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

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