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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"

27827 results found.

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

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