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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"

21458 results found.

  1. GRB 061121, Swift-BAT refined analysis
  2. GRB061121, optical observation
  3. GRB 061121: Faulkes Telescope North Optical Observation
  4. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  5. GRB 061121: Swift detection of a bright burst with an optical counterpart
  6. GRB 050915B: optical afterglow
  7. GRB 060111B: Swift UVOT Refined Magnitudes
  8. Swift-BAT triggers 238544 and 238546 are not GRBs
  9. GRB 061110B: NIR Observations
  10. Swift TOO observations of GRB061110A
  11. Swift/UVOT Upper Limits for GRB061110b
  12. Swift/UVOT Upper Limits for GRB061110a
  13. GRB 061110B: Swift XRT refined analysis
  14. GRB 061110B, Swift-BAT refined analysis
  15. GRB061110B: Optical observations at Crni Vrh
  16. GRB 061110A: Swift XRT refined analysis
  17. GRB 061110B: Swift/XRT position
  18. GRB 061110B: Swift-UVOT Initial Observation
  19. GRB 061110A, Swift-BAT refined analysis
  20. GRB 061110B: TAROT Calern observatory optical observations
  21. GRB 061110B: Swift detection of a burst
  22. GRB 061110: Candidate confirmed
  23. GRB 061110: ROTSE-III Optical Limits
  24. GRB 061110: Swift detection of a burst
  25. GRB061110A - Optical Non-detection
  26. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  27. GRB 061109: TAROT Calern observatory optical observations
  28. GRB 061109: Swift detection of a possible burst
  29. GRB061028: MAGIC telescope GeV observation
  30. GRB 061027: TAROT La Silla observatory optical observations
  31. GRB061019: second epoch CrAO observations
  32. GRB 061028: Swift/XRT Astrometry Correction
  33. GRB 061102: Swift/UVOT Magnitude Upper Limits
  34. GRB 061102, XRT refined analysis
  35. GRB 061004: Further VLT/NTT observations
  36. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  37. GRB061102B: Super-LOTIS observations
  38. GRB 061028: Optical R passband observations
  39. GRB 061102B: Swift detection of a possible burst
  40. GRB 061102, Swift-BAT refined analysis
  41. GRB 061102: Swift detection of a burst
  42. GRB 061028: VLA Observation
  43. GRB 061004: Swift/XRT Astrometry Correction
  44. GRB 060801: Swift/XRT Astrometry Correction
  45. GRB 061028: MDM Observations
  46. GRB 061028: P200 Observations
  47. GRB 061028: SARA upper limit
  48. GRB 061028: z band imaging
  49. GRB061028: XRT refined analysis
  50. GRB 061028: Swift/UVOT Observations
  51. GRB 061028, Swift-BAT refined analysis
  52. GRB 061028: TAROT Calern observatory late optical observations
  53. GRB 061028: TAROT Calern observatory optical observations
  54. GRB 061028: Swift detection of a burst
  55. GRB 061027, Swift refined analysis of a possible burst
  56. GRB 061027: Swift detection of a possible burst
  57. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  58. GRB061025: Swift XRT refined analysis
  59. GRB061025: Swift/UVOT observations
  60. GRB 061019: MITSuME upper limits
  61. GRB 061025: REM observations
  62. GRB 061025: Gemini-S observations
  63. GRB061025: Swift XRT position
  64. Swift XRT boresight update
  65. GRB 061021, Swift-BAT Lag analysis
  66. Konus-Wind observation of GRB 061021
  67. GRB 061021: Swift-XRT refined analysis
  68. GRB 061021: Swift/UVOT Observation
  69. GRB 061021, Swift-BAT refined analysis
  70. GRB 061021: Swift detection of a burst
  71. GRB 061019: Super-LOTIS upper limit
  72. GRB061019: optical observations
  73. GRB061019: optical observations
  74. GRB 061019: SARA upper limit
  75. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  76. GRB 061019: Swift/UVOT upper limit
  77. GRB061019: Swift XRT refined analysis
  78. GRB 061019, Swift-BAT refined analysis
  79. GRB 061019: TAROT La Silla observatory optical observations
  80. GRB061019: Swift/XRT position
  81. GRB 061019: Swift-BAT detection of a burst
  82. GRB 060825: GORT Observations
  83. GRB 061006: astrometry-corrected XRT position
  84. Konus-Wind observation of GRB 061007
  85. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  86. GRB061007: Swift UVOT followup observations
  87. GRB 061006: optical afterglow
  88. GRB 061007: Magellan Spectroscopy
  89. GRB 061007: Correction to GCN 5712
  90. GRB 061007: Swift-BAT refined analysis
  91. GRB 061007: Swift XRT refined analysis
  92. GRB 061006: Swift/UVOT optical observations
  93. Konus-Wind observation of the short hard GRB 061006
  94. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  95. GRB 061007: Swift detection of a burst with an optical counterpart
  96. GRB 061007: ROTSE-III Detection of Optical Counterpart
  97. GRB 061006: VLT observation
  98. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  99. GRB 061006: Swift-XRT Team Refined Analysis
  100. GRB061006 (Swift 232585) might be a short-hard GRB

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