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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"

26036 results found.

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

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