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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 071003: Keck HIRES spectroscopy
  2. GRB 071003, Swift-BAT refined analysis
  3. GRB 071003: MARGE Observations
  4. GRB 071003 Optical observations
  5. GRB 071003: P60 Confirmation of Optical Afterglow
  6. GRB 071003: KAIT optical afterglow observations
  7. GRB 071003: Swift detection of a bright burst
  8. GRB 070714B: host galaxy spectroscopic redshift
  9. GRB 071001: Swift-XRT Team refined analysis
  10. GRB 071001, Swift-BAT refined analysis
  11. Faulkes Telescope South observations of GRB 071001
  12. GRB 071001: Swift detection of a burst
  13. VLA observation of GRB 070923
  14. Disregard the Swift-XRT Notices today
  15. GRB 070911, SMARTS optical/IR afterglow observations
  16. GRB070925: Swift-XRT Afterglow confirmation
  17. GRB 070925: Gemini South Imaging
  18. GRB070925: Swift-XRT Position
  19. Update on Swift Status
  20. GRB 070920B: ROTSE-III Early Optical Limits
  21. GRB 070925: a long GRB detected by INTEGRAL
  22. Recent SGR1806-20 Activity
  23. GRB 070923, Swift-BAT refined analysis
  24. GRB 070920B: XRT observations
  25. GRB 070923: Galaxies within BAT localization
  26. GRB 070923: Swift detection of a short hard burst
  27. GRB 070917: Suzaku/WAM observation of the prompt emission
  28. GRB 070920B: TAROT La Silla observatory optical observations
  29. INTEGRAL ToO observations of SGR1806-20
  30. GRB 070920b, SMARTS optical observation
  31. GRB 070917: Confirmation of the X-ray afterglow
  32. GRB 070920b: LCO optical observations
  33. GRB 070920B, Swift-BAT refined analysis
  34. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  35. GRB 070920B: NOT optical observations
  36. GRB 070920B: Swift detection of a burst
  37. GRB 070920, Swift-BAT refined analysis
  38. GRB 070920: TAROT Calern observatory optical observations
  39. GRB 070920: Swift detection of a burst
  40. SGR1806-20: Swift-BAT detection of enhanced activity
  41. GRB070917: Confirmation of optical afterglow
  42. GRB920925C: search for host galaxy
  43. GRB070917: optical observations
  44. GRB 070917: P60 Observations
  45. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  46. Konus-Wind observation of GRB 070917
  47. Swift Status and XRT Calibration Uncertainties
  48. GRB 070917: Swift-XRT observations
  49. GRB 070917: KAIT optical limits
  50. GRB 070917: MITSuME Akeno Ic upper limit
  51. GRB 070917: R band observations
  52. GRB 070917, Swift-BAT refined analysis
  53. GRB 070917: Swift detection of a bright burst
  54. GRB 070911: Suzaku WAM observation of the prompt emission
  55. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  56. GRB 070809: The Swift evidence for the SHB nature of this burst
  57. GRB 070913: Afterglow candidate detected by TAROT La Silla observatory
  58. GRB 070913: Swift-BAT refined analysis
  59. GRB 070913: Corrected BAT position
  60. GRB 070913: SMARTS optical/IR observations
  61. GRB 070913: TAROT La Silla observatory optical observations
  62. GRB 070913: Swift detection of a burst
  63. Swift-BAT Notices back to autonomous real-time distribution
  64. GRB 070911: PAIRITEL IR Observations
  65. GRB 070911: Swift XRT refined analysis
  66. GRB 070911, Swift-BAT refined analysis
  67. GRB 070911: Swift detection of a burst
  68. IPN search for a GRB associated with TAROT transient on August 31
  69. Intense burst from SGR 1806-20 detected on September 7
  70. GRB 070809: Confirmation of optical transient
  71. Observations of possible TAROT GRB transient near IC 4779
  72. Candidate Orphan GRB Optical Transient in IC 4779
  73. GRB 070810b: Image Subtraction of Multiple Keck Observations
  74. Las Campanas observations of possible TAROT GRB transient near IC
  75. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  76. Konus-Wind observation of GRB 070824
  77. GRB 070824 - Combined SuperAGILE/IPN Localization
  78. Konus-Wind observation of very bright GRB 070821
  79. GRB 070731: Swift/UVOT Upper Limit
  80. IPN Localization of GRB 070821 (long, very bright)
  81. GRB 070805: UVOT afterglow candidate retraction
  82. GRB070810b: optical candidate
  83. GRB 070810A: ROTSE-III Refined Analysis
  84. Swift observatory off line
  85. GRB 061110A: redshift confirmed
  86. GRB 070810B : Faulkes Telescope South Observations
  87. GRB 070810A: Continued Keck Imaging
  88. GRB 070810B: Keck spectroscopy of possible host galaxies
  89. GRB070810B: Swift/UVOT Upper Limits
  90. GRB 070810B: XRT refined analysis
  91. GRB 070810B, Swift-BAT refined analysis
  92. GRB 070810: MASTER optical observation
  93. GRB 070809: Swift/UVOT Corrected Photometry
  94. Swift Alert 070810.8: MASTER optical observation
  95. Swift Trigger 287421: False trigger due to star tracker loss
  96. GRB 070810A: Swift-BAT refined analysis
  97. GRB 070810B: Xinglong TNT optical Upper Limit
  98. GRB070810B: Optical observations with KANATA
  99. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  100. GRB 070809: Swift/UVOT Upper Limits

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