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

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