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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"

45439 results found.

  1. GRB 050509b: Optical Counterpart Candidate
  2. GRB050509b: Radio Observations
  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. Swift Detection of GRB050509b: A short duration burst
  9. GRB 050509a: Swift XRT Position
  10. Swift Detection of the Burst GRB050509
  11. Swift-BAT detection of GRB 050507
  12. GRB 050505: Keck I-band Magnitude
  13. GRB 050505: early time observations
  14. GRB 050505 - Faulkes Telescope North observations
  15. GRB 050502a: Swift XRT Upper Limit
  16. GRB 050505, simultaneous optical observation
  17. GRB050505: Infrared observations
  18. GRB 050505: Further Swift UVOT observations.
  19. GRB050505: AAVSO observations
  20. GRB050416A : 1 GHz limit from GMRT
  21. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  22. GRB 050505 UVOT
  23. GRB050505: Optical Afterglow Candidate
  24. GRB 050505: Swift XRT Position
  25. GRB050505 Swift-BAT refined analysis
  26. GRB 050502a: Optical Observations
  27. GRB 050416b:Swift XRT afterglow upper limits
  28. GRB 050416b:Swift XRT afterglow upper limits
  29. Swift-BAT detection of GRB050505
  30. GRB 050504: Swift XRT position
  31. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  32. GRB050502b: Afterglow Confirmation
  33. GRB050502: P200 Observations (Correction)
  34. GRB050502: P200 Observations
  35. GRB 050504 : R band observation at Lulin observatory
  36. Swift UVOT observation of GRB 050504
  37. GRB 050504, R band Observations
  38. GRB050504: Faulkes North optical robotic limit
  39. GRB 050502b, V band Observations
  40. GRB050504: P60 Observations
  41. GRB 050504: A long GRB detected with INTEGRAL
  42. GRB (?) 050504: IR Observations, Intriguing Source
  43. GRB 050502b, Optical observations
  44. GRB050502a: P60 Observations (Correction)
  45. GRB050502a: P60 Observations
  46. Renewal of SGR 1806-20 activity
  47. GRB 050502a: RBO Observations
  48. GRB 050502A: WSRT Radio Observations
  49. GRB050502A: Optical Observations
  50. GRB050502B Swift-BAT refined analysis
  51. GRB050502B: I band source in XRT error circle
  52. Swift UVOT refined analysis
  53. Retraction of Swift-BAT trigger 116145
  54. GRB 050502a : R band observation at Lulin observatory
  55. GRB 050502b : optical observation at Lulin observatory
  56. GRB 050502b: Swift XRT Position
  57. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  58. GRB050502B: Optical Limits from ANU 1m
  59. Swift Detection of the Bright Burst GRB050502b
  60. GRB 050502: INTEGRAL results
  61. GRB050502: ANU 1m optical Observations
  62. GRB 050502: Confirmed variability of the afterglow candidate +
  63. GRB 050502: PAIRITEL IR Observations
  64. GRB050502 - Correction on the Optical Candidate from the Liverpool
  65. GRB050502 - Optical Candidate from the Liverpool Telescope
  66. GRB 050502 - A long GRB detected with INTEGRAL
  67. GRB 050502: ROTSE-III Detection of Possible Counterpart
  68. Swift-BAT Trigger 115881 is not a real GRB
  69. Swift/BAT possible detection of a weak burst GRB050430
  70. GRB 050401: Rc observation
  71. GRB050416a: Radio Detection
  72. GRB 050422: Swift-UVOT observation
  73. GRB 050422: Swift-BAT refined analysis
  74. GRB 050422: Swift XRT Position
  75. Swift Detection of GRB 050422
  76. GRB 050421: NIR observations
  77. GRB 050416: Optical/NIR observations
  78. GRB 050421: SLOTIS observations
  79. GRB 050421: Further Analysis of IR imaging
  80. GRB050421: Radio Observations
  81. GRB050421: Radio Observations
  82. GRB 050421: Swift-UVOT observation
  83. GRB 050421: IR Observations
  84. GRB 050421: Swift-BAT refined analysis
  85. GRB 050421: ROTSE-III Optical Limits
  86. GRB 050421: NIR observations re-examination
  87. GRB050421
  88. GRB 050421: early Swift XRT analysis results
  89. GRB 050421: NIR observations
  90. GRB050421: P60 Observations
  91. GRB 050421: BOOTES-2 simultaneous optical observations
  92. GRB 050421: Optical observations at the INT
  93. Swift Detection of GRB050421
  94. GRB 050416b: Tentative Swift XRT Position
  95. GRB 050315: potential host galaxy
  96. GRB050326: analysis of the XMM-Newton observation
  97. GRB050418: Null Optical Observations
  98. GRB 050412: Chandra observations
  99. GRB050416A, optical observations
  100. GRB 050418: Swift-BAT refined analysis

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