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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"

19603 results found.

  1. GRB 240414A: Skynet Optical Afterglow Observations
  2. Swift GRB 240414A: Global MASTER-Net observations report
  3. IPN triangulation of GRB 240410A
  4. IPN triangulation of GRB 240411A
  5. GRB 240414A : MITSuME Akeno optical upper limits
  6. GRB 240414A: Swift detection of a burst
  7. GRB 240411B: Swift-BAT refined analysis
  8. GRB 240411B: Swift-XRT refined Analysis
  9. GRB 240411B: 1.3m DFOT Optical observations
  10. GRB 240411B: Enhanced Swift-XRT position
  11. GRB 240411B: Swift detection of a burst
  12. EP240408A: MASTER optical observations
  13. EP240408a: GROND detection of a candidate counterpart
  14. EP240408a: Swift follow-up observation
  15. Swift Trigger 1220736: detection of 4U 1543-62.
  16. Swift satellite resumes pointed science observations
  17. GRB 240318A: Fermi GBM Observation
  18. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  19. GRB 240315C / X-ray transient EP240315a: Swift/BAT detection
  20. GRB 240318A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  21. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
  22. GRB 240317B: Swift/BAT-GUANO Angular Error Correction
  23. GRB 240317B: Fermi GBM Observation
  24. Swift satellite in safe mode
  25. GRB 240317B: Swift/BAT-GUANO arcminute localization of a burst
  26. Einstein Probe detected of a fast X-ray transient EP240315a
  27. GRID detection of GRB 240306A
  28. Swift Triggers 1220155, 1220156, 1220157, 1220158, 1220160 and 1220161 were not astrophysical
  29. Swift Triggers 1220093, 1220094, 1220095 and 1220096 are not astrophysical
  30. Swift Triggers 1220090, 1220091 and 1220092 are not astrophysical
  31. Swift triggers 1219917, 1219917 and 1219922 were not astrophysical
  32. Swift Trigger 1219909 and 1219910 are not a astrophysical
  33. Swift Trigger 1219905 is not a GRB
  34. Swift Trigger 1219874 is not astrophysical
  35. Swift GRB240309.61: Global MASTER-Net observations report
  36. Swift Trigger 1219325 is not a GRB
  37. GRB 240306A: Fermi GBM observation
  38. Konus-Wind detection of GRB 231118A
  39. GRB 240306A: AstroSat CZTI detection
  40. GRB 240306A: Swift/BAT-GUANO detection of a burst
  41. GRB 240305A: Fermi GBM observation
  42. Swift GRB240305.18: Global MASTER-Net observations report
  43. Swift GRB240305.16: Global MASTER-Net observations report
  44. GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
  45. GRB 240218A: Chandra Detection and Jet Break Confirmation
  46. Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
  47. Swift Trigger 1218696: Another trigger on Swift J151857.0-572147
  48. Swift Trigger 1218645: Another detection of Swift J151857.0-572147
  49. Swift J151857.0-572147: Swift-BAT refined analysis
  50. GRB 240225B: Swift-XRT afterglow detection
  51. Swift detection of Swift J151857.0-572147
  52. Swift GRB 240303A: Global MASTER-Net observations report
  53. Swift J151857.0-572147: Confirmation of a new galactic transient
  54. GRB 240215A: Swift-XRT afterglow detection
  55. GRB 240303A: Swift detection of a burst
  56. GRB 240225A (short): Glowbug gamma-ray detection
  57. Swift BAT Triggers 1218081 and 1218082 are not astrophysical
  58. GRB 240225B: Swift ToO observations
  59. GRB 240225B: 3.6m DOT observation
  60. Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up
  61. Swift Trigger 1217799 is not a GRB
  62. Swift-BAT triggers 1217733 - 1217736 are not astrophysical events
  63. Swift-BAT triggers 1217729-1217732 are not astrophysical
  64. GRB 240225B: Nanshan/HMT optical afterglow detection
  65. GRB 240225B: Swift-XRT observations
  66. GRB 240225B: GOTO detection of a candidate optical afterglow
  67. GRB 240225B: Tiled Swift observations
  68. Transient EPW20240219aa: Xinglong-2.16m optical upper limit
  69. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  70. GRB 240222A: GRBAlpha detection
  71. Swift-BAT triggers 1217218-1217222 are not astrophysical
  72. Transient EPW20240219aa: Mondy optical observations
  73. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  74. Swift BAT Sub-Threshold Detection of EPW20240219aa
  75. GRB 240222A: GECAM detection of a burst
  76. GRB 240222A: Swift-BAT refined analysis
  77. GRB 240222A: Swift-XRT refined Analysis
  78. Swift-BAT triggers 1216907-1216911 are not astrophysical
  79. GRB 240222A: Fermi GBM Observation
  80. GRB 240222A: Swift/UVOT Upper Limits
  81. Swift GRB 240222A: Global MASTER-Net observations report
  82. Swift Trigger 1216864 is not an astrophysical event
  83. GRB 240222A: Swift detection of a burst
  84. Swift-BAT triggers 1216751 and 1216753 are not astrophysical events
  85. Swift-BAT triggers 1216743-1216748 are not astrophysical
  86. Swift GRB240221.92: Global MASTER-Net observations report
  87. GRB 240218A: MeerLICHT upper limits
  88. GRB 240215B: Fermi GBM Observation
  89. GRB 240218A: LBT H-band detection
  90. GRB 240218A: Swift-BAT refined analysis
  91. Konus-Wind detection of GRB 240218A
  92. GRB 240218A: Swift-XRT refined Analysis
  93. GRB 240218A: VLT/X-shooter redshift of z = 6.782
  94. GRB 240218A: Fermi GBM Detection
  95. GRB 240215A: Fermi GBM Observation
  96. GRB 240215B: GRBAlpha detection
  97. IPN triangulation of GRB 240209A
  98. GRB 240218A: Enhanced Swift-XRT position
  99. GRB 240218A: REM detection of a NIR afterglow candidate
  100. GRB 240218A: Swift detection of a burst

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