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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"

27296 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. GRB 050520: OSN optical observations
  7. No Swift-BAT Lightcurves in real-time for next 3 weeks
  8. Swift-BAT trigger 122203 is not a real GRB
  9. XRF 050509C: REM NIR and Optical refined analysis
  10. GRB 050504: Swift XRT afterglow candidate has faded
  11. GRB 050509B: Subaru Optical Observations
  12. GRB050502b: Early Observation
  13. Refined Chandra analysis of GRB 050509b
  14. GRB050509b, SDSS pre-burst observations
  15. Chandra observation of GRB 050509b
  16. GRB 050509b: RAPTOR deep, early limits.
  17. GRB050509B: Optical/Infared observations
  18. GRB 050509b: Swift/UVOT follow-up measurements
  19. GRB 050509b Milagro GeV/TeV Observations
  20. GRB050509B: Optical observations at the Very Large Telescope
  21. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  22. GRB 050509a: Swift-BAT refined analysis
  23. GRB 050509B: WSRT Radio Observations
  24. GRB 050505: SARA Observations
  25. Swift UVOT Follow-up Observations of GRB 050509B
  26. GRB 050509B, Optical Observations
  27. GRB 050509B: Swift/XRT refined analysis
  28. GRB050509a: Swift UVOT observations
  29. GRB 050509b: Optical observations
  30. GRB 050509b: Possible Optical Counterpart
  31. GRB 050509A: Optical observations
  32. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  33. GRB 050509b: optical observations
  34. GRB 050509b: Swift XRT Position
  35. GRB 050509B: ROTSE-III Optical Limits
  36. Swift Detection of GRB050509b: A short duration burst
  37. GRB 050509a: Swift XRT Position
  38. Swift Detection of the Burst GRB050509
  39. Swift-BAT detection of GRB 050507
  40. GRB 050505: early time observations
  41. GRB 050505 - Faulkes Telescope North observations
  42. GRB 050502a: Swift XRT Upper Limit
  43. GRB 050505, simultaneous optical observation
  44. GRB 050505: Further Swift UVOT observations.
  45. GRB050416A : 1 GHz limit from GMRT
  46. GRB 050505 UVOT
  47. GRB 050505: Swift XRT Position
  48. GRB050505 Swift-BAT refined analysis
  49. GRB 050416b:Swift XRT afterglow upper limits
  50. GRB 050416b:Swift XRT afterglow upper limits
  51. Swift-BAT detection of GRB050505
  52. GRB 050504: Swift XRT position
  53. Swift UVOT observation of GRB 050504
  54. GRB 050502b, V band Observations
  55. GRB050502B Swift-BAT refined analysis
  56. GRB050502B: I band source in XRT error circle
  57. Swift UVOT refined analysis
  58. Retraction of Swift-BAT trigger 116145
  59. GRB 050502b : optical observation at Lulin observatory
  60. GRB 050502b: Swift XRT Position
  61. GRB050502B: Optical Limits from ANU 1m
  62. Swift Detection of the Bright Burst GRB050502b
  63. GRB050502: ANU 1m optical Observations
  64. GRB 050502: PAIRITEL IR Observations
  65. GRB 050502: ROTSE-III Detection of Possible Counterpart
  66. Swift-BAT Trigger 115881 is not a real GRB
  67. Swift/BAT possible detection of a weak burst GRB050430
  68. GRB 050401: Rc observation
  69. GRB050416a: Radio Detection
  70. GRB 050422: Swift-UVOT observation
  71. GRB 050422: Swift-BAT refined analysis
  72. GRB 050422: Swift XRT Position
  73. Swift Detection of GRB 050422
  74. GRB 050416: Optical/NIR observations
  75. GRB 050421: SLOTIS observations
  76. GRB050421: Radio Observations
  77. GRB050421: Radio Observations
  78. GRB 050421: Swift-UVOT observation
  79. GRB 050421: Swift-BAT refined analysis
  80. GRB 050421: ROTSE-III Optical Limits
  81. GRB050421
  82. GRB 050421: early Swift XRT analysis results
  83. GRB 050421: BOOTES-2 simultaneous optical observations
  84. GRB 050421: Optical observations at the INT
  85. Swift Detection of GRB050421
  86. GRB 050416b: Tentative Swift XRT Position
  87. GRB050326: analysis of the XMM-Newton observation
  88. GRB 050418: Swift-BAT refined analysis
  89. Swift-BAT detection of the bright and long GRB 050418
  90. GRB 050416B: optical observations
  91. GRB 050416b: Swift-BAT refined analysis
  92. GRB 050416: Swift/UVOT refined analysis
  93. Swift-BAT detection of GRB 050416b
  94. GRB050412: Radio Observations
  95. GRB 050416: Swift/UVOT detection of afterglow emission
  96. GRB050416: Refined Swift-XRT analysis
  97. GRB050416: Maidanak optical observations
  98. GRB 050416: Swift-BAT refined analysis
  99. GRB 050416,optical observation
  100. GRB 050416: KAIT observations

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