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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').
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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"

19953 results found.

  1. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  2. Konus-Wind detection of GRB 250225B
  3. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  4. GRB 250225B: VLT/FORS2 candidate optical afterglow
  5. GRB 250225B: SVOM/GRM observation of a long burst
  6. GRB 250221A: EP-FXT detection of the X-ray afterglow
  7. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  8. Swift GRB 250225B: Global MASTER-Net observations report
  9. GRB 250225B: Swift detection of a burst
  10. GRB 250221A: Swift-BAT refined analysis
  11. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  12. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  13. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  14. GRB 250207a: ATCA Radio Upper Limits
  15. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  16. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  17. GRB 250119B: VZLUSAT-2 detection
  18. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  19. GRB 250219A: EP-FXT afterglow detection
  20. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  21. EP250223a: REM NIR upper limit
  22. EP250223a: TRT optical afterglow observation
  23. EP250223a: refined analysis of the EP-WXT and FXT observations
  24. EP250223a: SVOM/VT optical observation
  25. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  26. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO trigger with ID 762004910: Identification of a GW compact binary merger candidate possibly associated with a sub-threshold Swift/BAT-GUANO trigger
  27. EP250223a: OASDG optical observations
  28. EP250223a: LCO detection of the afterglow
  29. EP250223a: early optical detection by BOOTES-4
  30. EP250223a: NOT redshift z = 2.756
  31. EP250223a: Swift/XRT localization
  32. GRB 250221A: VLA radio detection
  33. GRB 250221A: continued Assy optical observations, brightening afterglow confirmation
  34. GRB 250221A: continued Mondy optical observations, brightening afterglow
  35. GRB 250221A: Optical counterpart detection by LCO.
  36. GRB 250221A: Mondy optical observations
  37. Konus-Wind detection of GRB 250221A
  38. GRB 250221A: Assy optical observations
  39. GRB 250221A: GRANDMA/TAROT Detection
  40. GRB 250221A: Swift-XRT refined Analysis
  41. GRB 250221A: NOT optical observations
  42. GRB 250221A: 1.6m Mephisto optical detection
  43. GRB 250221A: AKO Optical Upper Limit
  44. GRB 250221A: Swift/UVOT Detection
  45. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  46. GRB 250221A: REM optical/NIR afterglow detection
  47. GRB 250221A: Enhanced Swift-XRT position
  48. GRB 250221A: COLIBRÍ/DDRAGO Confirmation of a Bright Optical Counterpart
  49. GRB 250221A: Swift detection of a burst with an optical counterpart
  50. Swift GRB250221.15: Global MASTER-Net OT detection
  51. Swift GRB250221.15: Global MASTER-Net observations report
  52. GRB 250219A: Swift/UVOT Upper Limits
  53. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  54. GRB 250219A: 1.6m Mephisto optical upper limits
  55. GRB 250219A: SVOM/VT optical counterpart
  56. GRB 250219A: Swift-XRT observations
  57. GRB 250219A: Swift ToO observations
  58. GRB 250217C: Swift-XRT observations
  59. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  60. GRB 250217C: Tiled Swift observations
  61. IPN triangulation of GRB 250217C (short)
  62. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  63. SVOM/sb25021804: SVOM detection of a long X-ray transient
  64. GRB 250213A: Swift-XRT observations
  65. GRB 250215A / EP250215a: LCO detection of the afterglow
  66. GRB 250215A: Swift/UVOT Upper Limits
  67. GRB 250215A: Fermi GBM Observation
  68. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  69. GRB 250215A: Swift-XRT refined Analysis
  70. GRB 250213A: Swift ToO observations
  71. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  72. GRB 250211A: Swift ToO observations
  73. GRB 250207A: Fermi GBM Observation
  74. Konus-Wind detection of GRB 250207A
  75. GRB 250207A: Skynet optical afterglow observations
  76. GRB 250207A: 1.3m DFOT Optical observations
  77. GRB 250206A: Swift-XRT observations
  78. GRB 250129A: GRANDMA Continued Afterglow Detection
  79. GRB 250207A: Swift-BAT refined analysis
  80. GRB 250205A: 1.3m DFOT optical upper limit
  81. GRB 250206A: Tiled Swift observations
  82. GRB 250206A: Fermi-LAT detection
  83. GRB 250207B: Swift-XRT observations
  84. EP250207a: EP-WXT detection and XRT follow-up observation
  85. GRB 250207A: Swift-XRT refined Analysis
  86. GRB 250207A: Enhanced Swift-XRT position
  87. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  88. GRB 250207A: REM IR afterglow detection
  89. GRB 250207A: FRAM-Auger optical detection
  90. GRB 250207B: Tiled Swift observations
  91. GRB 250207A: REM optical afterglow detection
  92. GRB 250207A: Swift/UVOT Detection
  93. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  94. GRB 250207A: Swift detection of a burst with optical counterpart
  95. GRB 250205A: Fermi GBM Observation
  96. GRB 250205A: Swift/UVOT Upper Limits
  97. GRB 250205A: Swift/XRT detection
  98. IPN triangulation of GRB 250201A
  99. GRB 250129A: Swift-BAT refined analysis
  100. IPN triangulation of GRB 250204B (short/hard)

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