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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"

19941 results found.

  1. GRB 240415A: Enhanced Swift-XRT position
  2. GRB 240415B: Swift ToO observations
  3. GRB 240415B: Swift/BAT-GUANO Correction
  4. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  5. GRB 240414A: Fermi GBM Observation
  6. GRB 240414A: Swift/UVOT Detection
  7. LXT 240402A/GRB 240402B: Swift follow-up observations
  8. GRB 240414A: Mondy optical observations
  9. GRB 240415A: Prompt Swift-XRT observations
  10. GRB 240415A: Swift detection of a burst
  11. GRB 240414A: Swift-XRT refined Analysis
  12. GRB 240414A: Enhanced Swift-XRT position
  13. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  14. GRB 240414A: Skynet Optical Afterglow Observations
  15. Swift GRB 240414A: Global MASTER-Net observations report
  16. IPN triangulation of GRB 240410A
  17. IPN triangulation of GRB 240411A
  18. GRB 240414A : MITSuME Akeno optical upper limits
  19. GRB 240414A: Swift detection of a burst
  20. GRB 240411B: Swift-BAT refined analysis
  21. GRB 240411B: Swift-XRT refined Analysis
  22. GRB 240411B: 1.3m DFOT Optical observations
  23. GRB 240411B: Enhanced Swift-XRT position
  24. GRB 240411B: Swift detection of a burst
  25. EP240408A: MASTER optical observations
  26. EP240408a: GROND detection of a candidate counterpart
  27. EP240408a: Swift follow-up observation
  28. Swift Trigger 1220736: detection of 4U 1543-62.
  29. Swift satellite resumes pointed science observations
  30. GRB 240318A: Fermi GBM Observation
  31. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  32. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  33. GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  34. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
  35. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  36. GRB 240317B: Fermi GBM Observation
  37. Swift satellite in safe mode
  38. GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
  39. Einstein Probe detected of a fast X-ray transient EP240315a
  40. GRID detection of GRB 240306A
  41. Swift Triggers 1220155, 1220156, 1220157, 1220158, 1220160 and 1220161 were not astrophysical
  42. Swift Triggers 1220093, 1220094, 1220095 and 1220096 are not astrophysical
  43. Swift Triggers 1220090, 1220091 and 1220092 are not astrophysical
  44. Swift triggers 1219917, 1219917 and 1219922 were not astrophysical
  45. Swift Trigger 1219909 and 1219910 are not a astrophysical
  46. Swift Trigger 1219905 is not a GRB
  47. Swift Trigger 1219874 is not astrophysical
  48. Swift GRB240309.61: Global MASTER-Net observations report
  49. Swift Trigger 1219325 is not a GRB
  50. GRB 240306A: Fermi GBM observation
  51. Konus-Wind detection of GRB 231118A
  52. GRB 240306A: AstroSat CZTI detection
  53. GRB 240306A: Swift/BAT-GUANO detection of a burst
  54. GRB 240305A: Fermi GBM observation
  55. Swift GRB240305.18: Global MASTER-Net observations report
  56. Swift GRB240305.16: Global MASTER-Net observations report
  57. GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
  58. GRB 240218A: Chandra Detection and Jet Break Confirmation
  59. Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
  60. Swift Trigger 1218696: Another trigger on Swift J151857.0-572147
  61. Swift Trigger 1218645: Another detection of Swift J151857.0-572147
  62. Swift J151857.0-572147: Swift-BAT refined analysis
  63. GRB 240225B: Swift-XRT afterglow detection
  64. Swift detection of Swift J151857.0-572147
  65. Swift GRB 240303A: Global MASTER-Net observations report
  66. Swift J151857.0-572147: Confirmation of a new galactic transient
  67. GRB 240215A: Swift-XRT afterglow detection
  68. GRB 240303A: Swift detection of a burst
  69. GRB 240225A (short): Glowbug gamma-ray detection
  70. Swift BAT Triggers 1218081 and 1218082 are not astrophysical
  71. GRB 240225B: Swift ToO observations
  72. GRB 240225B: 3.6m DOT observation
  73. Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up
  74. Swift Trigger 1217799 is not a GRB
  75. Swift-BAT triggers 1217733 - 1217736 are not astrophysical events
  76. Swift-BAT triggers 1217729-1217732 are not astrophysical
  77. GRB 240225B: Nanshan/HMT optical afterglow detection
  78. GRB 240225B: Swift-XRT observations
  79. GRB 240225B: GOTO detection of a candidate optical afterglow
  80. GRB 240225B: Tiled Swift observations
  81. Transient EPW20240219aa: Xinglong-2.16m optical upper limit
  82. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  83. GRB 240222A: GRBAlpha detection
  84. Swift-BAT triggers 1217218-1217222 are not astrophysical
  85. Transient EPW20240219aa: Mondy optical observations
  86. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  87. Swift BAT Sub-Threshold Detection of EPW20240219aa
  88. GRB 240222A: GECAM detection of a burst
  89. GRB 240222A: Swift-BAT refined analysis
  90. GRB 240222A: Swift-XRT refined Analysis
  91. Swift-BAT triggers 1216907-1216911 are not astrophysical
  92. GRB 240222A: Fermi GBM Observation
  93. GRB 240222A: Swift/UVOT Upper Limits
  94. Swift GRB 240222A: Global MASTER-Net observations report
  95. Swift Trigger 1216864 is not an astrophysical event
  96. GRB 240222A: Swift detection of a burst
  97. Swift-BAT triggers 1216751 and 1216753 are not astrophysical events
  98. Swift-BAT triggers 1216743-1216748 are not astrophysical
  99. Swift GRB240221.92: Global MASTER-Net observations report
  100. GRB 240218A: MeerLICHT upper limits

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