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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"

22212 results found.

  1. EP 250108A: Upper limits from Fermi-GBM Observations
  2. GRB 250129A: LCO late afterglow detection
  3. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  4. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  5. GRB 250129a: Liverpool Telescope optical follow-up
  6. GRB 240129A: further SAO RAS optical observations
  7. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  8. GRB 250129A: SVOM/C-GFT optical observations
  9. Swift GRB250129A: MASTER 4 days observations report
  10. GRB 250201A: INTEGRAL SPI/ACS detection
  11. GRB 250129A: 1.3m DFOT Optical observations
  12. GRB 250129A: Liverpool Telescope observations suggest continued engine activity
  13. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  14. GRB 250129A: Skynet Continued Optical Observations
  15. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  16. GRB 250129A: SAO RAS optical observations
  17. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  18. GRB 250129A: optical photometry from Konkoly
  19. GRB 250129A: COLIBRÍ Optical Observations
  20. GRB 250128B: VLA possible radio detection
  21. GRB 250129A: continued KAIT observations indicating steep decay after 28.5h
  22. GRB 250129A: NOT optical observations of continuining activity
  23. GRB 250129a: Liverpool Telescope optical follow-up
  24. GRB 250129A: TNG NIR afterglow detection
  25. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  26. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  27. GRB 250128B: VLA radio upper limit
  28. Ep250125A: 1.3m DFOT optical upper limit
  29. GRB 250129A: Skynet optical observations
  30. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  31. GRB 250128B: Gemini-North optical extended source detection
  32. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  33. GRB 250129A: Swift/UVOT Detection
  34. GRB 250128B: VLT/HAWKI near-infrared observations
  35. GRB 250127A: CrAO and Terskol optical upper limits
  36. GRB 250128B: VLT/FORS2 optical observations
  37. GRB 250129A: REM optical/NIR afterglow detection
  38. GRB 250129A: OHP/T193 optical and spectroscopy observations
  39. GRB 250129A: Early afterglow detection by LCO.
  40. GRB 250129A: LCO optical observations
  41. GRB 250129A: NOT optical observations and redshift confirmation
  42. GRB 250129A: GOTO optical observations show brightening afterglow
  43. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  44. Swift GRB 250129A: Global MASTER-Net observations report
  45. Fermi GRB 250128B: Global MASTER-Net observations report
  46. GRB 250128B: GOTO optical upper limit
  47. Swift GRB 250128B: Global MASTER-Net observations report
  48. EP250125a: Upper limits from Swift/BAT-GUANO
  49. GRB 250128B: LCO optical observations
  50. GRB 250127A: Swift-XRT observations
  51. GRB 250127B: DDOTI Upper Limit on the Afterglow
  52. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  53. Fermi GRB 250128A: Global MASTER-Net observations report
  54. Fermi GRB 250127B: Global MASTER-Net observations report
  55. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  56. GRB 250127A: SVOM/VT upper limit
  57. GRB 250127A: Swift ToO observations
  58. GRB 250127A: LCO optical upper limit
  59. EP250125A: Non-detection from Fermi-GBM Observations
  60. EP250125a: Optical upper limit with Kinder observations
  61. EP250125a: REM optical counterpart detection
  62. EP250125a: Swift/XRT detection of a fading counterpart
  63. EP250125a: a new X-ray transient detected by Einstein Probe
  64. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  65. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  66. EP250108a: AbAO, CMO and Terskol optical upper limits
  67. Konus-Wind detection of GRB 250119B
  68. GRB 250121A: INTEGRAL/SPI-ACS detection
  69. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  70. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  71. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  72. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  73. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  74. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  75. ATCA detection of possible radio counterpart to GRB 250114A
  76. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  77. GRB 250119B: INTEGRAL/SPI-ACS detection
  78. EP 250108A: Late-time optical observation by LCO
  79. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  80. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  81. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  82. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  83. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  84. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  85. GRB 250117A: GECAM observation of a short burst
  86. EP250108a / AT2025kg: GMG Optical Observations
  87. EP250108a / AT2025kg: VLA radio upper limit
  88. GRB 241217A / EP241217B: radio detection with the VLA
  89. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  90. GRB 250114B: Swift-XRT afterglow detection
  91. GRB 250114B: SVOM/VT upper limit
  92. EP250108a: MeerKAT radio upper limit
  93. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  94. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  95. Konus-Wind detection 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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