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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"

18651 results found.

  1. Possible GRB050528: no candidate from Liverpool Telescope
  2. Swift-BAT detection of possible GRB 050528
  3. GRB 050509b: refined XRT/Chandra afterglow position analysis
  4. GRB050525a: optical upper limits
  5. GRB 050525B: Swift-BAT observations
  6. GRB050525A,optical observation
  7. GRB050525: Super-LOTIS observations
  8. GRB 050525, spectral lag pseudo-redshift
  9. GRB050306: optical afterglow not confirmed
  10. GRB 050525A: BOOTES simultaneous optical observations
  11. GRB 050525A: Swift-BAT refined analysis
  12. Swift/UVOT UV and optical detections of GRB 050525
  13. Konus-Wind observation of GRB 050525
  14. GRB 050525: TAROT observations of the early afterglow
  15. INTEGRAL detection of GRB 050525
  16. GRB 050525: Optical observation
  17. GRB050525: ROTSE-III Refined Analysis
  18. GRB 050525 - Very Bright, Not Short
  19. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  20. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  21. XRF 050522: Swift XRT refined analysis
  22. Swift/UVOT observation of XRF 050522
  23. GRB 050509A: Further I-band imaging
  24. RBO Observations of GRB050522
  25. XRF 050522: Swift XRT observation
  26. GRB 050520: VLT/ULTRACAM observations
  27. Swift UVOT Observations of GRB 050520
  28. GRB 050520: Swift XRT refined analysis
  29. XRF050509C: Chandra Afterglow Detection
  30. XRF 050509c: Swift XRT Upper Limit
  31. RBO Observations of GRB050520
  32. GRB 050520: TAROT optical limit
  33. GRB 050520: Swift XRT position
  34. No Swift-BAT Lightcurves in real-time for next 3 weeks
  35. Swift-BAT trigger 122203 is not a real GRB
  36. GRB 050504: Swift XRT afterglow candidate has faded
  37. GRB 050509B: Subaru Optical Observations
  38. GRB050502b: Early Observation
  39. Refined Chandra analysis of GRB 050509b
  40. GRB050509b, SDSS pre-burst observations
  41. Chandra observation of GRB 050509b
  42. GRB 050509b: RAPTOR deep, early limits.
  43. GRB050509B: Optical/Infared observations
  44. GRB 050509b: Swift/UVOT follow-up measurements
  45. GRB 050509b Milagro GeV/TeV Observations
  46. GRB050509B: Optical observations at the Very Large Telescope
  47. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  48. GRB 050509a: Swift-BAT refined analysis
  49. GRB 050509B: WSRT Radio Observations
  50. GRB 050505: SARA Observations
  51. Swift UVOT Follow-up Observations of GRB 050509B
  52. GRB 050509B, Optical Observations
  53. GRB 050509B: Swift/XRT refined analysis
  54. GRB050509a: Swift UVOT observations
  55. GRB 050509b: Optical observations
  56. GRB 050509b: Possible Optical Counterpart
  57. GRB 050509A: Optical observations
  58. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  59. GRB 050509b: optical observations
  60. GRB 050509b: Swift XRT Position
  61. GRB 050509B: ROTSE-III Optical Limits
  62. Swift Detection of GRB050509b: A short duration burst
  63. GRB 050509a: Swift XRT Position
  64. Swift Detection of the Burst GRB050509
  65. Swift-BAT detection of GRB 050507
  66. GRB 050505: early time observations
  67. GRB 050505 - Faulkes Telescope North observations
  68. GRB 050502a: Swift XRT Upper Limit
  69. GRB 050505, simultaneous optical observation
  70. GRB 050505: Further Swift UVOT observations.
  71. GRB050416A : 1 GHz limit from GMRT
  72. GRB 050505 UVOT
  73. GRB 050505: Swift XRT Position
  74. GRB050505 Swift-BAT refined analysis
  75. GRB 050416b:Swift XRT afterglow upper limits
  76. GRB 050416b:Swift XRT afterglow upper limits
  77. Swift-BAT detection of GRB050505
  78. GRB 050504: Swift XRT position
  79. Swift UVOT observation of GRB 050504
  80. GRB 050502b, V band Observations
  81. GRB050502B Swift-BAT refined analysis
  82. GRB050502B: I band source in XRT error circle
  83. Swift UVOT refined analysis
  84. Retraction of Swift-BAT trigger 116145
  85. GRB 050502b : optical observation at Lulin observatory
  86. GRB 050502b: Swift XRT Position
  87. GRB050502B: Optical Limits from ANU 1m
  88. Swift Detection of the Bright Burst GRB050502b
  89. GRB050502: ANU 1m optical Observations
  90. Swift-BAT Trigger 115881 is not a real GRB
  91. Swift/BAT possible detection of a weak burst GRB050430
  92. GRB 050401: Rc observation
  93. GRB050416a: Radio Detection
  94. GRB 050422: Swift-UVOT observation
  95. GRB 050422: Swift-BAT refined analysis
  96. GRB 050422: Swift XRT Position
  97. Swift Detection of GRB 050422
  98. GRB 050421: SLOTIS observations
  99. GRB050421: Radio Observations
  100. GRB050421: Radio Observations

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