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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 220219A: BALROG localization (Fermi Trigger / GRB 220219473)
  2. GRB 220219A: Fermi GBM Final Real-time Localization
  3. GRB 220218A: Swift detection of a burst
  4. Swift GRB220218.94: Global MASTER-Net observations report
  5. GRB 220211A: redshift lower limit estimating
  6. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory continued optical observations
  7. Konus-Wind detection of GRB 220209A
  8. Swift resumes pointed science observations
  9. ZTF22aaajecp/AT2022cmc: VLT/X-shooter redshift
  10. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  11. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  12. Konus-Wind detection of GRB 220211A
  13. IPN triangulation of GRB 220209A
  14. ZTF22aaajecp: GIT optical follow-up observations
  15. GRB 211023A: evidence of supernova in LBT spectra
  16. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  17. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  18. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory optical observations
  19. ZTF22aaajecp/AT2022cmc: VLA radio detection
  20. GRB 220211A: Fermi GBM observation
  21. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  22. Fermi trigger No 666489765: Global MASTER-Net observations report
  23. GRB 220214A: Fermi GBM Final Real-time Localization
  24. Fermi GBM trigger 666393834/220212892 is not a GRB
  25. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  26. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  27. IPN triangulation of GRB 220211A (short)
  28. GRB 220210A: Insight-HXMT/HE detection
  29. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  30. GRB 220210A: 1.5m OSN optical upper limit
  31. GRB 220210A: Fermi GBM detection
  32. Fermi GRB 220211B: Global MASTER-Net observations report
  33. GRB 220211B: Fermi GBM Final Real-time Localization
  34. GRB 220209A: Fermi-LAT detection
  35. GRB 220210A: Fermi-LAT detection
  36. GRB 220210A: AGILE detection
  37. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  38. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  39. GRB 220210A: Swift/BAT-GUANO localization
  40. Fermi GRB 220211A: Global MASTER-Net observations report
  41. GRB 220211A: Fermi GBM Final Real-time Localization
  42. Fermi GRB 220210A: Global MASTER-Net observations report
  43. GRB 220210A: Fermi GBM Final Real-time Localization
  44. GRB 210919A: Maidanak optical observations
  45. GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
  46. GRB 220209A: Fermi GBM Detection
  47. GRB 220209A: GECAM detection
  48. GRB 220209A: AGILE/MCAL detection
  49. Fermi GRB 220209A: Global MASTER-Net observations report
  50. GRB 220209A: Fermi GBM Final Real-time Localization
  51. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  53. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  54. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  55. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  56. Konus-Wind detection of GRB 220130A
  57. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  58. Konus-Wind detection of GRB 220203A
  59. GRB 220203A: GECAM detection
  60. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  61. GRB 220203A: Swift/BAT-GUANO detection outside the coded FOV
  62. IPN triangulation of GRB 220203A (short)
  63. IPN triangulation of GRB 220130A
  64. Swift Reaction Wheel Anomaly Update (4 Feb 2022)
  65. Fermi-LAT Gamma-ray Observations of IceCube-220202A
  66. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  67. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  68. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  69. IceCube Alert 220202.49: Global MASTER-Net observations report
  70. GRB 220131B: Swift/BAT-GUANO detection outside the coded FOV
  71. GRB 220201A: Fermi GBM Final Localization
  72. GRB 220128A: AstroSat CZTI detection
  73. GRB 220130A: Fermi GBM Observation
  74. Konus-Wind detection of GRB 220128A
  75. IPN triangulation of GRB 220128A (long)
  76. Fermi GRB 220131A: Global MASTER-Net observations report
  77. GRB 220131B: GECAM detection
  78. GRB 220130A: GECAM detection
  79. GRB 220131A: Fermi GBM Final Real-time Localization
  80. Fermi GRB 220129A: Global MASTER-Net observations report
  81. GRB 220129A: Fermi GBM Final Real-time Localization
  82. IceCube-211208A: the optical observation of the candidate PKS0735+178
  83. GRB 220127A: GECAM detection
  84. GECAM observations of a series of bursts from SGR J1935+2154
  85. Konus-Wind detection of GRB 220124A
  86. IPN triangulation of GRB 220124A
  87. GRB 220124A: GECAM detection
  88. Fermi trigger No 664738369: Global MASTER-Net observations report
  89. GRB 220117A, GROND observations
  90. GRB 220124A: AstroSat CZTI detection of a bright long GRB
  91. GRB 220117A: Terskol and AbAO optical upper limits
  92. GRB 220118A: TARGET optical upper limit
  93. GRB 220117B: TARGET optical upper limit
  94. GRB 220121B: GECAM detection
  95. Fermi-LAT-ANTARES 220121a: upper limits from a search for coincident neutrinos with IceCube
  96. AGILE observations of a bright burst from SGR 1935+2154
  97. Fermi-LAT-ANTARES 220121a Coincidence
  98. Konus-Wind detection of an intermediate flare from SGR 1935+2154 on January 20
  99. IPN triangulation of a bright burst from SGR 1935+2154
  100. GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis

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