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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"

27415 results found.

  1. GRB 081121: Swift detection of a burst
  2. GRB 081121: ROTSE-III Detection of Optical Counterpart
  3. GRB081118 : optical upper limit
  4. GRB 081119: Fermi GBM detection
  5. GRB 081118: Swift-XRT refined analysis
  6. GRB 081118: GROND detection of afterglow
  7. GRB 081118: Swift UVOT Upper Limits
  8. GRB 081118: Swift-BAT refined analysis
  9. GRB 081118: Swift detection of a burst
  10. Further Swift-XRT observations of the probable GRB 081105.
  11. GRB 081113: Fermi GBM detection
  12. GRB 081102: RTT150 Optical observations
  13. GRB 081110: Fermi GBM detection
  14. GRB 081110: MASTER: first optical observations Fermi GRB
  15. GRB 081109: TAROT La Silla observatory optical observations
  16. GRB 081102: MASTER refind and final results
  17. GRB 081109: GROND redshift limit and host extinction
  18. Swift-BAT refined analysis of trigger 334129
  19. GRB 081109B: Swift/UVOT refined analysis
  20. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  21. GRB 081109A: Possible Swift-UVOT detection
  22. GRB 081109A, Swift-BAT refined analysis
  23. GRB 081109A: Swift-XRT refined analysis
  24. GRB 081109: Fermi GBM detection
  25. GRB 081109: Swift/UVOT upper limits
  26. Swift-BAT Trigger 334129: possible burst
  27. GRB 081109: Swift detection of a burst
  28. GRB 081028 - PAIRITEL NIR detection
  29. GRB 081024C: Fermi Gamma-ray Burst Monitor detection
  30. SGR 1806-20: Fermi GBM detection
  31. GRB 081102B: Fermi GBM detection
  32. GRB 081105B: Fermi GBM detection
  33. GRB 081107: Fermi GBM detection
  34. GRB 081104: GROND found no Optical/NIR Afterglow
  35. GRB 081105: GROND Upper Limits
  36. Radio observation of GRB 080523 with ATCA
  37. Radio observation of GRB 080520 with ATCA
  38. UVOT/Swift observations of GRB081105
  39. Swift-XRT observations of GRB 081105
  40. GRB 081101B: Fermi GBM detection
  41. Radio observation of GRB 080516 with ATCA
  42. GRB 081105 Swift/BAT and IPN Localization
  43. GRB 081025: Fermi GBM observation
  44. GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
  45. GRB 081104: refined XRT analysis
  46. GRB 081104: Swift-BAT refined analysis
  47. GRB081104: Swift/UVOT Upper Limits
  48. Fermi-GBM detection of a Solar Flare
  49. Fermi Detection of GRB 081102
  50. GRB 081104 : Faulkes Telescope South observations
  51. GRB 081104: Swift-XRT position
  52. GRB 081104: Swift detection of a burst
  53. Radio observation of GRB 080130 with ATCA
  54. GRB 081102: MASTER prompt optical limit
  55. GRB 081102: Swift-XRT refined analysis
  56. GRB 081102: Swift/UVOT refined analysis
  57. GRB 081102: Swift-BAT refined analysis
  58. Radio observation of GRB 080218b with ATCA
  59. Radio observation of GRB 080229a with ATCA
  60. GRB 081102: MASTER VWF promt observation
  61. GRB 081102: Swift detection of a burst
  62. GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
  63. SGR 0623-0006 or GRB 081101: Swift-XRT refined analysis
  64. SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
  65. Swift-BAT triggered on a probable GRB 081101 (trigger=333320)
  66. GRB 081029: UVOT Detection of the Optical Afterglow
  67. GRB 081029: PROMPT Detections
  68. GRB 081029: Swift-BAT refined analysis
  69. GRB 081028: GROND Confirmation of the Optical/NIR Afterglow
  70. Radio observation of GRB 080303 with ATCA
  71. Radio observation of GRB 080411 with ATCA
  72. GRB 081029: GROND Detection of the Optical/NIR Afterglow
  73. GRB 081029: ROTSE-III Detection of Optical Counterpart
  74. GRB 081029: Swift detection of a burst
  75. GRB 081028B: Fermi GBM detection
  76. GRB 081021: Fermi GBM detection
  77. GRB081028: UVOT detection of a brightening afterglow
  78. Swift UVOT observations of GRB081028
  79. GRB 081028: Swift-XRT refined analysis
  80. GRB 081028, Swift-BAT refined analysis
  81. GRB 081028: TAROT Calern observatory optical observations
  82. GRB 081028: GROND Detection of the Optical/NIR Afterglow Candidate
  83. GRB 081028: Swift detection of a burst
  84. GRB 081025: TLS upper limits
  85. GRB 081025 BAT refined analysis
  86. Swift UVOT observations of GRB081025
  87. Swift UVOT observations of GRB081024B
  88. GRB 081025: Swift-XRT position
  89. GRB 081024B: Swift-XRT observations
  90. GRB 081025: Burst detection from Swift-BAT slew data
  91. GRB 081024B: Fermi Gamma-ray Burst Monitor detection
  92. Fermi-LAT observation of GRB 081024B
  93. Swift UVOT observations of GRB 081024
  94. GRB 081024, Swift-BAT refined analysis
  95. GRB 081024: Faulkes Telescope North optical observations
  96. GRB 081024: Early Super-LOTIS Observations
  97. GRB 081024A: ROTSE-III Optical Limits
  98. GRB 081024: Swift detection of a burst
  99. GRB 081022, Swift-BAT refined analysis
  100. GRB 081016A: Swift-XRT refined analysis

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