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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"

19949 results found.

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

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