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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. Swift BAT Trigger 1107209 is not an astrophysical event
  2. GRB 220514A: AstroSat CZTI detection
  3. GRB 220518A: Swift-BAT refined analysis
  4. Swift GRB220519.84: Global MASTER-Net observations report
  5. GRB 220518A: Swift-XRT refined Analysis
  6. Fermi GRB 220518B: Global MASTER-Net observations report
  7. Continued Chandra monitoring of GW170817 at ~4.8 yr post-merger
  8. GRB 220518B: Fermi GBM Final Real-time Localization
  9. GRB 220518A: Swift/UVOT Detection
  10. GRB 220518A: Enhanced Swift-XRT position
  11. Swift GRB 220518A: Global MASTER-Net observations report
  12. GRB 220518A: Swift detection of a burst
  13. GRB 220514A: MITSuME Akeno optical observation
  14. GRB 220514A: GRANDMA Optical Afterglow Observations
  15. Konus-Wind detection of GRB 220506A
  16. Konus-Wind detection of GRB 220514B
  17. Fermi trigger No 674397342: Global MASTER-Net observations report
  18. GRB 220514A: Fermi GBM observation
  19. GRB 220514B: Swift-XRT observations
  20. GRB 220511A: Swift-XRT afterglow detection
  21. GRB 220514A: KAIT Optical Afterglow Confirmation
  22. Fermi-LAT Gamma-ray Observations of IceCube-220513A
  23. IceCube-220513A: Upper limits from a search for additional neutrino events in IceCube
  24. GRB 220514B: Tiled Swift observations
  25. IceCube-220513A: No significant detection in HAWC
  26. GRB 220514B: MAXI/GSC detection
  27. MAXI GRB220514.98: Global MASTER-Net observations report
  28. GRB 220514A: MeerLICHT optical afterglow candidate
  29. Integral GRB220514.52: Global MASTER-Net observations report
  30. Fermi GRB 220514A: Global MASTER-Net observations report
  31. GRB 220514A: a long GRB detected by INTEGRAL
  32. IceCube-220513A: No Candidate Counterparts from the Zwicky Transient Facility
  33. GRB 220514A: BALROG localization (Fermi Trigger 674223877 / GRB 220514517)
  34. GRB 220514A: Fermi GBM Final Real-time Localization
  35. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  36. IceCube Alert 220513.97: Global MASTER-Net observations report
  37. Fermi GRB 220513A: Global MASTER-Net observations report
  38. GRB 220513A: Fermi GBM Final Real-time Localization
  39. Konus-Wind detection of GRB 220511A
  40. GRB 220427A: MeerLICHT afterglow observations
  41. IceCube-220509A: No significant detection in HAWC
  42. GRB 220511A: Fermi GBM observation
  43. GRB 220511A: Swift-XRT observations
  44. GRB 220511A: AstroSat CZTI detection
  45. GRB 220511A: BOOTES-2/TELMA optical upper limit
  46. Fermi GRB 220512A: Global MASTER-Net observations report
  47. GRB 220512A: Fermi GBM Final Real-time Localization
  48. GRB 220511A: Swift ToO observations
  49. GRB 220511A: Swift/BAT-GUANO arcminute localization
  50. Fermi GRB 220511A: Global MASTER-Net observations report
  51. GRB 220511A: AGILE detection
  52. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 220511A: BALROG localization (Fermi Trigger 673969321/ GRB 220511571)
  54. GRB 220511A: Fermi GBM Final Real-time Localization
  55. GRB 220507A: AstroSat CZTI detection
  56. Fermi-LAT Gamma-ray Observations of IceCube-220509A
  57. Fermi trigger No 673846271: Global MASTER-Net observations report
  58. GRB 220506A: MITSuME Akeno optical upper limits
  59. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  60. GRB 220506A: GIT optical upper limit.
  61. IceCube Alert 220509.76: Global MASTER-Net observations report
  62. GRB 220508A: Fermi GBM Final Real-time Localization
  63. GRB 220507A: Fermi GBM Final Localization
  64. GRB 220506A: BOOTES-5/JGT optical upper limit
  65. Fermi trigger No 673610950: Global MASTER-Net observations report
  66. GRB 220506A: Swift-XRT afterglow detection
  67. GRB 220506A: Tiled Swift observations
  68. IceCube-220405B - ZTF19aavnpjv unrelated
  69. Swift-BAT triggers 1105560-1 are not GRBs
  70. Swift GRB220506.51: Global MASTER-Net observations report
  71. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  72. MAXI GRB220506.27: Global MASTER-Net observations report
  73. GRB 220430A: Nanshan/NEXT optical upper limit
  74. GRB 220430A: Nanshan/HMT optical upper limit
  75. GRB 220430A: GIT optical upper limits
  76. IPN triangulation of GRB 220423A
  77. GRB 220427A: LCO Optical Observations
  78. IceCube-220501A: Upper limits from a search for additional neutrino events in IceCube
  79. GRB 220501A: Swift-BAT refined analysis
  80. Fermi-LAT Gamma-ray Observations of IceCube-220501A
  81. GRB 220427A: GRANDMA Early Optical Afterglow Detection
  82. GRB 220501A: BOOTES-1 optical upper limit
  83. IceCube-220501A: No Candidate Counterparts from the Zwicky Transient Facility
  84. GRB 220501A: Fermi GBM observation
  85. GRB 220430A: AstroSat CZTI detection
  86. IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
  87. IceCube Alert 220501.95: Global MASTER-Net observations report
  88. GRB 220501A: GRANDMA/TJML Optical Observations
  89. GRB 220501A: Fermi GBM Final Real-time Localization
  90. GRB 220501A: Swift detection of a burst
  91. GRB 220430A: Swift-BAT refined analysis
  92. GRB 220430A: CAHA 2.2m telescope optical limit
  93. GRB 220430A: Swift-XRT refined Analysis
  94. Swift GRB 220430A: Global MASTER-Net observations report
  95. GRB 220430A: GRANDMA observations
  96. GRB 220430A: Mondy and AbAO optical upper limits
  97. GRB 220430A: AGILE detection
  98. GRB 220430A: MeerLICHT optical upper limits
  99. GRB 220430A: Enhanced Swift-XRT position
  100. GRB 220430A: Swift detection of a burst or Swift J0630.4+0932

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