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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"

11777 results found.

  1. GRB 230322B: Swift-XRT refined Analysis
  2. GRB 230322B: Swift detection of a burst with optical counterpart
  3. GRB 230322A: Fermi GBM Final Real-time Localization
  4. GRB 230320B: GRBAlpha detection
  5. GRB 230320B: CALET Gamma-Ray Burst Monitor detection
  6. Fermi trigger No 701071944: Global MASTER-Net observations report
  7. SGR 1806-20: Correction to GCN 33494
  8. INTEGRAL detection of a burst from SGR 1806-200
  9. GRB 230321B: AstroSat CZTI detection
  10. GRB 230320B: AstroSat CZTI detection
  11. GRB 230320A: Fermi GBM Final Real-time Localization
  12. GRB 230314A: TURBO Optical Upper Limit
  13. Fermi trigger No 700976129: Global MASTER-Net observations report
  14. IPN triangulation of GRB 230309A
  15. Fermi GRB 230316A: Global MASTER-Net observations report
  16. GRB 230304D: AstroSat CZTI detection
  17. GRB 230313A: AstroSat CZTI detection
  18. VZLUSAT-2 detection of SGR 1806-20
  19. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  20. Fermi GRB 230313A: Global MASTER-Net observations report
  21. GRB 230309A: AstroSat CZTI detection of a bright long GRB
  22. Further improved IPN localization for GRB 230307A
  23. Swift GRB230311.84: Global MASTER-Net observations report
  24. Trigger 1159327: Swift detection of SGR1806-20
  25. GRB 230310A: AstroSat CZTI detection
  26. GRB 230307A: GECKO optical observations and detections of the afterglow
  27. GRB 230307A: MAXI/GSC upper limit
  28. GRB 230307A: ASO-S/HXI detection
  29. GRB 230217A: ATCA rapid-response radio detection
  30. GRB 230307A: Upper limits from a neutrino search with IceCube
  31. Fermi GRB 230307A: Global MASTER-Net observations report
  32. Konus-Wind detection of GRB 230307A
  33. Fermi GRB 230308A: Global MASTER-Net observations report
  34. GRB 230307A: AstroSat CZTI detection
  35. Fermi-LAT gamma-ray observations of IceCube-230306A
  36. GRB 230307A: GECAM detection of an extremely bright burst
  37. GRB 230304C: AstroSat CZTI detection
  38. GRB 230304B: AstroSat CZTI detection
  39. GRB 230304A: AstroSat CZTI detection
  40. GRB 230304A: Fermi GBM Final Real-time Localization
  41. Fermi GRB 230301B: Global MASTER-Net observations report
  42. GRB 230228A: Fermi GBM Observation
  43. Fermi trigger No 699294715: Global MASTER-Net observations report
  44. GRB 230228A: Swift-XRT refined Analysis
  45. GRB 230228A: Swift detection of a possibly short burst
  46. Fermi trigger No 699029364: Global MASTER-Net observations report
  47. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  48. GRB 230216A Mondy Observations
  49. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  50. GRB 230220A: Correction to GCN 33352
  51. Fermi-LAT gamma-ray observations of IceCube-230220A
  52. Fermi GRB 230220B: Global MASTER-Net observations report
  53. GRB 230217A: AstroSat CZTI detection
  54. GRB 230217A: 6 GHz VLA observations
  55. GRB 230220B: Fermi GBM Final Real-time Localization
  56. GRB 230217A: Gemini-South Optical Observation
  57. IceCube-230217A: Upper limits from a search for additional neutrino events in IceCube
  58. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  59. GRB 230220A: MAXI/GSC detection
  60. IceCube-230217A: BOOTES-4/MET Optical Observations
  61. Fermi-LAT gamma-ray observations of IceCube-230217A
  62. Konus-Wind detection of GRB 230217A
  63. GRB 230216B: AstroSat CZTI detection
  64. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  65. GRB 230216A: Swift-BAT refined analysis
  66. GRB 230216A: Swift detection of a burst
  67. Fermi trigger No 697904388: Global MASTER-Net observations report
  68. Fermi GRB 230209B: Global MASTER-Net observations report
  69. Fermi Gamma-ray Burst Monitor triggers 230206723/697396830 and 230206797/697403223 are not GRBs
  70. Fermi trigger No 697403223: Global MASTER-Net observations report
  71. Fermi trigger No 697396830: Global MASTER-Net observations report
  72. GRB 230205A: Swift-XRT refined Analysis
  73. GRB 230205A: BOOTES-5/JGT early optical upper limit
  74. GRB 230204B: AGILE detection
  75. GRB 230205A: Swift detection of a burst
  76. IceCube-230201A: BOOTES-4/MET Optical Upper Limits
  77. GRB 230204B: AstroSat CZTI detection
  78. GRB 230204B: MAXI/GSC detection
  79. Fermi trigger No 697208885: Global MASTER-Net observations report
  80. Fermi trigger No 697098930: Global MASTER-Net observations report
  81. IceCube-230201A: Upper limits from a search for additional neutrino events in IceCube
  82. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  83. Fermi GRB 230201B: Global MASTER-Net observations report
  84. Fermi-LAT gamma-ray observations of IceCube-230201A
  85. GRB 230126A: Detection by VZLUSAT-2
  86. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  87. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  88. GRB 230129A: AstroSat CZTI detection
  89. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  90. AT2023avj ZTF Candidate: Assy optical observations
  91. GRB 230126A: Fermi GBM Final Real-time Localization
  92. GRB 230114B: Detection by VZLUSAT-2
  93. Fermi-LAT gamma-ray observations of IceCube-230122A
  94. GRB 230123A: Swift-XRT refined Analysis
  95. GRB 230123A: Swift detection of a burst
  96. GRB 230120A: AstroSat CZTI detection
  97. GRB 230116D: SAO RAS photometry
  98. Fermi GRB 230117A: Global MASTER-Net observations report
  99. GRB 230116D: GIT optical follow-up
  100. Swift GRB230116.88: Global MASTER-Net observations report

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