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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"

19531 results found.

  1. GRB 050416,optical observation
  2. GRB 050416: KAIT observations
  3. GRB 050416: Swift XRT Position
  4. GRB 050416: Radio observations
  5. Confirmation of OT for GRB050416
  6. GRB050416: P60 Afterglow Candidate
  7. Swift BAT/XRT Detection of GRB 050416
  8. GRB 050412: Subaru observations
  9. GRB 050412: optical limit
  10. GRB 050412: optical observations
  11. GRB 050408: refined XRT analysis, no jet break seen yet
  12. GRB 050412: early Swift XRT analysis results
  13. GRB 050412: Swift-BAT refined analysis
  14. GRB 050412: ANU 2.3m observations
  15. GRB 050412: Early Optical/Ultraviolet Observations with
  16. GRB 050412: retraction of UVOT transient report
  17. GRB 050412: UVOT transient not in XRT error circle
  18. GRB 050412: Swift XRT Position
  19. GRB050412: optical limit before and during GRB
  20. GRB050412: ROTSE-III Optical Limits
  21. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  22. GRB 050412: IR Observations
  23. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  24. GRB 050410, optical observations
  25. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  26. GRB 050410 R band Optical Observations
  27. GRB050410 : Null detection report
  28. GRB 050410, optical observations
  29. GRB050410: Radio Observations
  30. GRB 050408: Swift XRT measurement of possible jet break
  31. GRB050410: MASTER optical observations
  32. GRB 050410: Early observations with Swift-UVOT
  33. Swift-BAT detection of GRB 050410
  34. GRB 050410: Swift XRT Position
  35. GRB 050408: Properties of the Host Galaxy
  36. GRB 050408: Swift XRT analysis
  37. GRB 050408, optical observations
  38. GRB050408: REM NIR and Optical observation
  39. GRB 050408 Optical Observations
  40. GRB 050408: Optical afterglow confirmed
  41. GRB 050408, optical observations
  42. GRB 050408 optical candidate
  43. GRB 050408: Swift XRT Position
  44. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  45. GRB 050406: early Swift XRT analysis results
  46. GRB 050406 BAT refined analysis
  47. GRB 050406: Early observations with Swift-UVOT
  48. GRB 050406: Swift XRT Position
  49. Swift-BAT detection of GRB 050406
  50. Konus-Wind observation of GRB 050401
  51. GRB050401: Radio observation at 610 MHz with GMRT
  52. GRB 050401: VLT spectroscopic redshift
  53. GRB 050401 Optical Observations
  54. GRB050401: Maidanak optical observation
  55. GRB 050401 BAT refined analysis
  56. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  57. GRB 050402A: IR Observations
  58. GRB 050402: Early observations with Swift-UVOT
  59. Swift Trigger 113225: P60 Observations
  60. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  61. GRB 050401: Optical afterglow candidate
  62. Swift-BAT detection of GRB 050401
  63. GRB 050401: Prompt XRT position
  64. Retraction of three Swift GRB triggers
  65. Swift-BAT detection of GRB 050331b
  66. GRB 050331: Swift UVOT Source
  67. Swift-BAT detection of GRB 050331
  68. GRB 050331: Swift XRT Position
  69. Swift Data Publicly Available Starting April 5, 2005
  70. Konus-Wind observation of GRB 050326
  71. GRB050326: optical limit
  72. GRB 050326: Early observations with Swift-UVOT
  73. GRB 050326 XMM-Newton observation
  74. GRB 050326 : Planned XMM-Newton observation
  75. GRB 050326: Swift XRT Position
  76. GRB050326: optical limit 33min before GRB
  77. GRB 050326 BAT refined analysis
  78. GRB050326: delayed XRT observation
  79. Swift-BAT detection of a bright GRB 050326
  80. GRB050319, optical observations
  81. GRB050319, color indices
  82. GRB050319: RTT150 Optical Observations
  83. Swift-BAT detection of a bright outburst from SGR1806-20
  84. Swift-BAT trigger 112060 is not a real GRB
  85. GRB 050319: ROTSE-III Refined Analysis
  86. GRB 050318: Swift-BAT refined analysis
  87. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  88. GRB 050319 R band observations
  89. GRB 050319: Swift-UVOT detection of the afterglow
  90. GRB 050315: Variability Analysis of Swift BAT Time History
  91. GRB050319: BR optical photometry
  92. GRB 050318: SWIFT-UVOT refined analysis
  93. GRB 050319: Swift-BAT refined analysis
  94. GRB050319,optical observation
  95. Swift Detection of GRB 050319
  96. GRB 050319: Detection of Possible Optical Counterpart
  97. GRB 050318: Swift/UVOT detection of afterglow emission
  98. GRB050318: Swift XRT position
  99. Swift-BAT detection of GRB 050318
  100. GRB050223: analysis of the XMM-Newton observation

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