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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"

19255 results found.

  1. GRB050528, XRT observations
  2. Correction to GCN Circ 3502 on GRB 050528
  3. Swift-BAT GRB 050528: a soft burst
  4. Update on Swift-BAT GRB 050528 (Trigger 130679)
  5. Possible GRB050528: no candidate from Liverpool Telescope
  6. Swift-BAT detection of possible GRB 050528
  7. GRB 050509b: refined XRT/Chandra afterglow position analysis
  8. GRB050525a: optical upper limits
  9. GRB 050525B: Swift-BAT observations
  10. GRB050525A,optical observation
  11. GRB050525: Super-LOTIS observations
  12. GRB 050525, spectral lag pseudo-redshift
  13. GRB050306: optical afterglow not confirmed
  14. GRB 050525A: BOOTES simultaneous optical observations
  15. GRB 050525A: Swift-BAT refined analysis
  16. Swift/UVOT UV and optical detections of GRB 050525
  17. Konus-Wind observation of GRB 050525
  18. GRB 050525: TAROT observations of the early afterglow
  19. INTEGRAL detection of GRB 050525
  20. GRB 050525: Optical observation
  21. GRB050525: ROTSE-III Refined Analysis
  22. GRB 050525 - Very Bright, Not Short
  23. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  24. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  25. XRF 050522: Swift XRT refined analysis
  26. Swift/UVOT observation of XRF 050522
  27. GRB 050509A: Further I-band imaging
  28. RBO Observations of GRB050522
  29. XRF 050522: Swift XRT observation
  30. GRB 050520: VLT/ULTRACAM observations
  31. Swift UVOT Observations of GRB 050520
  32. GRB 050520: Swift XRT refined analysis
  33. XRF050509C: Chandra Afterglow Detection
  34. XRF 050509c: Swift XRT Upper Limit
  35. RBO Observations of GRB050520
  36. GRB 050520: TAROT optical limit
  37. GRB 050520: Swift XRT position
  38. No Swift-BAT Lightcurves in real-time for next 3 weeks
  39. Swift-BAT trigger 122203 is not a real GRB
  40. GRB 050504: Swift XRT afterglow candidate has faded
  41. GRB 050509B: Subaru Optical Observations
  42. GRB050502b: Early Observation
  43. Refined Chandra analysis of GRB 050509b
  44. GRB050509b, SDSS pre-burst observations
  45. Chandra observation of GRB 050509b
  46. GRB 050509b: RAPTOR deep, early limits.
  47. GRB050509B: Optical/Infared observations
  48. GRB 050509b: Swift/UVOT follow-up measurements
  49. GRB 050509b Milagro GeV/TeV Observations
  50. GRB050509B: Optical observations at the Very Large Telescope
  51. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  52. GRB 050509a: Swift-BAT refined analysis
  53. GRB 050509B: WSRT Radio Observations
  54. GRB 050505: SARA Observations
  55. Swift UVOT Follow-up Observations of GRB 050509B
  56. GRB 050509B, Optical Observations
  57. GRB 050509B: Swift/XRT refined analysis
  58. GRB050509a: Swift UVOT observations
  59. GRB 050509b: Optical observations
  60. GRB 050509b: Possible Optical Counterpart
  61. GRB 050509A: Optical observations
  62. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  63. GRB 050509b: optical observations
  64. GRB 050509b: Swift XRT Position
  65. GRB 050509B: ROTSE-III Optical Limits
  66. Swift Detection of GRB050509b: A short duration burst
  67. GRB 050509a: Swift XRT Position
  68. Swift Detection of the Burst GRB050509
  69. Swift-BAT detection of GRB 050507
  70. GRB 050505: early time observations
  71. GRB 050505 - Faulkes Telescope North observations
  72. GRB 050502a: Swift XRT Upper Limit
  73. GRB 050505, simultaneous optical observation
  74. GRB 050505: Further Swift UVOT observations.
  75. GRB050416A : 1 GHz limit from GMRT
  76. GRB 050505 UVOT
  77. GRB 050505: Swift XRT Position
  78. GRB050505 Swift-BAT refined analysis
  79. GRB 050416b:Swift XRT afterglow upper limits
  80. GRB 050416b:Swift XRT afterglow upper limits
  81. Swift-BAT detection of GRB050505
  82. GRB 050504: Swift XRT position
  83. Swift UVOT observation of GRB 050504
  84. GRB 050502b, V band Observations
  85. GRB050502B Swift-BAT refined analysis
  86. GRB050502B: I band source in XRT error circle
  87. Swift UVOT refined analysis
  88. Retraction of Swift-BAT trigger 116145
  89. GRB 050502b : optical observation at Lulin observatory
  90. GRB 050502b: Swift XRT Position
  91. GRB050502B: Optical Limits from ANU 1m
  92. Swift Detection of the Bright Burst GRB050502b
  93. GRB050502: ANU 1m optical Observations
  94. Swift-BAT Trigger 115881 is not a real GRB
  95. Swift/BAT possible detection of a weak burst GRB050430
  96. GRB 050401: Rc observation
  97. GRB050416a: Radio Detection
  98. GRB 050422: Swift-UVOT observation
  99. GRB 050422: Swift-BAT refined analysis
  100. GRB 050422: Swift XRT Position

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