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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"

36814 results found.

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

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