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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"

27768 results found.

  1. GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
  2. Swift Trigger 1153670 is probably not a GRB
  3. GRB 230210A: Fermi GBM Final Real-time Localization
  4. GRB 230209B: Fermi GBM Final Real-time Localization
  5. GRB 230209A: Fermi GBM Final Real-time Localization
  6. GRB 221009A: Continued Swift Observations
  7. GRB 230207B: Detection by GRBAlpha
  8. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  9. GRB 230204B: MASTER early OT detection
  10. GRB 230208A: Fermi GBM Final Real-time Localization
  11. GRB 230207B: Swift/BAT-GUANO detection outside the coded FOV
  12. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  13. GRB 230207B: AGILE detection of a burst
  14. GRB 230207A: Fermi GBM Final Real-time Localization
  15. GRB 230204B: Swift/UVOT Upper Limits
  16. GRB 230205A: Swift/UVOT Upper Limits
  17. GRB 230204B: Fermi GBM detection
  18. GRB 230204B: Swift-XRT afterglow detection
  19. GRB 230204B: 3.6m DOT optical observation
  20. GRB 230205A: SVOM/C-GFT optical upper limit
  21. GRB 230204B: VLT/X-shooter redshift
  22. GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s)
  23. GRB 230204A: Swift-BAT refined analysis
  24. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  25. GRB 230205A: Swift-XRT refined Analysis
  26. GRB 230204B: Swift ToO observations
  27. GRB 230205A: Enhanced Swift-XRT position
  28. GRB 230205A: BOOTES-5/JGT early optical upper limit
  29. GRB 230204B: Detection by GRBAlpha
  30. GRB 230204B: AGILE detection
  31. GRB 230205A: Swift detection of a burst
  32. GRB 230204B: GIT discovery of the likely optical afterglow
  33. GRB 230204B: AstroSat CZTI detection
  34. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  35. GRB 230204A: Swift/UVOT Upper Limits
  36. GRB 230204B: MAXI/GSC detection
  37. GRB 230204A: Swift-XRT refined Analysis
  38. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  39. GRB 230204A: Enhanced Swift-XRT position
  40. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  41. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  42. GRB 221216A: Swift-BAT refined analysis
  43. ZTF23aabmzlp/AT2023azs: VLA radio detection
  44. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  45. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  46. GRB 230201B: Fermi GBM Final Real-time Localization
  47. GRB 230126A: Detection by VZLUSAT-2
  48. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  49. GRB 221009A: radio afterglow detection with the EVN
  50. GRB 230201A: Fermi GBM Final Real-time Localization
  51. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  52. AT2023avj: X-ray Detection with Swift/XRT
  53. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  54. GRB 230129A: AstroSat CZTI detection
  55. GRB 230128A: AstroSat CZTI detection
  56. GRB 230130A: Fermi GBM Final Real-time Localization
  57. ZTF23aaarlti/AT2023avj: VLA radio detection
  58. GRB 230129A: Fermi GBM Final Real-time Localization
  59. GRB 230128A: Fermi GBM Final Real-time Localization
  60. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  61. ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
  62. GRB 230126A: Fermi GBM Final Real-time Localization
  63. Swift-XRT observations of NuEm-230125A
  64. Trigger 1150965: Swift detection of LS V +44 17
  65. GRB 230124A: Fermi GBM Observation
  66. GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
  67. GRB 230114B: Detection by VZLUSAT-2
  68. GRB 230124A: Fermi GBM Final Real-time Localization
  69. GRB 230123A: Swift-BAT refined analysis
  70. GRB 230122A: Swift/BAT-GUANO detection
  71. GRB 230123A: Swift/UVOT Upper Limits
  72. GRB 230123A: Swift-XRT refined Analysis
  73. GRB 230123A: Enhanced Swift-XRT position
  74. GRB 230123A: Zadko observatory - Gingin optical observations
  75. GRB 230116C: Swift-XRT observations
  76. GRB 230123A: Swift detection of a burst
  77. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  78. Trigger 1150107: Swift detection of LS V +44 17
  79. GRB 230120A: AstroSat CZTI detection
  80. IPN triangulation of GRB 230116B (short)
  81. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  82. GRB 230116D: 3.6m DOT optical upper limit
  83. GRB 230119A: Fermi GBM Final Real-time Localization
  84. GRB 230118A: Fermi GBM Final Real-time Localization
  85. GRB 230116D: Swift-BAT refined analysis
  86. GRB 230116C: Swift-BAT refined analysis
  87. GRB 230116D: Swift-XRT refined Analysis
  88. GRB 230117A: Fermi GBM Final Real-time Localization
  89. GRB 230116D: GIT optical follow-up
  90. GRB 230116D: Enhanced Swift-XRT position
  91. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  92. GRB 230116D: Nanshan/NEXT optical afterglow detection
  93. GRB 230116D: Swift detection of a burst
  94. Swift GRB230116.88: Global MASTER-Net observations report
  95. GRB 230116C: Swift detection of a burst
  96. GRB 230116B: Fermi GBM Final Real-time Localization
  97. GRB 230116A: Fermi GBM Final Real-time Localization
  98. GRB 230114A: Detection by VZLUSAT-2
  99. GRB 230114A: Fermi GBM Final Real-time Localization
  100. Trigger 1148770: Swift detection of Cyg X-1 due to Star Tracker loss of lock

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