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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. GRB 220319A: Enhanced Swift-XRT position
  2. GRB 220319A: MASTER Global Robotic Net optical observations
  3. GRB 220319A: Swift detection of a burst
  4. Fermi-LAT Gamma-ray Observations of IceCube-220317A
  5. IceCube-220317A: Upper limits from a search for additional neutrino events in IceCube
  6. GRB 220317A: Swift/BAT-GUANO detection outside the coded FOV
  7. GRB 220310A: MITSuME Akeno optical observation
  8. IceCube-220317A: MASTER Global Robotic Net optical observations
  9. GRB 220317A: Fermi GBM Final Real-time Localization
  10. IceCube-220317A - IceCube observation of a high-energy neutrino candidate track-like event
  11. GRB 220315A: MASTER Global Robotic Net optical observations
  12. GRB 220311A: Fermi GBM observation
  13. GRB 220306B: Swift/UVOT Upper Limits
  14. GRB 220315A: Fermi GBM Final Real-time Localization
  15. GRB 220311A: MITSuME Akeno optical upper limits
  16. IPN triangulation of GRB 220310A
  17. GRB 220310C: Fermi GBM observation
  18. GRB 210722A: TAROT Reunion observatory optical light curve
  19. GRB 210222B: TAROT Reunion observatory optical light curve
  20. GRB 201021C: TAROT Reunion observatory optical light curve
  21. GRB 220310A: K-800 of Terskol observatory optical upper limit
  22. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  23. GRB 220310C: Swift-XRT observations
  24. Konus-Wind detection of GRB 220310A
  25. GRB 220310C: Swift ToO observations
  26. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  27. GRB 220311A: MASTER OT retraction
  28. GRB 220311A: A long GRB detected by INTEGRAL
  29. Integral GRB220311.69: Global MASTER-Net observations report
  30. Integral GRB220311.69: Global MASTER-Net observations report
  31. Integral GRB220311.69: Global MASTER-Net OT detection
  32. GRB 220311A: Fermi GBM Final Real-time Localization
  33. ZTF22aabjpxh/AT2022cva (GRB 220219B): evidence of supernova in LBT spectra
  34. GRB 220310A: GIT confirmation of optical afterglow.
  35. GRB 220306B: Nanshan/NEXT optical upper limit
  36. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, possible photometric evidence of SN
  37. GRB 220310C: Fermi GBM Final Real-time Localization
  38. Fermi GBM Detection of GRB 220308A
  39. GRB 220308A: AGILE detection
  40. GRB 220310A: MASTER optical counterpart detection
  41. GRB 220310A: Swift ToO observations
  42. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  43. ZTF22aaajecp/AT2022cmc: Hubble Space Telescope Observations
  44. Fermi GRB 220310B: Global MASTER-Net observations report
  45. GRB 220310B: Fermi GBM Final Real-time Localization
  46. GRB 220308B: Fermi GBM detection
  47. GRB 220310A: MAXI/GSC detection
  48. MAXI GRB220310.02: Global MASTER-Net observations report
  49. Konus-Wind detection of GRB 220308A
  50. IceCube-220306A: No significant detection in HAWC
  51. IceCube-220303A: No significant detection in HAWC
  52. ZTF22aabjpxh/AT2022cva: AMI-LA radio observation
  53. CALET Gamma-Ray Burst Monitor detection of GRB 220308A and its possible precursor
  54. Fermi GRB 220309A: Global MASTER-Net observations report
  55. GRB 220309A: Fermi GBM Final Real-time Localization
  56. GRB 220308A: Swift/BAT-GUANO detection outside the coded FOV
  57. IPN triangulation of GRB 220308A (long / very bright)
  58. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  59. IPN triangulation of GRB 220305B
  60. Fermi trigger No 668410535: Global MASTER-Net observations report
  61. GRB 220306B: Tautenburg observations
  62. GRB 220304A Fermi GBM detection
  63. IceCube-220306A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-220304A: Upper limits from a search for additional neutrino events in IceCube
  65. GRB 220306B: Swift-BAT refined analysis
  66. Fermi-LAT Gamma-ray Observations of IceCube-220306A
  67. GRB 220306B: AbAO optical observations, possible afterglow candidate
  68. GRB 220306B: BOOTES-1 optical upper limit
  69. GRB 220306B: Swift-XRT refined Analysis
  70. GRB 220306B: Fermi GBM observation
  71. Fermi-LAT Gamma-ray Observations of IceCube-220304A
  72. GRB 220306B: Enhanced Swift-XRT position
  73. Swift GRB 220306B: Global MASTER-Net observations report
  74. GRB 220305A: Swift-BAT refined analysis
  75. GRB 220306B: Swift detection of a burst
  76. Fermi GBM Sub-Threshold Detection of GRB 220305A
  77. GRB 220305A: Swift-XRT refined Analysis
  78. Fermi GRB 220306A: Global MASTER-Net observations report
  79. GRB 220306A: Fermi GBM Final Real-time Localization
  80. IceCube-220306A - IceCube observation of a high-energy neutrino candidate track-like event
  81. Fermi GRB 220305A: Global MASTER-Net observations report
  82. Correction to GCN 31689: Fermi GBM Report of GRB 220305A should be GRB 220305B
  83. GRB 220305A: Fermi GBM observation
  84. GRB 220305A: Enhanced Swift-XRT position
  85. IceCube-220303A: One X-ray counterpart from Swift/XRT follow up observations
  86. Swift GRB 220305A: Global MASTER-Net observations report
  87. GRB 220305A: Swift-XRT observations
  88. GRB 220305A: Swift detection of a burst
  89. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, SN signature search
  90. GRB 220302A: Swift/UVOT Upper Limits
  91. IceCube-220303A: Upper limits from a search for additional neutrino events in IceCube
  92. Fermi-LAT Gamma-ray Observations of IceCube-220303A
  93. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  94. IceCube Alert 220304.74: Global MASTER-Net observations report
  95. GRB 220304A: Swift/BAT-GUANO detection outside the coded FOV
  96. Fermi GRB 220304A: Global MASTER-Net observations report
  97. Tev Blazar as possible optical counterpart of the high-energy neutrino IceCube-220303A
  98. GRB 220304A: BALROG localization (Fermi Trigger / GRB 220304228)
  99. GRB 220302A: Swift-XRT refined Analysis
  100. GRB 220304A: Fermi GBM Final Real-time Localization

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