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

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