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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"

362 results found.

  1. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  2. GRB 260809A: SVOM detection of a faint burst
  3. Fermi GRB 260808A: Global MASTER-Net observations report
  4. Fermi trigger No 801135305: Global MASTER-Net observations report
  5. GRB 260424B: AstroSat CZTI detection
  6. Konus-Wind detection of GRB 260424B
  7. Fermi trigger No 795185313: Global MASTER-Net observations report
  8. EP260302a: MeerKAT radio counterpart
  9. GRB 260307B: SVOM detection of a burst
  10. Fermi GRB 260223A: Global MASTER-Net observations report
  11. Fermi GRB 260208A: Global MASTER-Net observations report
  12. Fermi trigger No 792135758: Global MASTER-Net observations report
  13. GRB 260127B: AstroSat CZTI detection
  14. Fermi trigger No 790570272: Global MASTER-Net observations report
  15. SVOM GRB251227.07: Global MASTER-Net observations report
  16. EP251220a: EP detection of a fast X-ray transient
  17. Fermi GRB 251115A: Global MASTER-Net observations report
  18. Fermi trigger No 784717756: Global MASTER-Net observations report
  19. Fermi GRB 251114A: Global MASTER-Net observations report
  20. GRB 251013C: BOOTES-6 early optical detection
  21. Fermi GRB 251013A: Global MASTER-Net observations report
  22. GRB 251010A: AstroSat CZTI detection
  23. GRB 251006A: Fermi GBM Observation
  24. Fermi GRB 250919A: Global MASTER-Net observations report
  25. Fermi GRB 250909A: Global MASTER-Net observations report
  26. GRB 250625A: SVOM/C-GFT upper limit in early phase
  27. Fermi trigger No 771718064: Global MASTER-Net observations report
  28. Fermi trigger No 770867684: Global MASTER-Net observations report
  29. Swift GRB250603.05: Global MASTER-Net observations report
  30. Fermi GRB 250214A: Global MASTER-Net observations report
  31. Fermi GRB 241206A: Global MASTER-Net observations report
  32. Fermi GRB 241104A: Global MASTER-Net observations report
  33. EP240918a: EP observation update
  34. Fermi GRB 240828A: Global MASTER-Net observations report
  35. Fermi trigger No 746438824: Global MASTER-Net observations report
  36. Fermi GRB 240814C: Global MASTER-Net observations report
  37. Fermi trigger No 745306088: Global MASTER-Net observations report
  38. Fermi trigger No 740949590: Global MASTER-Net observations report
  39. Fermi GRB 240610A: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  41. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  42. GRB 240418A: Swift detection of a burst
  43. GRB 240329A: AstroSat CZTI detection
  44. IceCube Alert 240229.66: Global MASTER-Net observations report
  45. Fermi GRB 240213A: Global MASTER-Net observations report
  46. GRB 240102C: AstroSat CZTI detection
  47. Fermi trigger No 725806648: Global MASTER-Net observations report
  48. Fermi trigger No 724781422: Global MASTER-Net observations report
  49. Swift GRB231215.41: Global MASTER-Net observations report
  50. Fermi trigger No 723581802: Global MASTER-Net observations report
  51. IceCube Alert 231103.39: Global MASTER-Net observations report
  52. Fermi GRB 231030B: Global MASTER-Net observations report
  53. Fermi GRB 230827A: Global MASTER-Net observations report
  54. GRB 230824B: AstroSat CZTI detection
  55. Fermi GRB 230818A: Global MASTER-Net observations report
  56. Fermi trigger No 712713532: Global MASTER-Net observations report
  57. IceCube Alert 230724.08: Global MASTER-Net observations report
  58. Fermi GRB 230723A: Global MASTER-Net observations report
  59. Fermi GRB 230707A: Global MASTER-Net observations report
  60. Swift GRB 230622A: Global MASTER-Net observations report
  61. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  62. GRB 230217A: ATCA rapid-response radio detection
  63. Fermi GRB 221215B: Global MASTER-Net observations report
  64. IceCube Alert 221124.66: Global MASTER-Net observations report
  65. Integral GRB221010.89: Global MASTER-Net observations report
  66. Konus-Wind detection of GRB 221009A
  67. GRB 220907A: Fermi GBM observation
  68. Konus-Wind detection of GRB 220609B
  69. Fermi trigger No 675411172: Global MASTER-Net observations report
  70. IceCube Alert 220513.97: Global MASTER-Net observations report
  71. GRB 220426A: Swift-XRT and UVOT observations
  72. Fermi GRB 220411A: Global MASTER-Net observations report
  73. GRB 220315A: MASTER Global Robotic Net optical observations
  74. Fermi GRB 220310B: Global MASTER-Net observations report
  75. Fermi GRB 220211A: Global MASTER-Net observations report
  76. GRB 220101A: Swift-BAT refined analysis
  77. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  78. GRB 211221A: Swift detection of a burst
  79. Fermi GRB 211204C: Global MASTER-Net observations report
  80. Fermi trigger No 658971499: Global MASTER-Net observations report
  81. GRB 211110A: AstroSat CZTI detection
  82. Fermi trigger No 652927551: Global MASTER-Net observations report
  83. GRB 210807C: Fermi GBM detection
  84. Swift GRB210807.79: Global MASTER-Net observations report
  85. Fermi trigger No 649390368: Global MASTER-Net observations report
  86. GRB 210730A: Fermi GBM observation
  87. Fermi trigger No 647942198: Global MASTER-Net observations report
  88. Fermi GRB 210709A: Global MASTER-Net observations report
  89. Integral GRB210707.02: Global MASTER-Net observations report
  90. Fermi GRB 210627B: Global MASTER-Net observations report
  91. Fermi trigger No 645047470: Global MASTER-Net observations report
  92. Swift GRB 210610B: Global MASTER-Net observations report
  93. GRB 210528B: MAXI/GSC detection
  94. Fermi GRB 210503A: Global MASTER-Net observations report
  95. GRB 210226A: Fermi GBM detection
  96. GRB 210218A: Swift/UVOT observations
  97. GRB 210218A: Swift-XRT observations
  98. Konus-Wind detection of GRB 210124B
  99. Swift GRB 201221A: Global MASTER-Net observations report
  100. Fermi GRB 201121A: Global MASTER-Net observations report

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