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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"

358 results found.

  1. GRB 260424B: AstroSat CZTI detection
  2. Konus-Wind detection of GRB 260424B
  3. Fermi trigger No 795185313: Global MASTER-Net observations report
  4. EP260302a: MeerKAT radio counterpart
  5. GRB 260307B: SVOM detection of a burst
  6. Fermi GRB 260223A: Global MASTER-Net observations report
  7. Fermi GRB 260208A: Global MASTER-Net observations report
  8. Fermi trigger No 792135758: Global MASTER-Net observations report
  9. GRB 260127B: AstroSat CZTI detection
  10. Fermi trigger No 790570272: Global MASTER-Net observations report
  11. SVOM GRB251227.07: Global MASTER-Net observations report
  12. EP251220a: EP detection of a fast X-ray transient
  13. Fermi GRB 251115A: Global MASTER-Net observations report
  14. Fermi trigger No 784717756: Global MASTER-Net observations report
  15. Fermi GRB 251114A: Global MASTER-Net observations report
  16. GRB 251013C: BOOTES-6 early optical detection
  17. Fermi GRB 251013A: Global MASTER-Net observations report
  18. GRB 251010A: AstroSat CZTI detection
  19. GRB 251006A: Fermi GBM Observation
  20. Fermi GRB 250919A: Global MASTER-Net observations report
  21. Fermi GRB 250909A: Global MASTER-Net observations report
  22. GRB 250625A: SVOM/C-GFT upper limit in early phase
  23. Fermi trigger No 771718064: Global MASTER-Net observations report
  24. Fermi trigger No 770867684: Global MASTER-Net observations report
  25. Swift GRB250603.05: Global MASTER-Net observations report
  26. Fermi GRB 250214A: Global MASTER-Net observations report
  27. Fermi GRB 241206A: Global MASTER-Net observations report
  28. Fermi GRB 241104A: Global MASTER-Net observations report
  29. EP240918a: EP observation update
  30. Fermi GRB 240828A: Global MASTER-Net observations report
  31. Fermi trigger No 746438824: Global MASTER-Net observations report
  32. Fermi GRB 240814C: Global MASTER-Net observations report
  33. Fermi trigger No 745306088: Global MASTER-Net observations report
  34. Fermi trigger No 740949590: Global MASTER-Net observations report
  35. Fermi GRB 240610A: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
  37. LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
  38. GRB 240418A: Swift detection of a burst
  39. GRB 240329A: AstroSat CZTI detection
  40. IceCube Alert 240229.66: Global MASTER-Net observations report
  41. Fermi GRB 240213A: Global MASTER-Net observations report
  42. GRB 240102C: AstroSat CZTI detection
  43. Fermi trigger No 725806648: Global MASTER-Net observations report
  44. Fermi trigger No 724781422: Global MASTER-Net observations report
  45. Swift GRB231215.41: Global MASTER-Net observations report
  46. Fermi trigger No 723581802: Global MASTER-Net observations report
  47. IceCube Alert 231103.39: Global MASTER-Net observations report
  48. Fermi GRB 231030B: Global MASTER-Net observations report
  49. Fermi GRB 230827A: Global MASTER-Net observations report
  50. GRB 230824B: AstroSat CZTI detection
  51. Fermi GRB 230818A: Global MASTER-Net observations report
  52. Fermi trigger No 712713532: Global MASTER-Net observations report
  53. IceCube Alert 230724.08: Global MASTER-Net observations report
  54. Fermi GRB 230723A: Global MASTER-Net observations report
  55. Fermi GRB 230707A: Global MASTER-Net observations report
  56. Swift GRB 230622A: Global MASTER-Net observations report
  57. LIGO/Virgo S230601bf: Global MASTER-Net observations report
  58. GRB 230217A: ATCA rapid-response radio detection
  59. Fermi GRB 221215B: Global MASTER-Net observations report
  60. IceCube Alert 221124.66: Global MASTER-Net observations report
  61. Integral GRB221010.89: Global MASTER-Net observations report
  62. Konus-Wind detection of GRB 221009A
  63. GRB 220907A: Fermi GBM observation
  64. Konus-Wind detection of GRB 220609B
  65. Fermi trigger No 675411172: Global MASTER-Net observations report
  66. IceCube Alert 220513.97: Global MASTER-Net observations report
  67. GRB 220426A: Swift-XRT and UVOT observations
  68. Fermi GRB 220411A: Global MASTER-Net observations report
  69. GRB 220315A: MASTER Global Robotic Net optical observations
  70. Fermi GRB 220310B: Global MASTER-Net observations report
  71. Fermi GRB 220211A: Global MASTER-Net observations report
  72. GRB 220101A: Swift-BAT refined analysis
  73. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  74. GRB 211221A: Swift detection of a burst
  75. Fermi GRB 211204C: Global MASTER-Net observations report
  76. Fermi trigger No 658971499: Global MASTER-Net observations report
  77. GRB 211110A: AstroSat CZTI detection
  78. Fermi trigger No 652927551: Global MASTER-Net observations report
  79. GRB 210807C: Fermi GBM detection
  80. Swift GRB210807.79: Global MASTER-Net observations report
  81. Fermi trigger No 649390368: Global MASTER-Net observations report
  82. GRB 210730A: Fermi GBM observation
  83. Fermi trigger No 647942198: Global MASTER-Net observations report
  84. Fermi GRB 210709A: Global MASTER-Net observations report
  85. Integral GRB210707.02: Global MASTER-Net observations report
  86. Fermi GRB 210627B: Global MASTER-Net observations report
  87. Fermi trigger No 645047470: Global MASTER-Net observations report
  88. Swift GRB 210610B: Global MASTER-Net observations report
  89. GRB 210528B: MAXI/GSC detection
  90. Fermi GRB 210503A: Global MASTER-Net observations report
  91. GRB 210226A: Fermi GBM detection
  92. GRB 210218A: Swift/UVOT observations
  93. GRB 210218A: Swift-XRT observations
  94. Konus-Wind detection of GRB 210124B
  95. Swift GRB 201221A: Global MASTER-Net observations report
  96. Fermi GRB 201121A: Global MASTER-Net observations report
  97. GRB 201026A: Swift-BAT refined analysis
  98. Konus-Wind observation of GRB 200914A
  99. LAT GRB200803.15: Global MASTER-Net observations report
  100. Fermi GRB 200803A: Global MASTER-Net observations report

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