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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"

27817 results found.

  1. EP250911a: Optical detection with Kinder observations
  2. GRB 250911A: Swift/UVOT Detection
  3. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  4. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  5. GRB 250909B: Insight-HXMT detection
  6. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  7. EP250911a: LCO optical counterpart discovery
  8. EP250911a: Einstein Probe detection of an X-ray transient
  9. GRB 250911A: Enhanced Swift-XRT position
  10. GRB 250911A: Swift-XRT observations
  11. GRB 250911A: COLIBRÍ optical counterpart candidate
  12. GRB 250911A: Swift detection of a burst
  13. GRB 250910B: Fermi GBM Final Real-time Localization
  14. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  15. GRB 250909B: AstroSat CZTI detection of a long burst
  16. GRB 250909A: AstroSat CZTI detection
  17. GRB 250910A: SVOM/MXT possible afterglow detection
  18. GRB 250910A: SVOM detection of a faint burst
  19. LIGO/Virgo/KAGRA S250910b: Retraction of GW compact binary merger candidate
  20. GRB 250702B: Late time Chandra observations
  21. EP250908b/EP#01709240653: Swift/UVOT Detection
  22. EP#01709240653: Swift-XRT observations
  23. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  24. EP250908c: Einstein Probe detection of an X-ray transient
  25. GRB 250909A: Fermi GBM Final Real-time Localization
  26. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  27. GRB 250907A: GECAM-B detection
  28. GRB 250905A: Swift-BAT refined analysis
  29. GRB 250903A: Swift-XRT afterglow detection
  30. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  31. EP250905b: EP-FXT follow-up observation
  32. EP250905a: Liverpool Telescope observations
  33. EP250905b: EP-WXT detection of a fast X-ray transient
  34. GRB 250905A: Swift-XRT refined Analysis
  35. EP250905a: JinShan likely optical counterpart detection
  36. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  37. GRB 250904A: Swift-BAT refined analysis
  38. GRB 250905A: Swift/UVOT Upper Limits
  39. EP250905a: Einstein Probe detection of an X-ray transient
  40. GRB 250905B: Fermi GBM Final Localization
  41. GRB 250905A: Enhanced Swift-XRT position
  42. GRB 250904A: Swift/UVOT Detection
  43. GRB 250903A: Swift/UVOT detection
  44. GRB 250904A: Swift-XRT refined Analysis
  45. EP detected a brightening of LMXB 1ES 1735-26.9
  46. GRB 250905A: KAIT optical upper limit
  47. GRB 250905A: Swift detection of a burst
  48. Swift GRB250905.09: Global MASTER-Net observations report
  49. Swift GRB 250904A: Global MASTER-Net observations report
  50. GRB 250904A: Enhanced Swift-XRT position
  51. GRB 250904A: TRT optical counterpart detection
  52. GRB 250902B: CALET Gamma-Ray Burst Monitor detection
  53. GRB 250904A: Prompt enhanced Swift-XRT position
  54. GRB 250904A: Swift detection of a burst
  55. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  56. GRB 250902A: VZLUSAT-2 detection
  57. GRB 250903A: Swift-XRT observations
  58. EP250903a: Swift-XRT observations
  59. EP#01709201209: Swift-XRT observations
  60. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  61. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  62. GRB 250830C: VZLUSAT-2 detection
  63. GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
  64. GRB 250903A: EP-FXT counterpart detection
  65. GRB 250902A: GECAM-B detection
  66. GRB 250903A: LCO optical afterglow detection
  67. EP250901a: Mondy, Assy and SAO RAS optical limits
  68. Subject GRB 250903A: SVOM/MXT afterglow detection
  69. GRB 250903A: TRT optical counterpart detection
  70. GRB 250902B: AstroSat CZTI detection
  71. GRB 250903A: SVOM detection of a burst
  72. EP250903a: Einstein Probe detection of an X-ray transient
  73. EP 250827B: Detection of supernova counterpart by LCO.
  74. EP250827b: continued Liverpool Telescope observations
  75. EP250827b: SVOM/VT observation of AT 2025wkm
  76. GRB 250902A: Fermi GBM Detection
  77. GRB 250901A: Swift/UVOT Upper Limit
  78. GRB 250902B: Fermi GBM Final Real-time Localization
  79. GRB 250830B: Swift-XRT afterglow detection
  80. EP250827b: Liverpool Telescope observations
  81. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  82. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  83. GRB 250901A: EP-FXT follow-up observation
  84. GRB 250902A: Fermi GBM Final Real-time Localization
  85. GRB 250901A: SVOM/VT optical afterglow with VHF data
  86. GRB 250901A: Swift-XRT afterglow detection
  87. EP250901a: Swift-XRT observations
  88. GRB 250901A: LCO optical upper limit
  89. EP250827b: Swift observations of AT 2025wkm
  90. EP250831a: NOT optical observations and tentative afterglow candidate
  91. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  92. GRB 250901A: SVOM detection of a burst
  93. GRB 250830C: Insight-HXMT detection
  94. GRB 250830C: GECAM-B detection
  95. GRB 250830C: AstroSat CZTI detection of a long burst
  96. EP250901a: Einstein Probe detection of an X-ray transient
  97. EP250831a: EP-FXT follow-up observation
  98. EP250831a: Swift-XRT observations
  99. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  100. EP250831a: EP-WXT detection of a fast X-ray transient

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