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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"

27024 results found.

  1. GRB050502B Swift-BAT refined analysis
  2. Swift UVOT refined analysis
  3. Retraction of Swift-BAT trigger 116145
  4. Swift Detection of the Bright Burst GRB050502b
  5. GRB 050502: ROTSE-III Detection of Possible Counterpart
  6. Swift-BAT Trigger 115881 is not a real GRB
  7. Swift/BAT possible detection of a weak burst GRB050430
  8. GRB 050422: Swift-UVOT observation
  9. GRB 050422: Swift-BAT refined analysis
  10. Swift Detection of GRB 050422
  11. GRB 050421: SLOTIS observations
  12. GRB 050421: Swift-UVOT observation
  13. GRB 050421: Swift-BAT refined analysis
  14. GRB 050421: ROTSE-III Optical Limits
  15. GRB050421
  16. GRB 050421: early Swift XRT analysis results
  17. Swift Detection of GRB050421
  18. GRB 050418: Swift-BAT refined analysis
  19. Swift-BAT detection of the bright and long GRB 050418
  20. GRB 050416b: Swift-BAT refined analysis
  21. GRB050416B: IR observations
  22. GRB 050416: Swift/UVOT refined analysis
  23. Swift-BAT detection of GRB 050416b
  24. GRB 050416: Swift/UVOT detection of afterglow emission
  25. GRB050416: Refined Swift-XRT analysis
  26. GRB 050416: Swift-BAT refined analysis
  27. GRB 050416: ART observations
  28. GRB 050416,optical observation
  29. GRB 050416: KAIT observations
  30. Swift BAT/XRT Detection of GRB 050416
  31. GRB 050412: optical limit
  32. GRB 050412: early Swift XRT analysis results
  33. GRB 050412: Swift-BAT refined analysis
  34. GRB 050412: Optical limit
  35. GRB 050412: Optical observations
  36. GRB050412: ROTSE-III Optical Limits
  37. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  38. GRB 050412: IR Observations
  39. GRB 050401: Optical limit
  40. GRB 050408: Optical limit
  41. GRB 050410, optical observations
  42. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  43. GRB 050410 R band Optical Observations
  44. GRB 050408: Swift XRT measurement of possible jet break
  45. GRB 050410: Early observations with Swift-UVOT
  46. Swift-BAT detection of GRB 050410
  47. GRB 050410: Swift XRT Position
  48. GRB 050408: Swift XRT analysis
  49. GRB 050408,optical observation
  50. GRB 050408: Magellan astrometry and photometry
  51. GRB 050408: ROTSE-III Optical Limits
  52. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  53. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  54. GRB 050406: early Swift XRT analysis results
  55. GRB 050406 BAT refined analysis
  56. GRB 050406: Early observations with Swift-UVOT
  57. Swift-BAT detection of GRB 050406
  58. Konus-Wind observation of GRB 050401
  59. GRB 050401 Optical Observations
  60. GRB 050401 BAT refined analysis
  61. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  62. GRB 050402: Early observations with Swift-UVOT
  63. Swift Trigger 113225: P60 Observations
  64. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  65. GRB 050401: Optical afterglow candidate
  66. Swift-BAT detection of GRB 050401
  67. Swift-BAT detection of GRB 050331b
  68. GRB 050331: Swift UVOT Source
  69. Konus-Wind observation of GRB 050326
  70. GRB050326: optical limit
  71. GRB 050326: Early observations with Swift-UVOT
  72. GRB 050326 : Planned XMM-Newton observation
  73. GRB 050326 BAT refined analysis
  74. Swift-BAT detection of a bright GRB 050326
  75. GRB050319, optical observations
  76. Swift-BAT detection of a bright outburst from SGR1806-20
  77. Swift-BAT trigger 112060 is not a real GRB
  78. GRB 050319: ROTSE-III Refined Analysis
  79. GRB 050319: Swift-UVOT detection of the afterglow
  80. GRB 050318: SWIFT-UVOT refined analysis
  81. GRB050319,optical observation
  82. GRB 050318: Swift/UVOT detection of afterglow emission
  83. RXTE Observations of GRB050318
  84. Swift-BAT detection of GRB 050318
  85. GRB 050315: Swift-BAT further refined analysis
  86. GRB 050315: Early Observations with Swift/UVOT
  87. Swift-BAT detection of GRB 050315
  88. GRB050223: No XMM-Newton OM detection of afterglow emission
  89. GRB050309: CONCAM pre-trigger and trigger coincident optical
  90. Swift-BAT trigger 107873: No Swift XRT counterpart
  91. GRB 050309, Early optical limits from RAPTOR
  92. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  93. GRB 050309 : Lulin R-band observation
  94. Swift 107873: P60 Optical Observations
  95. GRB 050306: CORRECTION to date of observation
  96. GRB 050306: No Swift UVOT Optical Counterpart Detected
  97. Swift trigger 107518: optical observation
  98. GRB 050306,optical observation
  99. Ongoing activity of SGR 1806-20 after the giant flare
  100. GRB 050219b: candidate NIR afterglow

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