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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"

19608 results found.

  1. GRB 250806A: KAIT optical upper limit
  2. GRB 250806A: SVOM/VT refined analysis
  3. GRB 250806A: Swift-XRT counterpart detection
  4. GRB 250805A: SVOM/VT optical counterpart
  5. GRB 250805A: ESO/VLT observations
  6. GRB 250805A: Swift-XRT refined Analysis
  7. GRB 250804B: Swift-XRT observations
  8. GRB 250805A: Enhanced Swift-XRT position
  9. GRB 250805A: TRT optical upper limits
  10. GRB 250805A: Swift-XRT observations
  11. GRB 250805A: Swift detection of a burst
  12. Swift GRB250805.26: Global MASTER-Net observations report
  13. GRB 250804B: Tiled Swift observations
  14. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  15. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  16. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  17. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT follow up of AT 2025smm
  18. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  20. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  22. GRB 250725A: AstroSat CZTI detection
  23. GRB 250727A: EP-FXT follow-up observation
  24. GRB 250725A: PRIME near-infrared observations
  25. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  26. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  27. GRB 250728A: Swift-XRT observations
  28. GRB 250728A: COLIBRÍ optical upper limit
  29. GRB 250728A: Fermi GBM Observation
  30. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
  31. GRB 250728A: Swift ToO observations
  32. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  33. GRB 250727A: EP-FXT counterpart detection
  34. GRB250727A: SVOM/VT optical upper limit
  35. GRB 250727A: Swift-XRT observations
  36. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  37. GRB 250725A: Swift-XRT refined Analysis
  38. GRB 250725A: Fermi GBM Observation
  39. GRB 250725A: Swift-BAT refined analysis
  40. Konus-Wind detection of GRB 250725A
  41. GRB 250725A: SVOM/GRM observation
  42. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  43. GRB 250725A: Swift/UVOT Upper Limits
  44. GRB 250725A: Fermi-LAT detection
  45. GRB 250725A: BOOTES-7 early optical detection
  46. GRB 250725A: SVOM/VT optical candidate
  47. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  48. GRB 250725A: Enhanced Swift-XRT position
  49. GRB 250725A: Swift detection of a burst
  50. Swift GRB 250725A: Global MASTER-Net OT detection
  51. Swift GRB 250725A: Global MASTER-Net observations report
  52. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  53. Swift-BAT trigger 1334535 is not a GRB
  54. GRB 250721A: Swift-XRT observations
  55. GRB 250717B: SVOM/GRM observation
  56. GRB 250721A: Tiled Swift observations
  57. GRB 250717B: COLIBRÍ optical upper limit
  58. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  59. GRB 250717B: Swift-XRT observations
  60. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  61. Swift Trigger 1334535: a possible GRB 250718A
  62. Swift GRB250718.01: Global MASTER-Net observations report
  63. GRB 250717B: Swift ToO observations
  64. GRB 270713A: Kitab and AbAO Optical Observations
  65. GRB 250717B: Fermi GBM Observation
  66. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  67. GRB 250716A: Swift-XRT afterglow detection
  68. GRB 250716A: Swift ToO observations
  69. GRB 250713A: SVOM/C-GFT upper limit
  70. GRB 250713A: Swift-XRT observations
  71. GRB 250706A: Swift-BAT refined analysis
  72. GRB 250702F: Swift-BAT refined analysis
  73. GRB 250628A: Swift-BAT refined analysis
  74. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  75. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  76. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  77. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  78. GRB 250706B/C: Fermi-LAT detection
  79. GRB 250706B: Swift/UVOT Detection
  80. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  81. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 250702F: GRANDMA observations
  83. GRB 250706A: Swift-XRT refined Analysis
  84. GRB 250706A: Swift/UVOT Upper Limits
  85. GRB 250706A: REM optical/NIR observations
  86. Swift GRB 250706A: Global MASTER-Net observations report
  87. GRB 250706A: JinShan optical upper limits
  88. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  89. GRB250706B: Swift-XRT counterpart detection
  90. GRB 250706A: GROWTH-India Telescope optical upper limit
  91. GRB 250706A: Swift detection of a burst
  92. GRB 250704B: Swift-XRT refined Analysis
  93. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  94. GRB 250704B: Swift/UVOT Upper Limits
  95. GRB 250704A: Swift/UVOT Detection
  96. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  97. GRB 250702F: Kilonova-Catcher optical afterglow detection
  98. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  99. GRB 250704A: SVOM/VT optical observation
  100. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart

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