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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-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  2. GRB 220302A: BOOTES-5/JGT optical upper limit
  3. Swift resumes autonomous slewing
  4. ZTF22aaajecp/AT2022cmc: AMI-LA radio detection
  5. GRB 220302A: Enhanced Swift-XRT position
  6. ZTF22aaajecp/AT2022cmc: ATCA detection
  7. GRB 220302A: Swift afterglow detection
  8. GRB 220222A: CALET Gamma-Ray Burst Monitor detection
  9. Swift GRB 220302A: Global MASTER-Net observations report
  10. GRB 220302A: Swift detection of a burst
  11. GRB 220228A: Fermi GBM observation
  12. GRB 220228A: Fermi-LAT detection
  13. GRB 220228A: Fermi GBM Final Localization
  14. Konus-Wind detection of GRB 220222A
  15. IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube
  16. Fermi trigger No 667737010: Global MASTER-Net observations report
  17. ZTF22aaajecp/AT2022cmc: JCMT SCUBA-2 sub-mm observations
  18. Fermi-LAT Gamma-ray Observations of IceCube-220225A
  19. ZTF22aaajecp/AT2022cmc: Mondy optical observations
  20. IceCube Alert 220225.59: Global MASTER-Net observations report
  21. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  22. IPN triangulation of GRB 220222A
  23. GRB 220101A: The first example of a Petanova
  24. ZTF22aaajecp/AT2022cmc: DECam Photometry
  25. Konus-Wind observation of GRB 220219B
  26. GCN Circ.draft on GRB 220222A
  27. GRB 220219B: Swift-XRT observations
  28. ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations
  29. Fermi GRB 220223A: Global MASTER-Net observations report
  30. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  31. GRB 220223A: Fermi GBM Final Real-time Localization
  32. ZTF22aabjpxh/AT2022cva: 1.5m OSN optical observation
  33. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  34. Fermi GRB 220222B: Global MASTER-Net observations report
  35. GRB 220222B: Fermi GBM Final Real-time Localization
  36. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  37. GRB 220219B: Swift ToO observations
  38. GRB 220222A: Swift/BAT-GUANO detection outside the coded FOV
  39. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  40. Fermi GRB 220222A: Global MASTER-Net observations report
  41. GRB 220222A: Fermi GBM Final Real-time Localization
  42. ZTF22aabjpxh/AT2022cva: GMOS-N spectroscopy
  43. ZTF22aabjpxh/AT2022cva: Assy optical observations
  44. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  45. ZTF22aaajecb/AT 2022cmc: CAHA 2.2m/CAFOS detection, luminous transient
  46. ZTF22aaajecp/AT2022cmc: Terskol observatory optical observations
  47. IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva)
  48. IceCube Alert 220221.03: Global MASTER-Net observations report
  49. Konus-Wind observation of GRB 220219A
  50. IPN triangulation of GRB 220219A
  51. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  52. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  53. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  54. Fermi Gamma-ray Burst Monitor trigger 667074291/220220767 is not a GRB
  55. IceCube Alert 220220.60: Global MASTER-Net observations report
  56. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  57. Fermi trigger No 666962499: Global MASTER-Net observations report
  58. GRB 220218A: BOOTES-5/JGT optical upper limit
  59. ZTF22aaajecp/AT2022cmc: Keck DEIMOS Redshift
  60. GRB 220219A: AGILE/MCAL detection
  61. GRB 220219A: BALROG localization (Fermi Trigger / GRB 220219473)
  62. GRB 220219A: Fermi GBM Final Real-time Localization
  63. GRB 220218A: Swift detection of a burst
  64. Swift GRB220218.94: Global MASTER-Net observations report
  65. GRB 220211A: redshift lower limit estimating
  66. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory continued optical observations
  67. Konus-Wind detection of GRB 220209A
  68. Swift resumes pointed science observations
  69. ZTF22aaajecp/AT2022cmc: VLT/X-shooter redshift
  70. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  71. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  72. Konus-Wind detection of GRB 220211A
  73. IPN triangulation of GRB 220209A
  74. ZTF22aaajecp: GIT optical follow-up observations
  75. GRB 211023A: evidence of supernova in LBT spectra
  76. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  77. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  78. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory optical observations
  79. ZTF22aaajecp/AT2022cmc: VLA radio detection
  80. GRB 220211A: Fermi GBM observation
  81. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  82. Fermi trigger No 666489765: Global MASTER-Net observations report
  83. GRB 220214A: Fermi GBM Final Real-time Localization
  84. Fermi GBM trigger 666393834/220212892 is not a GRB
  85. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  86. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  87. IPN triangulation of GRB 220211A (short)
  88. GRB 220210A: Insight-HXMT/HE detection
  89. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  90. GRB 220210A: 1.5m OSN optical upper limit
  91. GRB 220210A: Fermi GBM detection
  92. Fermi GRB 220211B: Global MASTER-Net observations report
  93. GRB 220211B: Fermi GBM Final Real-time Localization
  94. GRB 220209A: Fermi-LAT detection
  95. GRB 220210A: Fermi-LAT detection
  96. GRB 220210A: AGILE detection
  97. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  98. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  99. GRB 220210A: Swift/BAT-GUANO localization
  100. Fermi GRB 220211A: Global MASTER-Net observations report

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