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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"

27777 results found.

  1. GRB 240227A: Fermi GBM Final Real-time Localization
  2. GRB 240225B: Nanshan/HMT optical afterglow detection
  3. GRB 240225B: CALET Gamma-Ray Burst Monitor detection
  4. GRB 240225B: Swift-XRT observations
  5. GRB 240226B: Fermi GBM Final Real-time Localization
  6. GRB 240225C: CALET Gamma-Ray Burst Monitor detection
  7. GRB 240225B: GOTO detection of a candidate optical afterglow
  8. GRB 240226A: Fermi GBM Final Real-time Localization
  9. Transient EPW20240219aa: REM optical/NIR upper limits
  10. GRB 240225C: GRBAlpha detection
  11. GRB 240225C: AstroSat CZTI detection
  12. GRB 240225B: AstroSat CZTI detection
  13. GRB 240225B: Tiled Swift observations
  14. GRB 240225B: MAXI/GSC detection
  15. Transient EPW20240219aa: Xinglong-2.16m optical upper limit
  16. GRB 240218A: VLA detection
  17. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  18. GRB 240222A: GRBAlpha detection
  19. Transient EPW20240219aa: 7DT Optical Upper Limits
  20. Swift-BAT triggers 1217218-1217222 are not astrophysical
  21. Transient EPW20240219aa: Mondy optical observations
  22. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  23. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  24. Swift BAT Sub-Threshold Detection of EPW20240219aa
  25. Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
  26. GRB 240222A: GECAM detection of a burst
  27. GRB 240222A: Swift-BAT refined analysis
  28. GRB 240222A: Swift-XRT refined Analysis
  29. Swift-BAT triggers 1216907-1216911 are not astrophysical
  30. GRB 240222A: Fermi GBM Observation
  31. GRB 240222A: Swift/UVOT Upper Limits
  32. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  33. Swift GRB 240222A: Global MASTER-Net observations report
  34. EPW20240219aa is Likely a GRB Event
  35. Swift Trigger 1216864 is not an astrophysical event
  36. GRB 240222A: Swift detection of a burst
  37. GRB 240222A: Fermi GBM Final Real-time Localization
  38. Swift-BAT triggers 1216751 and 1216753 are not astrophysical events
  39. Swift-BAT triggers 1216743-1216748 are not astrophysical
  40. Swift GRB240221.92: Global MASTER-Net observations report
  41. GRB 240218A: MeerLICHT upper limits
  42. GRB 240216A: Glowbug gamma-ray detection
  43. GRB 240215B: Fermi GBM Observation
  44. GRB 240218A: LBT H-band detection
  45. GRB 240218A: Swift-BAT refined analysis
  46. GRB 240220A: Fermi GBM Final Real-time Localization
  47. Konus-Wind detection of GRB 240218A
  48. GRB 240218A: Swift-XRT refined Analysis
  49. GRB 240218A: VLT/X-shooter redshift of z = 6.782
  50. GRB 240218A: Fermi GBM Detection
  51. GRB 240215A: Fermi GBM Observation
  52. GRB 240216A: GRBAlpha detection
  53. GRB 240215B: GRBAlpha detection
  54. IPN triangulation of GRB 240209A
  55. GRB 240218A: VLT/FORS2 z-band detection
  56. GRB 240218A: Enhanced Swift-XRT position
  57. GRB 240218A: REM detection of a NIR afterglow candidate
  58. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  59. GRB 240213A: GRBAlpha detection
  60. GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
  61. GRB 240218A: Swift detection of a burst
  62. Swift GRB240218.08: Global MASTER-Net observations report
  63. GRB 240215C: Fermi GBM Final Real-time Localization
  64. GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  65. Swift Triggers 12156887-1215690 are not astrophysical events.
  66. GRB 240216A: Fermi GBM Final Real-time Localization
  67. GRB 240215A: Tiled Swift observations
  68. GRB 240215A: Swift/BAT-GUANO localization of a burst
  69. GRB 240213A: Glowbug gamma-ray detection
  70. GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
  71. GRB 240128A: Further Swift-XRT observations
  72. GRB 240214A: Tiled Swift observations
  73. GRB 240214A/1H 0451-560: MAXI/GSC detection
  74. GRB 240213A: Fermi GBM Final Real-time Localization
  75. GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
  76. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  77. GRB 240209A: GOTO optical counterpart candidate
  78. Konus-Wind detection of GRB 240204A
  79. Konus-Wind detection of GRB 240205A (short)
  80. GRB 240209A: Fermi GBM Final Localization
  81. IPN triangulation of GRB 240205A (short)
  82. GRB 240205B: PRIME near infrared detection
  83. GRB 240205A (short): Glowbug gamma-ray detection
  84. Swift Trigger 1213872 is not an astrophysical event
  85. GRB240204A: Swift/UVOT Upper Limits
  86. GRB 240205B: AstroSat CZTI detection
  87. GRB 240205B: Swift-BAT refined analysis
  88. Konus-Wind detection of GRB 240205B (long / very soft)
  89. GRB 240207A: Fermi GBM Final Real-time Localization
  90. Konus-Wind detection of GRB 240125A
  91. GRB 240205B: VLT/X-shooter redshift
  92. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  93. GRB 240205B: BOOTES-6 optical afterglow follow-up
  94. GRB 240205B: ATCA detection of radio counterpart
  95. GRB 240205B: REM detection of the optical/NIR afterglow
  96. GRB 240205B: Fermi GBM Observation
  97. GRB 240204A: AstroSat CZTI detection
  98. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  99. GRB 240205B: GECAM detection of a long burst
  100. GRB 240204A: Swift-BAT refined analysis

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