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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"

11837 results found.

  1. GRB 230420A: LCOGT Optical Upper Limit
  2. IPN triangulation of GRB 230418A (short)
  3. GRB 230420A: Swift detection of a burst
  4. GRB 230418A: AstroSat CZTI detection
  5. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  6. IceCube-Cascade 230417A: Upper limits from a search for additional neutrino events in IceCube
  7. GRB 230402A: Fermi-LAT detection
  8. Fermi-LAT gamma-ray observations of IceCube-230416A
  9. GRB 230415A: Fermi GBM detection
  10. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  11. GRB 230415A: Swift/BAT-GUANO detection
  12. New GCN Circulars Portal for Rapid Communications on Astronomical Transients is Online
  13. GRB 230307A: iTelescope optical upper limit (likely)
  14. GRB 230414B: Swift-XRT refined Analysis
  15. Fermi GRB 230414A: Global MASTER-Net observations report
  16. GRB 230414B: Nanshan/HMT optical afterglow detection
  17. GRB 230414B: Swift detection of a burst
  18. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  19. Fermi GRB 230409C: Global MASTER-Net observations report
  20. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  21. Fermi-LAT gamma-ray observations of IceCube-230405A
  22. Konus-Wind detection of GRB 230405B
  23. GRB 230405B: MeerLICHT upper limits
  24. IceCube Alert 230405.56: Global MASTER-Net observations report
  25. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  26. GRB 230405B: AstroSat CZTI detection
  27. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  28. GRB 230404A: AstroSat CZTI detection
  29. GRB 230402A: AstroSat CZTI detection
  30. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  31. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  32. GRB 230228A: detection by GTC of the potential host galaxy
  33. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  34. GRB 230328B: 3.6m DOT multiband optical observation
  35. Fermi trigger No 701883729: Global MASTER-Net observations report
  36. Konus-Wind detection of GRB 230328B
  37. GRB 230328B: Liverpool Telescope afterglow detection
  38. GRB 230328B: OHP/T120 optical observations
  39. GRB 230328B: Swift-XRT refined Analysis
  40. GRB 230328B: AstroSat CZTI detection
  41. GRB 230328B: Mondy, AbAO and Kitab optical observations
  42. GRB 230328B: Swift detection of a burst with an optical afterglow
  43. GRB 230325A: Swift-XRT refined Analysis
  44. GRB 230325A: Swift detection of a burst
  45. GRB 230320B: Fermi GBM Observation
  46. Konus-Wind detection of GRB 230309A
  47. Konus-Wind detection of GRB 230308A
  48. Konus-Wind detection of GRB 230304B
  49. GRB 230322B: Swift-XRT refined Analysis
  50. GRB 230322B: Swift detection of a burst with optical counterpart
  51. GRB 230322A: Fermi GBM Final Real-time Localization
  52. GRB 230320B: GRBAlpha detection
  53. GRB 230320B: CALET Gamma-Ray Burst Monitor detection
  54. Fermi trigger No 701071944: Global MASTER-Net observations report
  55. SGR 1806-20: Correction to GCN 33494
  56. INTEGRAL detection of a burst from SGR 1806-200
  57. GRB 230321B: AstroSat CZTI detection
  58. GRB 230320B: AstroSat CZTI detection
  59. GRB 230320A: Fermi GBM Final Real-time Localization
  60. GRB 230314A: TURBO Optical Upper Limit
  61. Fermi trigger No 700976129: Global MASTER-Net observations report
  62. IPN triangulation of GRB 230309A
  63. Fermi GRB 230316A: Global MASTER-Net observations report
  64. GRB 230304D: AstroSat CZTI detection
  65. GRB 230313A: AstroSat CZTI detection
  66. VZLUSAT-2 detection of SGR 1806-20
  67. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  68. Fermi GRB 230313A: Global MASTER-Net observations report
  69. GRB 230309A: AstroSat CZTI detection of a bright long GRB
  70. Further improved IPN localization for GRB 230307A
  71. Swift GRB230311.84: Global MASTER-Net observations report
  72. Trigger 1159327: Swift detection of SGR1806-20
  73. GRB 230310A: AstroSat CZTI detection
  74. GRB 230307A: GECKO optical observations and detections of the afterglow
  75. GRB 230307A: MAXI/GSC upper limit
  76. GRB 230307A: ASO-S/HXI detection
  77. GRB 230217A: ATCA rapid-response radio detection
  78. GRB 230307A: Upper limits from a neutrino search with IceCube
  79. Fermi GRB 230307A: Global MASTER-Net observations report
  80. Konus-Wind detection of GRB 230307A
  81. Fermi GRB 230308A: Global MASTER-Net observations report
  82. GRB 230307A: AstroSat CZTI detection
  83. Fermi-LAT gamma-ray observations of IceCube-230306A
  84. GRB 230307A: GECAM detection of an extremely bright burst
  85. GRB 230304C: AstroSat CZTI detection
  86. GRB 230304B: AstroSat CZTI detection
  87. GRB 230304A: AstroSat CZTI detection
  88. GRB 230304A: Fermi GBM Final Real-time Localization
  89. GRB 230228A: Swift/UVOT Upper Limits
  90. Fermi GRB 230301B: Global MASTER-Net observations report
  91. GRB 230228A: Fermi GBM Observation
  92. Fermi trigger No 699294715: Global MASTER-Net observations report
  93. GRB 230228A: Swift-XRT refined Analysis
  94. GRB 230228A: Swift detection of a possibly short burst
  95. Fermi trigger No 699029364: Global MASTER-Net observations report
  96. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  97. GRB 230216A Mondy Observations
  98. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 230220A: Correction to GCN 33352
  100. Fermi-LAT gamma-ray observations of IceCube-230220A

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