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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"
  1. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  2. GRB 230414B: Nanshan/HMT optical afterglow detection
  3. GRB 230414A: Mondy optical afterglow candidate
  4. Swift GRB 230414B: Global MASTER-Net observations report
  5. GRB 230414B: Prompt enhanced Swift-XRT position
  6. GRB 230414B: Swift detection of a burst
  7. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  8. GRB 230414A: Fermi GBM Final Real-time Localization
  9. GRB 230328B: redshift lower limit estimating
  10. GRB 230409B: Mondy optical upper limit
  11. GRB 230409B: OHP/T193 optical upper limit
  12. GRB 230410B: VZLUSAT-2 detection
  13. GRB 230409D: VZLUSAT-2 detection
  14. GRB 230410B: AGILE detection of a burst
  15. GRB 230410A: Fermi GBM Final Real-time Localization
  16. Fermi GRB 230409C: Global MASTER-Net observations report
  17. Fermi GRB 230409A: Global MASTER-Net observations report
  18. GRB 230409C: Fermi GBM Final Real-time Localization
  19. GRB 230409B: Swift-XRT refined Analysis
  20. GRB 230409B: Swift-BAT refined analysis
  21. Fermi trigger No 702745263: Global MASTER-Net observations report
  22. Swift GRB 230409B: Global MASTER-Net observations report
  23. GRB 230409B: Swift/UVOT Detection
  24. GRB 230409B: Enhanced Swift-XRT position
  25. MAXI GRB230408.82: Global MASTER-Net observations report
  26. GRB 230409B: Swift detection of a burst
  27. GRB 230409A: Fermi GBM Final Real-time Localization
  28. GRB 230405B: VZLUSAT-2 detection
  29. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  30. Fermi-LAT gamma-ray observations of IceCube-230405A
  31. Konus-Wind detection of GRB 230405B
  32. GRB 230405B: AGILE detection
  33. GRB 230405B: Swift-XRT refined Analysis
  34. GRB 230405B: Fermi GBM Observation
  35. GRB 230405B: MeerLICHT upper limits
  36. IceCube Alert 230405.56: Global MASTER-Net observations report
  37. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  38. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  39. GRB 230307A: good match with kilonova models
  40. GRB 230307A: short mininum variability timescale compatible with a merger origin
  41. GRB 230405B: Swift/UVOT Upper Limits
  42. GRB 230405B: AstroSat CZTI detection
  43. GRB 230405B: Enhanced Swift-XRT position
  44. Swift GRB 230405B: Global MASTER-Net observations report
  45. GRB 230405B: Prompt enhanced Swift-XRT position
  46. GRB 230405B: Swift detection of a burst
  47. GRB 230405B: Fermi GBM Final Real-time Localization
  48. GRB 230307A: JWST observations consistent with the presence of a kilonova
  49. Fermi GRB 230405A: Global MASTER-Net observations report
  50. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  51. GRB 230405A: Fermi GBM Final Real-time Localization
  52. GRB 230404A: AstroSat CZTI detection
  53. GRB 230404A: Fermi GBM Final Real-time Localization
  54. GRB 230402A: CALET Gamma-Ray Burst Monitor detection
  55. GRB 230402A: AstroSat CZTI detection
  56. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  57. IceCube-230401A: Upper limits from a search for additional neutrino events in IceCube
  58. GRB 230328B: Multa observatory optical afterglow observation
  59. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  60. GRB 230228A: detection by GTC of the potential host galaxy
  61. GRB 230328B: Swift/UVOT Detection
  62. GRB 230402A: AGILE detection
  63. Fermi GRB 230402A: Global MASTER-Net observations report
  64. GRB 230402A: Fermi GBM Final Real-time Localization
  65. IceCube-230401A: IceCube observation of a high-energy neutrino candidate
  66. GRB 230307A: Bad Time Intervals for Fermi GBM data
  67. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  68. GRB 230328B: CAHA 2.2m/CAFOS detection
  69. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  70. GRB 230328B: 3.6m DOT multiband optical observation
  71. Fermi trigger No 701883729: Global MASTER-Net observations report
  72. GRB 230330B: Fermi GBM Final Localization
  73. Konus-Wind detection of GRB 230328B
  74. GRB 230328B: GRBAlpha detection
  75. GRB 230330A: Fermi GBM Final Real-time Localization
  76. GRB 230328B: Swift-BAT refined analysis
  77. GRB 230328B: Nanshan/NEXT 2nd optical observation
  78. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  79. GRB 230328B: Liverpool Telescope afterglow detection
  80. GRB 230328B: OHP/T120 optical observations
  81. GRB 230328B: GIT optical follow-up
  82. GRB 230328B: OASDG optical observations
  83. GRB 230328B: Nanshan/NEXT optical upper limit
  84. GRB 230328B: Swift-XRT refined Analysis
  85. GRB 230328B: AstroSat CZTI detection
  86. GRB 230328B: Fermi GBM observation
  87. GRB 230328B: Mondy, AbAO and Kitab optical observations
  88. GRB 230328B: Enhanced Swift-XRT position
  89. GRB 230328B: Mondy optical afterglow confirmation
  90. GRB 230328B: Swift detection of a burst with an optical afterglow
  91. GRB 230328B: Fermi GBM Final Real-time Localization
  92. Fermi GRB 230328A: Global MASTER-Net observations report
  93. GRB 230328A: Fermi GBM Final Real-time Localization
  94. GRB 230325A: Swift-BAT refined analysis
  95. GRB 230325A: Swift/UVOT Upper Limits
  96. GRB 230325A: X-shooter optical afterglow and redshift
  97. GRB 230325A: Swift-XRT refined Analysis
  98. GRB 230322B: Swift-BAT refined analysis
  99. GRB 230325A: Enhanced Swift-XRT position
  100. GRB 230325A: Prompt enhanced Swift-XRT position

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