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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. Swift/XRT discovery of multiple dust-scattering X-ray rings around GRB 221009A
  2. GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
  3. LHAASO observed GRB 221009A with more than 5000 VHE photons up to around 18 TeV
  4. GRB 221009A: Continued Swift/XRT observations
  5. GRB 221009A/Swift J1913.1+1946: Assy optical afterglow observation
  6. GRB 221009A/Swift J1913.1+1946: Lick/Nickel telescope optical observations
  7. GRB 221009A: Lulin SLT-40cm optical observations
  8. Swift J1913.1+1946: New Photometry
  9. GRB 221009A: Upper limits from a neutrino search with IceCube
  10. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  11. GRB221009A/Swift J1913.1+1946: SRG/ART-XC observation
  12. GRB 221009A / Swift J1913.1+1946: GIT detection of the optical afterglow
  13. GRB221009A/Swift J1913.1+1946: Solar Orbiter STIX measurements
  14. GRB221009A/Swift J1913.1+1946: INTEGRAL SPI/ACS observations
  15. GRB 221009A: Fermi-LAT refined analysis
  16. GRB 221009A (Swift J1913.1+1946): AGILE/GRID detection
  17. GRB 221009: Swift/UVOT Detection
  18. GRB221009A/Swift J1913.1+1946: ATA follow-up observations
  19. GRB 221009A or Swift J1913.1+1946: PRIME near-infrared detection
  20. GRB 221009A/Swift J1913.1+1946: AMI-LA observations
  21. GRB 221009A: Swift-XRT refined Analysis
  22. GRB 221009A (Swift J1913.1+1946): AGILE/MCAL detection
  23. Swift J1913.1+1946: Early Optical Photometry
  24. GRB 221009A: Nanshan/NEXT photometry and Xinglong-2.16m spectroscopy
  25. GRB 221009A (Swift J1913.1+1946): MeerLICHT observations
  26. GRB 221009A (Swift J1913.1+1946): Mondy optical observations
  27. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  28. Swift J1913.1+1946 : Pre-discovery limits from ZTF
  29. GRB 221009A: Fermi GBM observation
  30. IPN triangulation of extremely bright GRB 221009A
  31. Swift J1913.1+1946: Optical photometry
  32. Swift J1913.1+1946: Liverpool Telescope imaging and spectroscopy
  33. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  34. GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB
  35. GRB 221009A: Swift detected transient may be GRB
  36. Swift GRB221009.59: Global MASTER-Net OT detection
  37. GRB 221008A: Swift-XRT observations
  38. Swift J1913.1+1946 a new bright hard X-ray and optical transient
  39. GRB 221008A: Tiled Swift observations
  40. GRB 221006A: Swift-XRT observations
  41. GRB 221006A: Tiled Swift observations
  42. GRB 220930A: MITSuME Akeno optical upper limits
  43. GRB 220930A: AbAO Optical Upper Limit
  44. Konus-Wind detection of GRB 220930A
  45. GRB 220930A: AstroSat CZTI detection
  46. GRB 220930A: Swift-BAT refined analysis
  47. GRB 220930A: Swift-XRT refined Analysis
  48. GRB 220930A: LCOGT Optical Upper Limits
  49. GRB 220930A: Swift/UVOT Upper Limits
  50. GRB 220930A: Enhanced Swift-XRT position
  51. Swift GRB 220930A: Global MASTER-Net observations report
  52. GRB 220930A: BOOTES-5/JGT early optical upper limit
  53. GRB 220930A: Prompt enhanced Swift-XRT position
  54. GRB 220930A: COATLI Upper Limits
  55. GRB 220930A: Swift detection of a burst
  56. IPN triangulation of GRB 220927A (long)
  57. GRB 220924A: Fermi GBM detection
  58. Swift Trigger 1125354 (GRB 220926A) is not a GRB
  59. Swift GRB220926.34: Global MASTER-Net observations report
  60. Swift GRB 220926A: Global MASTER-Net observations report
  61. GRB 220926A: Swift detection of a burst
  62. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  63. Swift GRB220923.47: Global MASTER-Net observations report
  64. GRB 220921A: MeerLICHT afterglow observations
  65. GRB 220921A: Swift-XRT Observations
  66. GRB 220921A: Fermi-LAT detection
  67. GRB 220921A: Tiled Swift observations
  68. GRB 220909A: Fermi GBM observation
  69. GRB 220909A: Swift-XRT observations
  70. IPN triangulation of GRB 220905A
  71. GRB 220909A: Swift ToO observations
  72. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  73. GRB 220907A: Swift-BAT refined analysis
  74. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  75. IPN triangulation of GRB 220903A (long)
  76. GRB 220907A: Fermi GBM observation
  77. GRB 220907A: Nanshan/NEXT optical upper limits
  78. GRB 220907A: Swift/UVOT Upper Limits
  79. GRB 220907A: Swift-XRT refined Analysis
  80. GRB 220831A: ATCA 5/9 GHz radio observations
  81. GRB 220907A: Swift-XRT position
  82. GRB 220907A: Swift detection of a burst
  83. Swift GRB220907.59: Global MASTER-Net observations report
  84. GRB 220831A: Swift-UVOT Upper Limits
  85. GRB 220831A: DECam detection of a possible optical counterpart
  86. GRB 220831A, VLT/HAWK-I near-infrared observations
  87. GRB 220831A: Fermi GBM observation
  88. GRB 220831A: Swift-XRT observations
  89. GRB 220831A: Swift ToO observations
  90. GRB 220831A: Swift/BAT-GUANO localization of a short burst
  91. Konus-Wind detection of GRB 220826A
  92. GRB 220826A: Swift-BAT refined analysis
  93. GRB 220826A: Fermi GBM observation
  94. GRB 220826A: Swift-XRT refined Analysis
  95. GRB 220825A: Fermi GBM observation
  96. GRB 220826A: Lesedi optical afterglow detection
  97. GRB 220826A: Swift/UVOT Detection
  98. Swift GRB 220826A: Global MASTER-Net observations report
  99. GRB 220826A: Enhanced Swift-XRT position
  100. GRB 220826A: Swift detection of a burst with an optical counterpart

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