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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"

19588 results found.

  1. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  2. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  3. GRB 250129a: Liverpool Telescope optical follow-up
  4. GRB 240129A: further SAO RAS optical observations
  5. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  6. GRB 250129A: SVOM/C-GFT optical observations
  7. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  8. Swift GRB250129A: MASTER 4 days observations report
  9. Konus-Wind detection of GRB 250129A
  10. GRB 250129A: 1.3m DFOT Optical observations
  11. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  12. GRB 250129A: SAO RAS optical observations
  13. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  14. GRB 250129A: COLIBRÍ Optical Observations
  15. GRB 250129A: iTelescope optical observation
  16. GRB 250129a: Liverpool Telescope optical follow-up
  17. GRB 250129A: TNG NIR afterglow detection
  18. GRB 250129A: AKO Optical Afterglow Detection
  19. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  20. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  21. GRB 250128B: VLA radio upper limit
  22. Ep250125A: 1.3m DFOT optical upper limit
  23. GRB 250129A: Skynet optical observations
  24. GRB 250128B: TNG optical upper limit
  25. GRB 250129A: Swift/UVOT Detection
  26. GRB 250128B: VLT/HAWKI near-infrared observations
  27. GRB 250127A: CrAO and Terskol optical upper limits
  28. GRB 250129A: Enhanced Swift-XRT position
  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. GRB 250129A: LCO optical observations
  36. GRB 250128B: Enhanced Swift-XRT position
  37. GRB 250129A: Swift detection of a burst with an optical counterpart
  38. GRB 250128B: Swift-XRT refined Analysis
  39. GRB 250128B: GOTO optical upper limit
  40. EP250125a: Upper limits from Swift/BAT-GUANO
  41. GRB 250128B: LCO optical observations
  42. GRB 250128B: Swift detection of a short burst
  43. GRB 250127A: Swift-XRT observations
  44. GRB 250127B: DDOTI Upper Limit on the Afterglow
  45. IPN triangulation of GRB 250119C
  46. GRB 250127A: Swift ToO observations
  47. GRB 250127A: LCO optical upper limit
  48. GRB 241223A: cubesat Avion detection
  49. GRB 250127A: SVOM detection of a long burst
  50. EP250125a: Optical upper limit with Kinder observations
  51. EP250125a: REM optical counterpart detection
  52. EP250125a: a new X-ray transient detected by Einstein Probe
  53. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  54. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  55. EP250108a: AbAO, CMO and Terskol optical upper limits
  56. IPN triangulation of GRB 250118B
  57. IPN triangulation of GRB 250119B
  58. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  59. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  60. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  61. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  62. IPN triangulation of GRB 250117A (short)
  63. EP 250108A: Late-time optical observation by LCO
  64. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  65. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  68. EP250108a / AT2025kg: GMG Optical Observations
  69. GRB 241217A / EP241217B: radio detection with the VLA
  70. GRB 250114B: Swift-XRT afterglow detection
  71. EP250108a: MeerKAT radio upper limit
  72. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  73. IPN triangulation of GRB 250113A
  74. GRB 250114B: Liverpool Telescope optical upper limit
  75. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  76. GRB 250114A: LCO optical counterpart detection.
  77. GRB 250114B: OHP/T193 optical upper limit
  78. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  79. GRB 250114A: LCOGT optical afterglow i-band detection
  80. GRB 250114B : GIT optical upper limit
  81. GRB 250114B: Swift ToO observations
  82. EP250111a: SAO RAS optical upper limit
  83. GRB 250114A: Enhanced Swift-XRT position
  84. GRB 250114A: REM detection of the optical and NIR counterpart
  85. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  86. GRB 250114A: LCO optical observations
  87. GRB 250114A: TRT optical observations
  88. GRB 250114A: Swift detection of a burst with an optical counterpart
  89. GRB 250101A: Terskol Zeiss-2000 optical observations
  90. EP250108a / AT 2025kg: SAO RAS optical observations
  91. EP241021a: SMA radio observation
  92. GRB 250113A: SVOM/GRM observation of a long burst
  93. EP250109b: optical upper limits with the Liverpool Telescope
  94. GRB 250106A: Swift-XRT afterglow detection
  95. EP250111a: KAIT optical observations
  96. GRB 250109A / EP250109a: Mephisto optical upper limits
  97. EP250108a: Mephisto detection
  98. EP250111a: Mondy optical observation
  99. EP250108a / AT 2025kg: LCO optical observations
  100. EP250111a: NOT likely optical counterpart

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