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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"

19359 results found.

  1. GRB 050408: jet break in the XRT light curve
  2. GRB050528, XRT observations
  3. Correction to GCN Circ 3502 on GRB 050528
  4. Swift-BAT GRB 050528: a soft burst
  5. Update on Swift-BAT GRB 050528 (Trigger 130679)
  6. Possible GRB050528: no candidate from Liverpool Telescope
  7. Swift-BAT detection of possible GRB 050528
  8. GRB 050509b: refined XRT/Chandra afterglow position analysis
  9. GRB050525a: optical upper limits
  10. GRB 050525B: Swift-BAT observations
  11. GRB050525A,optical observation
  12. GRB050525: Super-LOTIS observations
  13. GRB 050525, spectral lag pseudo-redshift
  14. GRB050306: optical afterglow not confirmed
  15. GRB 050525A: BOOTES simultaneous optical observations
  16. GRB 050525A: Swift-BAT refined analysis
  17. Swift/UVOT UV and optical detections of GRB 050525
  18. Konus-Wind observation of GRB 050525
  19. GRB 050525: TAROT observations of the early afterglow
  20. INTEGRAL detection of GRB 050525
  21. GRB 050525: Optical observation
  22. GRB050525: ROTSE-III Refined Analysis
  23. GRB 050525 - Very Bright, Not Short
  24. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  25. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  26. XRF 050522: Swift XRT refined analysis
  27. Swift/UVOT observation of XRF 050522
  28. GRB 050509A: Further I-band imaging
  29. RBO Observations of GRB050522
  30. XRF 050522: Swift XRT observation
  31. GRB 050520: VLT/ULTRACAM observations
  32. Swift UVOT Observations of GRB 050520
  33. GRB 050520: Swift XRT refined analysis
  34. XRF050509C: Chandra Afterglow Detection
  35. XRF 050509c: Swift XRT Upper Limit
  36. RBO Observations of GRB050520
  37. GRB 050520: TAROT optical limit
  38. GRB 050520: Swift XRT position
  39. No Swift-BAT Lightcurves in real-time for next 3 weeks
  40. Swift-BAT trigger 122203 is not a real GRB
  41. GRB 050504: Swift XRT afterglow candidate has faded
  42. GRB 050509B: Subaru Optical Observations
  43. GRB050502b: Early Observation
  44. Refined Chandra analysis of GRB 050509b
  45. GRB050509b, SDSS pre-burst observations
  46. Chandra observation of GRB 050509b
  47. GRB 050509b: RAPTOR deep, early limits.
  48. GRB050509B: Optical/Infared observations
  49. GRB 050509b: Swift/UVOT follow-up measurements
  50. GRB 050509b Milagro GeV/TeV Observations
  51. GRB050509B: Optical observations at the Very Large Telescope
  52. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  53. GRB 050509a: Swift-BAT refined analysis
  54. GRB 050509B: WSRT Radio Observations
  55. GRB 050505: SARA Observations
  56. Swift UVOT Follow-up Observations of GRB 050509B
  57. GRB 050509B, Optical Observations
  58. GRB 050509B: Swift/XRT refined analysis
  59. GRB050509a: Swift UVOT observations
  60. GRB 050509b: Optical observations
  61. GRB 050509b: Possible Optical Counterpart
  62. GRB 050509A: Optical observations
  63. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  64. GRB 050509b: optical observations
  65. GRB 050509b: Swift XRT Position
  66. GRB 050509B: ROTSE-III Optical Limits
  67. Swift Detection of GRB050509b: A short duration burst
  68. GRB 050509a: Swift XRT Position
  69. Swift Detection of the Burst GRB050509
  70. Swift-BAT detection of GRB 050507
  71. GRB 050505: early time observations
  72. GRB 050505 - Faulkes Telescope North observations
  73. GRB 050502a: Swift XRT Upper Limit
  74. GRB 050505, simultaneous optical observation
  75. GRB 050505: Further Swift UVOT observations.
  76. GRB050416A : 1 GHz limit from GMRT
  77. GRB 050505 UVOT
  78. GRB 050505: Swift XRT Position
  79. GRB050505 Swift-BAT refined analysis
  80. GRB 050416b:Swift XRT afterglow upper limits
  81. GRB 050416b:Swift XRT afterglow upper limits
  82. Swift-BAT detection of GRB050505
  83. GRB 050504: Swift XRT position
  84. Swift UVOT observation of GRB 050504
  85. GRB 050502b, V band Observations
  86. GRB050502B Swift-BAT refined analysis
  87. GRB050502B: I band source in XRT error circle
  88. Swift UVOT refined analysis
  89. Retraction of Swift-BAT trigger 116145
  90. GRB 050502b : optical observation at Lulin observatory
  91. GRB 050502b: Swift XRT Position
  92. GRB050502B: Optical Limits from ANU 1m
  93. Swift Detection of the Bright Burst GRB050502b
  94. GRB050502: ANU 1m optical Observations
  95. Swift-BAT Trigger 115881 is not a real GRB
  96. Swift/BAT possible detection of a weak burst GRB050430
  97. GRB 050401: Rc observation
  98. GRB050416a: Radio Detection
  99. GRB 050422: Swift-UVOT observation
  100. GRB 050422: Swift-BAT refined analysis

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