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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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subject:"Swift"
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submitter:"Judith Racusin"

28124 results found.

  1. GRB 250805A: Swift-BAT refined analysis
  2. GRB 250806A: KAIT optical upper limit
  3. GRB 250806A: Swift-XRT counterpart detection
  4. EP250806a: COLIBRÍ optical upper limit
  5. GRB 250806A: Kilonova-Catcher optical upper limits
  6. EP250806a: Einstein Probe detection of an X-ray transient
  7. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  8. GRB 250806A: SVOM/VT optical upper limit
  9. GRB 250806A: SVOM detection of a soft burst
  10. GRB 250805A: SVOM/VT optical counterpart
  11. GRB 250805A: Swift-XRT refined Analysis
  12. GRB 250804B: Swift-XRT observations
  13. GRB 250805A: Enhanced Swift-XRT position
  14. GRB 250805A: TRT optical upper limits
  15. GRB 250805A: Swift-XRT observations
  16. GRB 250804B: SVOM/GRM observation of a short burst
  17. GRB 250804A: Fermi GBM Final Localization
  18. EP250802a: additional Liverpool Telescope upper limits
  19. EP250730a: SVOM/VT optical upper limit
  20. EP250802a: Liverpool Telescope optical upper limits
  21. EP250802a: Global MASTER-Net observations report
  22. EP250802a: GROWTH-India Telescope optical upper limit
  23. LIGO/Virgo/KAGRA S250802dn: Updated Sky localization
  24. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  25. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  26. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
  27. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  28. EP250711a: CrAO and Assy optical observations
  29. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  30. EP250730a: COLIBRÍ optical upper limit
  31. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  32. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  33. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  34. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  35. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  36. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  37. GRB 250727A: EP-FXT follow-up observation
  38. GRB 250725A: PRIME near-infrared observations
  39. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  40. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  41. GRB 250728A: Swift-XRT observations
  42. GRB 250728A: COLIBRÍ optical upper limit
  43. LIGO/Virgo/KAGRA S250727dc: Updated Sky localization
  44. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  45. LIGO/Virgo/KAGRA S250727cl: Updated Sky localization
  46. GRB 250727A: EP-FXT counterpart detection
  47. GRB 250727A: Swift-XRT observations
  48. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
  51. LIGO/Virgo/KAGRA S250725l: Updated Sky localization
  52. LIGO/Virgo/KAGRA S250726ak: Updated Sky localization
  53. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  54. GRB 250725A: Swift-XRT refined Analysis
  55. GRB 250725A: Fermi GBM Observation
  56. LIGO/Virgo/KAGRA S250725j: Updated Sky localization
  57. GRB 250725A: Swift-BAT refined analysis
  58. LIGO/Virgo/KAGRA S250725j: NED Galaxies in the 3-Initial Localization Volume
  59. GRB 250725A: SVOM/GRM observation
  60. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  61. GRB 250725A: Swift/UVOT Upper Limits
  62. GRB 250725A: Fermi-LAT detection
  63. GRB 250725A: BOOTES-7 early optical detection
  64. GRB 250725A: SVOM/VT optical candidate
  65. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  66. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
  68. GRB 250725A: Enhanced Swift-XRT position
  69. GRB 250725A: Swift detection of a burst
  70. Swift GRB 250725A: Global MASTER-Net OT detection
  71. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  72. SVOM J195836+32283 is not a real source
  73. EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
  74. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  75. GRB 250721A: Fermi GBM Observation
  76. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  77. GRB 250721A: Swift-XRT observations
  78. GRB 250717B: SVOM/GRM observation
  79. LIGO/Virgo/KAGRA S250711q: Updated Sky localization
  80. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  81. GRB 250721A: MAXI/GSC detection
  82. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  83. GRB 250717B: COLIBRÍ optical upper limit
  84. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  85. GRB 250717B: Swift-XRT observations
  86. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  87. Swift GRB250718.01: Global MASTER-Net observations report
  88. GRB 270713A: Kitab and AbAO Optical Observations
  89. GRB 250717B: Fermi GBM Observation
  90. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  91. GRB 250716A: Swift-XRT afterglow detection
  92. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  93. GRB 250716A: Fermi GBM Observation
  94. GRB 250714A: SVOM/GRM observation
  95. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  96. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  97. GRB 250713A: Mephisto optical upper limits
  98. GRB 250713A: SVOM/VT optical upper limit
  99. GRB 250713A: NOT optical upper limits
  100. GRB 250713A: OHP/T193 upper limit

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