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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"

14832 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 240226B: Fermi GBM Final Real-time Localization
  5. GRB 240225C: CALET Gamma-Ray Burst Monitor detection
  6. GRB 240225B: GOTO detection of a candidate optical afterglow
  7. GRB 240226A: Fermi GBM Final Real-time Localization
  8. Transient EPW20240219aa: REM optical/NIR upper limits
  9. GRB 240225C: GRBAlpha detection
  10. GRB 240225C: AstroSat CZTI detection
  11. GRB 240225B: AstroSat CZTI detection
  12. GRB 240225B: MAXI/GSC detection
  13. Transient EPW20240219aa: Xinglong-2.16m optical upper limit
  14. GRB 240218A: VLA detection
  15. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  16. GRB 240222A: GRBAlpha detection
  17. Transient EPW20240219aa: 7DT Optical Upper Limits
  18. Transient EPW20240219aa: Mondy optical observations
  19. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  20. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  21. Swift BAT Sub-Threshold Detection of EPW20240219aa
  22. Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
  23. GRB 240222A: GECAM detection of a burst
  24. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  25. EPW20240219aa is Likely a GRB Event
  26. GRB 240222A: Swift detection of a burst
  27. GRB 240222A: Fermi GBM Final Real-time Localization
  28. GRB 240218A: MeerLICHT upper limits
  29. GRB 240216A: Glowbug gamma-ray detection
  30. GRB 240218A: LBT H-band detection
  31. GRB 240220A: Fermi GBM Final Real-time Localization
  32. Konus-Wind detection of GRB 240218A
  33. GRB 240218A: VLT/X-shooter redshift of z = 6.782
  34. GRB 240218A: Fermi GBM Detection
  35. GRB 240216A: GRBAlpha detection
  36. GRB 240215B: GRBAlpha detection
  37. IPN triangulation of GRB 240209A
  38. GRB 240218A: VLT/FORS2 z-band detection
  39. GRB 240218A: REM detection of a NIR afterglow candidate
  40. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  41. GRB 240213A: GRBAlpha detection
  42. GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
  43. GRB 240218A: Swift detection of a burst
  44. GRB 240215C: Fermi GBM Final Real-time Localization
  45. GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  46. GRB 240216A: Fermi GBM Final Real-time Localization
  47. GRB 240213A: Glowbug gamma-ray detection
  48. GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
  49. GRB 240214A/1H 0451-560: MAXI/GSC detection
  50. GRB 240213A: Fermi GBM Final Real-time Localization
  51. GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
  52. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  53. GRB 240209A: GOTO optical counterpart candidate
  54. Konus-Wind detection of GRB 240204A
  55. Konus-Wind detection of GRB 240205A (short)
  56. GRB 240209A: Fermi GBM Final Localization
  57. IPN triangulation of GRB 240205A (short)
  58. GRB 240205B: PRIME near infrared detection
  59. GRB 240205A (short): Glowbug gamma-ray detection
  60. GRB 240205B: AstroSat CZTI detection
  61. Konus-Wind detection of GRB 240205B (long / very soft)
  62. GRB 240207A: Fermi GBM Final Real-time Localization
  63. Konus-Wind detection of GRB 240125A
  64. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 240205B: BOOTES-6 optical afterglow follow-up
  66. GRB 240205B: ATCA detection of radio counterpart
  67. GRB 240205B: REM detection of the optical/NIR afterglow
  68. GRB 240204A: AstroSat CZTI detection
  69. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  70. GRB 240205B: GECAM detection of a long burst
  71. GRB 240205B: BOOTES-7 optical afterglow follow-up
  72. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  73. GRB 240205B: Swift detection of a burst
  74. GRB 240205B: Fermi GBM Final Real-time Localization
  75. GRB 240205A: Fermi GBM Final Real-time Localization
  76. GRB 240204a: Liverpool Telescope optical afterglow detection
  77. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  78. GRB 240204A: Swift detection of a burst
  79. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  80. GRB 240204A: Fermi GBM Final Real-time Localization
  81. Konus-Wind detection of GRB 240124B
  82. Konus-Wind detection of GRB 240123C
  83. IPN triangulation of GRB 240124B
  84. GRB 240201A: AstroSat CZTI detection
  85. IPN triangulation of GRB 240125B (short)
  86. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  87. IPN triangulation of GRB 240125A (short)
  88. GRB 240128A: Glowbug gamma-ray detection
  89. GRB 240128A: GRBAlpha detection
  90. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  91. GRB 240128A: MAXI/GSC detection
  92. GRB 240125A: GRBAlpha detection
  93. GRB 240123C: GRBAlpha detection
  94. GRB 240122A: ATCA detection of radio counterpart
  95. GRB 240127A: Fermi GBM Final Real-time Localization
  96. GRB 240125A: CALET Gamma-Ray Burst Monitor detection
  97. GRB 240125A: AstroSat CZTI detection of a short burst
  98. GRB 240124B: AstroSat CZTI detection
  99. GRB 240123C: AstroSat CZTI detection
  100. GRB 240125B: Fermi GBM Final Localization

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