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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 GRB220926.34: Global MASTER-Net observations report
  2. Swift GRB 220926A: Global MASTER-Net observations report
  3. Analysis of long GRB 220926B detected by INTEGRAL
  4. GRB 220926B
  5. GRB 220926A: Swift detection of a burst
  6. Fermi GRB 220925A: Global MASTER-Net observations report
  7. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  8. GRB 220921A: further MeerLICHT observations
  9. GRB 220925A: Fermi GBM Final Real-time Localization
  10. Fermi trigger No 685748699: Global MASTER-Net observations report
  11. GRB 220924A: Fermi GBM Final Real-time Localization
  12. Swift GRB220923.47: Global MASTER-Net observations report
  13. GRB 220921A: ALMA detection
  14. GRB 220921A: DDOTI Detection of the Afterglow
  15. Konus-Wind detection of GRB 220921A
  16. GRB 220921A: Fermi GBM detection
  17. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  18. GRB 220921A: MeerLICHT afterglow observations
  19. GRB 220921A: Swift-XRT Observations
  20. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  21. LAT GRB220921.46: Global MASTER-Net observations report
  22. GRB 220921A: Fermi-LAT detection
  23. GRB 220921A: Tiled Swift observations
  24. Fermi trigger No 685452089: Global MASTER-Net observations report
  25. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  26. IceCube-220918A: Upper limits from a search for additional neutrino events in IceCube
  27. IceCube Alert 220918.53: Global MASTER-Net observations report
  28. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  29. Fermi trigger No 684894705: Global MASTER-Net observations report
  30. IceCube-220907A: No significant detection in HAWC
  31. Improved IPN error box for GRB 220910A
  32. Fermi trigger No 684927323: Global MASTER-Net observations report
  33. Fermi trigger No 684911625: Global MASTER-Net observations report
  34. GRB 220909A: Fermi GBM observation
  35. Konus-Wind detection of GRB 220910A
  36. GRB 220910B: Fermi GBM Final Localization
  37. Fermi trigger No 684716840: Global MASTER-Net observations report
  38. Fermi GRB 220912A: Global MASTER-Net observations report
  39. GRB 220910A: Fermi GBM observation
  40. IPN triangulation of GRB 220910A (bright/long)
  41. GRB 220912A: AstroSat CZTI detection
  42. GRB 220831A: DECam optical counterpart follow-up
  43. GRB 220909A: Swift-XRT observations
  44. GRB 220912A: Fermi GBM Final Real-time Localization
  45. IPN triangulation of GRB 220905A
  46. GRB 220909A: Swift ToO observations
  47. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  48. GRB 220831A: Gemini-South Infrared Observations
  49. GRB 220910A: AstroSat CZTI detection
  50. GRB 220910A: AGILE detection
  51. GRB 220909A: Fermi GBM Final Real-time Localization
  52. IceCube-220907A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 220907A: Swift-BAT refined analysis
  54. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  55. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  56. IPN triangulation of GRB 220903A (long)
  57. GRB 220907A: Fermi GBM observation
  58. GRB 220907A: Nanshan/NEXT optical upper limits
  59. GRB 220907A: Swift/UVOT Upper Limits
  60. GRB 220907A: Swift-XRT refined Analysis
  61. GRB 220831A: ATCA 5/9 GHz radio observations
  62. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  63. GRB 220907A: Swift-XRT position
  64. GRB 220907A: Swift detection of a burst
  65. GRB 220907A: Fermi GBM Final Real-time Localization
  66. Swift GRB220907.59: Global MASTER-Net observations report
  67. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube Alert 220907.28: Global MASTER-Net observations report
  69. GRB 220831A: Swift-UVOT Upper Limits
  70. Fermi GRB 220905A: Global MASTER-Net observations report
  71. GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
  72. GRB 220905A: Fermi GBM Final Real-time Localization
  73. Introducing Self-Service Configuration of GCN Notices over Email for Transient Alerts
  74. GRB 220831A: DECam detection of a possible optical counterpart
  75. Fermi GRB 220902A: Global MASTER-Net observations report
  76. GRB 220902A: Fermi GBM Final Real-time Localization
  77. GRB 220831A, VLT/HAWK-I near-infrared observations
  78. GRB 220831C: Fermi GBM Final Localization
  79. GRB 220831A: Fermi GBM observation
  80. GRB 220831A: Swift-XRT observations
  81. GRB 220831B: Fermi GBM Final Localization
  82. GRB 220831A: Swift ToO observations
  83. Fermi trigger No 683654200: Global MASTER-Net observations report
  84. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  85. Fermi trigger No 683646997: Global MASTER-Net observations report
  86. IceCube-220822A: No significant detection in HAWC
  87. Fermi trigger No 683537972: Global MASTER-Net observations report
  88. Fermi GBM trigger 683571622/220830709 is not a GRB
  89. Fermi trigger No 683476673: Global MASTER-Net observations report
  90. Konus-Wind detection of GRB 220826A
  91. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  93. GRB 220827A: Fermi GBM Final Real-time Localization
  94. GRB 220826A: Swift-BAT refined analysis
  95. GRB 220826A: Fermi GBM observation
  96. Fermi trigger No 683202084: Global MASTER-Net observations report
  97. Fermi trigger No 683183601: Global MASTER-Net observations report
  98. Fermi trigger No 683152759: Global MASTER-Net observations report
  99. GRB 220826A: Swift-XRT refined Analysis
  100. GRB 220825A: Fermi GBM observation

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