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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"

19602 results found.

  1. GRB 230415A: Swift/BAT-GUANO detection
  2. GRB 230307A: iTelescope optical upper limit (likely)
  3. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  4. GRB 230414B: Lulin 40cm-SLT optical limit
  5. GRB 230414B: Bassano Bresciano Observatory optical observations
  6. GRB 230414B: AbAO optical observations
  7. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  8. GRB 230414B: Swift-XRT refined Analysis
  9. GRB 230414B: Dabancheng/GHOST optical observations
  10. GRB 230414B: SAO RAS optical observations
  11. GRB 230414B: Enhanced Swift-XRT position
  12. GRB 230414B: 1.3m DFOT Optical observations
  13. GRB 230414B: GROWTH India Telescope afterglow confirmation
  14. GRB 230414B: Nanshan/HMT optical afterglow detection
  15. GRB 230414A: Mondy optical afterglow candidate
  16. Swift GRB 230414B: Global MASTER-Net observations report
  17. GRB 230414B: Prompt enhanced Swift-XRT position
  18. GRB 230414B: Swift detection of a burst
  19. GRB 230328B: redshift lower limit estimating
  20. GRB 230409B: Mondy optical upper limit
  21. GRB 230409B: Swift-XRT refined Analysis
  22. GRB 230409B: Swift-BAT refined analysis
  23. Swift GRB 230409B: Global MASTER-Net observations report
  24. GRB 230409B: Swift/UVOT Detection
  25. GRB 230409B: Enhanced Swift-XRT position
  26. GRB 230409B: Swift detection of a burst
  27. GRB 230405B: VZLUSAT-2 detection
  28. Konus-Wind detection of GRB 230405B
  29. GRB 230405B: AGILE detection
  30. GRB 230405B: Swift-XRT refined Analysis
  31. GRB 230405B: Fermi GBM Observation
  32. GRB 230405B: MeerLICHT upper limits
  33. GRB 230405B: Swift/UVOT Upper Limits
  34. GRB 230405B: AstroSat CZTI detection
  35. GRB 230405B: Enhanced Swift-XRT position
  36. Swift GRB 230405B: Global MASTER-Net observations report
  37. GRB 230405B: Prompt enhanced Swift-XRT position
  38. GRB 230405B: Swift detection of a burst
  39. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  40. GRB 230228A: detection by GTC of the potential host galaxy
  41. GRB 230328B: Swift/UVOT Detection
  42. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  43. GRB 230328B: CAHA 2.2m/CAFOS detection
  44. GRB 230328B: 3.6m DOT multiband optical observation
  45. Konus-Wind detection of GRB 230328B
  46. GRB 230328B: GRBAlpha detection
  47. GRB 230328B: Swift-BAT refined analysis
  48. GRB 230328B: Nanshan/NEXT 2nd optical observation
  49. GRB 230328B: Liverpool Telescope afterglow detection
  50. GRB 230328B: GIT optical follow-up
  51. GRB 230328B: OASDG optical observations
  52. GRB 230328B: Nanshan/NEXT optical upper limit
  53. GRB 230328B: Swift-XRT refined Analysis
  54. GRB 230328B: AstroSat CZTI detection
  55. GRB 230328B: Fermi GBM observation
  56. GRB 230328B: Mondy, AbAO and Kitab optical observations
  57. GRB 230328B: Enhanced Swift-XRT position
  58. GRB 230328B: Mondy optical afterglow confirmation
  59. GRB 230328B: Swift detection of a burst with an optical afterglow
  60. GRB 230325A: Swift-BAT refined analysis
  61. GRB 230325A: Swift/UVOT Upper Limits
  62. GRB 230325A: Swift-XRT refined Analysis
  63. GRB 230322B: Swift-BAT refined analysis
  64. GRB 230325A: Enhanced Swift-XRT position
  65. GRB 230325A: Prompt enhanced Swift-XRT position
  66. GRB 230325A: Swift detection of a burst
  67. GRB 230320B: Fermi GBM Observation
  68. GRB 230322B: Swift/UVOT Detection
  69. GRB 230322B: Swift-XRT refined Analysis
  70. GRB 230322B: Enhanced Swift-XRT position
  71. Swift GRB 230322B: Global MASTER-Net observations report
  72. GRB 230322B: Swift detection of a burst with optical counterpart
  73. GRB 230320B: GRBAlpha detection
  74. GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
  75. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  76. IPN triangulation of GRB 230309A
  77. VZLUSAT-2 detection of SGR 1806-20
  78. GRB 230307A: Swift/UVOT detection
  79. GRB 230307A: soft X-ray detection with LEIA
  80. GRB 230307A: Swift-XRT afterglow detection
  81. Swift GRB230311.85: Global MASTER-Net observations report
  82. Swift GRB230311.83: Global MASTER-Net observations report
  83. Further improved IPN localization for GRB 230307A
  84. Swift GRB230311.81: Global MASTER-Net observations report
  85. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  86. Swift GRB230311.84: Global MASTER-Net observations report
  87. Swift Trigger 1159438 is also due to the Star Tracker loss of lock.
  88. Swift GRB230311.82: Global MASTER-Net observations report
  89. Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
  90. Trigger 1159327: Swift detection of SGR1806-20
  91. GRB 230307A: MAXI/GSC upper limit
  92. GRB 230307A: Possible optical afterglow
  93. GRB 230307A: ASO-S/HXI detection
  94. GRB 230307A: optical upper limit
  95. GRB 230217A: ATCA rapid-response radio detection
  96. Swift Trigger 1159108 is not a GRB
  97. GRB 230307A: Swift/BAT upper limits on the early afterglow
  98. GRB 230307A: Swift-XRT observations
  99. Improved IPN localization for GRB 230307A
  100. GRB 230307A: Tiled Swift observations

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