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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"

18631 results found.

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

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