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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"

18683 results found.

  1. GRB 061007: Magellan Spectroscopy
  2. GRB 061007: Correction to GCN 5712
  3. GRB 061007: Swift-BAT refined analysis
  4. GRB 061007: Swift XRT refined analysis
  5. GRB 061006: Swift/UVOT optical observations
  6. Konus-Wind observation of the short hard GRB 061006
  7. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  8. GRB 061007: Swift detection of a burst with an optical counterpart
  9. GRB 061007: ROTSE-III Detection of Optical Counterpart
  10. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  11. GRB 061006: Swift-XRT Team Refined Analysis
  12. GRB061006 (Swift 232585) might be a short-hard GRB
  13. GRB061006: Faulkes Telescope South Observations
  14. GRB 061006: Swift detection of a burst
  15. GRB061004: Swift/UVOT optical observations
  16. GRB 061004: Swift-XRT Team Refined Analysis
  17. GRB 061004, Swift BAT refined analysis
  18. GRB 061004: Swift detection of a burst
  19. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  20. GRB 060928: Swift observations
  21. IPN triangulation of GRB060928 (long, exceptionally bright)
  22. GRB061002: Swift UVOT followup observations
  23. GRB 061002: Swift-XRT Team Refined Analysis
  24. GRB 061002, Swift-BAT refined analysis
  25. GRB061002: MASTER-VWF-Kislovodsk observations
  26. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  27. GRB 061002: Swift detection of a burst
  28. GRB 060929: Further XRT Refined Analysis
  29. GRB 060929: Swift/UVOT Optical Observations
  30. GRB060929: Swift-XRT refined analysis.
  31. GRB 060929, Swift-BAT further refined analysis - late-time flare
  32. GRB 060929, Swift-BAT refined analysis
  33. GRB 060929: BART observation
  34. GRB 060929: MASTER-VWF-Kislovodsk observations
  35. GRB 060929: BOOTES-IR & OSN observations
  36. Liverpool Telescope observations of GRB 060929
  37. GRB 060929: Swift detection of a burst
  38. GRB 060729: An update on the late-time Swift observations
  39. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  40. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  41. GRB 060927: Swift/UVOT Optical Observations
  42. GRB 060927: Swift XRT Team refined analysis
  43. GRB 060927, Swift-BAT refined analysis
  44. GRB060927: Faulkes Telescope South observation
  45. GRB060927 - SDSS Pre-Burst Observations
  46. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  47. Swift XRT boresight
  48. GRB 060927: Swift detection of a burst
  49. GRB060926: VLT redshift
  50. GRB 060926: Swift-UVOT Detections
  51. GRB 060926: Swift XRT refined analysis
  52. GRB 060926, Swift-BAT refined analysis
  53. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  54. GRB 060926: BOOTES-IR observations
  55. GRB060926 OPTIMA-Burst optical observation
  56. GRB 060926: Swift detection of a burst
  57. GRB 060923C, Swift-BAT refined analysis
  58. GRB 060923C: VLA Observation
  59. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  60. GRB060923B: Swift/UVOT upper limits
  61. GRB 060923B: Swift XRT Refined Analysis
  62. GRB 060923C: Swift XRT refined analysis
  63. GRB 060923C, Swift-BAT partial refined analysis
  64. GRB 060923A: Swift XRT refined analysis
  65. GRB 060923A: Keck and Gemini Observations
  66. GRB 060923B, Swift-BAT refined analysis
  67. GRB060923C : Faulkes Telescope South optical limits
  68. GRB060923C: Faulkes Telescope North optical observations
  69. GRB 060923C: Swift detection of a burst
  70. GRB 060923B: Swift detection of a burst
  71. GRB 060923, Swift-BAT refined analysis
  72. GRB 060923: Early Super-LOTIS Observations
  73. GRB060923: Faulkes Telescope North optical observations
  74. GRB 060923: KAIT observations
  75. GRB 060923: Swift detection of a burst
  76. Swift detection of IGR J17497-2821 (trigger 230504)
  77. Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
  78. GRB060919: Swift/UVOT optical observations
  79. GRB 060919, Swift-BAT refined analysis
  80. GRB060919: XRT refined analysis
  81. GRB 060919: TAROT optical observations
  82. GRB 060919: Swift detection of a burst
  83. GRB 060912A: VLA Observation
  84. GRB060825: MAGIC telescope GeV observation
  85. Konus-Wind observation of GRB 060912
  86. GRB060912: Swift/UVOT Observations
  87. GRB060912: OPTIMA-Burst optical observations
  88. GRB 060912: Swift XRT Team Refined Analysis
  89. GRB 060912, Swift-BAT refined analysis
  90. GRB 060912: Swift detection of a burst with an optical afterglow
  91. VLA observations of GRB 060908
  92. GRB 060908, Swift/XRT refined analysis
  93. GRB 060908: Swift/UVOT Observations
  94. GRB 060908, Swift-BAT refined analysis
  95. GRB 060908 - SDSS Pre-burst Observations
  96. GRB 060908: Swift detection of a burst with a bright optical counterpart
  97. GRB 060904A: Suzaku/WAM observation of the prompt emission
  98. GRB060904b optical detections (delayed report due to internet outage)
  99. GRB 060906: Early RAPTOR optical limits
  100. GRB 060906, Swift-BAT refined spectral analysis

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