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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. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  2. IPN triangulation of GRB 220222A
  3. GRB 220101A: The first example of a Petanova
  4. ZTF22aaajecp/AT2022cmc: DECam Photometry
  5. Konus-Wind observation of GRB 220219B
  6. GCN Circ.draft on GRB 220222A
  7. GRB 220219B: Swift-XRT observations
  8. ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations
  9. Fermi GRB 220223A: Global MASTER-Net observations report
  10. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  11. GRB 220223A: Fermi GBM Final Real-time Localization
  12. ZTF22aabjpxh/AT2022cva: 1.5m OSN optical observation
  13. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  14. Fermi GRB 220222B: Global MASTER-Net observations report
  15. GRB 220222B: Fermi GBM Final Real-time Localization
  16. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  17. GRB 220219B: Swift ToO observations
  18. GRB 220222A: Swift/BAT-GUANO detection outside the coded FOV
  19. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  20. Fermi GRB 220222A: Global MASTER-Net observations report
  21. GRB 220222A: Fermi GBM Final Real-time Localization
  22. ZTF22aabjpxh/AT2022cva: GMOS-N spectroscopy
  23. ZTF22aabjpxh/AT2022cva: Assy optical observations
  24. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  25. ZTF22aaajecb/AT 2022cmc: CAHA 2.2m/CAFOS detection, luminous transient
  26. ZTF22aaajecp/AT2022cmc: Terskol observatory optical observations
  27. IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva)
  28. IceCube Alert 220221.03: Global MASTER-Net observations report
  29. Konus-Wind observation of GRB 220219A
  30. IPN triangulation of GRB 220219A
  31. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  32. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  33. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  34. Fermi Gamma-ray Burst Monitor trigger 667074291/220220767 is not a GRB
  35. IceCube Alert 220220.60: Global MASTER-Net observations report
  36. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  37. Fermi trigger No 666962499: Global MASTER-Net observations report
  38. GRB 220218A: BOOTES-5/JGT optical upper limit
  39. ZTF22aaajecp/AT2022cmc: Keck DEIMOS Redshift
  40. GRB 220219A: AGILE/MCAL detection
  41. GRB 220219A: BALROG localization (Fermi Trigger / GRB 220219473)
  42. GRB 220219A: Fermi GBM Final Real-time Localization
  43. GRB 220218A: Swift detection of a burst
  44. Swift GRB220218.94: Global MASTER-Net observations report
  45. GRB 220211A: redshift lower limit estimating
  46. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory continued optical observations
  47. Konus-Wind detection of GRB 220209A
  48. Swift resumes pointed science observations
  49. ZTF22aaajecp/AT2022cmc: VLT/X-shooter redshift
  50. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  51. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  52. Konus-Wind detection of GRB 220211A
  53. IPN triangulation of GRB 220209A
  54. ZTF22aaajecp: GIT optical follow-up observations
  55. GRB 211023A: evidence of supernova in LBT spectra
  56. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  57. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  58. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory optical observations
  59. ZTF22aaajecp/AT2022cmc: VLA radio detection
  60. GRB 220211A: Fermi GBM observation
  61. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  62. Fermi trigger No 666489765: Global MASTER-Net observations report
  63. GRB 220214A: Fermi GBM Final Real-time Localization
  64. Fermi GBM trigger 666393834/220212892 is not a GRB
  65. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  66. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  67. IPN triangulation of GRB 220211A (short)
  68. GRB 220210A: Insight-HXMT/HE detection
  69. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  70. GRB 220210A: 1.5m OSN optical upper limit
  71. GRB 220210A: Fermi GBM detection
  72. Fermi GRB 220211B: Global MASTER-Net observations report
  73. GRB 220211B: Fermi GBM Final Real-time Localization
  74. GRB 220209A: Fermi-LAT detection
  75. GRB 220210A: Fermi-LAT detection
  76. GRB 220210A: AGILE detection
  77. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  78. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  79. GRB 220210A: Swift/BAT-GUANO localization
  80. Fermi GRB 220211A: Global MASTER-Net observations report
  81. GRB 220211A: Fermi GBM Final Real-time Localization
  82. Fermi GRB 220210A: Global MASTER-Net observations report
  83. GRB 220210A: Fermi GBM Final Real-time Localization
  84. GRB 210919A: Maidanak optical observations
  85. GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
  86. GRB 220209A: Fermi GBM Detection
  87. GRB 220209A: GECAM detection
  88. GRB 220209A: AGILE/MCAL detection
  89. Fermi GRB 220209A: Global MASTER-Net observations report
  90. GRB 220209A: Fermi GBM Final Real-time Localization
  91. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  93. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  94. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  95. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  96. Konus-Wind detection of GRB 220130A
  97. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  98. Konus-Wind detection of GRB 220203A
  99. GRB 220203A: GECAM detection
  100. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event

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