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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. ZTF22aabjpxh/AT2022cva: Assy optical observations
  2. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  3. ZTF22aaajecb/AT 2022cmc: CAHA 2.2m/CAFOS detection, luminous transient
  4. ZTF22aaajecp/AT2022cmc: Terskol observatory optical observations
  5. IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva)
  6. IceCube Alert 220221.03: Global MASTER-Net observations report
  7. Konus-Wind observation of GRB 220219A
  8. IPN triangulation of GRB 220219A
  9. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  10. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  11. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  12. Fermi Gamma-ray Burst Monitor trigger 667074291/220220767 is not a GRB
  13. IceCube Alert 220220.60: Global MASTER-Net observations report
  14. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  15. Fermi trigger No 666962499: Global MASTER-Net observations report
  16. GRB 220218A: BOOTES-5/JGT optical upper limit
  17. ZTF22aaajecp/AT2022cmc: Keck DEIMOS Redshift
  18. GRB 220219A: AGILE/MCAL detection
  19. GRB 220219A: BALROG localization (Fermi Trigger / GRB 220219473)
  20. GRB 220219A: Fermi GBM Final Real-time Localization
  21. GRB 220218A: Swift detection of a burst
  22. Swift GRB220218.94: Global MASTER-Net observations report
  23. GRB 220211A: redshift lower limit estimating
  24. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory continued optical observations
  25. Konus-Wind detection of GRB 220209A
  26. Swift resumes pointed science observations
  27. ZTF22aaajecp/AT2022cmc: VLT/X-shooter redshift
  28. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  29. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  30. Konus-Wind detection of GRB 220211A
  31. IPN triangulation of GRB 220209A
  32. ZTF22aaajecp: GIT optical follow-up observations
  33. GRB 211023A: evidence of supernova in LBT spectra
  34. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  35. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  36. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory optical observations
  37. ZTF22aaajecp/AT2022cmc: VLA radio detection
  38. GRB 220211A: Fermi GBM observation
  39. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  40. Fermi trigger No 666489765: Global MASTER-Net observations report
  41. GRB 220214A: Fermi GBM Final Real-time Localization
  42. Fermi GBM trigger 666393834/220212892 is not a GRB
  43. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  44. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  45. IPN triangulation of GRB 220211A (short)
  46. GRB 220210A: Insight-HXMT/HE detection
  47. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  48. GRB 220210A: 1.5m OSN optical upper limit
  49. GRB 220210A: Fermi GBM detection
  50. Fermi GRB 220211B: Global MASTER-Net observations report
  51. GRB 220211B: Fermi GBM Final Real-time Localization
  52. GRB 220209A: Fermi-LAT detection
  53. GRB 220210A: Fermi-LAT detection
  54. GRB 220210A: AGILE detection
  55. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  56. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  57. GRB 220210A: Swift/BAT-GUANO localization
  58. Fermi GRB 220211A: Global MASTER-Net observations report
  59. GRB 220211A: Fermi GBM Final Real-time Localization
  60. Fermi GRB 220210A: Global MASTER-Net observations report
  61. GRB 220210A: Fermi GBM Final Real-time Localization
  62. GRB 210919A: Maidanak optical observations
  63. GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
  64. GRB 220209A: Fermi GBM Detection
  65. GRB 220209A: GECAM detection
  66. GRB 220209A: AGILE/MCAL detection
  67. Fermi GRB 220209A: Global MASTER-Net observations report
  68. GRB 220209A: Fermi GBM Final Real-time Localization
  69. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  71. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  72. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  73. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  74. Konus-Wind detection of GRB 220130A
  75. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  76. Konus-Wind detection of GRB 220203A
  77. GRB 220203A: GECAM detection
  78. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 220203A: Swift/BAT-GUANO detection outside the coded FOV
  80. IPN triangulation of GRB 220203A (short)
  81. IPN triangulation of GRB 220130A
  82. Swift Reaction Wheel Anomaly Update (4 Feb 2022)
  83. Fermi-LAT Gamma-ray Observations of IceCube-220202A
  84. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  85. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  86. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  87. IceCube Alert 220202.49: Global MASTER-Net observations report
  88. GRB 220131B: Swift/BAT-GUANO detection outside the coded FOV
  89. GRB 220201A: Fermi GBM Final Localization
  90. GRB 220128A: AstroSat CZTI detection
  91. GRB 220130A: Fermi GBM Observation
  92. Konus-Wind detection of GRB 220128A
  93. IPN triangulation of GRB 220128A (long)
  94. Fermi GRB 220131A: Global MASTER-Net observations report
  95. GRB 220131B: GECAM detection
  96. GRB 220130A: GECAM detection
  97. GRB 220131A: Fermi GBM Final Real-time Localization
  98. Fermi GRB 220129A: Global MASTER-Net observations report
  99. GRB 220129A: Fermi GBM Final Real-time Localization
  100. IceCube-211208A: the optical observation of the candidate PKS0735+178

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