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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"

5039 results found.

  1. IceCube-211116A: Upper limits from a search for additional neutrino events in IceCube
  2. Fermi trigger No 658755664: Global MASTER-Net observations report
  3. Konus-Wind detection of GRB 211107B
  4. Fermi trigger No 658686687: Global MASTER-Net observations report
  5. GRB 211115A: MAXI/GSC detection
  6. Fermi GRB 211112A: Global MASTER-Net observations report
  7. Fermi trigger No 658214822: Global MASTER-Net observations report
  8. Fermi GRB 211109B: Global MASTER-Net observations report
  9. GRB 211023A: continued 1.3m DFOT Optical Observations and possible jet break
  10. GRB 211024A: MITSuME Akeno optical observation
  11. GRB 211023B: MITSuME Akeno optical upper limits
  12. GRB 211024A: 1.3m DFOT observations
  13. GRB 211024A: Fermi GBM detection
  14. IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube
  15. GRB 211025A: Swift-XRT refined Analysis
  16. GRB 211024B: Swift-XRT refined Analysis
  17. GRB 211023A: 1.5m OSN optical observation
  18. GRB 211024B: Nanshan/NEXT optical afterglow detection
  19. GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
  20. Fermi GRB 211023A: Global MASTER-Net observations report
  21. GRB 211023B: Swift-XRT refined Analysis
  22. Fermi GRB 211024A: Global MASTER-Net observations report
  23. GRB 211024A: Fermi GBM Final Real-time Localization
  24. IceCube Alert 211023.36: Global MASTER-Net observations report
  25. Fermi trigger No 656506979: Global MASTER-Net observations report
  26. Swift trigger 1078701: MITSuME Akeno optical upper limits
  27. Fermi trigger No 655673024: Global MASTER-Net observations report
  28. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  29. Fermi trigger No 655401471: Global MASTER-Net observations report
  30. GRB 210928A: Fermi GBM observation
  31. Fermi trigger No 654739449: Global MASTER-Net observations report
  32. Swift Trigger 1076121 is not a GRB
  33. GRB 210930A: Swift-XRT refined Analysis
  34. Fermi GRB 210929B: Global MASTER-Net observations report
  35. IceCube-210922A: JCMT/SCUBA2 observations
  36. GRB 210924A: Fermi GBM Final Real-time Localization
  37. GRB 210919A: MITSuME Akeno optical upper limits
  38. GRB 210912A: Swift-XRT refined Analysis
  39. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  40. Fermi trigger No 653066776: Global MASTER-Net observations report
  41. Fermi trigger No 653084584: Global MASTER-Net observations report
  42. Fermi trigger No 653083551: Global MASTER-Net observations report
  43. Fermi trigger No 653066130: Global MASTER-Net observations report
  44. Fermi trigger No 653071808: Global MASTER-Net observations report
  45. Fermi trigger No 653049776: Global MASTER-Net observations report
  46. Fermi trigger No 653022153: Global MASTER-Net observations report
  47. Fermi trigger No 652981861: Global MASTER-Net observations report
  48. GECAM observations of a series of bursts from SGR J1935+2154
  49. Fermi trigger No 652911693: Global MASTER-Net observations report
  50. Fermi trigger No 652906639: Global MASTER-Net observations report
  51. GRB 210905A: AstroSat CZTI detection
  52. Fermi trigger No 652585475: Global MASTER-Net observations report
  53. GRB 210610A: Maidanak and AbAO optical observations
  54. Fermi GRB 210903B: Global MASTER-Net observations report
  55. GRB 210827A: Fermi GBM Observation
  56. GRB 210826A: AstroSat CZTI detection
  57. Fermi GRB 210827A: Global MASTER-Net observations report
  58. GRB 210827A: Fermi GBM Final Real-time Localization
  59. Fermi GRB 210826A: Global MASTER-Net observations report
  60. GRB 210824A: MITSuME Akeno optical upper limits
  61. GRB 210822A: TSHAO continued optical observation
  62. GRB 210822A: VLA detection
  63. Swift GRB 210824A: Global MASTER-Net observations report
  64. GRB 210824A: Fermi GBM Observation
  65. Fermi GRB 210824A: Global MASTER-Net observations report
  66. GRB 210824A: Nanshan/NEXT optical upper limit
  67. GRB 210824A: Swift-XRT refined Analysis
  68. GRB 210824A: Fermi GBM Final Real-time Localization
  69. GRB 210822A: Swift-XRT refined Analysis
  70. Fermi GRB 210822B: Global MASTER-Net observations report
  71. GRB 210822B: Fermi GBM Final Real-time Localization
  72. Swift GRB 210822A: Global MASTER-Net observations report
  73. Fermi GRB 210821A: Global MASTER-Net observations report
  74. GRB 210820A: Swift-XRT refined Analysis
  75. GRB 210818A: Swift-XRT refined Analysis
  76. Fermi GRB 210813A: Global MASTER-Net observations report
  77. GRB 210807C: Swift-BAT refined analysis
  78. GRB 210807C: Enhanced Swift-XRT position
  79. Fermi GRB 210807C: Global MASTER-Net observations report
  80. GRB 210807C: Swift detection of a burst
  81. GRB 210807C: Fermi GBM Final Real-time Localization
  82. IPN Triangulation of a bright burst from SGR 1935+2154
  83. Fermi trigger No 649814537: Global MASTER-Net observations report
  84. GRB 210802A: MITSuME Okayama optical upper limits
  85. GRB 210803A: Fermi GBM observation
  86. GRB 210731A: Swift-XRT refined Analysis
  87. Fermi trigger No 649519043: Global MASTER-Net observations report
  88. GRB 210731A: Swift detection of a burst
  89. Trigger 1062273: Swift detection of 4U 1700-377
  90. Fermi trigger No 649390368: Global MASTER-Net observations report
  91. GRB 210730A: Swift-XRT refined Analysis
  92. GRB 210724A: Early CAHA 2.2m limit
  93. Fermi trigger No 649072251: Global MASTER-Net observations report
  94. Fermi trigger No 648959581: Global MASTER-Net observations report
  95. GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit
  96. GRB 210725A: Swift-XRT refined Analysis
  97. GRB 210725A: MITSuME Akeno optical upper limits
  98. GRB 210722A: continued Assy optical observations
  99. GRB 210722A: Nanshan/NEXT further optical observations
  100. Fermi trigger No 648868114: Global MASTER-Net observations report

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