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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"

21393 results found.

  1. GRB 050525A: BOOTES simultaneous optical observations
  2. GRB 050525A: Swift-BAT refined analysis
  3. Swift/UVOT UV and optical detections of GRB 050525
  4. Konus-Wind observation of GRB 050525
  5. GRB 050525: TAROT observations of the early afterglow
  6. INTEGRAL detection of GRB 050525
  7. GRB 050525: Optical observation
  8. GRB050525: ROTSE-III Refined Analysis
  9. GRB 050525 - Very Bright, Not Short
  10. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  11. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  12. XRF050522: NIR observations of XRT candidate
  13. XRF 050522: Swift XRT refined analysis
  14. Swift/UVOT observation of XRF 050522
  15. GRB 050509A: Further I-band imaging
  16. RBO Observations of GRB050522
  17. GRB050509b: optical observations
  18. GRB050520: Radio Observations
  19. XRF 050522: Swift XRT observation
  20. GRB 050520: VLT/ULTRACAM observations
  21. Swift UVOT Observations of GRB 050520
  22. GRB 050520: Swift XRT refined analysis
  23. XRF050509C: Chandra Afterglow Detection
  24. XRF 050509c: Swift XRT Upper Limit
  25. RBO Observations of GRB050520
  26. GRB 050520: P200 Observations
  27. GRB050520: Liverpool Telescope follow-up
  28. GRB 050520: TAROT optical limit
  29. GRB 050520: Swift XRT position
  30. No Swift-BAT Lightcurves in real-time for next 3 weeks
  31. Swift-BAT trigger 122203 is not a real GRB
  32. GRB 050504: Swift XRT afterglow candidate has faded
  33. GRB 050509B and short GRB-SN association? (corrected)
  34. GRB 050509B and short GRB-SN association?
  35. GRB 050509B: Subaru Optical Observations
  36. GRB050502b: Early Observation
  37. GRB050509b, Bok telescope B-band imaging
  38. Refined Chandra analysis of GRB 050509b
  39. GRB050509b, SDSS pre-burst observations
  40. GRB 050509b: Keck/Chandra Cross-Correlation
  41. GRB 050509b: Keck/Chandra Cross-Correlation
  42. Chandra observation of GRB 050509b
  43. GRB 050509b: RAPTOR deep, early limits.
  44. GRB050509B: Optical/Infared observations
  45. GRB 050509b: Swift/UVOT follow-up measurements
  46. GRB 050509b Milagro GeV/TeV Observations
  47. GRB050509B: Optical observations at the Very Large Telescope
  48. GRB 050509b: No Optical Variability in XRT Error Circle
  49. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  50. GRB 050509a: Swift-BAT refined analysis
  51. GRB 050509B: WSRT Radio Observations
  52. GRB 050505: SARA Observations
  53. Swift UVOT Follow-up Observations of GRB 050509B
  54. GRB 050509B, Optical Observations
  55. GRB 050509B: Swift/XRT refined analysis
  56. GRB050509a: Swift UVOT observations
  57. GRB 050509b: Optical observations
  58. GRB 050509b: Precision Astrometry
  59. GRB 050509b: Possible Optical Counterpart
  60. GRB 050509A: Optical observations
  61. GRB 050509b: Optical Counterpart Candidate
  62. GRB050509b: Radio Observations
  63. GRB 050509b: PAIRITEL and WIYN Observations
  64. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  65. GRB 050509b: optical observations
  66. GRB 050509b: Swift XRT Position
  67. GRB 050509B: ROTSE-III Optical Limits
  68. Swift Detection of GRB050509b: A short duration burst
  69. GRB 050509a: Swift XRT Position
  70. Swift Detection of the Burst GRB050509
  71. Swift-BAT detection of GRB 050507
  72. GRB 050505: early time observations
  73. GRB 050505 - Faulkes Telescope North observations
  74. GRB 050502a: Swift XRT Upper Limit
  75. GRB 050505, simultaneous optical observation
  76. GRB 050505: Further Swift UVOT observations.
  77. GRB050416A : 1 GHz limit from GMRT
  78. GRB 050505 UVOT
  79. GRB050505: Optical Afterglow Candidate
  80. GRB 050505: Swift XRT Position
  81. GRB050505 Swift-BAT refined analysis
  82. GRB 050416b:Swift XRT afterglow upper limits
  83. GRB 050416b:Swift XRT afterglow upper limits
  84. Swift-BAT detection of GRB050505
  85. GRB 050504: Swift XRT position
  86. Swift UVOT observation of GRB 050504
  87. GRB 050502b, V band Observations
  88. GRB050502B Swift-BAT refined analysis
  89. GRB050502B: I band source in XRT error circle
  90. Swift UVOT refined analysis
  91. Retraction of Swift-BAT trigger 116145
  92. GRB 050502b : optical observation at Lulin observatory
  93. GRB 050502b: Swift XRT Position
  94. GRB050502B: Optical Limits from ANU 1m
  95. Swift Detection of the Bright Burst GRB050502b
  96. GRB050502: ANU 1m optical Observations
  97. Swift-BAT Trigger 115881 is not a real GRB
  98. Swift/BAT possible detection of a weak burst GRB050430
  99. GRB 050401: Rc observation
  100. GRB050416a: Radio Detection

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