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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"

19532 results found.

  1. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  2. GRB 061109: TAROT Calern observatory optical observations
  3. GRB 061109: Swift detection of a possible burst
  4. GRB061028: MAGIC telescope GeV observation
  5. GRB 061027: TAROT La Silla observatory optical observations
  6. GRB 061028: Swift/XRT Astrometry Correction
  7. GRB 061102: Swift/UVOT Magnitude Upper Limits
  8. GRB 061102, XRT refined analysis
  9. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  10. GRB061102B: Super-LOTIS observations
  11. GRB 061028: Optical R passband observations
  12. GRB 061102B: Swift detection of a possible burst
  13. GRB 061102, Swift-BAT refined analysis
  14. GRB 061102: Swift detection of a burst
  15. GRB 061028: VLA Observation
  16. GRB 061004: Swift/XRT Astrometry Correction
  17. GRB 060801: Swift/XRT Astrometry Correction
  18. GRB 061028: MDM Observations
  19. GRB 061028: SARA upper limit
  20. GRB061028: XRT refined analysis
  21. GRB 061028: Swift/UVOT Observations
  22. GRB 061028, Swift-BAT refined analysis
  23. GRB 061028: TAROT Calern observatory optical observations
  24. GRB 061028: Swift detection of a burst
  25. GRB 061027, Swift refined analysis of a possible burst
  26. GRB 061027: Swift detection of a possible burst
  27. GRB061025: Swift XRT refined analysis
  28. GRB061025: Swift/UVOT observations
  29. GRB061025: Swift XRT position
  30. Swift XRT boresight update
  31. GRB 061021, Swift-BAT Lag analysis
  32. Konus-Wind observation of GRB 061021
  33. GRB 061021: Swift-XRT refined analysis
  34. GRB 061021: Swift/UVOT Observation
  35. GRB 061021, Swift-BAT refined analysis
  36. GRB 061021: Swift detection of a burst
  37. GRB 061019: Super-LOTIS upper limit
  38. GRB 061019: SARA upper limit
  39. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  40. GRB 061019: Swift/UVOT upper limit
  41. GRB061019: Swift XRT refined analysis
  42. GRB 061019, Swift-BAT refined analysis
  43. GRB 061019: TAROT La Silla observatory optical observations
  44. GRB061019: Swift/XRT position
  45. GRB 061019: Swift-BAT detection of a burst
  46. GRB 061006: astrometry-corrected XRT position
  47. Konus-Wind observation of GRB 061007
  48. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  49. GRB061007: Swift UVOT followup observations
  50. GRB 061007: Magellan Spectroscopy
  51. GRB 061007: Correction to GCN 5712
  52. GRB 061007: Swift-BAT refined analysis
  53. GRB 061007: Swift XRT refined analysis
  54. GRB 061006: Swift/UVOT optical observations
  55. Konus-Wind observation of the short hard GRB 061006
  56. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  57. GRB 061007: Swift detection of a burst with an optical counterpart
  58. GRB 061007: ROTSE-III Detection of Optical Counterpart
  59. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  60. GRB 061006: Swift-XRT Team Refined Analysis
  61. GRB061006 (Swift 232585) might be a short-hard GRB
  62. GRB061006: Faulkes Telescope South Observations
  63. GRB 061006: Swift detection of a burst
  64. GRB061004: Swift/UVOT optical observations
  65. GRB 061004: Swift-XRT Team Refined Analysis
  66. GRB 061004, Swift BAT refined analysis
  67. GRB 061004: Swift detection of a burst
  68. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  69. GRB 060928: Swift observations
  70. IPN triangulation of GRB060928 (long, exceptionally bright)
  71. GRB061002: Swift UVOT followup observations
  72. GRB 061002: Swift-XRT Team Refined Analysis
  73. GRB 061002, Swift-BAT refined analysis
  74. GRB061002: MASTER-VWF-Kislovodsk observations
  75. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  76. GRB 061002: Swift detection of a burst
  77. GRB 060929: Further XRT Refined Analysis
  78. GRB 060929: Swift/UVOT Optical Observations
  79. GRB060929: Swift-XRT refined analysis.
  80. GRB 060929, Swift-BAT further refined analysis - late-time flare
  81. GRB 060929, Swift-BAT refined analysis
  82. GRB 060929: BART observation
  83. GRB 060929: MASTER-VWF-Kislovodsk observations
  84. GRB 060929: BOOTES-IR & OSN observations
  85. Liverpool Telescope observations of GRB 060929
  86. GRB 060929: Swift detection of a burst
  87. GRB 060729: An update on the late-time Swift observations
  88. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  89. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  90. GRB 060927: Swift/UVOT Optical Observations
  91. GRB 060927: Swift XRT Team refined analysis
  92. GRB 060927, Swift-BAT refined analysis
  93. GRB060927: Faulkes Telescope South observation
  94. GRB060927 - SDSS Pre-Burst Observations
  95. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  96. Swift XRT boresight
  97. GRB 060927: Swift detection of a burst
  98. GRB060926: VLT redshift
  99. GRB 060926: Swift-UVOT Detections
  100. GRB 060926: Swift XRT refined analysis

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