2010/10/12 by J. N. Reeves, J. Gofford, V. Braito +1 · 23 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Emission spectrum #Galaxy #Ionization #Line (geometry) #Outflow #Plasma #Radiative transfer #Spectroscopy #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/725/1/803
published in The Astrophysical Journal 725(1), 803-815 (IOP Publishing) · 36 pages, 8 figures, 3 tables. ApJ accepted
arxiv created 2010/10/12 · openalex publication_date 2010/11/19 · arxiv updated 2015/05/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present evidence for X-ray line emitting and absorbing gas in the nucleus of the Broad-Line Radio Galaxy (BLRG), 3C 445. A 200ks Chandra LETG observation of 3C 445 reveals the presence of several highly ionized emission lines in the soft X-ray spectrum, primarily from the He and H-like ions of O, Ne, Mg and Si. Radiative recombination emission is detected from O VII and O VIII, indicating that the emitting gas is photoionized. The He-like emission appears to be resolved into forbidden and intercombination line components, which implies a high density of >1010 cm-3, while the Oxygen lines are velocity broadened with a mean width of ~2600 km s-1 (FWHM). The density and widths of the ionized lines indicate an origin of the gas on sub-parsec scales in the Broad Line Region (BLR).The X-ray continuum of 3C 445 is heavily obscured either by a partial coverer or by a photoionized absorber of column density NH=2x1023 cm-2 and ionization parameter log(xi)=1.4 erg cm s-1. However the view of the X-ray line emission is unobscured, which requires the absorber to be located at radii well within any parsec scale molecular torus. Instead, we suggest that the X-ray absorber in 3C 445 may be associated with an outflowing, but clumpy, accretion disk wind with an observed outflow velocity of ~10000 km/s.