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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

26040 results found.

  1. GRB 221009A: LCOGT Optical Afterglow Detection
  2. GRB 221009A: COATLI Detection of the Afterglow
  3. GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger
  4. GRB 221009A (Swift J1913.1+1946): Swift-BAT refined analysis
  5. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
  6. GRB 221009A: Detection by GRBAlpha
  7. GRB 221009A: Sintez-Newton/CrAO optical observations
  8. GRB 221009A: Upper limits from HAWC 8 hours after trigger
  9. GRB 221006A: Swift ToO observations
  10. Swift/XRT discovery of multiple dust-scattering X-ray rings around GRB 221009A
  11. GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
  12. LHAASO observed GRB 221009A with more than 5000 VHE photons up to around 18 TeV
  13. GRB 221009A: NOEMA mm detection
  14. GRB 221009A: Continued Swift/XRT observations
  15. GRB 221009A/Swift J1913.1+1946: Assy optical afterglow observation
  16. GRB 221009A/Swift J1913.1+1946: Lick/Nickel telescope optical observations
  17. GRB 221009A: Lulin SLT-40cm optical observations
  18. Swift J1913.1+1946: New Photometry
  19. GRB 221009A: Upper limits from a neutrino search with IceCube
  20. GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
  21. GRB221009A/Swift J1913.1+1946: SRG/ART-XC observation
  22. GRB 221009A / Swift J1913.1+1946: GIT detection of the optical afterglow
  23. GRB221009A/Swift J1913.1+1946: Solar Orbiter STIX measurements
  24. GRB221009A/Swift J1913.1+1946: INTEGRAL SPI/ACS observations
  25. ​GRB 221009A: Multi-color detection of the optical
  26. GRB 221009A: Fermi-LAT refined analysis
  27. GRB 221009A (Swift J1913.1+1946): AGILE/GRID detection
  28. GRB 221009: Swift/UVOT Detection
  29. GRB221009A/Swift J1913.1+1946: ATA follow-up observations
  30. GRB 221009A or Swift J1913.1+1946: PRIME near-infrared detection
  31. GRB 221009A/Swift J1913.1+1946: AMI-LA observations
  32. GRB 221009A: REM optical and NIR detection of the afterglow
  33. GRB 221009A: Swift-XRT refined Analysis
  34. GRB 221009A (Swift J1913.1+1946): AGILE/MCAL detection
  35. Swift J1913.1+1946: Early Optical Photometry
  36. GRB 221009A: Redshift from X-shooter/VLT
  37. GRB 221009A: Nanshan/NEXT photometry and Xinglong-2.16m spectroscopy
  38. GRB 221009A (Swift J1913.1+1946): MeerLICHT observations
  39. GRB 221009A (Swift J1913.1+1946): Mondy optical observations
  40. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  41. Swift J1913.1+1946 : Pre-discovery limits from ZTF
  42. GRB 221009A: Fermi GBM observation
  43. IPN triangulation of extremely bright GRB 221009A
  44. Swift J1913.1+1946: Optical photometry
  45. Swift J1913.1+1946: Liverpool Telescope imaging and spectroscopy
  46. GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
  47. GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB
  48. GRB 221009A: Swift detected transient may be GRB
  49. Swift GRB221009.59: Global MASTER-Net OT detection
  50. GRB 221008A: Swift-XRT observations
  51. Swift J1913.1+1946 a new bright hard X-ray and optical transient
  52. GRB 221008A: Tiled Swift observations
  53. GRB 221006A: Swift-XRT observations
  54. GRB 221006A: Tiled Swift observations
  55. GRB 220930A: MITSuME Akeno optical upper limits
  56. GRB 220921A: ATCA detection of radio counterpart
  57. GRB 220930A: AbAO Optical Upper Limit
  58. Konus-Wind detection of GRB 220930A
  59. GRB 220930A: AstroSat CZTI detection
  60. GRB 220930A: Swift-BAT refined analysis
  61. GRB 220930A: Swift-XRT refined Analysis
  62. GRB 220930A: LCOGT Optical Upper Limits
  63. GRB 220930A: Swift/UVOT Upper Limits
  64. GRB 220930A: Enhanced Swift-XRT position
  65. Swift GRB 220930A: Global MASTER-Net observations report
  66. GRB 220930A: BOOTES-5/JGT early optical upper limit
  67. GRB 220930A: Prompt enhanced Swift-XRT position
  68. GRB 220930A: COATLI Upper Limits
  69. GRB 220930A: Swift detection of a burst
  70. IPN triangulation of GRB 220927A (long)
  71. GRB 220921A: LCOGT Optical Observations
  72. GRB 220611A: Host galaxy redshift from VLT/X-shooter
  73. GRB 220924A: Fermi GBM detection
  74. Swift Trigger 1125354 (GRB 220926A) is not a GRB
  75. Swift GRB220926.34: Global MASTER-Net observations report
  76. Swift GRB 220926A: Global MASTER-Net observations report
  77. GRB 220926A: Swift detection of a burst
  78. GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
  79. GRB 220921A: further MeerLICHT observations
  80. Swift GRB220923.47: Global MASTER-Net observations report
  81. GRB 220921A: DDOTI Detection of the Afterglow
  82. GRB 220921A: MeerLICHT afterglow observations
  83. GRB 220921A: Swift-XRT Observations
  84. GRB 220921A: Fermi-LAT detection
  85. GRB 220921A: Tiled Swift observations
  86. GRB 220909A: Fermi GBM observation
  87. GRB 220831A: DECam optical counterpart follow-up
  88. GRB 220909A: Swift-XRT observations
  89. IPN triangulation of GRB 220905A
  90. GRB 220909A: Swift ToO observations
  91. GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
  92. GRB 220907A: Swift-BAT refined analysis
  93. GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
  94. IPN triangulation of GRB 220903A (long)
  95. GRB 220907A: Fermi GBM observation
  96. GRB 220907A: Nanshan/NEXT optical upper limits
  97. GRB 220907A: Swift/UVOT Upper Limits
  98. GRB 220907A: Swift-XRT refined Analysis
  99. GRB 220831A: ATCA 5/9 GHz radio observations
  100. GRB 220907A: Swift-XRT position

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