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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"

22112 results found.

  1. GRB 060929, Swift-BAT refined analysis
  2. GRB060929: Optical limit
  3. Liverpool Telescope observations of GRB 060929
  4. GRB060908: optical observations
  5. GRB 060729: An update on the late-time Swift observations
  6. GRB060923C: optical limit
  7. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  8. GRB 060927: Swift/UVOT Optical Observations
  9. GRB 060927: Swift XRT Team refined analysis
  10. GRB 060927 optical limit
  11. GRB 060927: Xinglong TNT optical observations
  12. GRB 060927, optical observation
  13. GRB060927 - SDSS Pre-Burst Observations
  14. GRB 060927: Swift detection of a burst
  15. GRB 060926: Swift-UVOT Detections
  16. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  17. GRB 060926: Swift XRT refined analysis
  18. GRB 060923A: Radio Observations
  19. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  20. GRB 060926: BOOTES-IR observations
  21. GRB 060926: Swift detection of a burst
  22. GRB 060923C: VLA Observation
  23. GRB 060923C: NIR afterglow confirmed
  24. GRB060923C: AROMA optical obsevation
  25. GRB 060923C, optical observation
  26. GRB 060923C: VLT J-band observations
  27. GRB060923B: Swift/UVOT upper limits
  28. GRB 060923A: Keck and Gemini Observations
  29. GRB 060923C: Xinglong TNT optical observations
  30. GRB 060923C: optical observation
  31. GRB 060923C: Swift detection of a burst
  32. GRB 060923B: Swift detection of a burst
  33. GRB 060923: Early Super-LOTIS Observations
  34. GRB 060923: UKIRT nIR observations - candidate afterglow
  35. GRB060923 - SDSS Pre-Burst Observations
  36. GRB 060923: Swift detection of a burst
  37. Swift detection of IGR J17497-2821 (trigger 230504)
  38. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  39. GRB060919: Swift/UVOT optical observations
  40. GRB 060919 : Faulkes South Telescope Observations
  41. GRB 060919: TAROT optical observations
  42. GRB 060919: Swift detection of a burst
  43. GRB 060912A: VLA Observation
  44. GRB 060912A: Probable Host Galaxy
  45. GRB 060912: Correction to GCN 5559
  46. GRB 060912: Swift detection of a burst with an optical afterglow
  47. GRB060906: Danish/DFOSC optical observations
  48. VLA observations of GRB 060908
  49. GRB 060908, Swift-BAT refined analysis
  50. GRB 060908 - SDSS Pre-burst Observations
  51. GRB 060904A : Optical limit
  52. GRB 060908: REM optical prompt observation
  53. GRB 060908: Swift detection of a burst with a bright optical counterpart
  54. GRB060906 , optical observation
  55. GRB 060906: Early RAPTOR optical limits
  56. GRB 060906, Swift-BAT refined spectral analysis
  57. GRB 060906: Swift-UVOT observations
  58. GRB 060906: KAIT observations
  59. GRB 060906: Confirmation of P60 Optical Afterglow
  60. GRB 060906 (?): P60 Optical Afterglow Candidate
  61. GRB 060906: Swift detection of a probable burst
  62. GRB060904b, optical observations
  63. GRB060904A: Swift/UVOT optical observations
  64. GRB 060904A: Subaru NIR observation
  65. GRB060904b: Optical observations with Swift/UVOT
  66. GRB 060904B: Swift-XRT refined analysis
  67. GRB 060904A: Refined analysis of the Swift-BAT burst
  68. GRB 060904A: Suzaku-XIS and -HXD observation plan
  69. GRB 060904A: P60 Observations
  70. GRB 060904B: Optical observations at Crni Vrh
  71. GRB 060904B: TAROT optical counterpart observations
  72. GRB060904B - SDSS Pre-Burst Observations
  73. GRB 060904: TAROT optical observations
  74. GRB 060904B: Swift detection of a burst with optical counterpart
  75. GRB060904 - SDSS Pre-Burst Observations
  76. GRB 060904: Swift detection of a bright burst
  77. GRB060901: Optical observations
  78. 060901: Swift UVOT followup observations
  79. GRB 060901: Swift/XRT Refined Analysis
  80. GRB 060901: Swift/XRT Position
  81. Two bright bursts from SGR 1806-20 detected with IBAS
  82. GRB 060605, observations using an Integral Field Unit
  83. GRB 060604: VLA Observation
  84. GRB 060605: VLA Observation
  85. GRB 060707: VLA observation
  86. GRB 060825: VLA observations
  87. GRB060826 - SDSS Pre-Burst Observations
  88. GRB 060826(?): Swift detection of a possible burst
  89. GRB 060825: TNG optical observations
  90. GRB 060825: TAROT optical observations
  91. GRB 060825: P60 Observations
  92. GRB 060825: Swift detection of a burst
  93. Radio observations of GRB 060719
  94. GRB 060729, SMARTS optical/IR observations
  95. GRB 060814: P60 Observations
  96. GRB 060814: P200 NIR Observations
  97. GRB060814: Swift/UVOT upper limits
  98. GRB 060814: VLT optical limits
  99. GRB 060814 - SDSS Pre-Burst Observations
  100. GRB 060814: TAROT optical observations

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