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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"

22077 results found.

  1. GRB 061028: P200 Observations
  2. GRB 061028: SARA upper limit
  3. GRB 061028: z band imaging
  4. GRB061028: XRT refined analysis
  5. GRB 061028: Swift/UVOT Observations
  6. GRB 061028: TAROT Calern observatory optical observations
  7. GRB 061028: Swift detection of a burst
  8. GRB 061027, Swift refined analysis of a possible burst
  9. GRB 061027: Swift detection of a possible burst
  10. GRB061025: Swift XRT refined analysis
  11. GRB061025: Swift/UVOT observations
  12. GRB 061019: MITSuME upper limits
  13. GRB 061025: REM observations
  14. GRB061025: Swift XRT position
  15. GRB 061025: ROTSE-III Optical Limits
  16. GRB 061021: Swift-XRT refined analysis
  17. GRB 061021: Swift/UVOT Observation
  18. GRB 061021: Swift detection of a burst
  19. GRB 061019: Super-LOTIS upper limit
  20. GRB061019: optical observations
  21. GRB061019: optical observations
  22. GRB 061019: SARA upper limit
  23. GRB 060930: MARGE Optical Limits
  24. GRB 061019: Swift/UVOT upper limit
  25. GRB061019: Swift XRT refined analysis
  26. GRB 061019, Swift-BAT refined analysis
  27. GRB 061019: TAROT La Silla observatory optical observations
  28. GRB 061019: REM K-band candidate afterglow
  29. GRB 061019: Swift-BAT detection of a burst
  30. GRB 060825: GORT Observations
  31. GRB 061006: astrometry-corrected XRT position
  32. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  33. GRB061007: Swift UVOT followup observations
  34. GRB 061006: optical afterglow
  35. GRB 061007: OA fading and VLT redshift
  36. GRB 061007: Swift XRT refined analysis
  37. GRB 061006: Swift/UVOT optical observations
  38. Konus-Wind observation of the short hard GRB 061006
  39. GRB 061007: Swift detection of a burst with an optical counterpart
  40. GRB 061006: VLT observation
  41. GRB 061006: Swift-XRT Team Refined Analysis
  42. GRB061006 (Swift 232585) might be a short-hard GRB
  43. GRB 060930: near-IR afterglow candidate retraction
  44. GRB 061006: Swift detection of a burst
  45. GRB 061004: Optical afterglow candidate and redshift
  46. GRB 061004: Las Campanas Optical/NIR Observations
  47. GRB061004: Swift/UVOT optical observations
  48. GRB 061004: Swift detection of a burst
  49. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  50. GRB 060928: Swift observations
  51. IPN triangulation of GRB060928 (long, exceptionally bright)
  52. GRB061002: Swift UVOT followup observations
  53. GRB 060930: near-IR afterglow candidate
  54. GRB 061002: Swift-XRT Team Refined Analysis
  55. VLA observations of GRB 060926
  56. GRB061002 - SDSS Pre-Burst Observations
  57. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  58. GRB 061002: Swift detection of a burst
  59. GRB 060908: Detection of a possible host
  60. GRB 060807: Detection of a possible host galaxy
  61. GRB 060923A: VLA K-band Observations
  62. GRB 060930: Xinglong TNT optical observations
  63. GRB 060929: Swift/UVOT Optical Observations
  64. GRB 060930: ROTSE-III Optical Limits
  65. GRB 060929: TNG K-band observations
  66. GRB 060929, Swift-BAT refined analysis
  67. GRB060929: Optical limit
  68. Liverpool Telescope observations of GRB 060929
  69. GRB060908: optical observations
  70. GRB 060729: An update on the late-time Swift observations
  71. GRB060923C: optical limit
  72. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  73. GRB 060927: Swift/UVOT Optical Observations
  74. GRB 060927: Swift XRT Team refined analysis
  75. GRB 060927 optical limit
  76. GRB 060927: Xinglong TNT optical observations
  77. GRB 060927, optical observation
  78. GRB060927 - SDSS Pre-Burst Observations
  79. GRB 060927: Swift detection of a burst
  80. GRB 060926: Swift-UVOT Detections
  81. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  82. GRB 060926: Swift XRT refined analysis
  83. GRB 060923A: Radio Observations
  84. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  85. GRB 060926: BOOTES-IR observations
  86. GRB 060926: Swift detection of a burst
  87. GRB 060923C: VLA Observation
  88. GRB 060923C: NIR afterglow confirmed
  89. GRB060923C: AROMA optical obsevation
  90. GRB 060923C, optical observation
  91. GRB 060923C: VLT J-band observations
  92. GRB060923B: Swift/UVOT upper limits
  93. GRB 060923A: Keck and Gemini Observations
  94. GRB 060923C: Xinglong TNT optical observations
  95. GRB 060923C: optical observation
  96. GRB 060923C: Swift detection of a burst
  97. GRB 060923B: Swift detection of a burst
  98. GRB 060923: Early Super-LOTIS Observations
  99. GRB 060923: UKIRT nIR observations - candidate afterglow
  100. GRB060923 - SDSS Pre-Burst Observations

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