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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"

19534 results found.

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

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