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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"

28200 results found.

  1. GRB 250912A: Fermi GBM Final Real-time Localization
  2. EP250908c: tentative VLT/FORS2 redshift z = 2.87
  3. GRB 250911A: GECAM-B detection
  4. EP250911a: GTC/OSIRIS+ spectroscopic redshift z = 3.84
  5. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  6. EP250911a: SVOM/VT optical observation
  7. GRB 250911A: MASTER optical counterpart observations
  8. GRB 250911A: Swift-XRT refined Analysis
  9. GRB 250910C: Fermi GBM Final Localization Correction
  10. EP250911a: Swift-XRT observations
  11. EP250911a: Optical detection with Kinder observations
  12. GRB 250911A: Swift/UVOT Detection
  13. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  14. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  15. GRB 250909B: Insight-HXMT detection
  16. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  17. EP250911a: LCO optical counterpart discovery
  18. EP250911a: Einstein Probe detection of an X-ray transient
  19. GRB 250911A: Enhanced Swift-XRT position
  20. GRB 250911A: Swift-XRT observations
  21. GRB 250911A: Swift detection of a burst
  22. GRB 250910B: Fermi GBM Final Real-time Localization
  23. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  24. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  25. GRB 250909B: AstroSat CZTI detection of a long burst
  26. GRB 250909A: AstroSat CZTI detection
  27. GRB 250910A: SVOM/MXT possible afterglow detection
  28. GRB 250910A: SVOM detection of a faint burst
  29. LIGO/Virgo/KAGRA S250910b: Retraction of GW compact binary merger candidate
  30. GRB 250702B: Late time Chandra observations
  31. EP250908b/EP#01709240653: Swift/UVOT Detection
  32. EP#01709240653: Swift-XRT observations
  33. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  34. EP250908c: VLT/FORS2 optical counterpart identification
  35. EP250908c: Einstein Probe detection of an X-ray transient
  36. GRB 250909A: Fermi GBM Final Real-time Localization
  37. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  38. GRB 250907A: GECAM-B detection
  39. GRB 250903A: Swift-XRT afterglow detection
  40. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  41. EP250905b: EP-FXT follow-up observation
  42. EP250905a: Liverpool Telescope observations
  43. EP250905b: EP-WXT detection of a fast X-ray transient
  44. GRB 250905A: Swift-XRT refined Analysis
  45. EP250905a: JinShan likely optical counterpart detection
  46. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  47. GRB 250905A: Swift/UVOT Upper Limits
  48. EP250905a: Einstein Probe detection of an X-ray transient
  49. GRB 250905B: Fermi GBM Final Localization
  50. GRB250904A: Liverpool Telescope upper limits
  51. GRB 250905A: Enhanced Swift-XRT position
  52. GRB 250904A: Swift/UVOT Detection
  53. GRB 250903A: Swift/UVOT detection
  54. GRB 250904A: Swift-XRT refined Analysis
  55. EP detected a brightening of LMXB 1ES 1735-26.9
  56. GRB 250905A: KAIT optical upper limit
  57. GRB 250905A: Swift detection of a burst
  58. GRB 250904A: Enhanced Swift-XRT position
  59. GRB 250904A: TRT optical counterpart detection
  60. GRB 250902B: CALET Gamma-Ray Burst Monitor detection
  61. GRB 250904A: Prompt enhanced Swift-XRT position
  62. GRB 250904A: Swift detection of a burst
  63. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  64. GRB 250902A: VZLUSAT-2 detection
  65. GRB 250903A: Swift-XRT observations
  66. EP250903a: Swift-XRT observations
  67. EP#01709201209: Swift-XRT observations
  68. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  69. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  70. GRB 250830C: VZLUSAT-2 detection
  71. GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
  72. GRB 250903A: EP-FXT counterpart detection
  73. GRB 250902A: GECAM-B detection
  74. GRB 250903A: LCO optical observation
  75. GRB 250903A: LCO optical afterglow detection
  76. EP250901a: Mondy, Assy and SAO RAS optical limits
  77. Subject GRB 250903A: SVOM/MXT afterglow detection
  78. EP250903a: LCO candidate counterpart discovery
  79. GRB 250903A: TRT optical counterpart detection
  80. GRB 250902B: AstroSat CZTI detection
  81. GRB 250903A: SVOM detection of a burst
  82. EP250903a: Einstein Probe detection of an X-ray transient
  83. EP 250827B: Detection of supernova counterpart by LCO.
  84. EP250827b: continued Liverpool Telescope observations
  85. EP250827b: SVOM/VT observation of AT 2025wkm
  86. GRB 250902A: Fermi GBM Detection
  87. GRB 250901A: Swift/UVOT Upper Limit
  88. GRB 250902B: Fermi GBM Final Real-time Localization
  89. GRB 250830B: Swift-XRT afterglow detection
  90. EP250827b: Liverpool Telescope observations
  91. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  92. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  93. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  94. GRB 250901A: EP-FXT follow-up observation
  95. GRB 250901A: NOT optical observations
  96. GRB 250902A: Fermi GBM Final Real-time Localization
  97. GRB 250901A: SVOM/VT optical afterglow with VHF data
  98. GRB 250901A: Swift-XRT afterglow detection
  99. EP250901a: Swift-XRT observations
  100. GRB 250901A: LCO optical upper limit

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