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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"
  1. GRB 071011: MARGE Optical Limits
  2. GRB 071010B: Super-LOTIS upper limit
  3. GRB 071010B optical photometry
  4. GRB 071011: XRT afterglow detection
  5. GRB 071010B: Keck/LRIS Spectroscopy
  6. GRB 071011, Swift-BAT refined analysis
  7. GRB 071010B: Gemini Spectroscopic Observations
  8. GRB 071011: Early Super-LOTIS Observations
  9. GRB 071011: NAYUTA Optical Observation
  10. GRB 071010A: Continued Keck Imaging
  11. GRB 071010B: Bright OT confirmed with TLS
  12. GRB 071011: Optical afterglow candidate
  13. GRB 071011: Swift detection of a burst
  14. Optical Observation: GRB 071010
  15. Optical observations: GRB 071010A
  16. Konus-Wind observation of GRB 071010B
  17. GRB071010B: Swift/XRT detection
  18. GRB 071010B, Swift-BAT refined analysis
  19. GRB 071010A: bright NIR afterglow
  20. GRB 071006, Swift-BAT refined analysis
  21. GRB071008: optical observations
  22. GRB 071010B possible optical transient
  23. GRB 071010A: Keck/LRIS Photometry
  24. GRB 071010B: Swift detection of a burst
  25. GRB 071010: Swift-XRT observation
  26. GRB 071008, Swift-BAT refined analysis
  27. GRB 071010, Swift-BAT refined analysis
  28. Konus-Wind observation of GRB 071006
  29. GRB071008: Swift-XRT observation
  30. GRB 071010 REM NIR observations
  31. GRB 071010: Keck/LRIS Spectroscopy
  32. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  33. GRB 071010: Rapid PROMPT Detections
  34. GRB 071010: Keck Observations of the Afterglow
  35. GRB 071010: TAROT La Silla observatory detection of the afterglow
  36. GRB 071010: Swift detection of a burst
  37. GRB 071006 Swift-BAT detection of a burst
  38. GRB071008: IAC80 observation
  39. GRB 071008: Swift detection of a burst
  40. GRB 071003: XRT refined analysis
  41. GRB070920A: MAGIC telescope GeV observation
  42. Radio detection of GRB 071003 with the VLA
  43. GRB 070810B: further XRT analysis
  44. GRB 071003: VLT spectroscopy
  45. GRB 071003: Keck spectroscopy
  46. Konus-Wind observation of GRB 071003
  47. GRB071003: Faulkes Telescope North observations
  48. GRB 071003: Possible rebrightening
  49. GRB 071003 : Lulin R-band observations
  50. GRB 071003: Swift XRT position
  51. GRB 071003: OA power-law decay indices from KAIT
  52. GRB 071003: Keck HIRES spectroscopy
  53. GRB 071003, Swift-BAT refined analysis
  54. GRB 071003: MARGE Observations
  55. GRB 071003 Optical observations
  56. GRB 071003: P60 Confirmation of Optical Afterglow
  57. GRB 071003: KAIT optical afterglow observations
  58. GRB 071003: Swift detection of a bright burst
  59. GRB 070714B: host galaxy spectroscopic redshift
  60. GRB 071001: Swift-XRT Team refined analysis
  61. GRB 071001, Swift-BAT refined analysis
  62. Faulkes Telescope South observations of GRB 071001
  63. GRB 071001: Swift detection of a burst
  64. VLA observation of GRB 070923
  65. Disregard the Swift-XRT Notices today
  66. GRB 070911, SMARTS optical/IR afterglow observations
  67. GRB070925: Swift-XRT Afterglow confirmation
  68. GRB 070925: Gemini South Imaging
  69. GRB070925: Swift-XRT Position
  70. Update on Swift Status
  71. GRB 070920B: ROTSE-III Early Optical Limits
  72. GRB 070925: a long GRB detected by INTEGRAL
  73. Recent SGR1806-20 Activity
  74. GRB 070923, Swift-BAT refined analysis
  75. GRB 070920B: XRT observations
  76. GRB 070923: Galaxies within BAT localization
  77. GRB 070923: Swift detection of a short hard burst
  78. GRB 070917: Suzaku/WAM observation of the prompt emission
  79. GRB 070920B: TAROT La Silla observatory optical observations
  80. INTEGRAL ToO observations of SGR1806-20
  81. GRB 070920b, SMARTS optical observation
  82. GRB 070917: Confirmation of the X-ray afterglow
  83. GRB 070920b: LCO optical observations
  84. GRB 070920B, Swift-BAT refined analysis
  85. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  86. GRB 070920B: NOT optical observations
  87. GRB 070920B: Swift detection of a burst
  88. GRB 070920, Swift-BAT refined analysis
  89. GRB 070920: TAROT Calern observatory optical observations
  90. GRB 070920: Swift detection of a burst
  91. SGR1806-20: Swift-BAT detection of enhanced activity
  92. GRB070917: Confirmation of optical afterglow
  93. GRB920925C: search for host galaxy
  94. GRB070917: optical observations
  95. GRB 070917: P60 Observations
  96. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  97. Konus-Wind observation of GRB 070917
  98. Swift Status and XRT Calibration Uncertainties
  99. GRB 070917: Swift-XRT observations
  100. GRB 070917: KAIT optical limits

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