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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 170208B: Swift/UVOT Upper Limits
  2. IPN Triangulation of GRB 170209A
  3. GRB 170208B: RATIR Optical and NIR Observations
  4. GRB 170208B: Swift-BAT refined analysis
  5. GRB 170208A: Swift-BAT refined analysis
  6. GRB 170209A: Fermi GBM Detection
  7. Correction to GCN 20640: GRB 170208B: GROND observations
  8. Fermi Trigger 508295323: MASTER-OAFA possible OT detection
  9. GRB 170208A: Swift-XRT refined Analysis
  10. LIGO/Virgo G270580: AstroSat CZTI upper limits
  11. GRB 170208B WHT nIR candidate afterglow
  12. GRB 170208B: Fermi GBM Detection
  13. GRB 170207A: POLAR Observation
  14. GRB 170208A: Swift/UVOT Upper Limits
  15. Konus-Wind observation of GRB 170208B
  16. GRB 170207A: AstroSat CZTI detection
  17. Konus-Wind observation of GRB 170208A
  18. GRB 170208B: GROND observations
  19. GRB 170206C: POLAR Observation
  20. GRB 170208B: NOT upper limits
  21. GRB 170208B: Swift-XRT refined Analysis
  22. GRB 170208B: Etelman observatory optical observations
  23. GRB 170208B: Enhanced Swift-XRT position
  24. GRB 170208A: Enhanced Swift-XRT position
  25. GRB 170208A: Fermi GBM Detection
  26. GRB 170208B: Swift detection of a burst
  27. GRB 170208A: Swift detection of a burst
  28. GRB 170207A: Fermi GBM observation
  29. Konus-Wind observation of GRB 170207A
  30. IPN Triangulation of GRB 170207A (long/very bright)
  31. LIGO/Virgo G270580: Gemini-South Spectroscopic Classification of Optical Transients
  32. GRB 170206B: Swift/UVOT Upper Limits
  33. Konus-Wind observation of GRB 170206A
  34. GRB 170206A: POLAR observation
  35. IPN Triangulation of GRB 170206A (short/hard)
  36. GRB 170206B: Swift-BAT refined analysis
  37. LIGO/Virgo G270580: ANTARES upper limits
  38. GRB 170206B: Swift-XRT refined Analysis
  39. GRB 170206B: Enhanced Swift-XRT position
  40. GRB 170206B: Swift detection of a burst
  41. GRB 170206A: Fermi-LAT detection
  42. GRB 170206A: Fermi GBM observation
  43. GRB 170205A: Swift/UVOT Detection of a Fading Afterglow
  44. Konus-Wind observation of GRB 170205A
  45. GRB 170205A: Swift-BAT refined analysis
  46. GRB 170205A: NOT afterglow observations
  47. GRB 170205A: Swift-XRT refined Analysis
  48. GRB 170205A: Enhanced Swift-XRT position
  49. GRB 170205A: RATIR Optical and NIR Observations
  50. Fermi GBM trigger 508010837/170205755 is not a GRB
  51. Fermi GBM trigger 507959893/170205165 is not a GRB
  52. GRB 170202A: SMARTS optical/IR afterglow observations
  53. GRB 170205A: LCO FTN observations
  54. Konus-Wind observation of GRB 170202A
  55. GRB 170205A: Swift detection of a burst with an optical counterpart
  56. GRB 170202B POLAR Observation
  57. GRB 170202A: SQUEAN Observation (2nd night)
  58. GRB 170131A: POLAR Observation
  59. GRB 170202A: Zadko observatory - Gingin optical observations
  60. GRB 170202A: Etelman Observatory optical observations
  61. GRB 170203A: Swift-BAT refined analysis
  62. GRB 170202A: Swift-BAT refined analysis
  63. GRB 170202A: RATIR Optical and NIR Observations
  64. GRB 170202A: SQUEAN Observation
  65. GRB 170202A: LCO FTN observations
  66. GRB 170202A: Swift-XRT refined Analysis
  67. GRB 170202A: T100 observations
  68. GRB 170202A VLT/X-shooter redshift [minor correction]
  69. GRB 170202A: Xinglong 2.16m photometry and spectroscopic redshift
  70. GRB 170202A: Swift/UVOT Detection
  71. GRB 170202A: Enhanced Swift-XRT position
  72. GRB 170202A: MITSuME Akeno Optical Observation
  73. GRB 170202A: Redshift from OSIRIS/GTC
  74. GRB 170203A: Swift detection of a burst
  75. GRB 170202A: NOT afterglow observations
  76. GRB 170202A: Kanata optical and infrared observations
  77. GRB 170202A: Zadko observatory - Gingin optical observations
  78. GRB 170202A: LCO Sutherland observations
  79. GRB 170202A: MASTGlobal ER-Net bright OT nonmonotonic light curve
  80. GRB 170202A: Mini-MegaTORTORA upper limits
  81. GRB 170202A : Xinglong TNT optical observation
  82. GRB 170202A: Swift detection of a burst with an optical afterglow
  83. GRB 170131A: Swift/UVOT Upper Limits
  84. GRB 170131A: Swift-XRT observations
  85. GRB 170131A: Fermi GBM observation
  86. GRB 170131A: Swift ToO observations
  87. GRB 170131A detected in Swift/BAT ground processing
  88. LIGO/Virgo G270580: Las Cumbres Observatory Follow-up Observations
  89. GRB 170130A: POLAR Observation
  90. Konus-Wind observation of GRB 170127C (short/hard GRB with extended emission)
  91. GRB 170127B: Swift-BAT refined analysis
  92. GRB 170127A: Swift-BAT refined analysis
  93. GRB 170127C: Swift-XRT observations
  94. GRB 170127C: POLAR Observation
  95. GRB 170127A: GROND Upper limits
  96. GRB 170127C: AstroSat CZTI detection
  97. GRB 170127B: Swift-XRT refined Analysis
  98. GRB 170124A: POLAR Observation
  99. GRB 170127A: Swift-XRT refined Analysis
  100. GRB 170126A, Swift-BAT refined analysis

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