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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"

27767 results found.

  1. Swift GRB230311.84: Global MASTER-Net observations report
  2. Swift Trigger 1159438 is also due to the Star Tracker loss of lock.
  3. Swift GRB230311.82: Global MASTER-Net observations report
  4. Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
  5. TESS Detection of the Optical Afterglow of GRB230307A
  6. GRB 230308A: CALET Gamma-Ray Burst Monitor detection
  7. Trigger 1159327: Swift detection of SGR1806-20
  8. GRB 230310A: AstroSat CZTI detection
  9. GRB 230307A: MAXI/GSC upper limit
  10. GRB 230310A: Fermi GBM Final Real-time Localization
  11. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  12. GRB 230307A: Erratum of the GCN 33441
  13. GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
  14. GRB 230308A: Fermi GBM detection
  15. GRB 230307A: Possible optical afterglow
  16. GRB 230307A: ASO-S/HXI detection
  17. GRB 230307A: AstroSat LAXPC detection
  18. GRB 230308A: AGILE/MCAL detection
  19. GRB 230307A: optical upper limit
  20. GRB 230217A: ATCA rapid-response radio detection
  21. Swift Trigger 1159108 is not a GRB
  22. GRB 230307A: Swift/BAT upper limits on the early afterglow
  23. GRB 230307A: Swift-XRT observations
  24. Konus-Wind detection of GRB 230307A
  25. Improved IPN localization for GRB 230307A
  26. GRB 230307A: VZLUSAT-2 detection
  27. GRB 230304B: CALET Gamma-Ray Burst Monitor detection
  28. GRB 230308A: Fermi GBM Final Real-time Localization
  29. GRB 230307A: Tiled Swift observations
  30. GRB 230307A: Detection by GRBAlpha
  31. GRB 230305A: Detection by GRBAlpha
  32. GRB 230307A: AstroSat CZTI detection
  33. GRB 230307A: possibly the second highest GRB energy fluence ever identified
  34. IPN triangulation of GRB 230307A (long/very bright)
  35. GRB 230307A: AGILE/MCAL detection
  36. GRB 230307A: Fermi GBM detection of a very bright GRB
  37. GRB 230307A: GECAM detection of an extremely bright burst
  38. GRB 230307A: Fermi GBM Final Real-time Localization
  39. IceCube-230306A - IceCube observation of a high-energy neutrino candidate
  40. GRB 230304C: AstroSat CZTI detection
  41. GRB 230304B: AstroSat CZTI detection
  42. GRB 230304A: AstroSat CZTI detection
  43. GRB 230304B: Detection by GRBAlpha
  44. GRB 230304C: Fermi GBM Final Real-time Localization
  45. GRB 230304B: Fermi GBM Final Real-time Localization
  46. GRB 230304A: Fermi GBM Final Real-time Localization
  47. GRB 230228A: Swift-BAT refined analysis
  48. GRB 230228A: Swift/UVOT Upper Limits
  49. GRB 230301B: Fermi GBM Final Real-time Localization
  50. GRB 230228A: Fermi GBM Observation
  51. GRB 230228A: OSN optical upper limit
  52. GRB 230301A: Fermi GBM Final Real-time Localization
  53. GRB 230228A: Swift-XRT refined Analysis
  54. GRB 230228A: Mondy optical upper limit
  55. GRB 230228A: Enhanced Swift-XRT position
  56. GRB 230228A: Nanshan/NEXT optical upper limit
  57. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  58. GRB 230228A: Prompt enhanced Swift-XRT position
  59. GRB 230228A: Swift detection of a possibly short burst
  60. GRB 230227A: Fermi GBM Final Real-time Localization
  61. GRB 230216A Mondy Observations
  62. GRB 230217A: Swift/UVOT Upper Limits
  63. GRB 230216A: Swift/UVOT Upper Limits
  64. GRB 230222A: Fermi GBM Final Real-time Localization
  65. GRB 230217A: Swift-XRT afterglow detection
  66. GRB 230217A: Swift-BAT refined analysis
  67. GRB 230217A: AstroSat CZTI detection
  68. GRB 230217A: Gemini South optical upper limits
  69. GRB 230216B: CALET Gamma-Ray Burst Monitor detection
  70. GRB 230217A: 6 GHz VLA observations
  71. GRB 230220B: Fermi GBM Final Real-time Localization
  72. IceCube-230220A - IceCube observation of a high-energy neutrino candidate
  73. GRB 230217A: Fermi GBM observation
  74. GRB 230220A: MAXI/GSC detection
  75. Konus-Wind detection of GRB 230217A
  76. GRB 230217A: Swift-XRT observations
  77. GRB 230218A: Fermi GBM Final Real-time Localization
  78. GRB 230217A: AGILE/MCAL detection
  79. GRB 230207B: CALET Gamma-Ray Burst Monitor detection
  80. GRB 230216B: AstroSat CZTI detection
  81. GRB 230216A: SVOM/C-GFT optical upper limit
  82. GRB 230217A: Swift detection of a short burst
  83. GRB 230217A: Fermi GBM Final Real-time Localization
  84. IceCube-230217A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 230216A: Swift-BAT refined analysis
  86. GRB 230216A: Swift-XRT refined Analysis
  87. Swift GRB 230216A: Global MASTER-Net observations report
  88. GRB 230216A: Enhanced Swift-XRT position
  89. GRB 230216A: AKO Upper Limit
  90. GRB 230216A: Zadko observatory - Gingin optical observations
  91. GRB 230216A: Swift detection of a burst
  92. GRB 230215A: Fermi GBM Final Real-time Localization
  93. GRB 230209B: AGILE detection
  94. GRB 230209B: Fermi GBM Observation
  95. IPN triangulation of GRB 230209B
  96. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  97. GRB 230204B: ATCA radio detection
  98. Outburst from LS V +44 17 / RX J0440.9+4431: Transient detection by GRBAlpha
  99. GRB 230211A: Fermi GBM Final Real-time Localization
  100. GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV

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