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

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