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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 220930A: BOOTES-5/JGT early optical upper limit
  2. GRB 220930A: Prompt enhanced Swift-XRT position
  3. GRB 220930A: COATLI Upper Limits
  4. GRB 220930A: Swift detection of a burst
  5. Fermi-LAT gamma-ray observations of IceCube-220928A
  6. IceCube-220928A: Upper limits from a search for additional neutrino events in IceCube
  7. Konus-Wind detection of GRB 220927A
  8. IceCube-220928A - IceCube observation of a high-energy neutrino candidate track-like event
  9. Fermi GRB 220927A: Global MASTER-Net observations report
  10. IPN triangulation of GRB 220927A (long)
  11. GRB 220921A: LCOGT Optical Observations
  12. GRB 220611A: Host galaxy redshift from VLT/X-shooter
  13. GRB 220927A: Fermi GBM Final Localization
  14. GRB 220924A: Fermi GBM detection
  15. Integral GRB220926.44: Global MASTER-Net observations report
  16. Ultra-long GRB 220525B: Konus-Wind and Fermi-GBM detection
  17. Swift Trigger 1125354 (GRB 220926A) is not a GRB
  18. Swift GRB220926.34: Global MASTER-Net observations report
  19. Swift GRB 220926A: Global MASTER-Net observations report
  20. Analysis of long GRB 220926B detected by INTEGRAL
  21. GRB 220926B
  22. GRB 220926A: Swift detection of a burst
  23. Fermi GRB 220925A: Global MASTER-Net observations report
  24. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  25. GRB 220921A: further MeerLICHT observations
  26. GRB 220925A: Fermi GBM Final Real-time Localization
  27. Fermi trigger No 685748699: Global MASTER-Net observations report
  28. GRB 220924A: Fermi GBM Final Real-time Localization
  29. Swift GRB220923.47: Global MASTER-Net observations report
  30. GRB 220921A: ALMA detection
  31. GRB 220921A: DDOTI Detection of the Afterglow
  32. Konus-Wind detection of GRB 220921A
  33. GRB 220921A: Fermi GBM detection
  34. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  35. GRB 220921A: MeerLICHT afterglow observations
  36. GRB 220921A: Swift-XRT Observations
  37. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  38. LAT GRB220921.46: Global MASTER-Net observations report
  39. GRB 220921A: Fermi-LAT detection
  40. GRB 220921A: Tiled Swift observations
  41. Fermi trigger No 685452089: Global MASTER-Net observations report
  42. Fermi-LAT gamma-ray observations of IceCube-220918A and detection of a new gamma-ray source, Fermi J0502.5+0037
  43. IceCube-220918A: Upper limits from a search for additional neutrino events in IceCube
  44. IceCube Alert 220918.53: Global MASTER-Net observations report
  45. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  46. Fermi trigger No 684894705: Global MASTER-Net observations report
  47. IceCube-220907A: No significant detection in HAWC
  48. Improved IPN error box for GRB 220910A
  49. Fermi trigger No 684927323: Global MASTER-Net observations report
  50. Fermi trigger No 684911625: Global MASTER-Net observations report
  51. GRB 220909A: Fermi GBM observation
  52. Konus-Wind detection of GRB 220910A
  53. GRB 220910B: Fermi GBM Final Localization
  54. Fermi trigger No 684716840: Global MASTER-Net observations report
  55. Fermi GRB 220912A: Global MASTER-Net observations report
  56. GRB 220910A: Fermi GBM observation
  57. IPN triangulation of GRB 220910A (bright/long)
  58. GRB 220912A: AstroSat CZTI detection
  59. GRB 220831A: DECam optical counterpart follow-up
  60. GRB 220909A: Swift-XRT observations
  61. GRB 220912A: Fermi GBM Final Real-time Localization
  62. IPN triangulation of GRB 220905A
  63. GRB 220909A: Swift ToO observations
  64. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  65. GRB 220831A: Gemini-South Infrared Observations
  66. GRB 220910A: AstroSat CZTI detection
  67. GRB 220910A: AGILE detection
  68. GRB 220909A: Fermi GBM Final Real-time Localization
  69. IceCube-220907A: Upper limits from a search for additional neutrino events in IceCube
  70. GRB 220907A: Swift-BAT refined analysis
  71. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  72. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  73. IPN triangulation of GRB 220903A (long)
  74. GRB 220907A: Fermi GBM observation
  75. GRB 220907A: Nanshan/NEXT optical upper limits
  76. GRB 220907A: Swift/UVOT Upper Limits
  77. GRB 220907A: Swift-XRT refined Analysis
  78. GRB 220831A: ATCA 5/9 GHz radio observations
  79. Fermi-LAT Gamma-ray Observations of IceCube-220907A
  80. GRB 220907A: Swift-XRT position
  81. GRB 220907A: Swift detection of a burst
  82. GRB 220907A: Fermi GBM Final Real-time Localization
  83. Swift GRB220907.59: Global MASTER-Net observations report
  84. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  85. IceCube Alert 220907.28: Global MASTER-Net observations report
  86. GRB 220831A: Swift-UVOT Upper Limits
  87. Fermi GRB 220905A: Global MASTER-Net observations report
  88. GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
  89. GRB 220905A: Fermi GBM Final Real-time Localization
  90. Introducing Self-Service Configuration of GCN Notices over Email for Transient Alerts
  91. GRB 220831A: DECam detection of a possible optical counterpart
  92. Fermi GRB 220902A: Global MASTER-Net observations report
  93. GRB 220902A: Fermi GBM Final Real-time Localization
  94. GRB 220831A, VLT/HAWK-I near-infrared observations
  95. GRB 220831C: Fermi GBM Final Localization
  96. GRB 220831A: Fermi GBM observation
  97. GRB 220831A: Swift-XRT observations
  98. GRB 220831B: Fermi GBM Final Localization
  99. GRB 220831A: Swift ToO observations
  100. Fermi trigger No 683654200: Global MASTER-Net observations report

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