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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"

27829 results found.

  1. Konus-Wind detection of GRB 250225B
  2. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  3. GRB 250225B: VLT/FORS2 candidate optical afterglow
  4. GRB 250225B: SVOM/GRM observation of a long burst
  5. GRB 250226A: GECAM-B detection
  6. GRB 250221A: EP-FXT detection of the X-ray afterglow
  7. EP250226a/GRB 250226A: GSP detects optical counterpart
  8. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  9. EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
  10. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  11. Swift GRB 250225B: Global MASTER-Net observations report
  12. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  13. GRB 250226A: Fermi GBM Final Real-time Localization
  14. EP250225a: GSP optical upper limit
  15. EP250225a: Einstein Probe detected of a fast X-ray transient
  16. GRB 250225B: Swift detection of a burst
  17. GRB 250221A: Swift-BAT refined analysis
  18. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  19. GRB 250225A: Fermi GBM Final Real-time Localization
  20. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  21. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  22. GRB 250207a: ATCA Radio Upper Limits
  23. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  24. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  25. GRB 250119B: VZLUSAT-2 detection
  26. GRB 250223C: Fermi GBM Final Real-time Localization
  27. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  28. GRB 250202B: VZLUSAT-2 detection
  29. GRB 250219A: EP-FXT afterglow detection
  30. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  31. GRB 250210A: VZLUSAT-2 detection
  32. GRB 250206A: VZLUSAT-2 detection
  33. EP250223a: REM NIR upper limit
  34. EP250223a: TRT optical afterglow observation
  35. EP250223a: refined analysis of the EP-WXT and FXT observations
  36. GRB 250221A: TNOT detection of the optical counterpart
  37. EP250223a: SVOM/VT optical observation
  38. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  39. 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
  40. EP250223a: OASDG optical observations
  41. EP250223a: LCO detection of the afterglow
  42. EP250223a: early optical detection by BOOTES-4
  43. EP250223a: NOT redshift z = 2.756
  44. EP250223a: Swift/XRT localization
  45. GRB 250223B: Fermi GBM Final Localization
  46. GRB 250221A: VLA radio detection
  47. GRB 250223A: Fermi GBM Final Real-time Localization
  48. EP250223a: Einstein Probe detection of an X-ray transient
  49. GRB 250221A: continued Assy optical observations, brightening afterglow confirmation
  50. GRB 250221A: continued Mondy optical observations, brightening afterglow
  51. GRB 250221A: Optical counterpart detection by LCO.
  52. GRB 250221A: Mondy optical observations
  53. Konus-Wind detection of GRB 250221A
  54. GRB 250221A: Assy optical observations
  55. EP250220a: EP-FXT follow-up observations
  56. GRB 250221A: GRANDMA/TAROT Detection
  57. GRB 250221A: Swift-XRT refined Analysis
  58. GRB 250221A: NOT optical observations
  59. GRB 250221A: 1.6m Mephisto optical detection
  60. GRB 250221A: AKO Optical Upper Limit
  61. GRB 250221A: Swift/UVOT Detection
  62. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  63. GRB 250221A: REM optical/NIR afterglow detection
  64. GRB 250221A: Enhanced Swift-XRT position
  65. EP250220a: Liverpool Telescope optical upper limits
  66. EP250220a: Optical upper limit with Kinder observations
  67. SVOM trigger sb25022102 is not an astrophysical event
  68. SVOM/sb25022102: SVOM detection of an X-ray transient
  69. GRB 250221A: COLIBRÍ/DDRAGO Confirmation of a Bright Optical Counterpart
  70. GRB 250221A: Swift detection of a burst with an optical counterpart
  71. Swift GRB250221.15: Global MASTER-Net OT detection
  72. Swift GRB250221.15: Global MASTER-Net observations report
  73. EP250220a: Xinglong optical upper limit
  74. GRB 250220B: Fermi GBM Final Real-time Localization
  75. GRB 250220A: Fermi GBM Final Real-time Localization
  76. EP250220a: EP-WXT detection of a fast X-ray transient
  77. Konus-Wind detection of GRB 250217C (short)
  78. GRB 250219A: Swift/UVOT Upper Limits
  79. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  80. GRB 250219A: 1.6m Mephisto optical upper limits
  81. GRB 250219A: SVOM/VT optical counterpart
  82. GRB 250219A: Swift-XRT observations
  83. GRB 250219A: Swift ToO observations
  84. GRB 250219A: SVOM detection of a burst
  85. Konus-Wind detection of GRB 250215A / EP250215a
  86. GRB 250217C: Swift-XRT observations
  87. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  88. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  89. GRB 250217C: Tiled Swift observations
  90. IPN triangulation of GRB 250217C (short)
  91. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  92. SVOM/sb25021804: SVOM detection of a long X-ray transient
  93. GRB 250213A: Swift-XRT observations
  94. GRB 250216A: AstroSat CZTI detection
  95. GRB 250217C: AstroSat CZTI detection of a short burst
  96. GRB 250217C: Fermi GBM Final Real-time Localization
  97. GRANDMA/OPD observations of GRB250215A
  98. GRB 250217B: Fermi GBM Final Real-time Localization
  99. GRB 250217A: Fermi GBM Final Real-time Localization
  100. GRB 250215A / EP250215a: LCO detection of the afterglow

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