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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 Alert 220303.75: Global MASTER-Net observations report
  2. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 220302A: BOOTES-5/JGT optical upper limit
  4. Swift resumes autonomous slewing
  5. ZTF22aaajecp/AT2022cmc: AMI-LA radio detection
  6. GRB 220302A: Enhanced Swift-XRT position
  7. ZTF22aaajecp/AT2022cmc: ATCA detection
  8. GRB 220302A: Swift afterglow detection
  9. GRB 220222A: CALET Gamma-Ray Burst Monitor detection
  10. Swift GRB 220302A: Global MASTER-Net observations report
  11. GRB 220302A: Swift detection of a burst
  12. GRB 220228A: Fermi GBM observation
  13. GRB 220228A: Fermi-LAT detection
  14. GRB 220228A: Fermi GBM Final Localization
  15. Konus-Wind detection of GRB 220222A
  16. IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube
  17. Fermi trigger No 667737010: Global MASTER-Net observations report
  18. ZTF22aaajecp/AT2022cmc: JCMT SCUBA-2 sub-mm observations
  19. Fermi-LAT Gamma-ray Observations of IceCube-220225A
  20. ZTF22aaajecp/AT2022cmc: Mondy optical observations
  21. IceCube Alert 220225.59: Global MASTER-Net observations report
  22. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  23. IPN triangulation of GRB 220222A
  24. GRB 220101A: The first example of a Petanova
  25. ZTF22aaajecp/AT2022cmc: DECam Photometry
  26. Konus-Wind observation of GRB 220219B
  27. GCN Circ.draft on GRB 220222A
  28. GRB 220219B: Swift-XRT observations
  29. ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations
  30. Fermi GRB 220223A: Global MASTER-Net observations report
  31. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  32. GRB 220223A: Fermi GBM Final Real-time Localization
  33. ZTF22aabjpxh/AT2022cva: 1.5m OSN optical observation
  34. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  35. Fermi GRB 220222B: Global MASTER-Net observations report
  36. GRB 220222B: Fermi GBM Final Real-time Localization
  37. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  38. GRB 220219B: Swift ToO observations
  39. GRB 220222A: Swift/BAT-GUANO detection outside the coded FOV
  40. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  41. Fermi GRB 220222A: Global MASTER-Net observations report
  42. GRB 220222A: Fermi GBM Final Real-time Localization
  43. ZTF22aabjpxh/AT2022cva: GMOS-N spectroscopy
  44. ZTF22aabjpxh/AT2022cva: Assy optical observations
  45. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  46. ZTF22aaajecb/AT 2022cmc: CAHA 2.2m/CAFOS detection, luminous transient
  47. ZTF22aaajecp/AT2022cmc: Terskol observatory optical observations
  48. IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva)
  49. IceCube Alert 220221.03: Global MASTER-Net observations report
  50. Konus-Wind observation of GRB 220219A
  51. IPN triangulation of GRB 220219A
  52. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  53. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  54. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  55. Fermi Gamma-ray Burst Monitor trigger 667074291/220220767 is not a GRB
  56. IceCube Alert 220220.60: Global MASTER-Net observations report
  57. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  58. Fermi trigger No 666962499: Global MASTER-Net observations report
  59. GRB 220218A: BOOTES-5/JGT optical upper limit
  60. ZTF22aaajecp/AT2022cmc: Keck DEIMOS Redshift
  61. GRB 220219A: AGILE/MCAL detection
  62. GRB 220219A: BALROG localization (Fermi Trigger / GRB 220219473)
  63. GRB 220219A: Fermi GBM Final Real-time Localization
  64. GRB 220218A: Swift detection of a burst
  65. Swift GRB220218.94: Global MASTER-Net observations report
  66. GRB 220211A: redshift lower limit estimating
  67. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory continued optical observations
  68. Konus-Wind detection of GRB 220209A
  69. Swift resumes pointed science observations
  70. ZTF22aaajecp/AT2022cmc: VLT/X-shooter redshift
  71. ZTF22aaajecp/AT2022cmc: NICER X-ray detection
  72. GRB 220211A: MASTER optical observations of ZTF22aaajecp/AT2022cmc
  73. Konus-Wind detection of GRB 220211A
  74. IPN triangulation of GRB 220209A
  75. ZTF22aaajecp: GIT optical follow-up observations
  76. GRB 211023A: evidence of supernova in LBT spectra
  77. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  78. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  79. ZTF22aaajecp/AT2022cmc: Zeiss-1000 of Koshka observatory optical observations
  80. ZTF22aaajecp/AT2022cmc: VLA radio detection
  81. GRB 220211A: Fermi GBM observation
  82. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  83. Fermi trigger No 666489765: Global MASTER-Net observations report
  84. GRB 220214A: Fermi GBM Final Real-time Localization
  85. Fermi GBM trigger 666393834/220212892 is not a GRB
  86. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  87. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  88. IPN triangulation of GRB 220211A (short)
  89. GRB 220210A: Insight-HXMT/HE detection
  90. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  91. GRB 220210A: 1.5m OSN optical upper limit
  92. GRB 220210A: Fermi GBM detection
  93. Fermi GRB 220211B: Global MASTER-Net observations report
  94. GRB 220211B: Fermi GBM Final Real-time Localization
  95. GRB 220209A: Fermi-LAT detection
  96. GRB 220210A: Fermi-LAT detection
  97. GRB 220210A: AGILE detection
  98. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  99. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  100. GRB 220210A: Swift/BAT-GUANO localization

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