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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"

15987 results found.

  1. GRB060927: optical observations
  2. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  3. GRB 060927: Swift/UVOT Optical Observations
  4. GRB 060927: Early color
  5. GRB 060927: Swift XRT Team refined analysis
  6. GRB 060927 optical limit
  7. GRB 060927: Xinglong TNT optical observations
  8. GRB 060927, optical observation
  9. GRB 060927 : Kiso optical observation
  10. GRB 060927: optical afterglow confirmation
  11. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  12. Swift XRT boresight
  13. GRB060926: VLT redshift
  14. GRB 060926: Swift-UVOT Detections
  15. GRB 060926: BOOTES-IR observations
  16. GRB060926 OPTIMA-Burst optical observation
  17. GRB 060926: MASTER optical observation
  18. GRB060923C: AROMA optical obsevation
  19. GRB 060923C, optical observation
  20. GRB060923B: Swift/UVOT upper limits
  21. GRB 060923C: Keck Observations
  22. GRB 060923C: Xinglong TNT optical observations
  23. GRB060923C : Faulkes Telescope South optical limits
  24. GRB060923C: Faulkes Telescope North optical observations
  25. GRB 060923C: optical observation
  26. GRB060923: Faulkes Telescope North optical observations
  27. GRB060919: Swift/UVOT optical observations
  28. GRB 060919 : Faulkes South Telescope Observations
  29. GRB 060919: TAROT optical observations
  30. GRB 060912A: Probable Host Galaxy
  31. GRB 060912: Redshift of nearby 2MASS galaxy
  32. GRB060912: optical observations
  33. GRB060912: Swift/UVOT Observations
  34. GRB060912: OPTIMA-Burst optical observations
  35. GRB 060912: Correction to GCN 5559
  36. GRB 060912: Xinglong TNT optical observations
  37. GRB 060912: Swift detection of a burst with an optical afterglow
  38. GRB060906: Danish/DFOSC optical observations
  39. GRB 060908: Swift/UVOT Observations
  40. GRB 060908: Danish/DFOSC optical observations
  41. GRB 060904B: Kiso Optical observation
  42. GRB 060904A : Optical limit
  43. GRB 060908: REM optical prompt observation
  44. GRB 060908: Swift detection of a burst with a bright optical counterpart
  45. GRB060906 , optical observation
  46. GRB060904b optical detections (delayed report due to internet outage)
  47. GRB 060906: optical observation
  48. GRB 060906: Early RAPTOR optical limits
  49. GRB 060906: Swift/XRT Refined Analysis
  50. GRB 060906: Swift-UVOT observations
  51. VLT redshift of GRB 060906
  52. GRB 060906: KAIT observations
  53. GRB 060906: Confirmation of P60 Optical Afterglow
  54. GRB 060906 (?): P60 Optical Afterglow Candidate
  55. GRB060904b, optical observations
  56. GRB 060904b: SMARTS optical/IR afterglow observations
  57. GRB 060904B: RTT150 optical observations
  58. GRB060904A: Swift/UVOT optical observations
  59. GRB060904b: Optical observations with Swift/UVOT
  60. GRB 060904B: VLT redshift
  61. GRB 060904B: Optical observations at Crni Vrh
  62. GRB060904B: Watcher observations
  63. GRB 060904B BOOTES-IR and 1.5m OSN observations
  64. GRB 060904B: TAROT optical counterpart observations
  65. GRB 060904: TAROT optical observations
  66. GRB 060904B: Swift detection of a burst with optical counterpart
  67. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  68. GRB060901: Optical observations
  69. GRB 060901: SMARTS optical/IR observations update
  70. GRB 060901: SMARTS optical/IR observations
  71. GRB 060605, observations using an Integral Field Unit
  72. GRB 060826(?): Swift detection of a possible burst
  73. GRB060825: Liverpool Telescope optical observations
  74. GRB 060825: TNG optical observations
  75. GRB 060825: TAROT optical observations
  76. GRB060825: BOOTES-IR optical observations
  77. GRB 060729, SMARTS optical/IR observations
  78. GRB060814: Break in the XRT light curve
  79. GRB060813: Break in the XRT light curve
  80. GRB060805B: optical observations
  81. GRB060814: Swift/UVOT upper limits
  82. GRB 060814: VLT optical limits
  83. GRB 060814: TAROT optical observations
  84. GRB060813: Swift/UVOT upper limits
  85. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  86. GRB060807: Possible Highly Significant X-ray Emission Lines
  87. GRB060714: optical observations
  88. GRB 060729: An update on the Swift XRT and UVOT observations
  89. GRB060717: optical observations
  90. GRB060807: Optical limiting magnitudes
  91. GRB 060805B: optical observation at Sierra Nevada
  92. GRB 060805B: XRT Team Analysis
  93. GRB 060807: UVOT Upper limits
  94. GRB 060807: afterglow confirmation
  95. GRB 060807: K- and R-band observations
  96. GRB060807: optical afterglow candidate
  97. GRB060807: optical upper limit in white light
  98. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  99. GRB 060805B: Swift/UVOT Upper Limits
  100. GRB 060807, optical observation

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