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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"

32716 results found.

  1. GRB 250129A: Liverpool Telescope observations suggest continued engine activity
  2. GRB 250129A: Skynet Continued Optical Observations
  3. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  4. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  5. GRB 250129A: SAO RAS optical observations
  6. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  7. GRB 250129A: optical photometry from Konkoly
  8. GRB 250129A: COLIBRÍ Optical Observations
  9. GRB 250128B: VLA possible radio detection
  10. GRB 250129A: continued KAIT observations indicating steep decay after 28.5h
  11. GRB 250129A: iTelescope optical observation
  12. GRB 250129A: NOT optical observations of continuining activity
  13. GRB 250129a: Liverpool Telescope optical follow-up
  14. GRB 250129A: TNG NIR afterglow detection
  15. GRB 250129A: AKO Optical Afterglow Detection
  16. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  17. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  18. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  19. GRB 250128B: VLA radio upper limit
  20. Ep250125A: 1.3m DFOT optical upper limit
  21. GRB 250129A: Skynet optical observations
  22. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  23. GRB 250128B: Gemini-North optical extended source detection
  24. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  25. GRB 250128B: TNG optical upper limit
  26. GRB 250129A: Swift/UVOT Detection
  27. GRB 250128B: VLT/HAWKI near-infrared observations
  28. GRB 250127A: CrAO and Terskol optical upper limits
  29. GRB 250128B: NOT optical upper limit
  30. GRB 250128B: VLT/FORS2 optical observations
  31. GRB 250129A: REM optical/NIR afterglow detection
  32. GRB 250129A: OHP/T193 optical and spectroscopy observations
  33. GRB 250129A: Early afterglow detection by LCO.
  34. GRB 250128B: OHP/T193 optical upper limit
  35. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  36. GRB 250129A: LCO optical observations
  37. GRB 250129A: NOT optical observations and redshift confirmation
  38. GRB 250129A: GOTO optical observations show brightening afterglow
  39. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  40. Swift GRB 250129A: Global MASTER-Net observations report
  41. Fermi GRB 250128B: Global MASTER-Net observations report
  42. GRB 250128B: Fermi GBM Observation
  43. GRB 250128B: GOTO optical upper limit
  44. Swift GRB 250128B: Global MASTER-Net observations report
  45. EP250125a: Upper limits from Swift/BAT-GUANO
  46. GRB 250128B: LCO optical observations
  47. GRB 250127A: Swift-XRT observations
  48. GRB 250127B: DDOTI Upper Limit on the Afterglow
  49. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  50. GRB 250127A: EP-FXT afterglow detection
  51. Fermi GRB 250128A: Global MASTER-Net observations report
  52. GRB 250117A: Fermi GBM Observation
  53. Fermi GRB 250127B: Global MASTER-Net observations report
  54. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  55. GRB 250127A: SVOM/VT upper limit
  56. IPN triangulation of GRB 250119C
  57. GRB 250127A: Swift ToO observations
  58. GRB 250127A: LCO optical upper limit
  59. GRB 241223A: cubesat Avion detection
  60. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  61. EP250125A: Non-detection from Fermi-GBM Observations
  62. GRB 250126A: MAXI/GSC detection
  63. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  64. GECAM-A detection of a bright burst from SGR 1E1841-045
  65. GRB 250118A: Fermi GBM Observation
  66. EP250125a: Optical upper limit with Kinder observations
  67. EP250125a: REM optical counterpart detection
  68. GRB 250119C: Fermi GBM Observation
  69. EP250125a: Swift/XRT detection of a fading counterpart
  70. EP250125a: a new X-ray transient detected by Einstein Probe
  71. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  72. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  73. IPN triangulation of a bright burst from SGR 1E1841-045
  74. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  75. EP250108a: AbAO, CMO and Terskol optical upper limits
  76. Konus-Wind detection of GRB 250118B
  77. GRB 250121A: Fermi GBM Observation
  78. IPN triangulation of GRB 250118B
  79. Konus-Wind detection of GRB 250119B
  80. IPN triangulation of GRB 250119B
  81. Improved IPN triangulation of GRB 250107C
  82. GRB 250114A: Swift-BAT refined analysis
  83. GRB 250121A: INTEGRAL/SPI-ACS detection
  84. GRB 250121A: Fermi-LAT detection
  85. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  86. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  87. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  88. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  89. GRB 250119B: Fermi GBM Observation
  90. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  91. Konus-Wind detection of GRB 250117A
  92. IPN triangulation of GRB 250117A (short)
  93. ATCA detection of possible radio counterpart to GRB 250114A
  94. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  95. GRB 250119B: INTEGRAL/SPI-ACS detection
  96. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  97. EP 250108A: Late-time optical observation by LCO
  98. GRB 250117A: SVOM/GRM observation of a short burst
  99. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  100. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst

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