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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 220831C: Fermi GBM Final Localization
  2. GRB 220831A: Fermi GBM observation
  3. GRB 220831A: Swift-XRT observations
  4. GRB 220831B: Fermi GBM Final Localization
  5. GRB 220831A: Swift ToO observations
  6. Fermi trigger No 683654200: Global MASTER-Net observations report
  7. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  8. Fermi trigger No 683646997: Global MASTER-Net observations report
  9. IceCube-220822A: No significant detection in HAWC
  10. Fermi trigger No 683537972: Global MASTER-Net observations report
  11. Fermi GBM trigger 683571622/220830709 is not a GRB
  12. Fermi trigger No 683476673: Global MASTER-Net observations report
  13. Konus-Wind detection of GRB 220826A
  14. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  15. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  16. GRB 220827A: Fermi GBM Final Real-time Localization
  17. GRB 220826A: Swift-BAT refined analysis
  18. GRB 220826A: Fermi GBM observation
  19. Fermi trigger No 683202084: Global MASTER-Net observations report
  20. Fermi trigger No 683183601: Global MASTER-Net observations report
  21. Fermi trigger No 683152759: Global MASTER-Net observations report
  22. GRB 220826A: Swift-XRT refined Analysis
  23. GRB 220825A: Fermi GBM observation
  24. GRB 220826A: Lesedi optical afterglow detection
  25. GRB 220826A: Swift/UVOT Detection
  26. GRB 220826A: iTelescope optical afterglow observations
  27. Swift GRB 220826A: Global MASTER-Net observations report
  28. GRB 220826A: Enhanced Swift-XRT position
  29. GRB 220826A: Swift detection of a burst with an optical counterpart
  30. GRB 220825A: Swift/BAT-GUANO detection
  31. GRB 220825A: Fermi GBM Final Localization
  32. IceCube-220822A: Upper limits from a search for additional neutrino events in IceCube
  33. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  34. GRB 220823A: Fermi GBM detection
  35. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  36. Fermi trigger No 682918137: Global MASTER-Net observations report
  37. GRB 220823A: Swift/BAT-GUANO detection of a short burst
  38. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  39. IceCube Alert 220822.85: Global MASTER-Net observations report
  40. GRB 220821A: Fermi GBM Final Real-time Localization
  41. Konus-Wind detection of GRB 220813A
  42. GRB 220813A: VLT optical observations and possible host galaxy
  43. GRB 220813A: Swift/UVOT Detection
  44. GRB 220810A: Further Swift-XRT observations
  45. GRB 220813A: Swift-XRT refined Analysis
  46. Swift GRB 220813A: Global MASTER-Net observations report
  47. GRB 220813A: Enhanced Swift-XRT position
  48. GRB 220813A: Swift detection of a burst with an optical counterpart
  49. GRB 220810A: Swift-XRT observations
  50. GRB 220719B: Detection by VZLUSAT-2
  51. Fermi trigger No 681998863: Global MASTER-Net observations report
  52. GRB 220810A: Swift ToO observations
  53. GRB 220810A: MeerLICHT detection of two afterglow candidates
  54. Fermi GBM trigger 681998863/220812505 is not a GRB
  55. Fermi trigger No 681890304: Global MASTER-Net observations report
  56. Fermi GBM trigger 681890304/220811249 is not a GRB
  57. Fermi GRB 220810A: Global MASTER-Net observations report
  58. GRB 220810A: Fermi GBM Final Real-time Localization
  59. GRB 220627A: MeerKAT radio observations
  60. GRB 220806A: Swift-BAT refined analysis
  61. Fermi trigger No 681719116: Global MASTER-Net observations report
  62. Fermi GBM trigger 681719116/220809267 is not a GRB
  63. Fermi trigger No 681633544: Global MASTER-Net observations report
  64. IceCube Astrotrack Bronze 136918_45252263.amon is likely background
  65. Fermi GBM trigger 681633544/220808277 is not a GRB
  66. IceCube Alert 220808.33: Global MASTER-Net observations report
  67. Fermi GBM trigger 681547990 / 220807287 is not a GRB
  68. GRB 220806A: Swift detection of a burst
  69. Swift GRB220806.76: Global MASTER-Net observations report
  70. GRB 220804A: Fermi GBM Final Localization
  71. Fermi trigger No 681271717: Global MASTER-Net observations report
  72. GRB 220803A: AstroSat CZTI detection
  73. Fermi trigger No 681212354: Global MASTER-Net observations report
  74. Konus-Wind detection of GRB 220730A (short)
  75. GRB 220730A: Swift-BAT refined analysis
  76. GRB 220730A: Fermi GBM detection
  77. GRB 220730A: Swift-XRT afterglow detection
  78. GRB 220730A: Swift/UVOT Upper Limits
  79. GRB 220730A: Swift-XRT observations
  80. GRB 220729A: AstroSat CZTI detection
  81. Swift GRB 220730A: Global MASTER-Net observations report
  82. GRB 220730A: Swift detection of a short hard burst
  83. Fermi trigger No 680782656: Global MASTER-Net observations report
  84. Fermi GRB 220728A: Global MASTER-Net observations report
  85. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220728A
  86. GRB 220728A: Fermi GBM Final Real-time Localization
  87. GRB 220726A: Fermi GBM Final Real-time Localization
  88. Fermi trigger No 680421061: Global MASTER-Net observations report
  89. Fermi GRB 220724A: Global MASTER-Net observations report
  90. GRB 220724A: Fermi GBM Final Real-time Localization
  91. GRB 220715B: VIRT Optical Upper Limit
  92. Fermi GRB 220721A: Global MASTER-Net observations report
  93. GRB 220721A: Fermi GBM Final Real-time Localization
  94. Introducing new GCN Kafka broker and web site for transient alerts, https://gcn.nasa.gov
  95. Retraction: Fermi GBM trigger 679932336.585264/220719587 is not a GRB
  96. GRB 220715A: CALET Gamma-Ray Burst Monitor detection
  97. GRB 220711B: CALET Gamma-Ray Burst Monitor detection
  98. GRB 220719A: Fermi GBM Final Real-time Localization
  99. GRB 220715B: Swift-BAT refined analysis
  100. GRB220714B: UVOT detections

Advanced

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