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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"

27415 results found.

  1. Swift-BAT GRB 050528: a soft burst
  2. Update on Swift-BAT GRB 050528 (Trigger 130679)
  3. GRB050528: BOOTES optical candidate (retraction)
  4. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  5. GRB050528: BOOTES optical candidate
  6. Possible GRB050528: no candidate from Liverpool Telescope
  7. Swift-BAT detection of possible GRB 050528
  8. GRB 050525B: Swift-BAT observations
  9. GRB050525A,optical observation
  10. GRB050525: Super-LOTIS observations
  11. GRB 050525, spectral lag pseudo-redshift
  12. GRB 050525A: BOOTES simultaneous optical observations
  13. GRB 050525A: Swift-BAT refined analysis
  14. Swift/UVOT UV and optical detections of GRB 050525
  15. Konus-Wind observation of GRB 050525
  16. GRB 050525 - Very Bright, Not Short
  17. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  18. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  19. GRB 050509A: Further I-band imaging
  20. GRB050522,optical observation
  21. GRB050520,optical observation
  22. GRB 050520: VLT/ULTRACAM observations
  23. GRB 050520: BART optical limit
  24. No Swift-BAT Lightcurves in real-time for next 3 weeks
  25. Swift-BAT trigger 122203 is not a real GRB
  26. XRF 050509C: REM NIR and Optical refined analysis
  27. XRF 050509c optical afterglow
  28. GRB050502b: Early Observation
  29. GRB050509b, SDSS pre-burst observations
  30. GRB 050509b: RAPTOR deep, early limits.
  31. GRB 050509b: Swift/UVOT follow-up measurements
  32. GRB050509B: Optical observations at the Very Large Telescope
  33. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  34. GRB 050509a: Swift-BAT refined analysis
  35. GRB 050509c: ROTSE-III Optical Limits
  36. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  37. GRB050509c: REM NIR and Optical observations
  38. Swift UVOT Follow-up Observations of GRB 050509B
  39. GRB 050509B: Swift/XRT refined analysis
  40. GRB050509a: Swift UVOT observations
  41. GRB 050509b: Optical observations
  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 050505, simultaneous optical observation
  54. GRB050505: Infrared observations
  55. GRB 050505: Further Swift UVOT observations.
  56. GRB 050505 UVOT
  57. GRB 050505: Swift XRT Position
  58. GRB050505 Swift-BAT refined analysis
  59. GRB 050416b:Swift XRT afterglow upper limits
  60. GRB 050416b:Swift XRT afterglow upper limits
  61. Swift-BAT detection of GRB050505
  62. Swift UVOT observation of GRB 050504
  63. GRB050504: Faulkes North optical robotic limit
  64. GRB 050502b, V band Observations
  65. GRB (?) 050504: IR Observations, Intriguing Source
  66. Renewal of SGR 1806-20 activity
  67. GRB050502B Swift-BAT refined analysis
  68. Swift UVOT refined analysis
  69. Retraction of Swift-BAT trigger 116145
  70. GRB 050502b: Swift XRT Position
  71. Swift Detection of the Bright Burst GRB050502b
  72. GRB050502: ANU 1m optical Observations
  73. GRB 050502: ROTSE-III Detection of Possible Counterpart
  74. Swift-BAT Trigger 115881 is not a real GRB
  75. Swift/BAT possible detection of a weak burst GRB050430
  76. GRB 050422: Swift-UVOT observation
  77. GRB 050422: Swift-BAT refined analysis
  78. GRB 050422: Swift XRT Position
  79. Swift Detection of GRB 050422
  80. GRB 050421: SLOTIS observations
  81. GRB050421: Radio Observations
  82. GRB050421: Radio Observations
  83. GRB 050421: Swift-UVOT observation
  84. GRB 050421: Swift-BAT refined analysis
  85. GRB 050421: ROTSE-III Optical Limits
  86. GRB050421
  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. GRB 050418: Swift-BAT refined analysis
  93. Swift-BAT detection of the bright and long GRB 050418
  94. GRB 050416B: optical observations
  95. GRB 050416b: Swift-BAT refined analysis
  96. GRB 050416b: LCO observations
  97. GRB 050416b: LCO observations
  98. GRB050416B: IR observations
  99. GRB 050416: Swift/UVOT refined analysis
  100. Swift-BAT detection of GRB 050416b

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