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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. Fermi trigger No 683476673: Global MASTER-Net observations report
  2. Konus-Wind detection of GRB 220826A
  3. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  5. GRB 220827A: Fermi GBM Final Real-time Localization
  6. GRB 220826A: Swift-BAT refined analysis
  7. GRB 220826A: Fermi GBM observation
  8. Fermi trigger No 683202084: Global MASTER-Net observations report
  9. Fermi trigger No 683183601: Global MASTER-Net observations report
  10. Fermi trigger No 683152759: Global MASTER-Net observations report
  11. GRB 220826A: Swift-XRT refined Analysis
  12. GRB 220825A: Fermi GBM observation
  13. GRB 220826A: Lesedi optical afterglow detection
  14. GRB 220826A: Swift/UVOT Detection
  15. GRB 220826A: iTelescope optical afterglow observations
  16. Swift GRB 220826A: Global MASTER-Net observations report
  17. GRB 220826A: Enhanced Swift-XRT position
  18. GRB 220826A: Swift detection of a burst with an optical counterpart
  19. GRB 220825A: Swift/BAT-GUANO detection
  20. GRB 220825A: Fermi GBM Final Localization
  21. IceCube-220822A: Upper limits from a search for additional neutrino events in IceCube
  22. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  23. GRB 220823A: Fermi GBM detection
  24. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  25. Fermi trigger No 682918137: Global MASTER-Net observations report
  26. GRB 220823A: Swift/BAT-GUANO detection of a short burst
  27. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  28. IceCube Alert 220822.85: Global MASTER-Net observations report
  29. GRB 220821A: Fermi GBM Final Real-time Localization
  30. Konus-Wind detection of GRB 220813A
  31. GRB 220813A: VLT optical observations and possible host galaxy
  32. GRB 220813A: Swift/UVOT Detection
  33. GRB 220810A: Further Swift-XRT observations
  34. GRB 220813A: Swift-XRT refined Analysis
  35. Swift GRB 220813A: Global MASTER-Net observations report
  36. GRB 220813A: Enhanced Swift-XRT position
  37. GRB 220813A: Swift detection of a burst with an optical counterpart
  38. GRB 220810A: Swift-XRT observations
  39. GRB 220719B: Detection by VZLUSAT-2
  40. Fermi trigger No 681998863: Global MASTER-Net observations report
  41. GRB 220810A: Swift ToO observations
  42. GRB 220810A: MeerLICHT detection of two afterglow candidates
  43. Fermi GBM trigger 681998863/220812505 is not a GRB
  44. Fermi trigger No 681890304: Global MASTER-Net observations report
  45. Fermi GBM trigger 681890304/220811249 is not a GRB
  46. Fermi GRB 220810A: Global MASTER-Net observations report
  47. GRB 220810A: Fermi GBM Final Real-time Localization
  48. GRB 220627A: MeerKAT radio observations
  49. GRB 220806A: Swift-BAT refined analysis
  50. Fermi trigger No 681719116: Global MASTER-Net observations report
  51. Fermi GBM trigger 681719116/220809267 is not a GRB
  52. Fermi trigger No 681633544: Global MASTER-Net observations report
  53. IceCube Astrotrack Bronze 136918_45252263.amon is likely background
  54. Fermi GBM trigger 681633544/220808277 is not a GRB
  55. IceCube Alert 220808.33: Global MASTER-Net observations report
  56. Fermi GBM trigger 681547990 / 220807287 is not a GRB
  57. GRB 220806A: Swift detection of a burst
  58. Swift GRB220806.76: Global MASTER-Net observations report
  59. GRB 220804A: Fermi GBM Final Localization
  60. Fermi trigger No 681271717: Global MASTER-Net observations report
  61. GRB 220803A: AstroSat CZTI detection
  62. Fermi trigger No 681212354: Global MASTER-Net observations report
  63. Konus-Wind detection of GRB 220730A (short)
  64. GRB 220730A: Swift-BAT refined analysis
  65. GRB 220730A: Fermi GBM detection
  66. GRB 220730A: Swift-XRT afterglow detection
  67. GRB 220730A: Swift/UVOT Upper Limits
  68. GRB 220730A: Swift-XRT observations
  69. GRB 220729A: AstroSat CZTI detection
  70. Swift GRB 220730A: Global MASTER-Net observations report
  71. GRB 220730A: Swift detection of a short hard burst
  72. Fermi trigger No 680782656: Global MASTER-Net observations report
  73. Fermi GRB 220728A: Global MASTER-Net observations report
  74. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220728A
  75. GRB 220728A: Fermi GBM Final Real-time Localization
  76. GRB 220726A: Fermi GBM Final Real-time Localization
  77. Fermi trigger No 680421061: Global MASTER-Net observations report
  78. Fermi GRB 220724A: Global MASTER-Net observations report
  79. GRB 220724A: Fermi GBM Final Real-time Localization
  80. GRB 220715B: VIRT Optical Upper Limit
  81. Fermi GRB 220721A: Global MASTER-Net observations report
  82. GRB 220721A: Fermi GBM Final Real-time Localization
  83. Introducing new GCN Kafka broker and web site for transient alerts, https://gcn.nasa.gov
  84. Retraction: Fermi GBM trigger 679932336.585264/220719587 is not a GRB
  85. GRB 220715A: CALET Gamma-Ray Burst Monitor detection
  86. GRB 220711B: CALET Gamma-Ray Burst Monitor detection
  87. GRB 220719A: Fermi GBM Final Real-time Localization
  88. GRB 220715B: Swift-BAT refined analysis
  89. GRB220714B: UVOT detections
  90. GRB 220715B: Fermi GBM detection
  91. GRB 220715B: Swift-XRT refined Analysis
  92. GRB 220715B: Swift/UVOT Upper Limits
  93. GRB 220715B: Enhanced Swift-XRT position
  94. GRB 220715B: BOOTES-network optical upper limits
  95. Swift GRB 220715B: Global MASTER-Net observations report
  96. GRB 220715B: Prompt enhanced Swift-XRT position
  97. GRB 220715B: Swift detection of a burst
  98. GRB 220715B: Fermi GBM Final Real-time Localization
  99. GRB 220714B: Swift-BAT refined analysis
  100. GRB 220714B: Fermi GBM observation

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