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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"

19590 results found.

  1. GRB 240205B: AstroSat CZTI detection
  2. GRB 240205B: Swift-BAT refined analysis
  3. Konus-Wind detection of GRB 240205B (long / very soft)
  4. GRB 240205B: VLT/X-shooter redshift
  5. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  6. GRB 240205B: BOOTES-6 optical afterglow follow-up
  7. GRB 240205B: ATCA detection of radio counterpart
  8. GRB 240205B: REM detection of the optical/NIR afterglow
  9. GRB 240205B: Fermi GBM Observation
  10. GRB 240204A: AstroSat CZTI detection
  11. GRB 240205B: GECAM detection of a long burst
  12. GRB 240204A: Swift-BAT refined analysis
  13. GRB 240205B: Skynet Optical Afterglow Observations
  14. GRB 240205B: BOOTES-7 optical afterglow follow-up
  15. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  16. GRB 240205B: Swift detection of a burst
  17. Swift GRB240205.93: Global MASTER-Net observations report
  18. GRB 240204A: Fermi GBM Observation
  19. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  20. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  21. GRB 240204A: Montarrenti Observatory optical observations
  22. GRB 240204A: Enhanced Swift-XRT position
  23. GRB 240204A: Mondy optical afterglow candidate
  24. GRB 240204A: Swift detection of a burst
  25. Swift Trigger 1212791 is not an astrophysical event.
  26. Swift-BAT triggers 1212787, 1212789 are not astrophysical.
  27. IPN triangulation of GRB 240124B
  28. GRB 240129A: Fermi GBM Observation
  29. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  30. IPN triangulation of GRB 240125A (short)
  31. GRB 240128A: Swift-XRT observations
  32. GRB 240128A: Tiled Swift observations
  33. GRB 240122A: ATCA detection of radio counterpart
  34. Swift Trigger 1211211 and 1211212 are not astrophysical
  35. GRB 240123C: AstroSat CZTI detection
  36. GRB240122A: PRIME near infrared detection
  37. GRB 240123B: Fermi GBM Observation
  38. GRB 240123A: Glowbug gamma-ray detection
  39. GRB 240123B: Swift/BAT-GUANO detection of a long burst
  40. GRB 240123A: GRBAlpha detection
  41. IPN triangulation of GRB 240123C (short)
  42. Swift trigger 1210856 is not astrophysical
  43. GRB 240123A: Swift-BAT refined analysis
  44. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  45. GRB 240123A: Enhanced Swift-XRT position
  46. GRB 240122A: Swift/UVOT Upper Limits
  47. GRB 240123A: Swift-XRT refined Analysis
  48. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  49. Fermi GBM Sub-Threshold Detection of GRB 240123A
  50. GRB 240118A: Swift/UVOT Upper Limits
  51. GRB 240123A: Swift detection of a burst with a possible optical counterpart
  52. Swift GRB240123.46: Global MASTER-Net observations report
  53. GRB 240122A: Swift-XRT afterglow detection
  54. GRB 240122A: Tiled Swift observations
  55. IPN triangulation of GRB 240119A (short)
  56. GRB 240118C: GECAM-B detection of a long burst
  57. GRB 240118A: Mondy optical observations
  58. GRB 240118A: Swift-XRT afterglow detection
  59. GRB 240118C: Fermi GBM Observation
  60. GRB 240118C: Swift/BAT-GUANO detection of a burst
  61. GRB 240118A: GRBAlpha detection
  62. GRB 240115A: Fermi GBM Observation
  63. Swift triggers 1209631, 1209632, 1209635 and 1209644 are not interesting astrophysical events
  64. GRB 240118A: Swift ToO observations
  65. GRB 240118A: AbAO optical upper limit
  66. GRB 240118A: NuSTAR Offline Analysis of the GRB
  67. GRB 240118A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  68. GRB 240118A: Fermi-LAT detection
  69. GRID detection of GRB 231230A
  70. GRB 240115A: Swift/BAT-GUANO detection of a short burst
  71. Swift Trigger 1209406 is not an astrophysical event
  72. Swift Triggers 1209401 and 1209403 are not astrophysical events
  73. Swift Triggers 1209371 through 1209374 are not astrophysical events
  74. Swift Triggers 1209369 and 1209370 are not astrophysical events
  75. LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO
  76. GRB 240112C: Glowbug gamma-ray detection
  77. GRB 240112C: VZLUSAT-2 detection
  78. Konus-Wind detection of GRB 240112C
  79. GRB 240112C: GRBAlpha detection
  80. GRB 240112C: Swift/UVOT Detection
  81. GRB 240112C: Fermi GBM Detection
  82. GRB 240112C: Swift-XRT refined Analysis
  83. GRB 240112C: SAO RAS optical observations
  84. Swift GRB 240112C: Global MASTER-Net observations report
  85. GRB 240109A: Swift-BAT refined analysis
  86. GRB 240112C: Swift detection of a burst with an optical counterpart
  87. GRB 240109A: Fermi GBM Observation
  88. GRB 231214A: ATCA Radio Upper Limits
  89. Konus-Wind detection of GRB 240101C
  90. Swift GRB240109.17: Global MASTER-Net observations report
  91. GRB 240109A: Swift detection of a short burst
  92. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  93. IPN triangulation of GRB 240101C (short)
  94. GRB GRB240101C: Fermi GBM observation
  95. GRB 240101A: 1.3m DFOT optical observations
  96. GRB 240102A: 1.3m DFOT optical upper limit
  97. GRB 240101B: 1.3m DFOT optical upper limit
  98. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  99. GRB 231220A: Swift-UVOT upper limit
  100. GRB 240102A: Swift-BAT refined analysis

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