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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"

34021 results found.

  1. GRB 050509a: Swift XRT Position
  2. Swift-BAT detection of GRB 050507
  3. GRB 050505: Keck I-band Magnitude
  4. GRB 050505: early time observations
  5. GRB 050505 - Faulkes Telescope North observations
  6. GRB 050502a: Swift XRT Upper Limit
  7. GRB 050505, simultaneous optical observation
  8. GRB 050505: Further Swift UVOT observations.
  9. GRB050505: AAVSO observations
  10. GRB050416A : 1 GHz limit from GMRT
  11. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  12. GRB 050505 UVOT
  13. GRB050505: Optical Afterglow Candidate
  14. GRB 050505: Swift XRT Position
  15. GRB 050502a: Optical Observations
  16. GRB 050416b:Swift XRT afterglow upper limits
  17. GRB 050416b:Swift XRT afterglow upper limits
  18. GRB 050504: Swift XRT position
  19. GRB050502: P200 Observations (Correction)
  20. GRB050502: P200 Observations
  21. GRB 050504 : R band observation at Lulin observatory
  22. Swift UVOT observation of GRB 050504
  23. GRB 050504, R band Observations
  24. GRB 050502b, V band Observations
  25. GRB050504: P60 Observations
  26. GRB 050504: A long GRB detected with INTEGRAL
  27. GRB (?) 050504: IR Observations, Intriguing Source
  28. GRB 050502b, Optical observations
  29. GRB050502a: P60 Observations (Correction)
  30. GRB050502a: P60 Observations
  31. Renewal of SGR 1806-20 activity
  32. GRB 050502a: RBO Observations
  33. GRB 050502A: WSRT Radio Observations
  34. GRB050502A: Optical Observations
  35. Swift UVOT refined analysis
  36. Retraction of Swift-BAT trigger 116145
  37. GRB 050502a : R band observation at Lulin observatory
  38. GRB 050502b : optical observation at Lulin observatory
  39. GRB 050502b: Swift XRT Position
  40. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  41. GRB 050502: INTEGRAL results
  42. GRB050502: ANU 1m optical Observations
  43. GRB 050502: Confirmed variability of the afterglow candidate +
  44. GRB 050502: PAIRITEL IR Observations
  45. GRB050502 - Correction on the Optical Candidate from the Liverpool
  46. GRB 050502 - A long GRB detected with INTEGRAL
  47. GRB 050502: ROTSE-III Detection of Possible Counterpart
  48. Swift-BAT Trigger 115881 is not a real GRB
  49. Swift/BAT possible detection of a weak burst GRB050430
  50. GRB 050401: Rc observation
  51. GRB050416a: Radio Detection
  52. GRB 050422: Swift-UVOT observation
  53. GRB 050422: Swift-BAT refined analysis
  54. GRB 050422: Swift XRT Position
  55. Swift Detection of GRB 050422
  56. GRB 050421: NIR observations
  57. GRB 050416: Optical/NIR observations
  58. GRB 050421: SLOTIS observations
  59. GRB 050421: Further Analysis of IR imaging
  60. GRB050421: Radio Observations
  61. GRB050421: Radio Observations
  62. GRB 050421: Swift-UVOT observation
  63. GRB 050421: IR Observations
  64. GRB 050421: Swift-BAT refined analysis
  65. GRB 050421: ROTSE-III Optical Limits
  66. GRB 050421: NIR observations re-examination
  67. GRB 050421: early Swift XRT analysis results
  68. GRB 050421: NIR observations
  69. GRB050421: P60 Observations
  70. GRB 050421: BOOTES-2 simultaneous optical observations
  71. GRB 050421: Optical observations at the INT
  72. GRB 050416b: Tentative Swift XRT Position
  73. GRB 050315: potential host galaxy
  74. GRB 050412: Chandra observations
  75. GRB050416A, optical observations
  76. GRB 050418: Swift-BAT refined analysis
  77. Swift-BAT detection of the bright and long GRB 050418
  78. GRB 050416: Mitsume optical observation
  79. GRB 050416 : optical observation at Xinglong observatory
  80. GRB 050416B: optical observations
  81. GRB 050416b: Swift-BAT refined analysis
  82. GRB 050416b: LCO observations
  83. GRB 050416b: LCO observations
  84. GRB050416B: IR observations
  85. GRB 050416: Swift/UVOT refined analysis
  86. Swift-BAT detection of GRB 050416b
  87. IBAS GRB Alert # 2463: not a GRB
  88. GRB050412: Radio Observations
  89. GRB 050416: Swift/UVOT detection of afterglow emission
  90. GRB 050416: Swift-BAT refined analysis
  91. GRB 050416: ART observations
  92. GRB 050416,optical observation
  93. GRB 050416: KAIT observations
  94. GRB050416: P200 NIR Observations
  95. GRB 050416: Swift XRT Position
  96. GRB 050416: Radio observations
  97. Confirmation of OT for GRB050416
  98. GRB050416: P60 Afterglow Candidate
  99. Swift BAT/XRT Detection of GRB 050416
  100. GRB 050412: Subaru observations

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