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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. Fermi GRB 230124A: Global MASTER-Net observations report
  2. GRB 230124A: Fermi GBM Final Real-time Localization
  3. GRB 230123A: Swift-BAT refined analysis
  4. GRB 230122A: Swift/BAT-GUANO detection
  5. Fermi-LAT gamma-ray observations of IceCube-230122A
  6. GRB 230123A: Swift/UVOT Upper Limits
  7. GRB 230123A: Swift-XRT refined Analysis
  8. GRB 230123A: Enhanced Swift-XRT position
  9. GRB 230123A: Zadko observatory - Gingin optical observations
  10. GRB 230116C: Swift-XRT observations
  11. GRB 230123A: Swift detection of a burst
  12. IceCube Alert 230122.16: Global MASTER-Net observations report
  13. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  14. GRB 230116B: Fermi GBM observation
  15. Trigger 1150107: Swift detection of LS V +44 17
  16. GRB 230120A: AstroSat CZTI detection
  17. IPN triangulation of GRB 230116B (short)
  18. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  19. GRB 230116D: 3.6m DOT optical upper limit
  20. GRB 230119A: Fermi GBM Final Real-time Localization
  21. Fermi GRB 230118A: Global MASTER-Net observations report
  22. GRB 230118A: Fermi GBM Final Real-time Localization
  23. GRB 230116D: Swift-BAT refined analysis
  24. GRB 230116C: Swift-BAT refined analysis
  25. GRB 230116D: SAO RAS further observations
  26. GRB 230116D: SAO RAS photometry
  27. GRB 230116D: KGO RC-25 optical observations
  28. GRB 230116D: Sintez-Newton/CrAO optical observations
  29. GRB 230116D: LCOGT Optical Upper Limit
  30. GRB 230116D: SAO RAS redshift
  31. Fermi trigger No 695569700: Global MASTER-Net observations report
  32. GRB 230116D: Swift-XRT refined Analysis
  33. Fermi GRB 230117A: Global MASTER-Net observations report
  34. GRB 230117A: Fermi GBM Final Real-time Localization
  35. GRB 230116D: GIT optical follow-up
  36. GRB 230116D: GIT optical follow-up
  37. GRB 230116D: Enhanced Swift-XRT position
  38. GRB 230116D: SAO RAS observations of OT brightening
  39. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  40. GRB 230116D: Nanshan/NEXT optical afterglow detection
  41. GRB 230116D: Swift detection of a burst
  42. Swift GRB230116.88: Global MASTER-Net observations report
  43. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  44. GRB 230116C: Swift detection of a burst
  45. GRB 230116B: Fermi GBM Final Real-time Localization
  46. GRB 230116A: Fermi GBM Final Real-time Localization
  47. GRB 230114A: Detection by VZLUSAT-2
  48. Fermi-LAT gamma-ray observations of IceCube-230112A
  49. GRB 230114A: Fermi GBM Final Real-time Localization
  50. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-230109A
  51. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
  52. IceCube-230112A: Upper limits from a search for additional neutrino events in IceCube
  53. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  54. Trigger 1148770: Swift detection of Cyg X-1 due to Star Tracker loss of lock
  55. GRB 230111A: Fermi GBM Observation
  56. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  57. Fermi GRB 230112A: Global MASTER-Net observations report
  58. IceCube Alert 230112.28: Global MASTER-Net observations report
  59. GRB 230112A: Fermi GBM Final Real-time Localization
  60. GRB 230111A: MAXI/GSC detection
  61. GRB 230111A: Fermi GBM Final Real-time Localization
  62. GRB 230106: AstroSat LAXPC detection
  63. IceCube-Cascade 230109A: Upper limits from a search for additional neutrino events in IceCube
  64. Fermi trigger No 695057654: Global MASTER-Net observations report
  65. IceCube-221223A: JCMT/SCUBA2 observations
  66. GRB 230102A: Fermi GBM Observation
  67. Fermi Gamma-ray Burst Monitor trigger 694043024/221229905 is not a GRB
  68. GRB 221231A: 3.6m DOT optical upper limit
  69. GRB 230104A: AGILE/MCAL detection of a burst
  70. GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
  71. GRB 221231A: Fermi GBM Observation
  72. GRB 221230A: CALET Gamma-Ray Burst Monitor detection
  73. Fermi Gamma-ray Burst Monitor trigger 694259491/230101411 is not a GRB
  74. GRB 230102A: Detection by GRBAlpha
  75. Fermi Gamma-ray Burst Monitor trigger 694302022/230101903 is not a GRB
  76. GRB 230101A: AstroSat CZTI detection
  77. Fermi trigger No 694259491: Global MASTER-Net observations report
  78. GRB 221231A: Swift-XRT afterglow detection
  79. GRB 230102A: AGILE/MCAL detection
  80. GRB 230102A: Fermi GBM Final Real-time Localization
  81. GRB 221231A: AKO Upper Limit
  82. GRB 221231A: Swift-XRT observations
  83. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  84. GRB 221231A: Swift ToO observations
  85. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  86. Fermi trigger No 694232203: Global MASTER-Net observations report
  87. GRB 230101A: Fermi GBM Final Real-time Localization
  88. GRB 221231A: Fermi GBM Final Real-time Localization
  89. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  91. Fermi-LAT gamma-ray observations of IceCube-221229A
  92. GRB 221226A: Fermi GBM detection
  93. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  94. IPN triangulation of GRB 221226A
  95. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  96. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  97. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  98. GRB 221226B: LCOGT Optical Upper Limits
  99. IceCube-221224A: Upper limits from a search for additional neutrino events in IceCube
  100. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube

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