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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"

295 results found.

  1. GRB 251024A: Swift/UVOT Upper Limits
  2. IceCube-251018A: Global MASTER-Net observations report
  3. GRB 251001B: Swift-XRT refined Analysis
  4. GRB 250314A: CIDER NB1008 upper limit
  5. Fermi trigger No 769611916: Global MASTER-Net observations report
  6. IceCube Alert 250330.35: Global MASTER-Net observations report
  7. Fermi GRB 250313A: Global MASTER-Net observations report
  8. IceCube Alert 250309.32: Global MASTER-Net observations report
  9. Fermi GRB 250226A: Global MASTER-Net observations report
  10. Integral GRB250211.89: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  12. GRB 250207B: Swift-XRT observations
  13. Swift GRB 250129A: Global MASTER-Net observations report
  14. GRB 250101A: Swift/UVOT Detection
  15. Fermi trigger No 756678579: Global MASTER-Net observations report
  16. Fermi GRB 241209D: Global MASTER-Net observations report
  17. Integral GRB241120.25: Global MASTER-Net observations report
  18. Fermi trigger No 753166198: Global MASTER-Net observations report
  19. EP EP241030a: Global MASTER-Net observations report
  20. Fermi trigger No 752006065: Global MASTER-Net observations report
  21. Swift GRB241030.77: Global MASTER-Net observations report
  22. Fermi trigger No 746587425: Global MASTER-Net observations report
  23. Integral GRB240816.79: Global MASTER-Net observations report
  24. Fermi trigger No 745057312: Global MASTER-Net observations report
  25. Fermi GRB 240805A: Global MASTER-Net observations report
  26. Fermi trigger No 740949590: Global MASTER-Net observations report
  27. Fermi trigger No 736197684: Global MASTER-Net observations report
  28. GRB 240303B: Fermi GBM Detection
  29. Integral GRB240115.70: Global MASTER-Net observations report
  30. Fermi trigger No 725592555: Global MASTER-Net observations report
  31. GRB 231115A: MASTER optical observations
  32. Fermi GRB 231030B: Global MASTER-Net observations report
  33. Fermi trigger No 715552087: Global MASTER-Net observations report
  34. Fermi GRB 230827A: Global MASTER-Net observations report
  35. Fermi GRB 230818A: Global MASTER-Net observations report
  36. Fermi trigger No 712927418: Global MASTER-Net observations report
  37. Fermi trigger No 711805358: Global MASTER-Net observations report
  38. Fermi trigger No 710117592: Global MASTER-Net observations report
  39. Fermi GRB 230628D: Global MASTER-Net observations report
  40. LIGO/Virgo S230622e: Global MASTER-Net observations report
  41. LIGO/Virgo S230620au: Global MASTER-Net observations report
  42. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  43. Swift GRB 230618A: Global MASTER-Net observations report
  44. LIGO/Virgo S230608as: Global MASTER-Net observations report
  45. Fermi GRB 230603A: Global MASTER-Net observations report
  46. LIGO/Virgo S230529ay: Global MASTER-Net observations report
  47. LIGO/Virgo S230525a: Global MASTER-Net observations report
  48. IceCube Alert 230524.47: Global MASTER-Net observations report
  49. Fermi trigger No 706610076: Global MASTER-Net observations report
  50. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  51. Fermi trigger No 704365743: Global MASTER-Net observations report
  52. GRB 230420A: MITSuME Akeno optical observation
  53. GRB 230325A: Swift/UVOT Upper Limits
  54. Integral GRB221218.34: Global MASTER-Net observations report
  55. GRB 221120A: GTC Confirmation of an Underlying Galaxy
  56. GRB220611A: Gemini Optical Afterglow Confirmation
  57. Fermi GRB 220512A: Global MASTER-Net observations report
  58. Konus-Wind detection of GRB 220403C
  59. GRB 220310C: Swift-XRT observations
  60. MAXI GRB220310.02: Global MASTER-Net observations report
  61. MAXI GRB211218.04: Global MASTER-Net observations report
  62. Fermi GRB 211130A: Global MASTER-Net observations report
  63. GRB 211105A: MASTER optical inspection
  64. GRB 211024A: MITSuME Akeno optical observation
  65. Swift trigger 1078701: MITSuME Akeno optical upper limits
  66. Fermi trigger No 654854799: Global MASTER-Net observations report
  67. Swift GRB 210919A: Global MASTER-Net observations report
  68. Swift GRB 210901A: Global MASTER-Net observations report
  69. Swift GRB210818.68: Global MASTER-Net observations report
  70. Swift GRB 210818A: Global MASTER-Net observations report
  71. Fermi GRB 210813A: Global MASTER-Net observations report
  72. Fermi GRB 210807C: Global MASTER-Net observations report
  73. Fermi trigger No 649524889: Global MASTER-Net observations report
  74. Swift GRB 210730A: Global MASTER-Net observations report
  75. Fermi trigger No 647120009: Global MASTER-Net observations report
  76. GRB 210323B: Fermi GBM observation
  77. Fermi trigger No 645047470: Global MASTER-Net observations report
  78. Swift GRB 210610B: Global MASTER-Net observations report
  79. Fermi trigger No 644155206: Global MASTER-Net observations report
  80. Swift GRB210514.71: Global MASTER-Net observations report
  81. Fermi trigger No 640695289: Global MASTER-Net observations report
  82. Swift GRB210403.35: Global MASTER-Net observations report
  83. GRB 210209A: Swift/UVOT Upper Limits
  84. GRB 210124B: AstroSat CZTI detection
  85. GRB 210104A: AROMA-N Optical Afterglow Detection
  86. GRB 201221A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  87. IceCube-201209A: No neutrino counterpart candidates in ANTARES search
  88. Swift GRB 201029A: Global MASTER-Net observations report
  89. SGR 1830-0645: Swift/UVOT Upper Limits
  90. Fermi trigger No 624121589: Global MASTER-Net observations report
  91. IceCube Alert 200926.33: Global MASTER-Net observations report
  92. GRB 200920B: AGILE/MCAL detection of a burst
  93. Integral GRB200914.53: Global MASTER-Net observations report
  94. Fermi GRB 200914A: Global MASTER-Net observations report
  95. IceCube Alert 200914.00: Global MASTER-Net observations report
  96. Fermi trigger No 612988790: Global MASTER-Net observations report
  97. Fermi GRB 200524A: Global MASTER-Net observations report
  98. IceCube Alert 200523.10: Global MASTER-Net observations report
  99. GRB 200502A: AstroSat CZTI detection
  100. IceCube Alert 200425.98: Global MASTER-Net observations report

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