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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"

11558 results found.

  1. GRB 240303B: VZLUSAT-2 detection
  2. GRB 240229A: VZLUSAT-2 detection
  3. Improved IPN triangulation of GRB 240227A (short)
  4. IPN triangulation of GRB 240229A
  5. GRB 240305A: Fermi GBM Final Real-time Localization
  6. Konus-Wind detection of GRB 240303B
  7. IPN triangulation of GRB 240303B
  8. GRB 240303B: Fermi GBM Detection
  9. GRB 240303B: CALET Gamma-Ray Burst Monitor detection
  10. Fermi trigger No 731161136: Global MASTER-Net observations report
  11. GRB 240303C: BALROG localization (Fermi Trigger 731189113 / GRB 240303837)
  12. GRB 240303B: BALROG localization (Fermi Trigger 731161136 / GRB 240303513)
  13. GRB 240303B: Fermi GBM Final Localization
  14. GRB 240229A: DDOTI Upper Limits on the Afterglow
  15. GRB 240229A: CALET Gamma-Ray Burst Monitor detection
  16. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  17. Fermi GRB 240229A: Global MASTER-Net observations report
  18. GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)
  19. GRB 240229A: Fermi GBM Final Real-time Localization
  20. GRB 240226A: GRBAlpha detection
  21. Fermi GRB 240227A: Global MASTER-Net observations report
  22. IPN triangulation of GRB 240227A (short)
  23. Fermi GRB 240226A: Global MASTER-Net observations report
  24. GRB 240227A: Fermi GBM Final Real-time Localization
  25. Fermi Gamma-ray Burst Monitor trigger 730618809/240226236 is not a GRB
  26. GRB 240226B: Fermi GBM Final Real-time Localization
  27. GRB 240226A: Fermi GBM Final Real-time Localization
  28. GRB 240222A: ATCA radio observations
  29. Fermi trigger No 730618809: Global MASTER-Net observations report
  30. Transient EPW20240219aa: Xinglong-2.16m optical upper limit
  31. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  32. GRB 240222A: GRBAlpha detection
  33. Transient EPW20240219aa: Mondy optical observations
  34. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  35. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  36. Swift BAT Sub-Threshold Detection of EPW20240219aa
  37. GRB 240222A: GECAM detection of a burst
  38. GRB 240222A: Fermi GBM Observation
  39. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  40. Fermi GRB 240222A: Global MASTER-Net observations report
  41. EPW20240219aa is Likely a GRB Event
  42. GRB 240222A: Fermi GBM Final Real-time Localization
  43. GRB 240216A: Glowbug gamma-ray detection
  44. GRB 240215B: Fermi GBM Observation
  45. GRB 240218A: LBT H-band detection
  46. Fermi GRB 240220A: Global MASTER-Net observations report
  47. GRB 240220A: Fermi GBM Final Real-time Localization
  48. Konus-Wind detection of GRB 240218A
  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. Fermi trigger No 729914426: Global MASTER-Net observations report
  56. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  57. GRB 240213A: GRBAlpha detection
  58. GRB 240215C: Fermi GBM Final Real-time Localization
  59. GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  60. Fermi GRB 240216A: Global MASTER-Net observations report
  61. GRB 240216A: Fermi GBM Final Real-time Localization
  62. Fermi trigger No 729719508: Global MASTER-Net observations report
  63. GRB 240215A: Swift/BAT-GUANO localization of a burst
  64. Fermi trigger No 729703985: Global MASTER-Net observations report
  65. Fermi trigger No 729650855: Global MASTER-Net observations report
  66. GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
  67. GRB 240209A: Fermi GBM observation
  68. GRB 240213A: Glowbug gamma-ray detection
  69. GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
  70. GRB 240209A: Wendelstein Optical Observations
  71. GRB 240213A: BALROG localization (Fermi Trigger / GRB 240213841)
  72. Fermi GRB 240213A: Global MASTER-Net observations report
  73. GRB 240213A: Fermi GBM Final Real-time Localization
  74. GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
  75. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  76. GRB 240209A: GOTO optical counterpart candidate
  77. Konus-Wind detection of GRB 240204A
  78. Konus-Wind detection of GRB 240205A (short)
  79. GRB 240209A: Fermi GBM Final Localization
  80. Fermi trigger No 729152364: Global MASTER-Net observations report
  81. IPN triangulation of GRB 240205A (short)
  82. Fermi-LAT gamma-ray observations of IceCube-240204A
  83. GRB 240205B: PRIME near infrared detection
  84. GRB 240205A (short): Glowbug gamma-ray detection
  85. GRB 240205B: AstroSat CZTI detection
  86. Fermi trigger No 729012023: Global MASTER-Net observations report
  87. Konus-Wind detection of GRB 240205B (long / very soft)
  88. GRB 240207A: Fermi GBM Final Real-time Localization
  89. GRB 240205B: VLT/X-shooter redshift
  90. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  91. GRB 240205B: BOOTES-6 optical afterglow follow-up
  92. GRB 240205B: ATCA detection of radio counterpart
  93. GRB 240205B: REM detection of the optical/NIR afterglow
  94. GRB 240205B: Fermi GBM Observation
  95. GRB 240204A: AstroSat CZTI detection
  96. GRB 240204A: Mondy optical afterglow observations
  97. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  98. GRB 240205B: GECAM detection of a long burst
  99. GRB 240205B: Skynet Optical Afterglow Observations
  100. GRB 240205B: BOOTES-7 optical afterglow follow-up

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