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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"

26012 results found.

  1. GRB 180821A: Enhanced Swift-XRT position
  2. GRB 180818B: 1.5m OSN optical afterglow candidate
  3. GRB 180821A: iTelescope optical afterglow detection
  4. GRB 180821A: Swift detection of a burst
  5. GRB180806A: confirmation of the X-ray afterglow
  6. GRB 180818B: Swift-XRT refined Analysis
  7. GRB 180818B: Swift-BAT refined analysis
  8. GRB 180818A: Swift-BAT refined analysis
  9. GRB 180818B: Fermi GBM observations
  10. GRB 180818B: Swift/UVOT Upper Limits
  11. GRB 180818B: Enhanced Swift-XRT position
  12. GRB 180818A: Swift/UVOT Upper Limits
  13. GRB 180818B: Swift detection of a burst
  14. GRB 180818A: Swift-XRT refined Analysis
  15. GRB 180818A: Enhanced Swift-XRT position
  16. GRB 180818A: Swift detection of a burst
  17. GRB 180728A: discovery of the associated supernova
  18. GRB 180809A: further Swift/XRT observations
  19. Correction: Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  20. GRB 180812A: Swift/UVOT Detection
  21. Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  22. GRB 180812A: Swift-BAT refined analysis
  23. GRB 180812A: Fermi GBM detection
  24. GRB 180812A: Swift-XRT refined Analysis
  25. GRB 180809B: ePESSTO NTT NIR observations
  26. GRB 180812A: COATLI Detection and Light Curve
  27. GRB 180812A: Enhanced Swift-XRT position
  28. GRB 180812A: Swift detection of a burst
  29. GRB180809B TUG T60 observations
  30. MASTER: OT detection during two Fermi GBM triggers (555263883 and 555263883) error boxes inspection in 22.5 mag SDSS galaxy direction
  31. GRB 180809B: Swift-XRT refined Analysis
  32. GRB 180809B: CrAO optical observations
  33. GRB 180809B, Swift-BAT refined analysis
  34. Swift Trigger 852625: Swift/BAT/XRT/UVOT observations
  35. GRB 180809B: Swift/UVOT Detection
  36. GRB 180809A: Fermi GBM observation
  37. Swift Trigger 852625: a possible GRB
  38. GRB 180809B: VLT optical upper limits
  39. GRB180809B: MASTER Triple Independent Automatic OT Detection
  40. GRB 180809B: LCO Sutherland observations
  41. GRB 180809B: GROND Detection of the NIR Afterglow
  42. GRB 180809B: RATIR Optical Observations and Confirmation of Rapid Fading
  43. GRB180809B: MASTER OT observation
  44. GRB 180805B: Teide LCO optical observations
  45. GRB 180809A: iTelescope optical limit
  46. GRB 180809A: Swift-XRT afterglow detection
  47. GRB 180809B: Swift detection of a burst with an optical afterglow
  48. GRB 180809A: MAXI/GSC detection
  49. GRB180806A: correction to Circular 23097
  50. GRB 180806A: Swift-XRT afterglow detection
  51. GRB 180806A/180806.98: RATIR Optical Observations of MASTER OT J004613.05+242014.1
  52. GRB 180806A: Fermi GBM detection
  53. GRB 180806A/180806.94: Refined COATLI Photometry of MASTER OT J004613.05+242014.1
  54. GRB 180806.94: COATLI Detection of MASTER OT J004613.05+242014.1 and Confirmation of Fading
  55. GRB 180805B: ESO/NTT optical observations
  56. GRB 180805B: COATLI Optical Observations
  57. GRB 180805B: GOTO optical limits
  58. GRB 180805B: VLT optical and near-infrared observations
  59. GRB 180805A: Swift-XRT refined Analysis
  60. GRB 180805B: Swift-XRT refined Analysis
  61. GRB 180805B: Swift-BAT refined analysis (short GRB with extended emission)
  62. GRB 180805A: Swift-BAT refined analysis
  63. GRB 180805B: Swift/UVOT Upper Limits
  64. GRB 180805B: Fermi GBM detection
  65. GRB 180805B: Enhanced Swift-XRT position
  66. GRB 180805B: Swift detection of a burst
  67. GRB 180805A: Enhanced Swift-XRT position
  68. GRB 180805A: Swift detection of a burst
  69. GRB 180728A: A long GRB of the X-ray flash (XRF) subclass, expecting supernova appearance
  70. GRB 180728B: MASTER optical observations short GRB IPN error box
  71. GRB 180728A: Swift/UVOT Detection
  72. GRB 180701A/MAXI J2119-045: CALET Gamma-Ray Burst Monitor data search
  73. GRB 180727A: Swift/UVOT Upper Limits
  74. Konus-Wind observation of the bright nearby GRB 180728A
  75. GRB 180715A: CALET CAL gamma-ray analysis
  76. GRB 180703B: CALET CAL gamma-ray analysis
  77. IPN Triangulation of GRB 180728B (short)
  78. GRB 180728A: Swift-BAT refined analysis
  79. GRB 180728A: Fermi GBM observation
  80. GRB 180728A: Swift-XRT refined Analysis
  81. GRB 180728A: Enhanced Swift-XRT position
  82. GRB 180728A: MASTER OT J165415.75-540239.27 is the Optical Counterpart of GRB
  83. GRB 180728A: Swift-XRT observations
  84. GRB 180727A: Swift-BAT refined analysis
  85. GRB 180727A: Swift-XRT refined Analysis
  86. NuSTAR observations of GRB 180720B
  87. GRB 180720B: OAJ optical observations
  88. GRB 180722B: Insight-HXMT/HE detection
  89. GRB 180724A: Insight-HXMT/HE detection
  90. GRB 180720B: AMI-LA 15.5 GHz observation
  91. GRB 180720B long follow up requested
  92. GRB 180723A: Fermi GBM detection
  93. GRB 180720B: KAIT Optical Observations
  94. GRB 180722A: Swift-XRT observations
  95. GRB 180718B: Swift-XRT observations
  96. GRB 180718A: Swift-XRT observations
  97. GRB 180723.13: MASTER optical observation of the short Fermi GBM trigger number 554008254
  98. GRB 180722A: MASTER second inspection
  99. GRB 180723.76: MASTER optical observation of the bright long Fermi GBM trigger number 554062193
  100. GRB 180720B: REM photometry

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