Misc,
No evidence for feedback: Unexceptional Low-ionization winds in Host galaxies of Low Luminosity Active Galactic Nuclei at Redshift z ~1
(2017)cite arxiv:1704.08348Comment: 24 pages, 11 figures, accepted in ApJ.
Abstract
We study winds in 12 X-ray AGN host galaxies at z ~ 1. We find, using the
low-ionization Fe II 2586 absorption in the stacked spectra, that the
probability distribution function (PDF) of the centroid velocity shift in AGN
has a median, 16th and 84th percentiles of (-87, -251, +86) km/s respectively.
The PDF of the velocity dispersion in AGN has a median, 84th and 16th
percentile of (139, 253, 52) km/s respectively. The centroid velocity and the
velocity dispersions are obtained from a two component (ISM+wind) absorption
line model. The equivalent width PDF of the outflow in AGN has median, 84th and
16th percentiles of (0.4, 0.8, 0.1) Angstrom. There is a strong ISM component
in Fe II 2586 absorption with (1.2, 1.5, 0.8) Angstrom, implying presence of
substantial amount cold gas in the host galaxies. For comparison, star-forming
and X-ray undetected galaxies at a similar redshift, matched roughly in stellar
mass and galaxy inclination, have a centroid velocity PDF with percentiles of
(-74, -258, +90) km/s, and a velocity dispersion PDF percentiles of (150, 259,
57) km/s. Thus, winds in the AGN are similar to star-formation-driven winds,
and are too weak to escape and expel substantial cool gas from galaxies. Our
sample doubles the previous sample of AGN studied at z ~ 0.5 and extends the
analysis to z ~ 1. A joint reanalysis of the z ~ 0.5 AGN sample and our sample
yields consistent results to the measurements above.
