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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 050502a : R band observation at Lulin observatory
  2. GRB 050502b : optical observation at Lulin observatory
  3. GRB 050502b: Swift XRT Position
  4. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  5. GRB050502B: Optical Limits from ANU 1m
  6. Swift Detection of the Bright Burst GRB050502b
  7. GRB 050502: INTEGRAL results
  8. GRB050502: ANU 1m optical Observations
  9. GRB 050502: Confirmed variability of the afterglow candidate +
  10. GRB 050502: PAIRITEL IR Observations
  11. GRB050502 - Correction on the Optical Candidate from the Liverpool
  12. GRB050502 - Optical Candidate from the Liverpool Telescope
  13. GRB 050502 - A long GRB detected with INTEGRAL
  14. GRB 050502: ROTSE-III Detection of Possible Counterpart
  15. Swift-BAT Trigger 115881 is not a real GRB
  16. Swift/BAT possible detection of a weak burst GRB050430
  17. GRB 050401: Rc observation
  18. GRB050416a: Radio Detection
  19. GRB 050422: Swift-UVOT observation
  20. GRB 050422: Swift-BAT refined analysis
  21. GRB 050422: Swift XRT Position
  22. Swift Detection of GRB 050422
  23. GRB 050421: NIR observations
  24. GRB 050416: Optical/NIR observations
  25. GRB 050421: SLOTIS observations
  26. GRB 050421: Further Analysis of IR imaging
  27. GRB050421: Radio Observations
  28. GRB050421: Radio Observations
  29. GRB 050421: Swift-UVOT observation
  30. GRB 050421: IR Observations
  31. GRB 050421: Swift-BAT refined analysis
  32. GRB 050421: ROTSE-III Optical Limits
  33. GRB 050421: NIR observations re-examination
  34. GRB050421
  35. GRB 050421: early Swift XRT analysis results
  36. GRB 050421: NIR observations
  37. GRB050421: P60 Observations
  38. GRB 050421: BOOTES-2 simultaneous optical observations
  39. GRB 050421: Optical observations at the INT
  40. Swift Detection of GRB050421
  41. GRB 050416b: Tentative Swift XRT Position
  42. GRB 050315: potential host galaxy
  43. GRB050326: analysis of the XMM-Newton observation
  44. GRB050418: Null Optical Observations
  45. GRB 050412: Chandra observations
  46. GRB050416A, optical observations
  47. GRB 050418: Swift-BAT refined analysis
  48. Swift-BAT detection of the bright and long GRB 050418
  49. GRB 050416: Mitsume optical observation
  50. GRB 050416 : optical observation at Xinglong observatory
  51. GRB 050416B: optical observations
  52. GRB 050416b: Swift-BAT refined analysis
  53. GRB 050416b: LCO observations
  54. GRB 050416b: LCO observations
  55. GRB050416B: IR observations
  56. GRB 050416: Swift/UVOT refined analysis
  57. Swift-BAT detection of GRB 050416b
  58. IBAS GRB Alert # 2463: not a GRB
  59. GRB050412: Radio Observations
  60. GRB 050416: Swift/UVOT detection of afterglow emission
  61. GRB050416: Refined Swift-XRT analysis
  62. GRB050416: Maidanak optical observations
  63. GRB 050416: Swift-BAT refined analysis
  64. GRB 050416: ART observations
  65. GRB 050416,optical observation
  66. GRB 050416: KAIT observations
  67. GRB050416: P200 NIR Observations
  68. GRB 050416: Swift XRT Position
  69. GRB 050416: Radio observations
  70. Confirmation of OT for GRB050416
  71. GRB050416: P60 Afterglow Candidate
  72. Swift BAT/XRT Detection of GRB 050416
  73. GRB 050412: Subaru observations
  74. GRB 050408: RTT150 optical observations
  75. GRB050408: optical observation
  76. GRB 050412: PROMPT VRcIc Observations
  77. GRB 050408: Kuiper 1.5m observations
  78. GRB 050412: optical limit
  79. GRB 050412: optical observations
  80. GRB 050408: refined XRT analysis, no jet break seen yet
  81. GRB 050412: early Swift XRT analysis results
  82. GRB 050412 : XingLong optical observation
  83. GRB 050412: Swift-BAT refined analysis
  84. GRB 050412: ANU 2.3m observations
  85. GRB 050412: Early Optical/Ultraviolet Observations with
  86. GRB 050412: retraction of UVOT transient report
  87. GRB 050412: UVOT transient not in XRT error circle
  88. GRB 050408: SDSS Field Calibration
  89. GRB 050412: Optical limit
  90. GRB 050412: LCO Optical Observations
  91. GRB 050412: Optical observations
  92. GRB050412: P60 Observations
  93. GRB 050412: Swift XRT Position
  94. GRB050412: optical limit before and during GRB
  95. GRB 050412: LCO optical observations
  96. GRB050412: ROTSE-III Optical Limits
  97. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  98. GRB 050412: IR and Optical observations
  99. GRB 050412: IR Observations
  100. GRB050408: Radio Observations

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