Ionized Gas Outflows in Low Excitation Radio Galaxies Are Radiation Driven. (arXiv:2106.02086v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Singha_M/0/1/0/all/0/1">Mainak Singha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+ODea_C/0/1/0/all/0/1">Christopher P. O'Dea</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gordon_Y/0/1/0/all/0/1">Yjan A. Gordon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lawlor_Forsyth_C/0/1/0/all/0/1">Cameron Lawlor-Forsyth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baum_S/0/1/0/all/0/1">Stefi A. Baum</a>
Low excitation radio galaxies (LERGs) are weakly accreting active galactic
nuclei (AGN) believed to be fuelled by radiatively inefficient accretion
processes. Despite this, recent works have shown evidence for ionized and
neutral hydrogen gas outflows in these galaxies. To investigate the potential
drivers of such outflows we select a sample of 802 LERGs using the Best &
Heckman (2012) catalogue of radio galaxies. By modelling the [O III] $lambda
5007$ profile in Sloan Digital Sky Survey spectra of a sample of 802 LERGs, we
determine that the ionized outflows are present in $sim 1.5%$ of the
population. Using $1.4~text{GHz}$ imaging from the Faint Images of the Radio
Sky at Twenty Centimeters survey we analyze the radio morphology of LERGs with
outflows and find these to be consistent with the parent LERG population.
However, we note that unlike the majority of the LERG population, those LERGs
showing outflows have Eddington scaled accretion rates close to $1%$. This is
indicative that ionized outflows in LERGs are driven by the radiation pressure
from the accretion disk of the AGN rather than the radio jets. We report
specific star formation rates in the range of $10^{-12} < text{sSFR} <
10^{-9}~text{yr}^{-1}$. Moreover, we observe higher mass outflow rates of
$7-150~M_{odot}~text{yr}^{-1}$ for these LERGs than luminous quasars for a
given bolometric luminosity, which could possibly be due to the radio source in
LERGs boosting the mass-loading. This scenario could indicate that these
outflows could potentially drive feedback in LERGs.
Low excitation radio galaxies (LERGs) are weakly accreting active galactic
nuclei (AGN) believed to be fuelled by radiatively inefficient accretion
processes. Despite this, recent works have shown evidence for ionized and
neutral hydrogen gas outflows in these galaxies. To investigate the potential
drivers of such outflows we select a sample of 802 LERGs using the Best &
Heckman (2012) catalogue of radio galaxies. By modelling the [O III] $lambda
5007$ profile in Sloan Digital Sky Survey spectra of a sample of 802 LERGs, we
determine that the ionized outflows are present in $sim 1.5%$ of the
population. Using $1.4~text{GHz}$ imaging from the Faint Images of the Radio
Sky at Twenty Centimeters survey we analyze the radio morphology of LERGs with
outflows and find these to be consistent with the parent LERG population.
However, we note that unlike the majority of the LERG population, those LERGs
showing outflows have Eddington scaled accretion rates close to $1%$. This is
indicative that ionized outflows in LERGs are driven by the radiation pressure
from the accretion disk of the AGN rather than the radio jets. We report
specific star formation rates in the range of $10^{-12} < text{sSFR} <
10^{-9}~text{yr}^{-1}$. Moreover, we observe higher mass outflow rates of
$7-150~M_{odot}~text{yr}^{-1}$ for these LERGs than luminous quasars for a
given bolometric luminosity, which could possibly be due to the radio source in
LERGs boosting the mass-loading. This scenario could indicate that these
outflows could potentially drive feedback in LERGs.
http://arxiv.org/icons/sfx.gif
