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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"

45798 results found.

  1. GRB 250202B: Fermi GBM Final Real-time Localization
  2. Swift GRB250129A: MASTER 4 days observations report
  3. GRB 250202A: Fermi GBM Final Real-time Localization
  4. GRB 250201A: INTEGRAL SPI/ACS detection
  5. Konus-Wind detection of GRB 250129A
  6. GRB 250129A: 1.3m DFOT Optical observations
  7. GRB 250129A: Liverpool Telescope observations suggest continued engine activity
  8. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  9. GRB 250201A: Fermi GBM Final Real-time Localization
  10. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  11. GRB 250129A: Skynet Continued Optical Observations
  12. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  13. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  14. GRB 250129A: SAO RAS optical observations
  15. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  16. GRB 250129A: optical photometry from Konkoly
  17. GRB 250129A: COLIBRÍ Optical Observations
  18. GRB 250128B: VLA possible radio detection
  19. GRB 250129A: continued KAIT observations indicating steep decay after 28.5h
  20. GRB 250129A: iTelescope optical observation
  21. GRB 250129A: NOT optical observations of continuining activity
  22. GRB 250129a: Liverpool Telescope optical follow-up
  23. GRB 250129A: TNG NIR afterglow detection
  24. GRB 250129A: AKO Optical Afterglow Detection
  25. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  26. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  27. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  28. GRB 250128B: VLA radio upper limit
  29. Ep250125A: 1.3m DFOT optical upper limit
  30. GRB 250129A: Skynet optical observations
  31. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  32. GRB 250129A: Swift-XRT refined Analysis
  33. GRB 250128B: Gemini-North optical extended source detection
  34. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  35. GRB 250128B: TNG optical upper limit
  36. GRB 250129A: Swift/UVOT Detection
  37. GRB 250128B: VLT/HAWKI near-infrared observations
  38. GRB 250127A: CrAO and Terskol optical upper limits
  39. GRB 250129A: Enhanced Swift-XRT position
  40. GRB 250128B: NOT optical upper limit
  41. GRB 250128B: VLT/FORS2 optical observations
  42. GRB 250129A: REM optical/NIR afterglow detection
  43. GRB 250129A: OHP/T193 optical and spectroscopy observations
  44. GRB 250129A: Early afterglow detection by LCO.
  45. GRB 250128B: OHP/T193 optical upper limit
  46. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  47. GRB 250129A: LCO optical observations
  48. GRB 250129A: NOT optical observations and redshift confirmation
  49. GRB 250129A: GOTO optical observations show brightening afterglow
  50. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  51. Swift GRB 250129A: Global MASTER-Net observations report
  52. GRB 250128B: Enhanced Swift-XRT position
  53. The EP-WXT trigger 01709131085 is likely a flaring star
  54. Fermi GRB 250128B: Global MASTER-Net observations report
  55. GRB 250129A: Swift detection of a burst with an optical counterpart
  56. Swift GRB 250129A: Global MASTER-Net OT detection
  57. GRB 250128B: Swift-XRT refined Analysis
  58. GRB 250128B: Fermi GBM Observation
  59. GRB 250128B: GOTO optical upper limit
  60. Swift GRB 250128B: Global MASTER-Net observations report
  61. EP250125a: Upper limits from Swift/BAT-GUANO
  62. GRB 250128B: LCO optical observations
  63. GRB 250128B: Swift detection of a short burst
  64. GRB 250128B: Fermi GBM Final Real-time Localization
  65. GRB 250127A: Swift-XRT observations
  66. GRB 250127B: DDOTI Upper Limit on the Afterglow
  67. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  68. GRB 250127A: EP-FXT afterglow detection
  69. Fermi GRB 250128A: Global MASTER-Net observations report
  70. GRB 250128A: Fermi GBM Final Real-time Localization
  71. GRB 250117A: Fermi GBM Observation
  72. Fermi GRB 250127B: Global MASTER-Net observations report
  73. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  74. GRB 250127A: SVOM/VT upper limit
  75. GRB 250127B: Fermi GBM Final Real-time Localization
  76. IPN triangulation of GRB 250119C
  77. GRB 250127A: Swift ToO observations
  78. GRB 250127A: LCO optical upper limit
  79. GRB 241223A: cubesat Avion detection
  80. GRB 250127A: SVOM detection of a long burst
  81. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  82. EP250125A: Non-detection from Fermi-GBM Observations
  83. GRB 250126A: MAXI/GSC detection
  84. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  85. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  86. GRB 250126A: Fermi GBM Final Real-time Localization
  87. GECAM-A detection of a bright burst from SGR 1E1841-045
  88. GRB 250118A: Fermi GBM Observation
  89. EP250125a: Optical upper limit with Kinder observations
  90. EP250125a: REM optical counterpart detection
  91. GRB 250119C: Fermi GBM Observation
  92. EP250125a: Swift/XRT detection of a fading counterpart
  93. EP250125a: a new X-ray transient detected by Einstein Probe
  94. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  95. The EP-WXT trigger 01709130758 is a false trigger
  96. The EP-WXT trigger 01709130758 is a false trigger
  97. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  98. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  99. IPN triangulation of a bright burst from SGR 1E1841-045
  100. GRB 250121A: CALET Gamma-Ray Burst Monitor detection

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