

  1. GRB 081128: Swift-BAT refined analysis
  2. GRB 081128: Enhanced Swift-XRT position
  3. GRB 081128: Swift detection of a burst
  4. GRB 081126: Swift observations continuing
  5. GRB081126: Afterglow photometry from Crni Vrh
  6. GRB 081126: GRT Optical Observation
  7. GRB 081127: Swift/UVOT Upper Limits
  8. GRB 081127: Swift-XRT refined analysis
  9. GRB 081127: Enhanced Swift-XRT position
  10. GRB 081126: Confirmation of the Optical Afterglow
  11. GRB 081127: Swift-BAT refined analysis
  12. GRB 081126: Swift-XRT refined analysis
  13. GRB 081127: Swift detection of a burst
  14. GRB 081126: Swift/UVOT Observations
  15. GRB 081126: optical observations
  16. GRB 081126: Swift-BAT refined analysis
  17. GRB 081126: Enhanced Swift-XRT position
  18. GRB 081126: TAROT Calern observatory optical observations
  19. GRB 081126: Swift detection of a burst
  20. GRB 081125: Fermi GBM detection
  21. GRB 081124: Fermi GBM detection
  22. GRB 081120: Fermi GBM detection
  23. GRB 081118: Fermi GBM detection.
  24. GRB 081122: Fermi GBM detection
  25. Konus-Wind observation of GRB 081121
  26. GRB081121: Fermi GBM detection
  27. Fermi GBM detection of a weak source
  28. GRB081121: Refined Swift/UVOT observations
  29. GRB 081121: Swift-XRT refined analysis
  30. GRB 081121: Enhanced Swift-XRT position
  31. GRB 081121: GROND observations
  32. GRB 081121: Swift-BAT refined analysis
  33. GRB081121: Swift/UVOT observations
  34. GRB 081121: Swift detection of a burst
  35. GRB 081121: ROTSE-III Detection of Optical Counterpart
  36. GRB081118 : optical upper limit
  37. GRB 081119: Fermi GBM detection
  38. GRB 081118: Swift-XRT refined analysis
  39. GRB 081118: GROND detection of afterglow
  40. GRB 081118: Swift UVOT Upper Limits
  41. GRB 081118: Swift-BAT refined analysis
  42. GRB 081118: Enhanced Swift-XRT position
  43. GRB 081118: Swift detection of a burst
  44. GRB 081109A: confirmation of possible detection host galaxy
  45. Further Swift-XRT observations of the probable GRB 081105.
  46. GRB 081113: Fermi GBM detection
  47. GRB 081102: RTT150 Optical observations
  48. GRB 081110: Fermi GBM detection
  49. GRB 081109: TAROT La Silla observatory optical observations
  50. GRB 081102: MASTER refind and final results
  51. GRB 081109: GROND redshift limit and host extinction
  52. GRB 081025: Swift-XRT further analysis
  53. GRB 081024B: Swift-XRT late-time observations
  54. Swift-BAT refined analysis of trigger 334129
  55. GRB 081109B: Swift/UVOT refined analysis
  56. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  57. GRB 081109A: Possible Swift-UVOT detection
  58. GRB 081109A, Swift-BAT refined analysis
  59. GRB 081109A: Swift-XRT refined analysis
  60. GRB 081109: Fermi GBM detection
  61. GRB 081109: Swift/UVOT upper limits
  62. Swift-BAT Trigger 334129: possible burst
  63. GRB 081109: REM NIR afterglow detection
  64. GRB 081109: Swift detection of a burst
  65. GRB 081028 - PAIRITEL NIR detection
  66. GRB 081024C: Fermi Gamma-ray Burst Monitor detection
  67. SGR 1806-20: Fermi GBM detection
  68. GRB 081102B: Fermi GBM detection
  69. GRB 081105B: Fermi GBM detection
  70. GRB 081107: Fermi GBM detection
  71. GRB 081105: GROND Upper Limits
  72. UVOT/Swift observations of GRB081105
  73. Swift-XRT observations of GRB 081105
  74. GRB 081101B: Fermi GBM detection
  75. GRB 081105 Swift/BAT and IPN Localization
  76. GRB 081025: Fermi GBM observation
  77. GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
  78. GRB 081104: refined XRT analysis
  79. GRB 081104: Enhanced Swift-XRT position
  80. GRB 081104: Swift-BAT refined analysis
  81. GRB081104: Swift/UVOT Upper Limits
  82. Fermi-GBM detection of a Solar Flare
  83. Fermi Detection of GRB 081102
  84. GRB 081104: Swift-XRT position
  85. GRB 081104: Swift detection of a burst
  86. GRB 081102: MASTER prompt optical limit
  87. GRB 081102: Swift-XRT refined analysis
  88. GRB 081102: Swift/UVOT refined analysis
  89. GRB 081102: Swift-BAT refined analysis
  90. GRB 081102: Enhanced Swift-XRT position
  91. Radio observation of GRB 080218b with ATCA
  92. GRB 081102: MASTER VWF promt observation
  93. GRB 081102: Swift detection of a burst
  94. GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
  95. SGR 0623-0006 or GRB 081101: Swift-XRT refined analysis
  96. SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
  97. Swift-BAT triggered on a probable GRB 081101 (trigger=333320)
  98. GRB 081024B: BTA deep optical observations
  99. GRB 081028: CrAO optical observations
  100. GRB 081024B: new Swift-XRT observations

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