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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.

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

19614 results found.

  1. GRB 250806A: EP-FXT observation
  2. EP#01709198415/EP250806a: Swift-XRT observations
  3. GRB 250805A: Swift-BAT refined analysis
  4. GRB 250806A: KAIT optical upper limit
  5. GRB 250806A: SVOM/VT refined analysis
  6. GRB 250806A: Swift-XRT counterpart detection
  7. GRB 250805A: SVOM/VT optical counterpart
  8. GRB 250805A: ESO/VLT observations
  9. GRB 250805A: Swift-XRT refined Analysis
  10. GRB 250804B: Swift-XRT observations
  11. GRB 250805A: Enhanced Swift-XRT position
  12. GRB 250805A: TRT optical upper limits
  13. GRB 250805A: Swift-XRT observations
  14. GRB 250805A: Swift detection of a burst
  15. Swift GRB250805.26: Global MASTER-Net observations report
  16. GRB 250804B: Tiled Swift observations
  17. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  18. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  19. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  20. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT follow up of AT 2025smm
  21. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  22. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  23. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  24. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  25. GRB 250725A: AstroSat CZTI detection
  26. GRB 250727A: EP-FXT follow-up observation
  27. GRB 250725A: PRIME near-infrared observations
  28. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  29. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  30. GRB 250728A: Swift-XRT observations
  31. GRB 250728A: COLIBRÍ optical upper limit
  32. GRB 250728A: Fermi GBM Observation
  33. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
  34. GRB 250728A: Swift ToO observations
  35. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  36. GRB 250727A: EP-FXT counterpart detection
  37. GRB250727A: SVOM/VT optical upper limit
  38. GRB 250727A: Swift-XRT observations
  39. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  40. GRB 250725A: Swift-XRT refined Analysis
  41. GRB 250725A: Fermi GBM Observation
  42. GRB 250725A: Swift-BAT refined analysis
  43. Konus-Wind detection of GRB 250725A
  44. GRB 250725A: SVOM/GRM observation
  45. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  46. GRB 250725A: Swift/UVOT Upper Limits
  47. GRB 250725A: Fermi-LAT detection
  48. GRB 250725A: BOOTES-7 early optical detection
  49. GRB 250725A: SVOM/VT optical candidate
  50. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  51. GRB 250725A: Enhanced Swift-XRT position
  52. GRB 250725A: Swift detection of a burst
  53. Swift GRB 250725A: Global MASTER-Net OT detection
  54. Swift GRB 250725A: Global MASTER-Net observations report
  55. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  56. Swift-BAT trigger 1334535 is not a GRB
  57. GRB 250721A: Swift-XRT observations
  58. GRB 250717B: SVOM/GRM observation
  59. GRB 250721A: Tiled Swift observations
  60. GRB 250717B: COLIBRÍ optical upper limit
  61. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  62. GRB 250717B: Swift-XRT observations
  63. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  64. Swift Trigger 1334535: a possible GRB 250718A
  65. Swift GRB250718.01: Global MASTER-Net observations report
  66. GRB 250717B: Swift ToO observations
  67. GRB 270713A: Kitab and AbAO Optical Observations
  68. GRB 250717B: Fermi GBM Observation
  69. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  70. GRB 250716A: Swift-XRT afterglow detection
  71. GRB 250716A: Swift ToO observations
  72. GRB 250713A: SVOM/C-GFT upper limit
  73. GRB 250713A: Swift-XRT observations
  74. GRB 250706A: Swift-BAT refined analysis
  75. GRB 250702F: Swift-BAT refined analysis
  76. GRB 250628A: Swift-BAT refined analysis
  77. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  78. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  79. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  80. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  81. GRB 250706B/C: Fermi-LAT detection
  82. GRB 250706B: Swift/UVOT Detection
  83. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  84. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  85. GRB 250702F: GRANDMA observations
  86. GRB 250706A: Swift-XRT refined Analysis
  87. GRB 250706A: Swift/UVOT Upper Limits
  88. GRB 250706A: REM optical/NIR observations
  89. Swift GRB 250706A: Global MASTER-Net observations report
  90. GRB 250706A: JinShan optical upper limits
  91. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  92. GRB250706B: Swift-XRT counterpart detection
  93. GRB 250706A: GROWTH-India Telescope optical upper limit
  94. GRB 250706A: Swift detection of a burst
  95. GRB 250704B: Swift-XRT refined Analysis
  96. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  97. GRB 250704B: Swift/UVOT Upper Limits
  98. GRB 250704A: Swift/UVOT Detection
  99. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  100. GRB 250702F: Kilonova-Catcher optical afterglow detection

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