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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"

28104 results found.

  1. GRB 250129A: iTelescope optical observation
  2. GRB 250129A: NOT optical observations of continuining activity
  3. GRB 250129a: Liverpool Telescope optical follow-up
  4. GRB 250129A: TNG NIR afterglow detection
  5. GRB 250129A: AKO Optical Afterglow Detection
  6. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  7. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  8. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  9. GRB 250128B: VLA radio upper limit
  10. Ep250125A: 1.3m DFOT optical upper limit
  11. GRB 250129A: Skynet optical observations
  12. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  13. GRB 250129A: Swift-XRT refined Analysis
  14. GRB 250128B: Gemini-North optical extended source detection
  15. GRB 250128B: TNG optical upper limit
  16. GRB 250129A: Swift/UVOT Detection
  17. GRB 250128B: VLT/HAWKI near-infrared observations
  18. GRB 250127A: CrAO and Terskol optical upper limits
  19. GRB 250129A: Enhanced Swift-XRT position
  20. GRB 250128B: NOT optical upper limit
  21. GRB 250128B: VLT/FORS2 optical observations
  22. GRB 250129A: REM optical/NIR afterglow detection
  23. GRB 250129A: OHP/T193 optical and spectroscopy observations
  24. GRB 250129A: Early afterglow detection by LCO.
  25. GRB 250128B: OHP/T193 optical upper limit
  26. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  27. GRB 250129A: LCO optical observations
  28. GRB 250129A: GOTO optical observations show brightening afterglow
  29. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  30. GRB 250128B: Enhanced Swift-XRT position
  31. GRB 250129A: Swift detection of a burst with an optical counterpart
  32. Swift GRB 250129A: Global MASTER-Net OT detection
  33. GRB 250128B: Swift-XRT refined Analysis
  34. GRB 250128B: GOTO optical upper limit
  35. GRB 250128B: LCO optical observations
  36. GRB 250128B: Swift detection of a short burst
  37. GRB 250128B: Fermi GBM Final Real-time Localization
  38. GRB 250127A: Swift-XRT observations
  39. GRB 250127B: DDOTI Upper Limit on the Afterglow
  40. GRB 250127A: EP-FXT afterglow detection
  41. GRB 250128A: Fermi GBM Final Real-time Localization
  42. GRB 250127A: SVOM/VT upper limit
  43. GRB 250127B: Fermi GBM Final Real-time Localization
  44. IPN triangulation of GRB 250119C
  45. GRB 250127A: Swift ToO observations
  46. GRB 241223A: cubesat Avion detection
  47. GRB 250127A: SVOM detection of a long burst
  48. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  49. EP250125A: Non-detection from Fermi-GBM Observations
  50. GRB 250126A: MAXI/GSC detection
  51. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  52. GRB 250126A: Fermi GBM Final Real-time Localization
  53. GECAM-A detection of a bright burst from SGR 1E1841-045
  54. EP250125a: Optical upper limit with Kinder observations
  55. EP250125a: REM optical counterpart detection
  56. EP250125a: Swift/XRT detection of a fading counterpart
  57. EP250125a: a new X-ray transient detected by Einstein Probe
  58. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  59. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  60. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  61. Konus-Wind detection of GRB 250118B
  62. Konus-Wind detection of GRB 250119B
  63. IPN triangulation of GRB 250119B
  64. GRB 250122A: Fermi GBM Final Real-time Localization
  65. Improved IPN triangulation of GRB 250107C
  66. GRB 250121A: INTEGRAL/SPI-ACS detection
  67. GRB 250121A: Fermi-LAT detection
  68. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  69. GRB 250121A: Fermi GBM Final Real-time Localization
  70. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  71. Konus-Wind detection of GRB 250117A
  72. IPN triangulation of GRB 250117A (short)
  73. ATCA detection of possible radio counterpart to GRB 250114A
  74. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  75. GRB 250119B: INTEGRAL/SPI-ACS detection
  76. GRB 250119C: Fermi GBM Final Real-time Localization
  77. GRB 250119B: Fermi GBM Final Real-time Localization
  78. GRB 250119A: Fermi GBM Final Real-time Localization
  79. GRB 250118A: Fermi GBM Final Real-time Localization
  80. EP250108a / AT2025kg: VLA radio upper limit
  81. Konus-Wind detection of GRB 250116A
  82. GRB 250116A: GECAM-B detection of a long burst
  83. GRB 241217A / EP241217B: radio detection with the VLA
  84. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  85. GRB 250116A: Fermi-LAT detection
  86. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  87. GRB 250114B: Swift-XRT afterglow detection
  88. GRB 250114B: SVOM/VT upper limit
  89. Konus-Wind detection of GRB 250113A
  90. IPN triangulation of GRB 250113A
  91. GRB 250114B: Liverpool Telescope optical upper limit
  92. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  93. GRB 250114B: Swift-XRT observations
  94. GRB 250114A: LCO optical counterpart detection.
  95. GRB 250114B: OHP/T193 optical upper limit
  96. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  97. GRB 250114A: Swift-XRT refined Analysis
  98. GRB 250114A: LCOGT optical afterglow i-band detection
  99. GRB 250114B: Swift ToO observations
  100. GRB 250114A: Enhanced Swift-XRT position

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