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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"

16083 results found.

  1. GRB 061110 : Optical afterglow candidate
  2. GRB 061110: ROTSE-III Optical Limits
  3. GRB061110A - Optical Non-detection
  4. GRB 061109: optical observation
  5. GRB 061109: TAROT Calern observatory optical observations
  6. GRB061028: MAGIC telescope GeV observation
  7. GRB 061027: TAROT La Silla observatory optical observations
  8. GRB 061007: Third Epoch ATCA Radio Observations
  9. GRB061019: second epoch CrAO observations
  10. GRB 061028: Swift/XRT Astrometry Correction
  11. GRB 061102: Swift/UVOT Magnitude Upper Limits
  12. GRB 061004: Further VLT/NTT observations
  13. GRB 061028: Optical R passband observations
  14. GRB 061004: Swift/XRT Astrometry Correction
  15. GRB 060801: Swift/XRT Astrometry Correction
  16. GRB 061028: SARA upper limit
  17. GRB 061028: TAROT Calern observatory late optical observations
  18. GRB 061028: TAROT Calern observatory optical observations
  19. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  20. GRB 061025: REM observations
  21. GRB 061025: ROTSE-III Optical Limits
  22. GRB 061021: Swift/UVOT Observation
  23. GRB060904b: optical observations
  24. GRB061019: optical observations
  25. GRB061019: optical observations
  26. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  27. GRB 060930: MARGE Optical Limits
  28. GRB 061019: Swift/UVOT upper limit
  29. GRB 061019: SMARTS afterglow confirmation
  30. GRB 061019: TAROT La Silla observatory optical observations
  31. GRB 061019: REM K-band candidate afterglow
  32. GRB 060825: GORT Observations
  33. GRB 061007: Second Epoch ATCA Radio Observations
  34. GRB 061006: astrometry-corrected XRT position
  35. GRB 061007: ATCA Radio Observations
  36. GRB 061006: optical afterglow
  37. GRB 061007: OA fading and VLT redshift
  38. GRB 061006: Swift/UVOT optical observations
  39. GRB 061007 - FTS early brightening and power law decay
  40. GRB 061007: Swift detection of a burst with an optical counterpart
  41. GRB 061007: ROTSE-III Detection of Optical Counterpart
  42. GRB 061004: Optical afterglow candidate and redshift
  43. GRB 061004: Las Campanas Optical/NIR Observations
  44. GRB061004: Swift/UVOT optical observations
  45. GRB 060930: Xinglong TNT optical observations
  46. GRB 060929: Swift/UVOT Optical Observations
  47. GRB 060930: ROTSE-III Optical Limits
  48. GRB 060927 : GAO 150cm telescope optical observation
  49. GRB060929: Optical limit
  50. GRB 060929: BOOTES-IR & OSN observations
  51. GRB060908: optical observations
  52. GRB 060729: An update on the late-time Swift observations
  53. GRB060923C: optical limit
  54. GRB060927: optical observations
  55. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  56. GRB 060927: Swift/UVOT Optical Observations
  57. GRB 060927: Early color
  58. GRB 060927: Swift XRT Team refined analysis
  59. GRB 060927 optical limit
  60. GRB 060927: Xinglong TNT optical observations
  61. GRB 060927, optical observation
  62. GRB 060927 : Kiso optical observation
  63. GRB 060927: optical afterglow confirmation
  64. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  65. Swift XRT boresight
  66. GRB060926: VLT redshift
  67. GRB 060926: Swift-UVOT Detections
  68. GRB 060926: MASTER OT alert observation
  69. GRB 060926: BOOTES-IR observations
  70. GRB060926 OPTIMA-Burst optical observation
  71. GRB 060926: MASTER optical observation
  72. GRB060923C: AROMA optical obsevation
  73. GRB 060923C, optical observation
  74. GRB060923B: Swift/UVOT upper limits
  75. GRB 060923C: Keck Observations
  76. GRB 060923C: Xinglong TNT optical observations
  77. GRB060923C : Faulkes Telescope South optical limits
  78. GRB060923C: Faulkes Telescope North optical observations
  79. GRB 060923C: optical observation
  80. GRB060923: Faulkes Telescope North optical observations
  81. GRB060919: Swift/UVOT optical observations
  82. GRB 060919 : Faulkes South Telescope Observations
  83. GRB 060919: TAROT optical observations
  84. GRB 060912A: Probable Host Galaxy
  85. GRB 060912: Redshift of nearby 2MASS galaxy
  86. GRB060912: optical observations
  87. GRB060912: Swift/UVOT Observations
  88. GRB060912: OPTIMA-Burst optical observations
  89. GRB 060912: Correction to GCN 5559
  90. GRB 060912: Xinglong TNT optical observations
  91. GRB 060912: Swift detection of a burst with an optical afterglow
  92. GRB060906: Danish/DFOSC optical observations
  93. GRB 060908: Swift/UVOT Observations
  94. GRB 060908: Danish/DFOSC optical observations
  95. GRB 060904B: Kiso Optical observation
  96. GRB 060904A : Optical limit
  97. GRB 060908: REM optical prompt observation
  98. GRB 060908: Swift detection of a burst with a bright optical counterpart
  99. GRB060906 , optical observation
  100. GRB060904b optical detections (delayed report due to internet outage)

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