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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 180828A: Swift-BAT refined analysis
  2. GRB 180829A: Tiled Swift observations
  3. GRB 180829A/MAXI J0406-019: MAXI/GSC detection
  4. GRB 180828A: Swift-XRT refined Analysis
  5. GRB 180828A / Swift J1754.9-2548: Enhanced Swift-XRT position
  6. GRB 180828A: Fermi GBM observation
  7. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  8. GRB 180728A: classification of the associated SN 2018fip
  9. Konus-Wind observation of GRB 180824A
  10. Fermi GBM trigger 557014342/180826925 is not a GRB
  11. Fermi GBM trigger 557008382/180826856 is not a GRB
  12. GRB 180818B: TSHAO optical upper limit
  13. GRB 180824A: MASTER inspection IPN short GRB error box
  14. GRB 180823A, Swift-BAT refined analysis
  15. IPN Triangulation of GRB 180824A (short)
  16. GRB 180823A: Swift/UVOT Upper Limits
  17. GRB 180823A: RATIR Optical and NIR Observations
  18. GRB 180823A: Swift-XRT refined Analysis
  19. GRB 180823A: Enhanced Swift-XRT position
  20. GRB 180823A: Swift detection of a burst
  21. GRB 180821A: VLT observations
  22. GRB 180821A: Swift/UVOT Upper Limits
  23. GRB 180821A: Swift-BAT refined analysis
  24. GRB 180821A: iTelescope counterpart is not the afterglow
  25. GRB 180821A: Swift-XRT refined Analysis
  26. GRB 180821A: LCO Siding Springs observations
  27. GRB 180821A: Enhanced Swift-XRT position
  28. GRB 180818B: 1.5m OSN optical afterglow candidate
  29. GRB 180821A: iTelescope optical afterglow detection
  30. GRB 180821A: BOOTES-3/YA optical observations
  31. GRB 180821A: Swift detection of a burst
  32. GRB180806A: confirmation of the X-ray afterglow
  33. GRB 180818B: Swift-XRT refined Analysis
  34. GRB 180818B: Swift-BAT refined analysis
  35. GRB 180818A: Swift-BAT refined analysis
  36. GRB 180818B: Fermi GBM observations
  37. GRB 180818B: Swift/UVOT Upper Limits
  38. GRB 180818B: Enhanced Swift-XRT position
  39. GRB 180818A: Swift/UVOT Upper Limits
  40. GRB 180818B: Swift detection of a burst
  41. GRB 180818A: Swift-XRT refined Analysis
  42. GRB 180818A: Enhanced Swift-XRT position
  43. GRB 180818A: Swift detection of a burst
  44. Swift Trigger 853790 is probably not an astrophysical source
  45. GRB 180809B: AstroSat CZTI detection
  46. GRB 180728A: MASTER early polarization and 19 days monitoring
  47. GRB 180728A: discovery of the associated supernova
  48. GRB 180809A: further Swift/XRT observations
  49. Correction: Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  50. LIGO/Virgo GW170817: A steep decline in the radio light curve and prediction for the X-rays
  51. GRB 180812A: Swift/UVOT Detection
  52. Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  53. GRB 180812A: Swift-BAT refined analysis
  54. GRB 180812A: Fermi GBM detection
  55. GRB 180812A: Swift-XRT refined Analysis
  56. GRB 180809B: ePESSTO NTT NIR observations
  57. GRB 180812A: COATLI Detection and Light Curve
  58. GRB 180812A: Enhanced Swift-XRT position
  59. GRB 180812A: BOOTES-5/JGT optical afterglow detection
  60. GRB 180812A: Swift detection of a burst
  61. Konus-Wind observation of GRB 180809B
  62. GRB180809B TUG T60 observations
  63. MASTER: OT detection during two Fermi GBM triggers (555263883 and 555263883) error boxes inspection in 22.5 mag SDSS galaxy direction
  64. GRB 180809B: Swift-XRT refined Analysis
  65. GRB 180809B: CrAO optical observations
  66. GRB 180809B, Swift-BAT refined analysis
  67. GRB 180806A: AstroSat CZTI detection
  68. Swift Trigger 852625: Swift/BAT/XRT/UVOT observations
  69. GRB 180809B: Swift/UVOT Detection
  70. Konus-Wind observation of GRB 180806A
  71. GRB 180809A: Fermi GBM observation
  72. GRB 180809A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 180809B: CALET Gamma-Ray Burst Monitor detection
  74. Swift Trigger 852625: a possible GRB
  75. GRB 180809B: VLT optical upper limits
  76. GRB180809B: MASTER Triple Independent Automatic OT Detection
  77. GRB 180809B: LCO Sutherland observations
  78. GRB 180809B: GROND Detection of the NIR Afterglow
  79. GRB 180809B: RATIR Optical Observations and Confirmation of Rapid Fading
  80. GRB180809B: MASTER OT observation
  81. GRB 180805B: Teide LCO optical observations
  82. GRB 180809A: iTelescope optical limit
  83. GRB 180809A: Swift-XRT afterglow detection
  84. GRB 180809B: Swift detection of a burst with an optical afterglow
  85. GRB 180809A: Tiled Swift observations
  86. GRB 180809A: MAXI/GSC detection
  87. GRB 180728A: AstroSat CZTI detection
  88. GRB180806A: correction to Circular 23097
  89. GRB 180724A: AstroSat CZTI detection
  90. GRB 180723A: AstroSat CZTI detection
  91. GRB 180806A: NOT optical observations
  92. GRB 180806A: Swift-XRT afterglow detection
  93. GRB 180806A/180806.98: RATIR Optical Observations of MASTER OT J004613.05+242014.1
  94. GRB 180806A: Fermi GBM detection
  95. GRB 180806A/180806.94: Refined COATLI Photometry of MASTER OT J004613.05+242014.1
  96. GRB 180806A: Swift ToO observations
  97. GRB 180806.94: COATLI Detection of MASTER OT J004613.05+242014.1 and Confirmation of Fading
  98. GRB 180806.94: MASTER possible OT detection in Fermi GMB trigger 555287944 error box
  99. GRB 180805B: ESO/NTT optical observations
  100. GRB 180805B: COATLI Optical Observations

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