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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

19663 results found.

  1. GRB 201221D: Swift-XRT refined Analysis
  2. Swift GRB 201221D: Global MASTER-Net observations report
  3. GRB 201221D: Enhanced Swift-XRT position
  4. GRB 201221A: Swift-BAT refined analysis
  5. GRB 201221D: Prompt enhanced Swift-XRT position
  6. GRB 201221D: Swift detection of a bright short burst
  7. correction to GCN 29110 - Fermi GBM Sub-Threshold Detection of GRB 201221A
  8. Fermi GBM Sub-Threshold Detection of GRB 201221A
  9. GRB 201221A: Swift/UVOT Upper Limits
  10. GRB 201221A: Swift-XRT refined Analysis
  11. GRB 201221C: MASTER optical observtion
  12. Swift Trigger 1014012: possible GRB 201221C
  13. GRB 201221A: Enhanced Swift-XRT position
  14. GRB 201221A: FRAM-Auger optical limit
  15. Swift GRB 201221A: Global MASTER-Net observations report
  16. GRB 201221A: Prompt enhanced Swift-XRT position
  17. GRB 201221A: Swift detection of a burst
  18. GRB 201214A: Swift-XRT afterglow detection
  19. GRB 201214A: 1.3m DFOT, optical upper limits
  20. IPN triangulation of GRB 201218A
  21. GRB201216C: No significant detection in HAWC
  22. GRB 201216C: Liverpool Telescope First Hour Observations
  23. Konus-Wind detection of GRB 201216C
  24. GRB 201216C: Swift-BAT refined analysis
  25. GRB 201216C: Fermi-LAT upper limit
  26. GRB 201216C: MAGIC detection in very high energy gamma rays
  27. GRB 201216C: AstroSat CZTI detection
  28. GRB 201216C: Fermi GBM detection
  29. GRB 201216A: Fermi GBM detection
  30. GRB 201216C: Swift/UVOT Upper Limits
  31. GRB 201216A: Swift-XRT observations
  32. GRB 201216C: Enhanced Swift-XRT position
  33. GRB 201216C: VLT afterglow candidate discovery
  34. GRB 201216A: Swift ToO observations
  35. GRB 201216C: Swift-XRT observations
  36. Swift GRB201216.96: Global MASTER-Net observations report
  37. GRB 201216C: Swift detection of a burst
  38. GRB 201216A: Swift/BAT-GUANO detection and arcminute localization
  39. GRB 201214B: MITSuME Akeno optical upper limits
  40. GRB 201214B: Lowell Discovery Telescope optical observations
  41. GRB 201214B: Swift-XRT observations
  42. GRB 201209A: Insight-HXMT/HE detection
  43. GRB 201214A: Swift-XRT observations
  44. GRB 201214B: Swift BAT location of short burst
  45. GRB 201214B: Swift ToO observations
  46. GRB 201214A: Swift ToO observations
  47. GRB 201203A: 1.3m DFOT, optical upper limits
  48. GRB 201209A: Swift/UVOT Upper Limits
  49. GRB 201209A: Swift-BAT refined analysis
  50. GRB 201208A: Swift-XRT afterglow detection
  51. GRB 201209A: Swift-XRT refined Analysis
  52. GRB 201209A: AstroSat CZTI detection
  53. GRB 201209A: Enhanced Swift-XRT position
  54. IceCube-201130A: Optical and NIR Imaging Follow-up by Kanata Telescope
  55. GRB 201209A: KAIT Optical Upper Limit
  56. GRB 201209A: FRAM-Auger optical limit
  57. GRB 201209A: Swift detection of a burst
  58. Swift GRB201209.24: Global MASTER-Net observations report
  59. GRB 201208A: Fermi-LAT detection
  60. GRB 201208A: Swift ToO observations
  61. GRB 201203A: Swift-BAT refined analysis
  62. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A
  63. GRB 201203A: GROWTH-India Telescope optical upper limit.
  64. GRB 201203A: MITSuME Okayama optical upper limits
  65. Swift GRB 201203A: Global MASTER-Net observations report
  66. GRB 201203A: Swift-XRT afterglow detection
  67. GRB 201203A: KAIT Optical Upper Limit
  68. GRB 201203A: DDOTI Observations
  69. GRB 201203A: FRAM-Auger optical limit
  70. GRB 201203A: Swift detection of a burst
  71. GRB 201128B: Swift-XRT observations
  72. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  73. GRB 201128B: Swift ToO observations
  74. Swift-XRT observations of IceCube 201130A
  75. GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
  76. GRB 201128A: Swift/UVOT Upper Limits
  77. GRB 201128A: Swift-BAT refined analysis
  78. GRB 201128A: Swift-XRT refined Analysis
  79. GRB 201128A: Enhanced Swift-XRT position
  80. GRB 201128A: DDOTI Observations
  81. GRB 201128A: Swift detection of a burst
  82. IceCube-201114A: DECam observations and candidate optical counterpart
  83. IceCube-201120A: Swift-XRT non-detection of 4FGL J2028.6+4110e
  84. IceCube 201114A: Swift followup of Fermi J0703.5+0505
  85. Trigger 1007266: Swift detection of 1A 0535+262
  86. GRB 201116A: NOT optical observations
  87. GRB 201116A: Swift-XRT afterglow detection
  88. GRB 201116A: OSN Afterglow Candidate
  89. Swift Trigger 1006917 is Be/X-ray binary pulsar 1A 0535+262
  90. GRB 201116A: Fermi-LAT detection
  91. GRB 201116A: Tiled Swift observations
  92. Swift XRT observations of the Fermi-LAT source 4FGL J0658.6+0636, positionally consistent with the IceCube high-energy neutrino alert
  93. Swift-XRT observations of IceCube 201114A
  94. Swift Trigger 1005428: Detection of SGR 1830-0645
  95. GRB 201104A: AstroSat CZTI detection
  96. Konus-Wind detection of GRB 201105A
  97. GRB 201104B: 1.3m DFOT optical observations
  98. GRB 201104A: Swift-XRT observations
  99. Swift XRT and UVOT detection of ZTF20acozryr/AT2020yxz/GRB201103B
  100. GRB 201015A: Swift-XRT late time observations

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