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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

27803 results found.

  1. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  2. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  3. GRB 250128B: VLA radio upper limit
  4. Ep250125A: 1.3m DFOT optical upper limit
  5. GRB 250129A: Skynet optical observations
  6. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  7. GRB 250129A: Swift-XRT refined Analysis
  8. GRB 250128B: Gemini-North optical extended source detection
  9. GRB 250128B: TNG optical upper limit
  10. GRB 250129A: Swift/UVOT Detection
  11. GRB 250127A: CrAO and Terskol optical upper limits
  12. GRB 250129A: Enhanced Swift-XRT position
  13. GRB 250128B: NOT optical upper limit
  14. GRB 250129A: REM optical/NIR afterglow detection
  15. GRB 250129A: Early afterglow detection by LCO.
  16. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  17. GRB 250129A: LCO optical observations
  18. GRB 250129A: GOTO optical observations show brightening afterglow
  19. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  20. Swift GRB 250129A: Global MASTER-Net observations report
  21. GRB 250128B: Enhanced Swift-XRT position
  22. GRB 250129A: Swift detection of a burst with an optical counterpart
  23. Swift GRB 250129A: Global MASTER-Net OT detection
  24. GRB 250128B: Swift-XRT refined Analysis
  25. GRB 250128B: Fermi GBM Observation
  26. GRB 250128B: GOTO optical upper limit
  27. Swift GRB 250128B: Global MASTER-Net observations report
  28. EP250125a: Upper limits from Swift/BAT-GUANO
  29. GRB 250128B: LCO optical observations
  30. GRB 250128B: Swift detection of a short burst
  31. GRB 250128B: Fermi GBM Final Real-time Localization
  32. GRB 250127A: Swift-XRT observations
  33. GRB 250127B: DDOTI Upper Limit on the Afterglow
  34. GRB 250127A: EP-FXT afterglow detection
  35. GRB 250128A: Fermi GBM Final Real-time Localization
  36. GRB 250117A: Fermi GBM Observation
  37. GRB 250127A: SVOM/VT upper limit
  38. GRB 250127B: Fermi GBM Final Real-time Localization
  39. IPN triangulation of GRB 250119C
  40. GRB 250127A: Swift ToO observations
  41. GRB 241223A: cubesat Avion detection
  42. GRB 250127A: SVOM detection of a long burst
  43. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  44. EP250125A: Non-detection from Fermi-GBM Observations
  45. GRB 250126A: MAXI/GSC detection
  46. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  47. GRB 250126A: Fermi GBM Final Real-time Localization
  48. GECAM-A detection of a bright burst from SGR 1E1841-045
  49. GRB 250118A: Fermi GBM Observation
  50. EP250125a: Optical upper limit with Kinder observations
  51. EP250125a: REM optical counterpart detection
  52. GRB 250119C: Fermi GBM Observation
  53. EP250125a: Swift/XRT detection of a fading counterpart
  54. EP250125a: a new X-ray transient detected by Einstein Probe
  55. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  56. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  57. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  58. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  59. Konus-Wind detection of GRB 250118B
  60. IPN triangulation of GRB 250118B
  61. Konus-Wind detection of GRB 250119B
  62. IPN triangulation of GRB 250119B
  63. GRB 250122A: Fermi GBM Final Real-time Localization
  64. Improved IPN triangulation of GRB 250107C
  65. GRB 250114A: Swift-BAT refined analysis
  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 250119C: Swift/BAT-GUANO localization skymap of a short burst
  70. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  71. GRB 250121A: Fermi GBM Final Real-time Localization
  72. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  73. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  74. Konus-Wind detection of GRB 250117A
  75. IPN triangulation of GRB 250117A (short)
  76. ATCA detection of possible radio counterpart to GRB 250114A
  77. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  78. GRB 250119B: INTEGRAL/SPI-ACS detection
  79. GRB 250117A: SVOM/GRM observation of a short burst
  80. GRB 250119C: Fermi GBM Final Real-time Localization
  81. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  82. GRB 250119B: Fermi GBM Final Real-time Localization
  83. GRB 250119A: Fermi GBM Final Real-time Localization
  84. GRB 250118A: Fermi GBM Final Real-time Localization
  85. Konus-Wind detection of GRB 250116A
  86. GRB 250116A: GECAM-B detection of a long burst
  87. GRB 241217A / EP241217B: radio detection with the VLA
  88. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  89. Swift Trigger 1282245 is not a GRB
  90. GRB 250116A: Fermi-LAT detection
  91. GRB 250114B: Swift-XRT afterglow detection
  92. GRB 250114B: SVOM/VT upper limit
  93. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  94. Konus-Wind detection of GRB 250113A
  95. IPN triangulation of GRB 250113A
  96. GRB 250114B: Liverpool Telescope optical upper limit
  97. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  98. GRB 250114B: Swift-XRT observations
  99. GRB 250114A: LCO optical counterpart detection.
  100. GRB 250114A: GRANDMA/TAROT optical afterglow detection

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