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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"

18695 results found.

  1. GRB 071020: BTA spectroscopy
  2. Possible radio detection of GRB 071021 with the VLA
  3. Radio detection of GRB 071020 with the VLA
  4. GRB 071021: optical and NIR observations
  5. GRB 071021, Swift-BAT refined analysis
  6. GRB 071021: Swift-XRT Team refined analysis
  7. Konus-Wind observation of GRB 071020
  8. GRB 071021: Swift detection of a burst
  9. GRB 071020: Swift-XRT refined analysis
  10. GRB 071020, Swift-BAT refined analysis
  11. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  12. GRB071020 - SDSS Pre-burst Observations
  13. GRB 071020: Swift detection of a bright burst
  14. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  15. GRB 071018: Mercator Telescope optical observations
  16. Swift autonomous slewing re-enabled
  17. GRB 071018: Swift-XRT observation
  18. GRB 071017 - Swift XRT observations
  19. VLA radio observation of GRB 071018
  20. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  21. GRB 071018, Swift-BAT refined analysis
  22. GRB 071018?: Swift detection of a possible burst
  23. GRB 071010B: Suzaku WAM observation of the prompt emission
  24. GRB 071013: 3rd TLS Epoch - constraints on variability
  25. GRB 071013: TLS Upper Limit
  26. VLA detection of radio afterglow of GRB 071010B
  27. VLA non-detection of GRB 071011
  28. GRB 071013: Optical observations
  29. GRB 071013, Swift-BAT refined analysis
  30. GRB 071013: Swift detection of a burst
  31. GRB 071010C Swift-BAT detection of a burst
  32. GRB 071011: Swift-XRT refined analysis
  33. VLA non-detection of GRB 071010A
  34. GRB 071011, Optical afterglow
  35. GRB 071011: MARGE Optical Limits
  36. GRB 071011: XRT afterglow detection
  37. GRB 071011, Swift-BAT refined analysis
  38. GRB 071011: Early Super-LOTIS Observations
  39. GRB 071010B: Bright OT confirmed with TLS
  40. GRB 071011: Swift detection of a burst
  41. Optical Observation: GRB 071010
  42. Optical observations: GRB 071010A
  43. Konus-Wind observation of GRB 071010B
  44. GRB071010B: Swift/XRT detection
  45. GRB 071010B, Swift-BAT refined analysis
  46. GRB 071006, Swift-BAT refined analysis
  47. GRB 071010B: Swift detection of a burst
  48. GRB 071010: Swift-XRT observation
  49. GRB 071008, Swift-BAT refined analysis
  50. GRB 071010, Swift-BAT refined analysis
  51. GRB071008: Swift-XRT observation
  52. GRB 071010: TAROT La Silla observatory detection of the afterglow
  53. GRB 071010: Swift detection of a burst
  54. GRB 071006 Swift-BAT detection of a burst
  55. GRB071008: IAC80 observation
  56. GRB 071008: Swift detection of a burst
  57. GRB 071003: XRT refined analysis
  58. GRB070920A: MAGIC telescope GeV observation
  59. Radio detection of GRB 071003 with the VLA
  60. GRB 070810B: further XRT analysis
  61. Konus-Wind observation of GRB 071003
  62. GRB 071003: Swift XRT position
  63. GRB 071003, Swift-BAT refined analysis
  64. GRB 071003: MARGE Observations
  65. GRB 071003 Optical observations
  66. GRB 071003: KAIT optical afterglow observations
  67. GRB 071003: Swift detection of a bright burst
  68. GRB 070714B: host galaxy spectroscopic redshift
  69. GRB 071001: Swift-XRT Team refined analysis
  70. GRB 071001, Swift-BAT refined analysis
  71. Faulkes Telescope South observations of GRB 071001
  72. GRB 071001: Swift detection of a burst
  73. VLA observation of GRB 070923
  74. Disregard the Swift-XRT Notices today
  75. GRB070925: Swift-XRT Afterglow confirmation
  76. GRB070925: Swift-XRT Position
  77. Update on Swift Status
  78. GRB 070920B: ROTSE-III Early Optical Limits
  79. Recent SGR1806-20 Activity
  80. GRB 070923, Swift-BAT refined analysis
  81. GRB 070920B: XRT observations
  82. GRB 070923: Swift detection of a short hard burst
  83. GRB 070917: Suzaku/WAM observation of the prompt emission
  84. GRB 070920B: TAROT La Silla observatory optical observations
  85. GRB 070917: Confirmation of the X-ray afterglow
  86. GRB 070920B, Swift-BAT refined analysis
  87. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  88. GRB 070920B: NOT optical observations
  89. GRB 070920B: Swift detection of a burst
  90. GRB 070920, Swift-BAT refined analysis
  91. GRB 070920: TAROT Calern observatory optical observations
  92. GRB 070920: Swift detection of a burst
  93. SGR1806-20: Swift-BAT detection of enhanced activity
  94. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  95. Konus-Wind observation of GRB 070917
  96. Swift Status and XRT Calibration Uncertainties
  97. GRB 070917: Swift-XRT observations
  98. GRB 070917: KAIT optical limits
  99. GRB 070917: R band observations
  100. GRB 070917, Swift-BAT refined analysis

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