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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"
  1. GRB 060908: Detection of a possible host
  2. GRB 060923A: Probable host galaxy in the R-band
  3. GRB 060807: Detection of a possible host galaxy
  4. GRB 060923A: VLA K-band Observations
  5. GRB060930: Faulkes Telescope South observation
  6. GRB 060930: Xinglong TNT optical observations
  7. GRB 060929: Further XRT Refined Analysis
  8. GRB 060929: Swift/UVOT Optical Observations
  9. GRB 060930: ROTSE-III Optical Limits
  10. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  11. GRB 060927 : GAO 150cm telescope optical observation
  12. GRB060929: Swift-XRT refined analysis.
  13. GRB 060929, Swift-BAT further refined analysis - late-time flare
  14. GRB 060929: TNG K-band observations
  15. GRB 060929, Swift-BAT refined analysis
  16. GRB060929: Optical limit
  17. GRB 060929: BART observation
  18. GRB 060929: MASTER-VWF-Kislovodsk observations
  19. GRB 060929: BOOTES-IR & OSN observations
  20. Liverpool Telescope observations of GRB 060929
  21. GRB 060929: Swift detection of a burst
  22. GRB060908: optical observations
  23. GRB 060729: An update on the late-time Swift observations
  24. GRB 060927: Spectroscopic redshift z=5.6
  25. IBAS Alert n.3501: not a GRB
  26. IBAS Alert n.3500: not a GRB
  27. GRB060923C: optical limit
  28. GRB060927: optical observations
  29. test of new software, grb
  30. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  31. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  32. GRB 060927: Swift/UVOT Optical Observations
  33. GRB 060927: Early color
  34. GRB 060927: Swift XRT Team refined analysis
  35. GRB 060927 optical limit
  36. GRB 060927, Swift-BAT refined analysis
  37. GRB 060927: Xinglong TNT optical observations
  38. GRB060926: improved redshift
  39. GRB 060927, optical observation
  40. GRB 060927: Possible host galaxy (star?) in the SDSS
  41. GRB 060927 : Kiso optical observation
  42. GRB060927: Faulkes Telescope South observation
  43. GRB 060926: MASTER: first minutes decay
  44. GRB060927 - SDSS Pre-Burst Observations
  45. GRB 060927: optical afterglow confirmation
  46. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  47. Swift XRT boresight
  48. GRB 060927: Swift detection of a burst
  49. GRB060926: VLT redshift
  50. GRB 060926: Swift-UVOT Detections
  51. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  52. GRB 060926: OPTIMA-Burst -- further observations
  53. GRB 060926: Swift XRT refined analysis
  54. GRB 060926, Swift-BAT refined analysis
  55. GRB 060923A: Radio Observations
  56. GRB 060926: MASTER OT alert observation
  57. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  58. GRB 060912A: Redshift of probable host galaxy
  59. GRB 060926: BOOTES-IR observations
  60. GRB 060926: Watcher observations
  61. GRB060926 OPTIMA-Burst optical observation
  62. GRB 060926: MASTER optical observation
  63. GRB 060926: Swift detection of a burst
  64. GRB 060923C, Swift-BAT refined analysis
  65. GRB 060923C: VLA Observation
  66. GRB 060923C: NIR afterglow confirmed
  67. GRB060923C: AROMA optical obsevation
  68. GRB 060923C: Gemini Observations and Afterglow Candidate
  69. GRB 060923C, optical observation
  70. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  71. GRB 060923C: VLT J-band observations
  72. GRB060923B: Swift/UVOT upper limits
  73. GRB 060923B: Swift XRT Refined Analysis
  74. GRB 060923C: Swift XRT refined analysis
  75. GRB 060923C, Swift-BAT partial refined analysis
  76. GRB 060923A: Swift XRT refined analysis
  77. GRB 060923C: Keck Observations
  78. GRB 060923A: Keck and Gemini Observations
  79. GRB 060923C: Xinglong TNT optical observations
  80. GRB 060923B, Swift-BAT refined analysis
  81. GRB060923C : Faulkes Telescope South optical limits
  82. GRB060923C: Faulkes Telescope North optical observations
  83. GRB 060923C: optical observation
  84. GRB 060923C: Swift detection of a burst
  85. GRB 060923B: Swift detection of a burst
  86. GRB 060923, Swift-BAT refined analysis
  87. GRB 060923: Early Super-LOTIS Observations
  88. GRB 060923: UKIRT nIR observations - candidate afterglow
  89. GRB060923: Faulkes Telescope North optical observations
  90. GRB060923 - SDSS Pre-Burst Observations
  91. GRB 060923: KAIT observations
  92. GRB 060923: Swift detection of a burst
  93. Swift detection of IGR J17497-2821 (trigger 230504)
  94. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  95. GRB060919: Swift/UVOT optical observations
  96. GRB 060919 : Faulkes South Telescope Observations
  97. GRB 060919, Swift-BAT refined analysis
  98. GRB060919: XRT refined analysis
  99. GRB 060919: TAROT optical observations
  100. GRB 060919: Swift detection of a burst

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