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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"

28075 results found.

  1. Swift Detection of the Burst GRB050509
  2. Swift-BAT detection of GRB 050507
  3. GRB050505: Infrared observations
  4. GRB 050505: Further Swift UVOT observations.
  5. GRB 050505 UVOT
  6. GRB050505 Swift-BAT refined analysis
  7. GRB 050416b:Swift XRT afterglow upper limits
  8. GRB 050416b:Swift XRT afterglow upper limits
  9. Swift-BAT detection of GRB050505
  10. Swift UVOT observation of GRB 050504
  11. GRB050504: Faulkes North optical robotic limit
  12. GRB 050502b, V band Observations
  13. GRB (?) 050504: IR Observations, Intriguing Source
  14. Renewal of SGR 1806-20 activity
  15. GRB050502B Swift-BAT refined analysis
  16. Swift UVOT refined analysis
  17. Retraction of Swift-BAT trigger 116145
  18. Swift Detection of the Bright Burst GRB050502b
  19. GRB 050502: ROTSE-III Detection of Possible Counterpart
  20. Swift-BAT Trigger 115881 is not a real GRB
  21. Swift/BAT possible detection of a weak burst GRB050430
  22. GRB 050422: Swift-UVOT observation
  23. GRB 050422: Swift-BAT refined analysis
  24. Swift Detection of GRB 050422
  25. GRB 050421: SLOTIS observations
  26. GRB 050421: Swift-UVOT observation
  27. GRB 050421: Swift-BAT refined analysis
  28. GRB 050421: ROTSE-III Optical Limits
  29. GRB050421
  30. GRB 050421: early Swift XRT analysis results
  31. Swift Detection of GRB050421
  32. GRB 050418: Swift-BAT refined analysis
  33. Swift-BAT detection of the bright and long GRB 050418
  34. GRB 050416b: Swift-BAT refined analysis
  35. GRB050416B: IR observations
  36. GRB 050416: Swift/UVOT refined analysis
  37. Swift-BAT detection of GRB 050416b
  38. GRB 050416: Swift/UVOT detection of afterglow emission
  39. GRB050416: Refined Swift-XRT analysis
  40. GRB 050416: Swift-BAT refined analysis
  41. GRB 050416: ART observations
  42. GRB 050416,optical observation
  43. GRB 050416: KAIT observations
  44. Swift BAT/XRT Detection of GRB 050416
  45. GRB 050412: optical limit
  46. GRB 050412: early Swift XRT analysis results
  47. GRB 050412: Swift-BAT refined analysis
  48. GRB 050412: Optical limit
  49. GRB 050412: Optical observations
  50. GRB050412: ROTSE-III Optical Limits
  51. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  52. GRB 050412: IR Observations
  53. GRB 050401: Optical limit
  54. GRB 050408: Optical limit
  55. GRB 050410, optical observations
  56. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  57. GRB 050410 R band Optical Observations
  58. GRB 050408: Swift XRT measurement of possible jet break
  59. GRB 050410: Early observations with Swift-UVOT
  60. Swift-BAT detection of GRB 050410
  61. GRB 050410: Swift XRT Position
  62. GRB 050408: Swift XRT analysis
  63. GRB 050408,optical observation
  64. GRB 050408: Magellan astrometry and photometry
  65. GRB 050408: ROTSE-III Optical Limits
  66. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  67. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  68. GRB 050406: early Swift XRT analysis results
  69. GRB 050406 BAT refined analysis
  70. GRB 050406: Early observations with Swift-UVOT
  71. Swift-BAT detection of GRB 050406
  72. Konus-Wind observation of GRB 050401
  73. GRB 050401 Optical Observations
  74. GRB 050401 BAT refined analysis
  75. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  76. GRB 050402: Early observations with Swift-UVOT
  77. Swift Trigger 113225: P60 Observations
  78. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  79. GRB 050401: Optical afterglow candidate
  80. Swift-BAT detection of GRB 050401
  81. Swift-BAT detection of GRB 050331b
  82. GRB 050331: Swift UVOT Source
  83. Konus-Wind observation of GRB 050326
  84. GRB050326: optical limit
  85. GRB 050326: Early observations with Swift-UVOT
  86. GRB 050326 : Planned XMM-Newton observation
  87. GRB 050326 BAT refined analysis
  88. Swift-BAT detection of a bright GRB 050326
  89. GRB050319, optical observations
  90. Swift-BAT detection of a bright outburst from SGR1806-20
  91. Swift-BAT trigger 112060 is not a real GRB
  92. GRB 050319: ROTSE-III Refined Analysis
  93. GRB 050319: Swift-UVOT detection of the afterglow
  94. GRB 050318: SWIFT-UVOT refined analysis
  95. GRB050319,optical observation
  96. GRB 050318: Swift/UVOT detection of afterglow emission
  97. RXTE Observations of GRB050318
  98. Swift-BAT detection of GRB 050318
  99. GRB 050315: Swift-BAT further refined analysis
  100. GRB 050315: Early Observations with Swift/UVOT

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