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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"

28050 results found.

  1. GRB 210826A: further Swift-XRT observations
  2. GRB 210909B: GECAM detection
  3. Swift detection of a burst from SGR Swift J1555.2-5402
  4. GECAM observation of a burst from SGR J1935+2154
  5. GECAM observation of a burst from SGR J1935+2154
  6. Fermi trigger No 652927551: Global MASTER-Net observations report
  7. GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
  8. GRB 210905A: Swift/UVOT Upper Limits
  9. GRB 210905A: AstroSat CZTI detection
  10. GRB 210905A, GROND observations
  11. Fermi GBM Sub-Threshold Detection of GRB 210905A
  12. GRB 210905A: Swift-XRT refined Analysis
  13. GRB 210610A: Maidanak and AbAO optical observations
  14. GRB 210827B: GECAM detection
  15. GRB 210905A: REM NIR afterglow detection
  16. GRB 210905A: Continued LCO Optical Observations
  17. GRB 210905A: LCO Optical Detection
  18. GRB 210905A: Enhanced Swift-XRT position
  19. GRB 210901A: Swift/UVOT Upper Limits
  20. GRB 210905A: Swift detection of a burst
  21. GRB 210820A: TSHAO optical upper limit
  22. GRB 210901A: GROND observations
  23. GRB 210901A: Swift-XRT refined Analysis
  24. GRB 210901A: Swift-BAT refined analysis
  25. GRB 210901A: Enhanced Swift-XRT position
  26. GRB 210901A: LCO Optical Upper Limit
  27. GRB 210901A: Swift detection of a burst
  28. GRB 210827A: further Swift-XRT observations
  29. GRB 210827A: Fermi GBM Observation
  30. GRB 210826A: AstroSat CZTI detection
  31. Fermi GRB 210827A: Global MASTER-Net observations report
  32. GRB 210827A: Swift-XRT observations
  33. GRB 210827A: Swift/BAT-GUANO detection and arcminute localization
  34. GRB 210820A: CAHA 2.2m Optical Detection
  35. GRB 210824A: Swift/UVOT Upper Limits
  36. GRB 210826A: Swift/UVOT Upper Limits
  37. POLAR detection of a SGR-like burst
  38. GRB 210827B: BALROG localization (Fermi Trigger 651751821 / GRB 210827424)
  39. GRB 210826A: Swift-XRT observations
  40. GRB 210824A: Swift-BAT refined analysis
  41. GRB 210824A: MITSuME Akeno optical upper limits
  42. GRB 210826A: BALROG localization (Fermi Trigger 651654110 / GRB 210826293)
  43. Swift GRB210825.29: Global MASTER-Net observations report
  44. Swift detection of an outburst from SGR Swift J1555.2-5402
  45. GRB 210822A: Swift/UVOT Detection
  46. GRB 210824A: Fermi GBM Observation
  47. GRB 210824A: Nanshan/NEXT optical upper limit
  48. GRB 210824A: Swift-XRT refined Analysis
  49. GRB 210822A: GROND observations
  50. GRB 210824A: Enhanced Swift-XRT position
  51. GRB 210824A: Swift detection of a burst
  52. GRB 210822B: DDOTI Upper Limits on the Afterglow
  53. GRB 210820A: GROND observations
  54. Konus-Wind detection of GRB 210822A
  55. GRB 210822A: AstroSat CZTI detection
  56. GRB 210822A: NOT photometry and spectroscopy
  57. GRB 210822A: Swift-XRT refined Analysis
  58. GRB 210822A: Swift-BAT refined analysis
  59. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  60. GRB 210820A: Swift/UVOT Detection
  61. GRB 210822A: Nanshan/NEXT optical observations
  62. GRB 210822A: Enhanced Swift-XRT position
  63. GRB 210822A: RATIR Optical Detections
  64. GRB 210822A: Swift detection of a burst with an optical afterglow
  65. GRB 210820A: Swift-BAT refined analysis
  66. GRB 210820A: LCO Optical Upper Limit
  67. GRB 210820A: RATIR Optical Detections
  68. GRB 210820A: NOT optical upper limit
  69. GRB 210820A: Nanshan/NEXT optical upper limit
  70. GRB 210820A: Swift-XRT refined Analysis
  71. GRB 210820A: Enhanced Swift-XRT position
  72. GRB 210820A: Swift detection of a burst with an optical counterpart
  73. GRB 210818A: Swift-XRT refined Analysis
  74. GRB 210818A: Swift-BAT refined analysis
  75. Swift Trigger 1069242 is Cyg X-1
  76. GRB 210818A: AstroSat CZTI detection
  77. GRB 210818A: Enhanced Swift-XRT position
  78. GRB 210818A: Swift detection of a burst with an optical counterpart
  79. IceCube-210811A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 210815A: BALROG localization (Fermi Trigger 650687034 / GRB 210815100)
  81. GRB 210712A: Fermi GBM observation
  82. GRB 210813A: BALROG localization (Fermi Trigger 650508868 / GRB 210813038)
  83. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  84. GRB 210812A: BALROG localization (Fermi Trigger 650479626 / GRB 210812699)
  85. GRB 080101A: Fermi GBM Final Real-time Localization
  86. GRB 210730A: Tautenburg observations
  87. GRB 210807A: Tautenburg observations
  88. GRB 210807C: Swift-BAT refined analysis
  89. GRB 210807A: Swift-BAT refined analysis
  90. GRB 210807C: Swift-XRT refined Analysis
  91. GRB 210807C: Fermi GBM detection
  92. GRB 210807C: Swift/UVOT Upper Limits
  93. GRB 210807A: Swift/UVOT Detection
  94. GRB 210807A: Swift-XRT refined Analysis
  95. GRB 210807C: Enhanced Swift-XRT position
  96. GRB 210610B: Assy optical observations
  97. GRB 210807C: Swift detection of a burst
  98. GRB 210807A: Enhanced Swift-XRT position
  99. GRB 210807A: Swift detection of a burst with an optical counterpart
  100. IPN Triangulation of a bright burst from SGR 1935+2154

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