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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 GRB220907.59: Global MASTER-Net observations report
  2. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  3. IceCube Alert 220907.28: Global MASTER-Net observations report
  4. GRB 220831A: Swift-UVOT Upper Limits
  5. Fermi GRB 220905A: Global MASTER-Net observations report
  6. GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
  7. GRB 220905A: Fermi GBM Final Real-time Localization
  8. Introducing Self-Service Configuration of GCN Notices over Email for Transient Alerts
  9. GRB 220831A: DECam detection of a possible optical counterpart
  10. Fermi GRB 220902A: Global MASTER-Net observations report
  11. GRB 220902A: Fermi GBM Final Real-time Localization
  12. GRB 220831A, VLT/HAWK-I near-infrared observations
  13. GRB 220831C: Fermi GBM Final Localization
  14. GRB 220831A: Fermi GBM observation
  15. GRB 220831A: Swift-XRT observations
  16. GRB 220831B: Fermi GBM Final Localization
  17. GRB 220831A: Swift ToO observations
  18. Fermi trigger No 683654200: Global MASTER-Net observations report
  19. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  20. Fermi trigger No 683646997: Global MASTER-Net observations report
  21. IceCube-220822A: No significant detection in HAWC
  22. Fermi trigger No 683537972: Global MASTER-Net observations report
  23. Fermi GBM trigger 683571622/220830709 is not a GRB
  24. Fermi trigger No 683476673: Global MASTER-Net observations report
  25. Konus-Wind detection of GRB 220826A
  26. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  27. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  28. GRB 220827A: Fermi GBM Final Real-time Localization
  29. GRB 220826A: Swift-BAT refined analysis
  30. GRB 220826A: Fermi GBM observation
  31. Fermi trigger No 683202084: Global MASTER-Net observations report
  32. Fermi trigger No 683183601: Global MASTER-Net observations report
  33. Fermi trigger No 683152759: Global MASTER-Net observations report
  34. GRB 220826A: Swift-XRT refined Analysis
  35. GRB 220825A: Fermi GBM observation
  36. GRB 220826A: Lesedi optical afterglow detection
  37. GRB 220826A: Swift/UVOT Detection
  38. GRB 220826A: iTelescope optical afterglow observations
  39. Swift GRB 220826A: Global MASTER-Net observations report
  40. GRB 220826A: Enhanced Swift-XRT position
  41. GRB 220826A: Swift detection of a burst with an optical counterpart
  42. GRB 220825A: Swift/BAT-GUANO detection
  43. GRB 220825A: Fermi GBM Final Localization
  44. IceCube-220822A: Upper limits from a search for additional neutrino events in IceCube
  45. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  46. GRB 220823A: Fermi GBM detection
  47. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  48. Fermi trigger No 682918137: Global MASTER-Net observations report
  49. GRB 220823A: Swift/BAT-GUANO detection of a short burst
  50. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  51. IceCube Alert 220822.85: Global MASTER-Net observations report
  52. GRB 220821A: Fermi GBM Final Real-time Localization
  53. Konus-Wind detection of GRB 220813A
  54. GRB 220813A: VLT optical observations and possible host galaxy
  55. GRB 220813A: Swift/UVOT Detection
  56. GRB 220810A: Further Swift-XRT observations
  57. GRB 220813A: Swift-XRT refined Analysis
  58. Swift GRB 220813A: Global MASTER-Net observations report
  59. GRB 220813A: Enhanced Swift-XRT position
  60. GRB 220813A: Swift detection of a burst with an optical counterpart
  61. GRB 220810A: Swift-XRT observations
  62. GRB 220719B: Detection by VZLUSAT-2
  63. Fermi trigger No 681998863: Global MASTER-Net observations report
  64. GRB 220810A: Swift ToO observations
  65. GRB 220810A: MeerLICHT detection of two afterglow candidates
  66. Fermi GBM trigger 681998863/220812505 is not a GRB
  67. Fermi trigger No 681890304: Global MASTER-Net observations report
  68. Fermi GBM trigger 681890304/220811249 is not a GRB
  69. Fermi GRB 220810A: Global MASTER-Net observations report
  70. GRB 220810A: Fermi GBM Final Real-time Localization
  71. GRB 220627A: MeerKAT radio observations
  72. GRB 220806A: Swift-BAT refined analysis
  73. Fermi trigger No 681719116: Global MASTER-Net observations report
  74. Fermi GBM trigger 681719116/220809267 is not a GRB
  75. Fermi trigger No 681633544: Global MASTER-Net observations report
  76. IceCube Astrotrack Bronze 136918_45252263.amon is likely background
  77. Fermi GBM trigger 681633544/220808277 is not a GRB
  78. IceCube Alert 220808.33: Global MASTER-Net observations report
  79. Fermi GBM trigger 681547990 / 220807287 is not a GRB
  80. GRB 220806A: Swift detection of a burst
  81. Swift GRB220806.76: Global MASTER-Net observations report
  82. GRB 220804A: Fermi GBM Final Localization
  83. Fermi trigger No 681271717: Global MASTER-Net observations report
  84. GRB 220803A: AstroSat CZTI detection
  85. Fermi trigger No 681212354: Global MASTER-Net observations report
  86. Konus-Wind detection of GRB 220730A (short)
  87. GRB 220730A: Swift-BAT refined analysis
  88. GRB 220730A: Fermi GBM detection
  89. GRB 220730A: Swift-XRT afterglow detection
  90. GRB 220730A: Swift/UVOT Upper Limits
  91. GRB 220730A: Swift-XRT observations
  92. GRB 220729A: AstroSat CZTI detection
  93. Swift GRB 220730A: Global MASTER-Net observations report
  94. GRB 220730A: Swift detection of a short hard burst
  95. Fermi trigger No 680782656: Global MASTER-Net observations report
  96. Fermi GRB 220728A: Global MASTER-Net observations report
  97. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220728A
  98. GRB 220728A: Fermi GBM Final Real-time Localization
  99. GRB 220726A: Fermi GBM Final Real-time Localization
  100. Fermi trigger No 680421061: Global MASTER-Net observations report

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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