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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"

19332 results found.

  1. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  2. XRF 050522: Swift XRT refined analysis
  3. Swift/UVOT observation of XRF 050522
  4. GRB 050509A: Further I-band imaging
  5. RBO Observations of GRB050522
  6. XRF 050522: Swift XRT observation
  7. GRB 050520: VLT/ULTRACAM observations
  8. Swift UVOT Observations of GRB 050520
  9. GRB 050520: Swift XRT refined analysis
  10. XRF050509C: Chandra Afterglow Detection
  11. XRF 050509c: Swift XRT Upper Limit
  12. RBO Observations of GRB050520
  13. GRB 050520: TAROT optical limit
  14. GRB 050520: Swift XRT position
  15. No Swift-BAT Lightcurves in real-time for next 3 weeks
  16. Swift-BAT trigger 122203 is not a real GRB
  17. GRB 050504: Swift XRT afterglow candidate has faded
  18. GRB 050509B: Subaru Optical Observations
  19. GRB050502b: Early Observation
  20. Refined Chandra analysis of GRB 050509b
  21. GRB050509b, SDSS pre-burst observations
  22. Chandra observation of GRB 050509b
  23. GRB 050509b: RAPTOR deep, early limits.
  24. GRB050509B: Optical/Infared observations
  25. GRB 050509b: Swift/UVOT follow-up measurements
  26. GRB 050509b Milagro GeV/TeV Observations
  27. GRB050509B: Optical observations at the Very Large Telescope
  28. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  29. GRB 050509a: Swift-BAT refined analysis
  30. GRB 050509B: WSRT Radio Observations
  31. GRB 050505: SARA Observations
  32. Swift UVOT Follow-up Observations of GRB 050509B
  33. GRB 050509B, Optical Observations
  34. GRB 050509B: Swift/XRT refined analysis
  35. GRB050509a: Swift UVOT observations
  36. GRB 050509b: Optical observations
  37. GRB 050509b: Possible Optical Counterpart
  38. GRB 050509A: Optical observations
  39. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  40. GRB 050509b: optical observations
  41. GRB 050509b: Swift XRT Position
  42. GRB 050509B: ROTSE-III Optical Limits
  43. Swift Detection of GRB050509b: A short duration burst
  44. GRB 050509a: Swift XRT Position
  45. Swift Detection of the Burst GRB050509
  46. Swift-BAT detection of GRB 050507
  47. GRB 050505: early time observations
  48. GRB 050505 - Faulkes Telescope North observations
  49. GRB 050502a: Swift XRT Upper Limit
  50. GRB 050505, simultaneous optical observation
  51. GRB 050505: Further Swift UVOT observations.
  52. GRB050416A : 1 GHz limit from GMRT
  53. GRB 050505 UVOT
  54. GRB 050505: Swift XRT Position
  55. GRB050505 Swift-BAT refined analysis
  56. GRB 050416b:Swift XRT afterglow upper limits
  57. GRB 050416b:Swift XRT afterglow upper limits
  58. Swift-BAT detection of GRB050505
  59. GRB 050504: Swift XRT position
  60. Swift UVOT observation of GRB 050504
  61. GRB 050502b, V band Observations
  62. GRB050502B Swift-BAT refined analysis
  63. GRB050502B: I band source in XRT error circle
  64. Swift UVOT refined analysis
  65. Retraction of Swift-BAT trigger 116145
  66. GRB 050502b : optical observation at Lulin observatory
  67. GRB 050502b: Swift XRT Position
  68. GRB050502B: Optical Limits from ANU 1m
  69. Swift Detection of the Bright Burst GRB050502b
  70. GRB050502: ANU 1m optical Observations
  71. Swift-BAT Trigger 115881 is not a real GRB
  72. Swift/BAT possible detection of a weak burst GRB050430
  73. GRB 050401: Rc observation
  74. GRB050416a: Radio Detection
  75. GRB 050422: Swift-UVOT observation
  76. GRB 050422: Swift-BAT refined analysis
  77. GRB 050422: Swift XRT Position
  78. Swift Detection of GRB 050422
  79. GRB 050421: SLOTIS observations
  80. GRB050421: Radio Observations
  81. GRB050421: Radio Observations
  82. GRB 050421: Swift-UVOT observation
  83. GRB 050421: Swift-BAT refined analysis
  84. GRB 050421: ROTSE-III Optical Limits
  85. GRB 050421: early Swift XRT analysis results
  86. GRB 050421: BOOTES-2 simultaneous optical observations
  87. GRB 050421: Optical observations at the INT
  88. Swift Detection of GRB050421
  89. GRB 050416b: Tentative Swift XRT Position
  90. GRB050326: analysis of the XMM-Newton observation
  91. GRB 050418: Swift-BAT refined analysis
  92. Swift-BAT detection of the bright and long GRB 050418
  93. GRB 050416B: optical observations
  94. GRB 050416b: Swift-BAT refined analysis
  95. GRB 050416: Swift/UVOT refined analysis
  96. Swift-BAT detection of GRB 050416b
  97. GRB050412: Radio Observations
  98. GRB 050416: Swift/UVOT detection of afterglow emission
  99. GRB050416: Refined Swift-XRT analysis
  100. GRB050416: Maidanak optical observations

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