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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"

19548 results found.

  1. XRF050509C: Chandra Afterglow Detection
  2. XRF 050509c: Swift XRT Upper Limit
  3. RBO Observations of GRB050520
  4. GRB 050520: TAROT optical limit
  5. GRB 050520: Swift XRT position
  6. No Swift-BAT Lightcurves in real-time for next 3 weeks
  7. Swift-BAT trigger 122203 is not a real GRB
  8. GRB 050504: Swift XRT afterglow candidate has faded
  9. GRB 050509B: Subaru Optical Observations
  10. GRB050502b: Early Observation
  11. Refined Chandra analysis of GRB 050509b
  12. GRB050509b, SDSS pre-burst observations
  13. Chandra observation of GRB 050509b
  14. GRB 050509b: RAPTOR deep, early limits.
  15. GRB050509B: Optical/Infared observations
  16. GRB 050509b: Swift/UVOT follow-up measurements
  17. GRB 050509b Milagro GeV/TeV Observations
  18. GRB050509B: Optical observations at the Very Large Telescope
  19. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  20. GRB 050509a: Swift-BAT refined analysis
  21. GRB 050509B: WSRT Radio Observations
  22. GRB 050505: SARA Observations
  23. Swift UVOT Follow-up Observations of GRB 050509B
  24. GRB 050509B, Optical Observations
  25. GRB 050509B: Swift/XRT refined analysis
  26. GRB050509a: Swift UVOT observations
  27. GRB 050509b: Optical observations
  28. GRB 050509b: Possible Optical Counterpart
  29. GRB 050509A: Optical observations
  30. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  31. GRB 050509b: optical observations
  32. GRB 050509b: Swift XRT Position
  33. GRB 050509B: ROTSE-III Optical Limits
  34. Swift Detection of GRB050509b: A short duration burst
  35. GRB 050509a: Swift XRT Position
  36. Swift Detection of the Burst GRB050509
  37. Swift-BAT detection of GRB 050507
  38. GRB 050505: early time observations
  39. GRB 050505 - Faulkes Telescope North observations
  40. GRB 050502a: Swift XRT Upper Limit
  41. GRB 050505, simultaneous optical observation
  42. GRB 050505: Further Swift UVOT observations.
  43. GRB050416A : 1 GHz limit from GMRT
  44. GRB 050505 UVOT
  45. GRB 050505: Swift XRT Position
  46. GRB050505 Swift-BAT refined analysis
  47. GRB 050416b:Swift XRT afterglow upper limits
  48. GRB 050416b:Swift XRT afterglow upper limits
  49. Swift-BAT detection of GRB050505
  50. GRB 050504: Swift XRT position
  51. Swift UVOT observation of GRB 050504
  52. GRB 050502b, V band Observations
  53. Renewal of SGR 1806-20 activity
  54. GRB050502B Swift-BAT refined analysis
  55. GRB050502B: I band source in XRT error circle
  56. Swift UVOT refined analysis
  57. Retraction of Swift-BAT trigger 116145
  58. GRB 050502b : optical observation at Lulin observatory
  59. GRB 050502b: Swift XRT Position
  60. GRB050502B: Optical Limits from ANU 1m
  61. Swift Detection of the Bright Burst GRB050502b
  62. GRB050502: ANU 1m optical Observations
  63. Swift-BAT Trigger 115881 is not a real GRB
  64. Swift/BAT possible detection of a weak burst GRB050430
  65. GRB 050401: Rc observation
  66. GRB050416a: Radio Detection
  67. GRB 050422: Swift-UVOT observation
  68. GRB 050422: Swift-BAT refined analysis
  69. GRB 050422: Swift XRT Position
  70. Swift Detection of GRB 050422
  71. GRB 050421: SLOTIS observations
  72. GRB050421: Radio Observations
  73. GRB050421: Radio Observations
  74. GRB 050421: Swift-UVOT observation
  75. GRB 050421: Swift-BAT refined analysis
  76. GRB 050421: ROTSE-III Optical Limits
  77. GRB 050421: early Swift XRT analysis results
  78. GRB 050421: BOOTES-2 simultaneous optical observations
  79. GRB 050421: Optical observations at the INT
  80. Swift Detection of GRB050421
  81. GRB 050416b: Tentative Swift XRT Position
  82. GRB050326: analysis of the XMM-Newton observation
  83. GRB 050418: Swift-BAT refined analysis
  84. Swift-BAT detection of the bright and long GRB 050418
  85. GRB 050416B: optical observations
  86. GRB 050416b: Swift-BAT refined analysis
  87. GRB 050416: Swift/UVOT refined analysis
  88. Swift-BAT detection of GRB 050416b
  89. GRB050412: Radio Observations
  90. GRB 050416: Swift/UVOT detection of afterglow emission
  91. GRB050416: Refined Swift-XRT analysis
  92. GRB050416: Maidanak optical observations
  93. GRB 050416: Swift-BAT refined analysis
  94. GRB 050416,optical observation
  95. GRB 050416: KAIT observations
  96. GRB 050416: Swift XRT Position
  97. GRB 050416: Radio observations
  98. Confirmation of OT for GRB050416
  99. GRB050416: P60 Afterglow Candidate
  100. Swift BAT/XRT Detection of GRB 050416

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