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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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. IceCube Alert 230122.16: Global MASTER-Net observations report
  2. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 230116B: Fermi GBM observation
  4. Trigger 1150107: Swift detection of LS V +44 17
  5. GRB 230120A: AstroSat CZTI detection
  6. IPN triangulation of GRB 230116B (short)
  7. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  8. GRB 230116D: 3.6m DOT optical upper limit
  9. GRB 230119A: Fermi GBM Final Real-time Localization
  10. Fermi GRB 230118A: Global MASTER-Net observations report
  11. GRB 230118A: Fermi GBM Final Real-time Localization
  12. GRB 230116D: Swift-BAT refined analysis
  13. GRB 230116C: Swift-BAT refined analysis
  14. GRB 230116D: SAO RAS further observations
  15. GRB 230116D: SAO RAS photometry
  16. GRB 230116D: KGO RC-25 optical observations
  17. GRB 230116D: Sintez-Newton/CrAO optical observations
  18. GRB 230116D: LCOGT Optical Upper Limit
  19. GRB 230116D: SAO RAS redshift
  20. Fermi trigger No 695569700: Global MASTER-Net observations report
  21. GRB 230116D: Swift-XRT refined Analysis
  22. Fermi GRB 230117A: Global MASTER-Net observations report
  23. GRB 230117A: Fermi GBM Final Real-time Localization
  24. GRB 230116D: GIT optical follow-up
  25. GRB 230116D: GIT optical follow-up
  26. GRB 230116D: Enhanced Swift-XRT position
  27. GRB 230116D: SAO RAS observations of OT brightening
  28. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  29. GRB 230116D: Nanshan/NEXT optical afterglow detection
  30. GRB 230116D: Swift detection of a burst
  31. Swift GRB230116.88: Global MASTER-Net observations report
  32. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  33. GRB 230116C: Swift detection of a burst
  34. GRB 230116B: Fermi GBM Final Real-time Localization
  35. GRB 230116A: Fermi GBM Final Real-time Localization
  36. GRB 230114A: Detection by VZLUSAT-2
  37. Fermi-LAT gamma-ray observations of IceCube-230112A
  38. GRB 230114A: Fermi GBM Final Real-time Localization
  39. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-230109A
  40. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
  41. IceCube-230112A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  43. Trigger 1148770: Swift detection of Cyg X-1 due to Star Tracker loss of lock
  44. GRB 230111A: Fermi GBM Observation
  45. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  46. Fermi GRB 230112A: Global MASTER-Net observations report
  47. IceCube Alert 230112.28: Global MASTER-Net observations report
  48. GRB 230112A: Fermi GBM Final Real-time Localization
  49. GRB 230111A: MAXI/GSC detection
  50. GRB 230111A: Fermi GBM Final Real-time Localization
  51. GRB 230106: AstroSat LAXPC detection
  52. IceCube-Cascade 230109A: Upper limits from a search for additional neutrino events in IceCube
  53. Fermi trigger No 695057654: Global MASTER-Net observations report
  54. IceCube-221223A: JCMT/SCUBA2 observations
  55. GRB 230102A: Fermi GBM Observation
  56. Fermi Gamma-ray Burst Monitor trigger 694043024/221229905 is not a GRB
  57. GRB 221231A: 3.6m DOT optical upper limit
  58. GRB 230104A: AGILE/MCAL detection of a burst
  59. GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
  60. GRB 221231A: Fermi GBM Observation
  61. GRB 221230A: CALET Gamma-Ray Burst Monitor detection
  62. Fermi Gamma-ray Burst Monitor trigger 694259491/230101411 is not a GRB
  63. GRB 230102A: Detection by GRBAlpha
  64. Fermi Gamma-ray Burst Monitor trigger 694302022/230101903 is not a GRB
  65. GRB 230101A: AstroSat CZTI detection
  66. Fermi trigger No 694259491: Global MASTER-Net observations report
  67. GRB 221231A: Swift-XRT afterglow detection
  68. GRB 230102A: AGILE/MCAL detection
  69. GRB 230102A: Fermi GBM Final Real-time Localization
  70. GRB 221231A: AKO Upper Limit
  71. GRB 221231A: Swift-XRT observations
  72. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  73. GRB 221231A: Swift ToO observations
  74. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  75. Fermi trigger No 694232203: Global MASTER-Net observations report
  76. GRB 230101A: Fermi GBM Final Real-time Localization
  77. GRB 221231A: Fermi GBM Final Real-time Localization
  78. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  79. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  80. Fermi-LAT gamma-ray observations of IceCube-221229A
  81. GRB 221226A: Fermi GBM detection
  82. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  83. IPN triangulation of GRB 221226A
  84. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  86. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  87. GRB 221226B: LCOGT Optical Upper Limits
  88. IceCube-221224A: Upper limits from a search for additional neutrino events in IceCube
  89. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube
  90. GRB 221228A: Fermi GBM Final Real-time Localization
  91. GRB 221226B Swift-BAT refined analysis
  92. GRB 221226B: Swift-UVOT Detection
  93. GRB 221226A: AGILE detection
  94. GRB 221226B: Fermi GBM Observation
  95. GRB 221226B: Swift-XRT refined Analysis
  96. GRB 221226B: VLT/X-shooter redshift and host galaxy
  97. GRB 221226B: Enhanced Swift-XRT position
  98. GRB 221226B: Swift detection of a burst
  99. GRB 221226B: Fermi GBM Final Real-time Localization
  100. Swift GRB221226.95: Global MASTER-Net observations report

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