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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"

27166 results found.

  1. GRB 250806A: EP-FXT observation
  2. EP#01709198415/EP250806a: Swift-XRT observations
  3. EP250806a: Global MASTER-Net observations report
  4. EP250802a: EP-FXT follow-up observation
  5. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  6. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  7. EP250806a: SVOM /VT optical candidate
  8. GRB 250806A: J-band upper limit from WINTER
  9. GRB 250805A: Swift-BAT refined analysis
  10. GRB 250806A: SVOM/VT refined analysis
  11. GRB 250806A: Swift-XRT counterpart detection
  12. EP250806a: COLIBRÍ optical upper limit
  13. GRB 250806A: Kilonova-Catcher optical upper limits
  14. EP250806a: Einstein Probe detection of an X-ray transient
  15. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  16. GRB 250806A: SVOM/VT optical upper limit
  17. GRB 250806A: SVOM detection of a soft burst
  18. GRB 250805A: SVOM/VT optical counterpart
  19. GRB 250805A: Swift-XRT refined Analysis
  20. GRB 250804C: AstroSat CZTI detection of a long burst
  21. GRB 250805A: TRT optical upper limits
  22. GRB 250805A: Swift-XRT observations
  23. GRB 250805A: Swift detection of a burst
  24. Swift GRB250805.26: Global MASTER-Net observations report
  25. Fermi trigger No 776041355: Global MASTER-Net observations report
  26. GRB 250804B: SVOM/GRM observation of a short burst
  27. GRB 250804A: Fermi GBM Final Localization
  28. EP250730a: SVOM/VT optical upper limit
  29. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  30. EP250802a: Liverpool Telescope optical upper limits
  31. EP250802a: Global MASTER-Net observations report
  32. EP250802a: GROWTH-India Telescope optical upper limit
  33. EP250802a: Einstein Probe detection of an X-ray transient
  34. The EP-WXT trigger 01709198251 is likely a flaring star
  35. The EP-WXT trigger 01709198202 is likely a flaring star
  36. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  37. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  38. EP250711a: CrAO and Assy optical observations
  39. EP250730a: Global MASTER-Net observations report
  40. EP250730a: COLIBRÍ optical upper limit
  41. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  42. EP250730a: Einstein Probe detection of an X-ray transient
  43. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT follow up of AT 2025smm
  44. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  45. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  47. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  48. GRB 250727A: EP-FXT follow-up observation
  49. GRB 250727A: SVOM/ECLAIRs refined analysis
  50. EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  51. GRB 250728A: COLIBRÍ optical upper limit
  52. GRB 250728A: Fermi GBM Observation
  53. Fermi trigger No 775387550: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
  55. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  56. GRB 250727A: EP-FXT counterpart detection
  57. GRB250727A: SVOM/VT optical upper limit
  58. GRB 250727A: Swift-XRT observations
  59. GRB 250727A: SVOM detection of a burst
  60. The EP-WXT trigger 01709195487 is likely a flaring star
  61. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  62. GRB 250725A: Swift-XRT refined Analysis
  63. GRB 250725A: Fermi GBM Observation
  64. GRB 250725A: Swift-BAT refined analysis
  65. GRB 250725A: SVOM/GRM observation
  66. GRB 250725A: Swift/UVOT Upper Limits
  67. GRB 250725A: Fermi-LAT detection
  68. GRB 250725A: SVOM/VT optical candidate
  69. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  70. GRB 250725A: Swift detection of a burst
  71. Swift GRB 250725A: Global MASTER-Net OT detection
  72. GRB 250725A: Fermi GBM Final Real-time Localization
  73. Fermi GRB 250725A: Global MASTER-Net observations report
  74. Swift GRB 250725A: Global MASTER-Net observations report
  75. SVOM J195836+32283/sb25072103: Second VT observation
  76. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  77. GRB 250723B: Fermi GBM Final Real-time Localization
  78. GRB 250721A: Fermi GBM Observation
  79. GRB 250723A: Fermi GBM Final Real-time Localization
  80. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  81. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  82. Swift-BAT trigger 1334535 is not a GRB
  83. GRB 250722A: Fermi GBM Final Real-time Localization
  84. GRB 250713A : SVOM/ECLAIRs refined analysis
  85. GRB 250717B: SVOM/GRM observation
  86. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  87. GRB 250721A: Fermi GBM Final Localization
  88. GRB 250720B: Fermi GBM Final Localization Correction
  89. GRB 250720A: Fermi GBM Final Localization
  90. Fermi trigger No 774730635: Global MASTER-Net observations report
  91. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  92. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  93. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  94. GRB 250717B: COLIBRÍ optical upper limit
  95. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  96. GRB 250718B: Fermi GBM Final Localization Correction
  97. GRB 250718B: Fermi GBM Final Real-time Localization
  98. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  99. Swift Trigger 1334535: a possible GRB 250718A
  100. Swift GRB250718.01: Global MASTER-Net observations report

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