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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"

19538 results found.

  1. GRB 050525: Optical observation
  2. GRB050525: ROTSE-III Refined Analysis
  3. GRB 050525 - Very Bright, Not Short
  4. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  5. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  6. XRF 050522: Swift XRT refined analysis
  7. Swift/UVOT observation of XRF 050522
  8. GRB 050509A: Further I-band imaging
  9. RBO Observations of GRB050522
  10. XRF 050522: Swift XRT observation
  11. GRB 050520: VLT/ULTRACAM observations
  12. Swift UVOT Observations of GRB 050520
  13. GRB 050520: Swift XRT refined analysis
  14. XRF050509C: Chandra Afterglow Detection
  15. XRF 050509c: Swift XRT Upper Limit
  16. RBO Observations of GRB050520
  17. GRB 050520: TAROT optical limit
  18. GRB 050520: Swift XRT position
  19. No Swift-BAT Lightcurves in real-time for next 3 weeks
  20. Swift-BAT trigger 122203 is not a real GRB
  21. GRB 050504: Swift XRT afterglow candidate has faded
  22. GRB 050509B: Subaru Optical Observations
  23. GRB050502b: Early Observation
  24. Refined Chandra analysis of GRB 050509b
  25. GRB050509b, SDSS pre-burst observations
  26. Chandra observation of GRB 050509b
  27. GRB 050509b: RAPTOR deep, early limits.
  28. GRB050509B: Optical/Infared observations
  29. GRB 050509b: Swift/UVOT follow-up measurements
  30. GRB 050509b Milagro GeV/TeV Observations
  31. GRB050509B: Optical observations at the Very Large Telescope
  32. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  33. GRB 050509a: Swift-BAT refined analysis
  34. GRB 050509B: WSRT Radio Observations
  35. GRB 050505: SARA Observations
  36. Swift UVOT Follow-up Observations of GRB 050509B
  37. GRB 050509B, Optical Observations
  38. GRB 050509B: Swift/XRT refined analysis
  39. GRB050509a: Swift UVOT observations
  40. GRB 050509b: Optical observations
  41. GRB 050509b: Possible Optical Counterpart
  42. GRB 050509A: Optical observations
  43. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  44. GRB 050509b: optical observations
  45. GRB 050509b: Swift XRT Position
  46. GRB 050509B: ROTSE-III Optical Limits
  47. Swift Detection of GRB050509b: A short duration burst
  48. GRB 050509a: Swift XRT Position
  49. Swift Detection of the Burst GRB050509
  50. Swift-BAT detection of GRB 050507
  51. GRB 050505: early time observations
  52. GRB 050505 - Faulkes Telescope North observations
  53. GRB 050502a: Swift XRT Upper Limit
  54. GRB 050505, simultaneous optical observation
  55. GRB 050505: Further Swift UVOT observations.
  56. GRB050416A : 1 GHz limit from GMRT
  57. GRB 050505 UVOT
  58. GRB 050505: Swift XRT Position
  59. GRB050505 Swift-BAT refined analysis
  60. GRB 050416b:Swift XRT afterglow upper limits
  61. GRB 050416b:Swift XRT afterglow upper limits
  62. Swift-BAT detection of GRB050505
  63. GRB 050504: Swift XRT position
  64. Swift UVOT observation of GRB 050504
  65. GRB 050502b, V band Observations
  66. GRB050502B Swift-BAT refined analysis
  67. GRB050502B: I band source in XRT error circle
  68. Swift UVOT refined analysis
  69. Retraction of Swift-BAT trigger 116145
  70. GRB 050502b : optical observation at Lulin observatory
  71. GRB 050502b: Swift XRT Position
  72. GRB050502B: Optical Limits from ANU 1m
  73. Swift Detection of the Bright Burst GRB050502b
  74. GRB050502: ANU 1m optical Observations
  75. Swift-BAT Trigger 115881 is not a real GRB
  76. Swift/BAT possible detection of a weak burst GRB050430
  77. GRB 050401: Rc observation
  78. GRB050416a: Radio Detection
  79. GRB 050422: Swift-UVOT observation
  80. GRB 050422: Swift-BAT refined analysis
  81. GRB 050422: Swift XRT Position
  82. Swift Detection of GRB 050422
  83. GRB 050421: SLOTIS observations
  84. GRB050421: Radio Observations
  85. GRB050421: Radio Observations
  86. GRB 050421: Swift-UVOT observation
  87. GRB 050421: Swift-BAT refined analysis
  88. GRB 050421: ROTSE-III Optical Limits
  89. GRB 050421: early Swift XRT analysis results
  90. GRB 050421: BOOTES-2 simultaneous optical observations
  91. GRB 050421: Optical observations at the INT
  92. Swift Detection of GRB050421
  93. GRB 050416b: Tentative Swift XRT Position
  94. GRB050326: analysis of the XMM-Newton observation
  95. GRB 050418: Swift-BAT refined analysis
  96. Swift-BAT detection of the bright and long GRB 050418
  97. GRB 050416B: optical observations
  98. GRB 050416b: Swift-BAT refined analysis
  99. GRB 050416: Swift/UVOT refined analysis
  100. Swift-BAT detection of GRB 050416b

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