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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').
  1. Swift GRB 220305A: Global MASTER-Net observations report
  2. GRB 220305A: Swift-XRT observations
  3. GRB 220305A: Swift detection of a burst
  4. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, SN signature search
  5. GRB 220302A: Swift/UVOT Upper Limits
  6. IceCube-220303A: Upper limits from a search for additional neutrino events in IceCube
  7. Fermi-LAT Gamma-ray Observations of IceCube-220303A
  8. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  9. IceCube Alert 220304.74: Global MASTER-Net observations report
  10. GRB 220304A: Swift/BAT-GUANO detection outside the coded FOV
  11. Fermi GRB 220304A: Global MASTER-Net observations report
  12. Tev Blazar as possible optical counterpart of the high-energy neutrino IceCube-220303A
  13. GRB 220304A: BALROG localization (Fermi Trigger / GRB 220304228)
  14. GRB 220302A: Swift-XRT refined Analysis
  15. GRB 220304A: Fermi GBM Final Real-time Localization
  16. IceCube Alert 220303.75: Global MASTER-Net observations report
  17. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  18. GRB 220302A: BOOTES-5/JGT optical upper limit
  19. Swift resumes autonomous slewing
  20. ZTF22aaajecp/AT2022cmc: AMI-LA radio detection
  21. GRB 220302A: Enhanced Swift-XRT position
  22. ZTF22aaajecp/AT2022cmc: ATCA detection
  23. GRB 220302A: Swift afterglow detection
  24. GRB 220222A: CALET Gamma-Ray Burst Monitor detection
  25. Swift GRB 220302A: Global MASTER-Net observations report
  26. GRB 220302A: Swift detection of a burst
  27. GRB 220228A: Fermi GBM observation
  28. GRB 220228A: Fermi-LAT detection
  29. GRB 220228A: Fermi GBM Final Localization
  30. Konus-Wind detection of GRB 220222A
  31. IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube
  32. Fermi trigger No 667737010: Global MASTER-Net observations report
  33. ZTF22aaajecp/AT2022cmc: JCMT SCUBA-2 sub-mm observations
  34. Fermi-LAT Gamma-ray Observations of IceCube-220225A
  35. ZTF22aaajecp/AT2022cmc: Mondy optical observations
  36. IceCube Alert 220225.59: Global MASTER-Net observations report
  37. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  38. IPN triangulation of GRB 220222A
  39. GRB 220101A: The first example of a Petanova
  40. ZTF22aaajecp/AT2022cmc: DECam Photometry
  41. Konus-Wind observation of GRB 220219B
  42. GCN Circ.draft on GRB 220222A
  43. GRB 220219B: Swift-XRT observations
  44. ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations
  45. Fermi GRB 220223A: Global MASTER-Net observations report
  46. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  47. GRB 220223A: Fermi GBM Final Real-time Localization
  48. ZTF22aabjpxh/AT2022cva: 1.5m OSN optical observation
  49. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  50. Fermi GRB 220222B: Global MASTER-Net observations report
  51. GRB 220222B: Fermi GBM Final Real-time Localization
  52. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  53. GRB 220219B: Swift ToO observations
  54. GRB 220222A: Swift/BAT-GUANO detection outside the coded FOV
  55. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  56. Fermi GRB 220222A: Global MASTER-Net observations report
  57. GRB 220222A: Fermi GBM Final Real-time Localization
  58. ZTF22aabjpxh/AT2022cva: GMOS-N spectroscopy
  59. ZTF22aabjpxh/AT2022cva: Assy optical observations
  60. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  61. ZTF22aaajecb/AT 2022cmc: CAHA 2.2m/CAFOS detection, luminous transient
  62. ZTF22aaajecp/AT2022cmc: Terskol observatory optical observations
  63. IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva)
  64. IceCube Alert 220221.03: Global MASTER-Net observations report
  65. Konus-Wind observation of GRB 220219A
  66. IPN triangulation of GRB 220219A
  67. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  68. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  69. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  70. Fermi Gamma-ray Burst Monitor trigger 667074291/220220767 is not a GRB
  71. IceCube Alert 220220.60: Global MASTER-Net observations report
  72. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  73. Fermi trigger No 666962499: Global MASTER-Net observations report
  74. GRB 220218A: BOOTES-5/JGT optical upper limit
  75. ZTF22aaajecp/AT2022cmc: Keck DEIMOS Redshift
  76. GRB 220219A: AGILE/MCAL detection
  77. GRB 220219A: BALROG localization (Fermi Trigger / GRB 220219473)
  78. GRB 220219A: Fermi GBM Final Real-time Localization
  79. GRB 220218A: Swift detection of a burst
  80. Swift GRB220218.94: Global MASTER-Net observations report
  81. GRB 220211A: redshift lower limit estimating
  82. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory continued optical observations
  83. Konus-Wind detection of GRB 220209A
  84. Swift resumes pointed science observations
  85. ZTF22aaajecp/AT2022cmc: VLT/X-shooter redshift
  86. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  87. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  88. Konus-Wind detection of GRB 220211A
  89. IPN triangulation of GRB 220209A
  90. ZTF22aaajecp: GIT optical follow-up observations
  91. GRB 211023A: evidence of supernova in LBT spectra
  92. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  93. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  94. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory optical observations
  95. ZTF22aaajecp/AT2022cmc: VLA radio detection
  96. GRB 220211A: Fermi GBM observation
  97. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  98. Fermi trigger No 666489765: Global MASTER-Net observations report
  99. GRB 220214A: Fermi GBM Final Real-time Localization
  100. Fermi GBM trigger 666393834/220212892 is not a GRB

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