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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. Konus-Wind detection of GRB 220927A
  2. IceCube-220928A - IceCube observation of a high-energy neutrino candidate track-like event
  3. Fermi GRB 220927A: Global MASTER-Net observations report
  4. IPN triangulation of GRB 220927A (long)
  5. GRB 220921A: LCOGT Optical Observations
  6. GRB 220611A: Host galaxy redshift from VLT/X-shooter
  7. GRB 220927A: Fermi GBM Final Localization
  8. GRB 220924A: Fermi GBM detection
  9. Integral GRB220926.44: Global MASTER-Net observations report
  10. Ultra-long GRB 220525B: Konus-Wind and Fermi-GBM detection
  11. Swift Trigger 1125354 (GRB 220926A) is not a GRB
  12. Swift GRB220926.34: Global MASTER-Net observations report
  13. Swift GRB 220926A: Global MASTER-Net observations report
  14. Analysis of long GRB 220926B detected by INTEGRAL
  15. GRB 220926B
  16. GRB 220926A: Swift detection of a burst
  17. Fermi GRB 220925A: Global MASTER-Net observations report
  18. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  19. GRB 220921A: further MeerLICHT observations
  20. GRB 220925A: Fermi GBM Final Real-time Localization
  21. Fermi trigger No 685748699: Global MASTER-Net observations report
  22. GRB 220924A: Fermi GBM Final Real-time Localization
  23. Swift GRB220923.47: Global MASTER-Net observations report
  24. GRB 220921A: ALMA detection
  25. GRB 220921A: DDOTI Detection of the Afterglow
  26. Konus-Wind detection of GRB 220921A
  27. GRB 220921A: Fermi GBM detection
  28. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  29. GRB 220921A: MeerLICHT afterglow observations
  30. GRB 220921A: Swift-XRT Observations
  31. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  32. LAT GRB220921.46: Global MASTER-Net observations report
  33. GRB 220921A: Fermi-LAT detection
  34. GRB 220921A: Tiled Swift observations
  35. Fermi trigger No 685452089: Global MASTER-Net observations report
  36. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  37. IceCube-220918A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube Alert 220918.53: Global MASTER-Net observations report
  39. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  40. Fermi trigger No 684894705: Global MASTER-Net observations report
  41. IceCube-220907A: No significant detection in HAWC
  42. Improved IPN error box for GRB 220910A
  43. Fermi trigger No 684927323: Global MASTER-Net observations report
  44. Fermi trigger No 684911625: Global MASTER-Net observations report
  45. GRB 220909A: Fermi GBM observation
  46. Konus-Wind detection of GRB 220910A
  47. GRB 220910B: Fermi GBM Final Localization
  48. Fermi trigger No 684716840: Global MASTER-Net observations report
  49. Fermi GRB 220912A: Global MASTER-Net observations report
  50. GRB 220910A: Fermi GBM observation
  51. IPN triangulation of GRB 220910A (bright/long)
  52. GRB 220912A: AstroSat CZTI detection
  53. GRB 220831A: DECam optical counterpart follow-up
  54. GRB 220909A: Swift-XRT observations
  55. GRB 220912A: Fermi GBM Final Real-time Localization
  56. IPN triangulation of GRB 220905A
  57. GRB 220909A: Swift ToO observations
  58. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  59. GRB 220831A: Gemini-South Infrared Observations
  60. GRB 220910A: AstroSat CZTI detection
  61. GRB 220910A: AGILE detection
  62. GRB 220909A: Fermi GBM Final Real-time Localization
  63. IceCube-220907A: Upper limits from a search for additional neutrino events in IceCube
  64. GRB 220907A: Swift-BAT refined analysis
  65. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  66. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  67. IPN triangulation of GRB 220903A (long)
  68. GRB 220907A: Fermi GBM observation
  69. GRB 220907A: Nanshan/NEXT optical upper limits
  70. GRB 220907A: Swift/UVOT Upper Limits
  71. GRB 220907A: Swift-XRT refined Analysis
  72. GRB 220831A: ATCA 5/9 GHz radio observations
  73. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  74. GRB 220907A: Swift-XRT position
  75. GRB 220907A: Swift detection of a burst
  76. GRB 220907A: Fermi GBM Final Real-time Localization
  77. Swift GRB220907.59: Global MASTER-Net observations report
  78. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  79. IceCube Alert 220907.28: Global MASTER-Net observations report
  80. GRB 220831A: Swift-UVOT Upper Limits
  81. Fermi GRB 220905A: Global MASTER-Net observations report
  82. GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
  83. GRB 220905A: Fermi GBM Final Real-time Localization
  84. Introducing Self-Service Configuration of GCN Notices over Email for Transient Alerts
  85. GRB 220831A: DECam detection of a possible optical counterpart
  86. Fermi GRB 220902A: Global MASTER-Net observations report
  87. GRB 220902A: Fermi GBM Final Real-time Localization
  88. GRB 220831A, VLT/HAWK-I near-infrared observations
  89. GRB 220831C: Fermi GBM Final Localization
  90. GRB 220831A: Fermi GBM observation
  91. GRB 220831A: Swift-XRT observations
  92. GRB 220831B: Fermi GBM Final Localization
  93. GRB 220831A: Swift ToO observations
  94. Fermi trigger No 683654200: Global MASTER-Net observations report
  95. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  96. Fermi trigger No 683646997: Global MASTER-Net observations report
  97. IceCube-220822A: No significant detection in HAWC
  98. Fermi trigger No 683537972: Global MASTER-Net observations report
  99. Fermi GBM trigger 683571622/220830709 is not a GRB
  100. Fermi trigger No 683476673: Global MASTER-Net observations report

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