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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 220921A: Swift-XRT Observations
  2. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  3. LAT GRB220921.46: Global MASTER-Net observations report
  4. GRB 220921A: Fermi-LAT detection
  5. GRB 220921A: Tiled Swift observations
  6. Fermi trigger No 685452089: Global MASTER-Net observations report
  7. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  8. IceCube-220918A: Upper limits from a search for additional neutrino events in IceCube
  9. IceCube Alert 220918.53: Global MASTER-Net observations report
  10. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  11. Fermi trigger No 684894705: Global MASTER-Net observations report
  12. IceCube-220907A: No significant detection in HAWC
  13. Improved IPN error box for GRB 220910A
  14. Fermi trigger No 684927323: Global MASTER-Net observations report
  15. Fermi trigger No 684911625: Global MASTER-Net observations report
  16. GRB 220909A: Fermi GBM observation
  17. Konus-Wind detection of GRB 220910A
  18. GRB 220910B: Fermi GBM Final Localization
  19. Fermi trigger No 684716840: Global MASTER-Net observations report
  20. Fermi GRB 220912A: Global MASTER-Net observations report
  21. GRB 220910A: Fermi GBM observation
  22. IPN triangulation of GRB 220910A (bright/long)
  23. GRB 220912A: AstroSat CZTI detection
  24. GRB 220831A: DECam optical counterpart follow-up
  25. GRB 220909A: Swift-XRT observations
  26. GRB 220912A: Fermi GBM Final Real-time Localization
  27. IPN triangulation of GRB 220905A
  28. GRB 220909A: Swift ToO observations
  29. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  30. GRB 220831A: Gemini-South Infrared Observations
  31. GRB 220910A: AstroSat CZTI detection
  32. GRB 220910A: AGILE detection
  33. GRB 220909A: Fermi GBM Final Real-time Localization
  34. IceCube-220907A: Upper limits from a search for additional neutrino events in IceCube
  35. GRB 220907A: Swift-BAT refined analysis
  36. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  37. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  38. IPN triangulation of GRB 220903A (long)
  39. GRB 220907A: Fermi GBM observation
  40. GRB 220907A: Nanshan/NEXT optical upper limits
  41. GRB 220907A: Swift/UVOT Upper Limits
  42. GRB 220907A: Swift-XRT refined Analysis
  43. GRB 220831A: ATCA 5/9 GHz radio observations
  44. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  45. GRB 220907A: Swift-XRT position
  46. GRB 220907A: Swift detection of a burst
  47. GRB 220907A: Fermi GBM Final Real-time Localization
  48. Swift GRB220907.59: Global MASTER-Net observations report
  49. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  50. IceCube Alert 220907.28: Global MASTER-Net observations report
  51. GRB 220831A: Swift-UVOT Upper Limits
  52. Fermi GRB 220905A: Global MASTER-Net observations report
  53. GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
  54. GRB 220905A: Fermi GBM Final Real-time Localization
  55. Introducing Self-Service Configuration of GCN Notices over Email for Transient Alerts
  56. GRB 220831A: DECam detection of a possible optical counterpart
  57. Fermi GRB 220902A: Global MASTER-Net observations report
  58. GRB 220902A: Fermi GBM Final Real-time Localization
  59. GRB 220831A, VLT/HAWK-I near-infrared observations
  60. GRB 220831C: Fermi GBM Final Localization
  61. GRB 220831A: Fermi GBM observation
  62. GRB 220831A: Swift-XRT observations
  63. GRB 220831B: Fermi GBM Final Localization
  64. GRB 220831A: Swift ToO observations
  65. Fermi trigger No 683654200: Global MASTER-Net observations report
  66. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  67. Fermi trigger No 683646997: Global MASTER-Net observations report
  68. IceCube-220822A: No significant detection in HAWC
  69. Fermi trigger No 683537972: Global MASTER-Net observations report
  70. Fermi GBM trigger 683571622/220830709 is not a GRB
  71. Fermi trigger No 683476673: Global MASTER-Net observations report
  72. Konus-Wind detection of GRB 220826A
  73. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  74. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  75. GRB 220827A: Fermi GBM Final Real-time Localization
  76. GRB 220826A: Swift-BAT refined analysis
  77. GRB 220826A: Fermi GBM observation
  78. Fermi trigger No 683202084: Global MASTER-Net observations report
  79. Fermi trigger No 683183601: Global MASTER-Net observations report
  80. Fermi trigger No 683152759: Global MASTER-Net observations report
  81. GRB 220826A: Swift-XRT refined Analysis
  82. GRB 220825A: Fermi GBM observation
  83. GRB 220826A: Lesedi optical afterglow detection
  84. GRB 220826A: Swift/UVOT Detection
  85. GRB 220826A: iTelescope optical afterglow observations
  86. Swift GRB 220826A: Global MASTER-Net observations report
  87. GRB 220826A: Enhanced Swift-XRT position
  88. GRB 220826A: Swift detection of a burst with an optical counterpart
  89. GRB 220825A: Swift/BAT-GUANO detection
  90. GRB 220825A: Fermi GBM Final Localization
  91. IceCube-220822A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  93. GRB 220823A: Fermi GBM detection
  94. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  95. Fermi trigger No 682918137: Global MASTER-Net observations report
  96. GRB 220823A: Swift/BAT-GUANO detection of a short burst
  97. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  98. IceCube Alert 220822.85: Global MASTER-Net observations report
  99. GRB 220821A: Fermi GBM Final Real-time Localization
  100. Konus-Wind detection of GRB 220813A

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