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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 071010: Keck/LRIS Spectroscopy
  2. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  3. GRB 071010: Rapid PROMPT Detections
  4. GRB 071010: Keck Observations of the Afterglow
  5. GRB 071010: TAROT La Silla observatory detection of the afterglow
  6. GRB 071010: Swift detection of a burst
  7. GRB 071006 Swift-BAT detection of a burst
  8. GRB071008: IAC80 observation
  9. GRB 071008: Swift detection of a burst
  10. GRB 071003: XRT refined analysis
  11. GRB070920A: MAGIC telescope GeV observation
  12. Radio detection of GRB 071003 with the VLA
  13. GRB 070810B: further XRT analysis
  14. GRB 071003: VLT spectroscopy
  15. GRB 071003: Keck spectroscopy
  16. Konus-Wind observation of GRB 071003
  17. GRB071003: Faulkes Telescope North observations
  18. GRB 071003: Possible rebrightening
  19. GRB 071003 : Lulin R-band observations
  20. GRB 071003: Swift XRT position
  21. GRB 071003: OA power-law decay indices from KAIT
  22. GRB 071003: Keck HIRES spectroscopy
  23. GRB 071003, Swift-BAT refined analysis
  24. GRB 071003: MARGE Observations
  25. GRB 071003 Optical observations
  26. GRB 071003: P60 Confirmation of Optical Afterglow
  27. GRB 071003: KAIT optical afterglow observations
  28. GRB 071003: Swift detection of a bright burst
  29. GRB 070714B: host galaxy spectroscopic redshift
  30. GRB 071001: Swift-XRT Team refined analysis
  31. GRB 071001, Swift-BAT refined analysis
  32. Faulkes Telescope South observations of GRB 071001
  33. GRB 071001: Swift detection of a burst
  34. VLA observation of GRB 070923
  35. Disregard the Swift-XRT Notices today
  36. GRB 070911, SMARTS optical/IR afterglow observations
  37. GRB070925: Swift-XRT Afterglow confirmation
  38. GRB 070925: Gemini South Imaging
  39. GRB070925: Swift-XRT Position
  40. Update on Swift Status
  41. GRB 070920B: ROTSE-III Early Optical Limits
  42. GRB 070925: a long GRB detected by INTEGRAL
  43. Recent SGR1806-20 Activity
  44. GRB 070923, Swift-BAT refined analysis
  45. GRB 070920B: XRT observations
  46. GRB 070923: Galaxies within BAT localization
  47. GRB 070923: Swift detection of a short hard burst
  48. GRB 070917: Suzaku/WAM observation of the prompt emission
  49. GRB 070920B: TAROT La Silla observatory optical observations
  50. INTEGRAL ToO observations of SGR1806-20
  51. GRB 070920b, SMARTS optical observation
  52. GRB 070917: Confirmation of the X-ray afterglow
  53. GRB 070920b: LCO optical observations
  54. GRB 070920B, Swift-BAT refined analysis
  55. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  56. GRB 070920B: NOT optical observations
  57. GRB 070920B: Swift detection of a burst
  58. GRB 070920, Swift-BAT refined analysis
  59. GRB 070920: TAROT Calern observatory optical observations
  60. GRB 070920: Swift detection of a burst
  61. SGR1806-20: Swift-BAT detection of enhanced activity
  62. GRB070917: Confirmation of optical afterglow
  63. GRB920925C: search for host galaxy
  64. GRB070917: optical observations
  65. GRB 070917: P60 Observations
  66. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  67. Konus-Wind observation of GRB 070917
  68. Swift Status and XRT Calibration Uncertainties
  69. GRB 070917: Swift-XRT observations
  70. GRB 070917: KAIT optical limits
  71. GRB 070917: MITSuME Akeno Ic upper limit
  72. GRB 070917: R band observations
  73. GRB 070917, Swift-BAT refined analysis
  74. GRB 070917: Swift detection of a bright burst
  75. GRB 070911: Suzaku WAM observation of the prompt emission
  76. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  77. GRB 070809: The Swift evidence for the SHB nature of this burst
  78. GRB 070913: Afterglow candidate detected by TAROT La Silla observatory
  79. GRB 070913: Swift-BAT refined analysis
  80. GRB 070913: Corrected BAT position
  81. GRB 070913: SMARTS optical/IR observations
  82. GRB 070913: TAROT La Silla observatory optical observations
  83. GRB 070913: Swift detection of a burst
  84. Swift-BAT Notices back to autonomous real-time distribution
  85. GRB 070911: PAIRITEL IR Observations
  86. GRB 070911: Swift XRT refined analysis
  87. GRB 070911, Swift-BAT refined analysis
  88. GRB 070911: Swift detection of a burst
  89. IPN search for a GRB associated with TAROT transient on August 31
  90. Intense burst from SGR 1806-20 detected on September 7
  91. GRB 070809: Confirmation of optical transient
  92. Observations of possible TAROT GRB transient near IC 4779
  93. Candidate Orphan GRB Optical Transient in IC 4779
  94. GRB 070810b: Image Subtraction of Multiple Keck Observations
  95. Las Campanas observations of possible TAROT GRB transient near IC
  96. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  97. Konus-Wind observation of GRB 070824
  98. GRB 070824 - Combined SuperAGILE/IPN Localization
  99. Konus-Wind observation of very bright GRB 070821
  100. GRB 070731: Swift/UVOT Upper Limit

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