2008/05/29 by J. C. A. Miller-Jones, J. C. A. Miller‐Jones, E. Gallo +9
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Binary number #Black hole (networking) #Brightness #Flare #Galaxy #Interferometry #Optics #Physics #Sensitivity (control systems) #Synchrotron radiation #Very Long Baseline Array #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13495.x
Accepted for publication in MNRAS. 9 pages, 3 figures
arxiv created 2008/05/29 · openalex publication_date 2008/06/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Observations of the black hole X-ray binary V404 Cyg with the very long baseline interferometer the High Sensitivity Array (HSA) have detected the source at a frequency of 8.4 GHz, providing a source position accurate to 0.3 mas relative to the calibrator source. The observations put an upper limit of 1.3 mas on the source size (5.2 au at 4 kpc) and a lower limit of 7 × 106 K on its brightness temperature during the normal quiescent state, implying that the radio emission must be non-thermal, most probably synchrotron radiation, possibly from a jet. The radio light curves show a short flare, with a rise time of ∼30 min, confirming that the source remains active in the quiescent state.