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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 220214A: Fermi GBM Final Real-time Localization
  2. Fermi GBM trigger 666393834/220212892 is not a GRB
  3. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  4. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  5. IPN triangulation of GRB 220211A (short)
  6. GRB 220210A: Insight-HXMT/HE detection
  7. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  8. GRB 220210A: 1.5m OSN optical upper limit
  9. GRB 220210A: Fermi GBM detection
  10. Fermi GRB 220211B: Global MASTER-Net observations report
  11. GRB 220211B: Fermi GBM Final Real-time Localization
  12. GRB 220209A: Fermi-LAT detection
  13. GRB 220210A: Fermi-LAT detection
  14. GRB 220210A: AGILE detection
  15. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  16. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  17. GRB 220210A: Swift/BAT-GUANO localization
  18. Fermi GRB 220211A: Global MASTER-Net observations report
  19. GRB 220211A: Fermi GBM Final Real-time Localization
  20. Fermi GRB 220210A: Global MASTER-Net observations report
  21. GRB 220210A: Fermi GBM Final Real-time Localization
  22. GRB 210919A: Maidanak optical observations
  23. GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
  24. GRB 220209A: Fermi GBM Detection
  25. GRB 220209A: GECAM detection
  26. GRB 220209A: AGILE/MCAL detection
  27. Fermi GRB 220209A: Global MASTER-Net observations report
  28. GRB 220209A: Fermi GBM Final Real-time Localization
  29. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  30. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  31. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  32. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  33. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  34. Konus-Wind detection of GRB 220130A
  35. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  36. Konus-Wind detection of GRB 220203A
  37. GRB 220203A: GECAM detection
  38. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  39. GRB 220203A: Swift/BAT-GUANO detection outside the coded FOV
  40. IPN triangulation of GRB 220203A (short)
  41. IPN triangulation of GRB 220130A
  42. Swift Reaction Wheel Anomaly Update (4 Feb 2022)
  43. Fermi-LAT Gamma-ray Observations of IceCube-220202A
  44. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  45. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  46. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  47. IceCube Alert 220202.49: Global MASTER-Net observations report
  48. GRB 220131B: Swift/BAT-GUANO detection outside the coded FOV
  49. GRB 220201A: Fermi GBM Final Localization
  50. GRB 220128A: AstroSat CZTI detection
  51. GRB 220130A: Fermi GBM Observation
  52. Konus-Wind detection of GRB 220128A
  53. IPN triangulation of GRB 220128A (long)
  54. Fermi GRB 220131A: Global MASTER-Net observations report
  55. GRB 220131B: GECAM detection
  56. GRB 220130A: GECAM detection
  57. GRB 220131A: Fermi GBM Final Real-time Localization
  58. Fermi GRB 220129A: Global MASTER-Net observations report
  59. GRB 220129A: Fermi GBM Final Real-time Localization
  60. IceCube-211208A: the optical observation of the candidate PKS0735+178
  61. GRB 220127A: GECAM detection
  62. GECAM observations of a series of bursts from SGR J1935+2154
  63. Konus-Wind detection of GRB 220124A
  64. IPN triangulation of GRB 220124A
  65. GRB 220124A: GECAM detection
  66. Fermi trigger No 664738369: Global MASTER-Net observations report
  67. GRB 220117A, GROND observations
  68. GRB 220124A: AstroSat CZTI detection of a bright long GRB
  69. GRB 220117A: Terskol and AbAO optical upper limits
  70. GRB 220118A: TARGET optical upper limit
  71. GRB 220117B: TARGET optical upper limit
  72. GRB 220121B: GECAM detection
  73. Fermi-LAT-ANTARES 220121a: upper limits from a search for coincident neutrinos with IceCube
  74. AGILE observations of a bright burst from SGR 1935+2154
  75. Fermi-LAT-ANTARES 220121a Coincidence
  76. Konus-Wind detection of an intermediate flare from SGR 1935+2154 on January 20
  77. IPN triangulation of a bright burst from SGR 1935+2154
  78. GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  79. IPN triangulation of GRB 211226A
  80. GRB 220120A: Fermi GBM Final Localization
  81. GRB 220117C: Fermi GBM Observation
  82. GRB 220118A: 2.2m CAHA/CAFOS detections
  83. GRB 220118A: Fermi GBM detection
  84. GRB 220118A: COATLI Optical Observations
  85. GRB 220101A: KAO optical-R observation
  86. GRB 211221A: No V & R detection, KAO telescope
  87. GRB 220118A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  88. GRB 220117C: Swift/BAT-GUANO arcminute localization
  89. Swift currently in safe hold with science slews disabled
  90. GRB 220118A: Swift-BAT refined analysis
  91. GRB 220118A: Swift/UVOT Detection
  92. Konus-Wind observation of the recent SGR 1935+2154 activity
  93. GRB 220118A: GIT optical observations
  94. GRB 220118A: Enhanced Swift-XRT position
  95. Swift GRB220118.50: Global MASTER-Net observations report
  96. GRB 220118A: MITSuME Akeno optical observation
  97. GRB 220117B: z-band limit
  98. Swift GRB 220118A: Global MASTER-Net observations report
  99. GRB 220118A: Swift detection of a burst with an optical counterpart
  100. GRB 220118A: Fermi GBM Final Real-time Localization

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