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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"

363 results found.

  1. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  2. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  3. GRB 260809A: SVOM detection of a faint burst
  4. Fermi GRB 260808A: Global MASTER-Net observations report
  5. Fermi trigger No 801135305: Global MASTER-Net observations report
  6. GRB 260424B: AstroSat CZTI detection
  7. Konus-Wind detection of GRB 260424B
  8. Fermi trigger No 795185313: Global MASTER-Net observations report
  9. EP260302a: MeerKAT radio counterpart
  10. GRB 260307B: SVOM detection of a burst
  11. Fermi GRB 260223A: Global MASTER-Net observations report
  12. Fermi GRB 260208A: Global MASTER-Net observations report
  13. Fermi trigger No 792135758: Global MASTER-Net observations report
  14. GRB 260127B: AstroSat CZTI detection
  15. Fermi trigger No 790570272: Global MASTER-Net observations report
  16. SVOM GRB251227.07: Global MASTER-Net observations report
  17. EP251220a: EP detection of a fast X-ray transient
  18. Fermi GRB 251115A: Global MASTER-Net observations report
  19. Fermi trigger No 784717756: Global MASTER-Net observations report
  20. Fermi GRB 251114A: Global MASTER-Net observations report
  21. GRB 251013C: BOOTES-6 early optical detection
  22. Fermi GRB 251013A: Global MASTER-Net observations report
  23. GRB 251010A: AstroSat CZTI detection
  24. GRB 251006A: Fermi GBM Observation
  25. Fermi GRB 250919A: Global MASTER-Net observations report
  26. Fermi GRB 250909A: Global MASTER-Net observations report
  27. GRB 250625A: SVOM/C-GFT upper limit in early phase
  28. Fermi trigger No 771718064: Global MASTER-Net observations report
  29. Fermi trigger No 770867684: Global MASTER-Net observations report
  30. Swift GRB250603.05: Global MASTER-Net observations report
  31. Fermi GRB 250214A: Global MASTER-Net observations report
  32. Fermi GRB 241206A: Global MASTER-Net observations report
  33. Fermi GRB 241104A: Global MASTER-Net observations report
  34. EP240918a: EP observation update
  35. Fermi GRB 240828A: Global MASTER-Net observations report
  36. Fermi trigger No 746438824: Global MASTER-Net observations report
  37. Fermi GRB 240814C: Global MASTER-Net observations report
  38. Fermi trigger No 745306088: Global MASTER-Net observations report
  39. Fermi trigger No 740949590: Global MASTER-Net observations report
  40. Fermi GRB 240610A: Global MASTER-Net observations report
  41. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  42. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  43. GRB 240418A: Swift detection of a burst
  44. GRB 240329A: AstroSat CZTI detection
  45. IceCube Alert 240229.66: Global MASTER-Net observations report
  46. Fermi GRB 240213A: Global MASTER-Net observations report
  47. GRB 240102C: AstroSat CZTI detection
  48. Fermi trigger No 725806648: Global MASTER-Net observations report
  49. Fermi trigger No 724781422: Global MASTER-Net observations report
  50. Swift GRB231215.41: Global MASTER-Net observations report
  51. Fermi trigger No 723581802: Global MASTER-Net observations report
  52. IceCube Alert 231103.39: Global MASTER-Net observations report
  53. Fermi GRB 231030B: Global MASTER-Net observations report
  54. Fermi GRB 230827A: Global MASTER-Net observations report
  55. GRB 230824B: AstroSat CZTI detection
  56. Fermi GRB 230818A: Global MASTER-Net observations report
  57. Fermi trigger No 712713532: Global MASTER-Net observations report
  58. IceCube Alert 230724.08: Global MASTER-Net observations report
  59. Fermi GRB 230723A: Global MASTER-Net observations report
  60. Fermi GRB 230707A: Global MASTER-Net observations report
  61. Swift GRB 230622A: Global MASTER-Net observations report
  62. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  63. GRB 230217A: ATCA rapid-response radio detection
  64. Fermi GRB 221215B: Global MASTER-Net observations report
  65. IceCube Alert 221124.66: Global MASTER-Net observations report
  66. Integral GRB221010.89: Global MASTER-Net observations report
  67. Konus-Wind detection of GRB 221009A
  68. GRB 220907A: Fermi GBM observation
  69. Konus-Wind detection of GRB 220609B
  70. Fermi trigger No 675411172: Global MASTER-Net observations report
  71. IceCube Alert 220513.97: Global MASTER-Net observations report
  72. GRB 220426A: Swift-XRT and UVOT observations
  73. Fermi GRB 220411A: Global MASTER-Net observations report
  74. GRB 220315A: MASTER Global Robotic Net optical observations
  75. Fermi GRB 220310B: Global MASTER-Net observations report
  76. Fermi GRB 220211A: Global MASTER-Net observations report
  77. GRB 220101A: Swift-BAT refined analysis
  78. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  79. GRB 211221A: Swift detection of a burst
  80. Fermi GRB 211204C: Global MASTER-Net observations report
  81. Fermi trigger No 658971499: Global MASTER-Net observations report
  82. GRB 211110A: AstroSat CZTI detection
  83. Fermi trigger No 652927551: Global MASTER-Net observations report
  84. GRB 210807C: Fermi GBM detection
  85. Swift GRB210807.79: Global MASTER-Net observations report
  86. Fermi trigger No 649390368: Global MASTER-Net observations report
  87. GRB 210730A: Fermi GBM observation
  88. Fermi trigger No 647942198: Global MASTER-Net observations report
  89. Fermi GRB 210709A: Global MASTER-Net observations report
  90. Integral GRB210707.02: Global MASTER-Net observations report
  91. Fermi GRB 210627B: Global MASTER-Net observations report
  92. Fermi trigger No 645047470: Global MASTER-Net observations report
  93. Swift GRB 210610B: Global MASTER-Net observations report
  94. GRB 210528B: MAXI/GSC detection
  95. Fermi GRB 210503A: Global MASTER-Net observations report
  96. GRB 210226A: Fermi GBM detection
  97. GRB 210218A: Swift/UVOT observations
  98. GRB 210218A: Swift-XRT observations
  99. Konus-Wind detection of GRB 210124B
  100. Swift GRB 201221A: Global MASTER-Net observations report

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