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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"

19530 results found.

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

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