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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"
  1. GRB050421: Radio Observations
  2. GRB 050421: Swift-UVOT observation
  3. GRB 050421: IR Observations
  4. GRB 050421: Swift-BAT refined analysis
  5. GRB 050421: ROTSE-III Optical Limits
  6. GRB 050421: NIR observations re-examination
  7. GRB050421
  8. GRB 050421: early Swift XRT analysis results
  9. GRB 050421: NIR observations
  10. GRB050421: P60 Observations
  11. GRB 050421: BOOTES-2 simultaneous optical observations
  12. GRB 050421: Optical observations at the INT
  13. Swift Detection of GRB050421
  14. GRB 050416b: Tentative Swift XRT Position
  15. GRB 050315: potential host galaxy
  16. GRB050326: analysis of the XMM-Newton observation
  17. GRB050418: Null Optical Observations
  18. GRB 050412: Chandra observations
  19. GRB050416A, optical observations
  20. GRB 050418: Swift-BAT refined analysis
  21. Swift-BAT detection of the bright and long GRB 050418
  22. GRB 050416: Mitsume optical observation
  23. GRB 050416 : optical observation at Xinglong observatory
  24. GRB 050416B: optical observations
  25. GRB 050416b: Swift-BAT refined analysis
  26. GRB 050416b: LCO observations
  27. GRB 050416b: LCO observations
  28. GRB050416B: IR observations
  29. GRB 050416: Swift/UVOT refined analysis
  30. Swift-BAT detection of GRB 050416b
  31. IBAS GRB Alert # 2463: not a GRB
  32. GRB050412: Radio Observations
  33. GRB 050416: Swift/UVOT detection of afterglow emission
  34. GRB050416: Refined Swift-XRT analysis
  35. GRB050416: Maidanak optical observations
  36. GRB 050416: Swift-BAT refined analysis
  37. GRB 050416: ART observations
  38. GRB 050416,optical observation
  39. GRB 050416: KAIT observations
  40. GRB050416: P200 NIR Observations
  41. GRB 050416: Swift XRT Position
  42. GRB 050416: Radio observations
  43. Confirmation of OT for GRB050416
  44. GRB050416: P60 Afterglow Candidate
  45. Swift BAT/XRT Detection of GRB 050416
  46. GRB 050412: Subaru observations
  47. GRB 050408: RTT150 optical observations
  48. GRB050408: optical observation
  49. GRB 050412: PROMPT VRcIc Observations
  50. GRB 050408: Kuiper 1.5m observations
  51. GRB 050412: optical limit
  52. GRB 050412: optical observations
  53. GRB 050408: refined XRT analysis, no jet break seen yet
  54. GRB 050412: early Swift XRT analysis results
  55. GRB 050412 : XingLong optical observation
  56. GRB 050412: Swift-BAT refined analysis
  57. GRB 050412: ANU 2.3m observations
  58. GRB 050412: Early Optical/Ultraviolet Observations with
  59. GRB 050412: retraction of UVOT transient report
  60. GRB 050412: UVOT transient not in XRT error circle
  61. GRB 050408: SDSS Field Calibration
  62. GRB 050412: Optical limit
  63. GRB 050412: LCO Optical Observations
  64. GRB 050412: Optical observations
  65. GRB050412: P60 Observations
  66. GRB 050412: Swift XRT Position
  67. GRB050412: optical limit before and during GRB
  68. GRB 050412: LCO optical observations
  69. GRB050412: ROTSE-III Optical Limits
  70. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  71. GRB 050412: IR and Optical observations
  72. GRB 050412: IR Observations
  73. GRB050408: Radio Observations
  74. GRB 050401: Optical limit
  75. GRB 050408: Optical limit
  76. GRB050410: P60 Observations
  77. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  78. GRB 050410, optical observations
  79. GRB 050408: PROMPT VRcIc Observations
  80. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  81. GRB 050410 R band Optical Observations
  82. GRB050410 : Null detection report
  83. GRB 050410, optical observations
  84. GRB050410: Radio Observations
  85. GRB 050408: Swift XRT measurement of possible jet break
  86. GRB050410: MASTER optical observations
  87. GRB 050410: Early observations with Swift-UVOT
  88. Swift-BAT detection of GRB 050410
  89. GRB 050410: Swift XRT Position
  90. GRB 050408: Retraction of Proposed Host Galaxy
  91. GRB 050408: Inconsistency of host galaxy identification
  92. GRB 050408: Subaru Observations
  93. GRB 050408: WIDGET simultaneous optical observations
  94. GRB 050408: SOAR UBVRc Observations
  95. GRB 050408: Properties of the Host Galaxy
  96. GRB 050408: Mercator Optical Observations
  97. GRB050408: Radio Observations
  98. GRB 050408: Swift XRT analysis
  99. GRB 050408, SMARTS optical/IR afterglow observations
  100. GRB 050408: Optical limit at 20 min after the burst

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