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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"

26359 results found.

  1. GRB 061006: Swift/UVOT optical observations
  2. GRB 061007: Swift detection of a burst with an optical counterpart
  3. GRB 061007: ROTSE-III Detection of Optical Counterpart
  4. GRB 061006: VLT observation
  5. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  6. GRB 061006: Swift-XRT Team Refined Analysis
  7. GRB061006 (Swift 232585) might be a short-hard GRB
  8. GRB 060930: near-IR afterglow candidate retraction
  9. GRB 061004: Optical afterglow candidate and redshift
  10. GRB 061004: Swift-XRT Team Refined Analysis
  11. GRB 061004, Swift BAT refined analysis
  12. GRB 061004: Swift detection of a burst
  13. GRB 060928: Suzaku/WAM observation of the prompt emission
  14. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  15. GRB 060928: Swift observations
  16. IPN triangulation of GRB060928 (long, exceptionally bright)
  17. GRB 060930: near-IR afterglow candidate
  18. GRB 061002: Swift-XRT Team Refined Analysis
  19. VLA observations of GRB 060926
  20. GRB061002 - SDSS Pre-Burst Observations
  21. GRB 061002, Swift-BAT refined analysis
  22. GRB 060908: Detection of a possible host
  23. GRB 060807: Detection of a possible host galaxy
  24. GRB 060923A: VLA K-band Observations
  25. GRB 060930: Xinglong TNT optical observations
  26. GRB 060929: Further XRT Refined Analysis
  27. GRB 060929: Swift/UVOT Optical Observations
  28. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  29. GRB060929: Swift-XRT refined analysis.
  30. GRB 060929: TNG K-band observations
  31. GRB 060929, Swift-BAT refined analysis
  32. GRB060929: Optical limit
  33. Liverpool Telescope observations of GRB 060929
  34. GRB060908: optical observations
  35. GRB 060927: Swift/UVOT Optical Observations
  36. GRB 060927: Swift XRT Team refined analysis
  37. GRB 060927 optical limit
  38. GRB 060927, Swift-BAT refined analysis
  39. GRB 060927: Xinglong TNT optical observations
  40. GRB 060927, optical observation
  41. GRB060927 - SDSS Pre-Burst Observations
  42. Swift XRT boresight
  43. GRB060926: VLT redshift
  44. GRB 060926: Swift-UVOT Detections
  45. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  46. GRB 060926, Swift-BAT refined analysis
  47. GRB 060923A: Radio Observations
  48. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  49. GRB 060926: Swift detection of a burst
  50. GRB 060923C, Swift-BAT refined analysis
  51. GRB 060923C: VLA Observation
  52. GRB 060923C: NIR afterglow confirmed
  53. GRB060923C: AROMA optical obsevation
  54. GRB 060923C, optical observation
  55. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  56. GRB 060923C: VLT J-band observations
  57. GRB 060923B: Swift XRT Refined Analysis
  58. GRB 060923A: Swift XRT refined analysis
  59. GRB 060923A: Keck and Gemini Observations
  60. GRB 060923C: Xinglong TNT optical observations
  61. GRB 060923B, Swift-BAT refined analysis
  62. GRB 060923C: Swift detection of a burst
  63. GRB 060923B: Swift detection of a burst
  64. GRB 060923, Swift-BAT refined analysis
  65. GRB 060923: UKIRT nIR observations - candidate afterglow
  66. GRB060923 - SDSS Pre-Burst Observations
  67. GRB 060923: Swift detection of a burst
  68. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  69. GRB 060919 : Faulkes South Telescope Observations
  70. GRB 060919, Swift-BAT refined analysis
  71. GRB060919: XRT refined analysis
  72. GRB 060919: TAROT optical observations
  73. GRB 060919: Swift detection of a burst
  74. GRB 060912A: VLA Observation
  75. GRB 060912A: Probable Host Galaxy
  76. GRB 060912, Swift-BAT refined analysis
  77. GRB 060912: Correction to GCN 5559
  78. GRB 060912: Swift detection of a burst with an optical afterglow
  79. VLA observations of GRB 060908
  80. GRB 060908, Swift-BAT refined analysis
  81. GRB 060908 - SDSS Pre-burst Observations
  82. GRB 060908: REM optical prompt observation
  83. GRB 060908: Swift detection of a burst with a bright optical counterpart
  84. GRB 060904A: Suzaku/WAM observation of the prompt emission
  85. GRB060906 , optical observation
  86. GRB 060906: Early RAPTOR optical limits
  87. GRB 060906, Swift-BAT refined spectral analysis
  88. GRB 060906: Swift/XRT Refined Analysis
  89. VLT redshift of GRB 060906
  90. GRB 060906, Swift-BAT refined analysis
  91. GRB 060906: Confirmation of P60 Optical Afterglow
  92. GRB 060906 (?): P60 Optical Afterglow Candidate
  93. GRB060904b, optical observations
  94. GRB060904A: Swift/UVOT optical observations
  95. GRB 060904A: Subaru NIR observation
  96. GRB 060904B: Swift-BAT refined analysis
  97. GRB 060904A: Refined analysis of the Swift-BAT burst
  98. GRB 060904A: Suzaku-XIS and -HXD observation plan
  99. GRB 060904A: P60 Observations
  100. GRB 060904B: Optical observations at Crni Vrh

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