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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"

26042 results found.

  1. GRB 230421: Swift/BAT-GUANO arcminute localization
  2. GRB230420A: VLT optical observation
  3. GRB 230420A: Swift-BAT refined analysis
  4. GRB 230420A: Swift-XRT refined Analysis
  5. GRB 230420A: MITSuME Akeno optical observation
  6. GRB 230420A: NOT optical afterglow confirmation
  7. GRB 230420A: Gaoyazi/GOT optical upper limit
  8. GRB 230420A: BOOTES-5/JGT optical afterglow detection
  9. GRB 230420A: LCOGT Optical Upper Limit
  10. GRB 230420A: Enhanced Swift-XRT position
  11. IPN triangulation of GRB 230418A (short)
  12. GRB 230420A: Swift detection of a burst
  13. GRB 230418A: AstroSat CZTI detection
  14. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  15. GRB 230414B: Nickel and KAIT telescope optical observations
  16. GRB 230414B Swift-BAT refined analysis
  17. GRB 230415A: Fermi GBM detection
  18. GRB 230414B: Swift/UVOT Detection
  19. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  20. GRB 230415A: Swift/BAT-GUANO detection
  21. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  22. GRB 230307A: iTelescope optical upper limit (likely)
  23. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  24. GRB 230414B: Lulin 40cm-SLT optical limit
  25. GRB 230414B: Bassano Bresciano Observatory optical observations
  26. GRB 230414B: Redshift from OSIRIS/GTC
  27. GRB 230414B: AbAO optical observations
  28. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  29. GRB 230414B: Swift-XRT refined Analysis
  30. GRB 230414B: Dabancheng/GHOST optical observations
  31. GRB 230414B: slow optical light curve decay
  32. GRB 230414B: SAO RAS optical observations
  33. GRB 230414B: Enhanced Swift-XRT position
  34. GRB 230414B: 1.3m DFOT Optical observations
  35. GRB 230414B: GROWTH India Telescope afterglow confirmation
  36. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  37. GRB 230414B: Nanshan/HMT optical afterglow detection
  38. GRB 230414A: Mondy optical afterglow candidate
  39. Swift GRB 230414B: Global MASTER-Net observations report
  40. GRB 230414B: Prompt enhanced Swift-XRT position
  41. GRB 230414B: Swift detection of a burst
  42. GRB 230328B: redshift lower limit estimating
  43. GRB 230409B: Mondy optical upper limit
  44. GRB 230409B: Swift-XRT refined Analysis
  45. GRB 230409B: Swift-BAT refined analysis
  46. Swift GRB 230409B: Global MASTER-Net observations report
  47. GRB 230409B: Swift/UVOT Detection
  48. GRB 230409B: Enhanced Swift-XRT position
  49. GRB 230409B: Swift detection of a burst
  50. GRB 230405B: VZLUSAT-2 detection
  51. Konus-Wind detection of GRB 230405B
  52. GRB 230405B: AGILE detection
  53. GRB 230405B: Swift-XRT refined Analysis
  54. GRB 230405B: Fermi GBM Observation
  55. GRB 230405B: MeerLICHT upper limits
  56. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  57. GRB 230405B: Swift/UVOT Upper Limits
  58. GRB 230405B: AstroSat CZTI detection
  59. GRB 230405B: Enhanced Swift-XRT position
  60. Swift GRB 230405B: Global MASTER-Net observations report
  61. GRB 230405B: Prompt enhanced Swift-XRT position
  62. GRB 230405B: Swift detection of a burst
  63. GRB 230307A: JWST observations consistent with the presence of a kilonova
  64. GRB 230328B: Multa observatory optical afterglow observation
  65. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  66. GRB 230228A: detection by GTC of the potential host galaxy
  67. GRB 230328B: Swift/UVOT Detection
  68. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  69. GRB 230328B: CAHA 2.2m/CAFOS detection
  70. GRB 230328B: 3.6m DOT multiband optical observation
  71. Konus-Wind detection of GRB 230328B
  72. GRB 230328B: GRBAlpha detection
  73. GRB 230328B: Swift-BAT refined analysis
  74. GRB 230328B: Nanshan/NEXT 2nd optical observation
  75. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  76. GRB 230328B: Liverpool Telescope afterglow detection
  77. GRB 230328B: GIT optical follow-up
  78. GRB 230328B: OASDG optical observations
  79. GRB 230328B: Nanshan/NEXT optical upper limit
  80. GRB 230328B: Swift-XRT refined Analysis
  81. GRB 230328B: AstroSat CZTI detection
  82. GRB 230328B: Fermi GBM observation
  83. GRB 230328B: Mondy, AbAO and Kitab optical observations
  84. GRB 230328B: Enhanced Swift-XRT position
  85. GRB 230328B: Mondy optical afterglow confirmation
  86. GRB 230328B: Swift detection of a burst with an optical afterglow
  87. GRB 230325A: Swift-BAT refined analysis
  88. GRB 230325A: Swift/UVOT Upper Limits
  89. GRB 230325A: X-shooter optical afterglow and redshift
  90. GRB 230325A: Swift-XRT refined Analysis
  91. GRB 230322B: Swift-BAT refined analysis
  92. GRB 230325A: Enhanced Swift-XRT position
  93. GRB 230325A: Prompt enhanced Swift-XRT position
  94. GRB 230325A: Swift detection of a burst
  95. GRB 230320B: Fermi GBM Observation
  96. GRB 230322B: Swift/UVOT Detection
  97. GRB 230322B: Swift-XRT refined Analysis
  98. GRB 230322B: Enhanced Swift-XRT position
  99. Swift GRB 230322B: Global MASTER-Net observations report
  100. GRB 230322B: Swift detection of a burst with optical counterpart

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