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Register a new userA census of ionized gas outflows in type 1 AGNs: gas outflows in AGNs. V
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We present a systematic study of ionized gas outflows based on the velocity shift and dispersion of the [O III] {lambda}5007 $AA$ emission line, using a sample of ~ 5000 Type 1 AGNs at z < 0.3 selected from Sloan Digital Sky Survey. This analysis is supplemented by the gas kinematics of Type 2 AGNs from Woo et al. (2016). For the majority of Type 1 AGNs (i.e., ~ 89%), the [O III] line profile is best represented by a double Gaussian model, presenting the kinematic signature of the non-virial motion. Blueshifted [O III] is more frequently detected than redshifted [O III] by a factor of 3.6 in Type 1 AGNs, while the ratio between blueshifted to redshifted [O III] is only 1.08 in Type 2 AGNs due to the projection and orientation effect. The fraction of AGNs with outflow signatures is found to increase steeply with [O III] luminosity and Eddington ratio, while Type 1 AGNs have larger velocity dispersion and more negative velocity shift than Type 2 AGNs. The [O III] velocity - velocity dispersion (VVD) diagram of Type 1 AGNs expands towards higher values with increasing luminosity and Eddington ratio, suggesting that the radiation pressure or wind is the main driver of gas outflows, as similarly found in Type 2 AGNs. In contrast, the kinematics of gas outflows is not directly linked to the radio activity of AGN.
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To investigate the connection between radio activity and AGN outflows, we present a study of ionized gas kinematics based on [O III] $lambda$5007 emission line along the large-scale radio jet for six radio AGNs. These AGNs are selected based on the radio activity (i.e., $mathrm{L_{1.4GHz}}$ $geqslant$ 10$^{39.8}$ erg s$^{-1}$) as well as optical emission line properties as type 2 AGNs. Using the Red Channel Cross Dispersed Echellette Spectrograph at the Multiple Mirror Telescope, we investigate in detail the [O III] and stellar kinematics. We spatially resolve and probe the central AGN-photoionization sizes, which is important in understanding the structures and evolutions of galaxies. We find that the typical central AGN-photoionization radius of our targets are in range of 0.9$-$1.6 kpc, consistent with the size-luminosity relation of [O III] in the previous studies. We investigate the [O III] kinematics along the large-scale radio jets to test whether there is a link between gas outflows in the narrow-line region and extended radio jet emissions. Contrary to our expectation, we find no evidence that the gas outflows are directly connected to the large scale radio jets.
We present the spatially resolved gas and stellar kinematics of a sample of ten hidden type 1 AGNs in order to investigate the true nature of the central source and the scaling relation with host galaxy stellar velocity dispersion. The sample is selected from a large number of hidden type 1 AGN, which are identified based on the presence of a broad component in the ha line profile (i.e., full-width-at-half-maximum $>$ $sim$1000 kms), while they are often mis-classified as type 2 AGN because AGN continuum and broad emission lines are weak or obscured in the optical spectral range. We used the Blue Channel Spectrograph at the 6.5-m MMT (Multiple Mirror Telescope) to obtain long-slit data. We detected a broad hb for only two targets, however, the presence of a strong broad ha indicates that these AGNs are low-luminosity type 1 AGNs. We measured the velocity, velocity dispersion and flux of stellar continuum and gas emission lines (i.e., hb and oiii) as a function of distance from the center with a spatial scale of 0.3 arcsec pixel$^{-1}$. Spatially resolved gas kinematics traced by hb or oiii are generally similar to stellar kinematics except for the very center, where signatures of gas outflows are detected. We compare the luminosity-weighted effective stellar velocity dispersion with black hole mass, finding that these hidden type 1 AGN with relatively low back hole mass follow the scaling relation of the reverberation-mapped type 1 AGN and more massive inactive galaxies. }
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.
We investigate the ionized gas excitation and kinematics in the inner $4.3 times 6.2$ kpc$^{2}$ of the merger radio galaxy 4C +29.30. Using optical integral field spectroscopy with the Gemini North Telescope, we present flux distributions, line-ratio maps, peak velocities and velocity dispersion maps as well as channel maps with a spatial resolution of $approx 955$ pc. We observe high blueshifts of up to $sim -650$ km s$^{-1}$, in a region $sim 1$ south of the nucleus (the southern knot, SK), which also presents high velocity dispersions ($sim 250$ km s$^{-1}$), which we attribute to an outflow. A possible redshifted counterpart is observed north from the nucleus (the northern knot, NK). We propose that these regions correspond to a bipolar outflow possibly due to the interaction of the radio jet with the ambient gas. We estimate a total ionized gas mass outflow rate of $dot{M}_{out} = 25.4 substack{+11.5 -7.5}$ M$_odot$ yr$^{-1}$ with a kinetic power of $dot{E} = 8.1 substack{+10.7 -4.0} times 10^{42}$ erg s$^{-1}$, which represents $5.8 substack{+7.6 -2.9} %$ of the AGN bolometric luminosity. These values are higher than usually observed in nearby active galaxies with the same bolometric luminosities and could imply a significant impact of the outflows in the evolution of the host galaxy. The excitation is higher in the NK (that correlates with extended X-ray emission, indicating the presence of hotter gas) than in the SK, supporting a scenario in which an obscuring dust lane is blocking part of the AGN radiation to reach the southern region of the galaxy.
The torus is the central element of the most popular theory unifying various classes of AGNs, but it is usually described as putative because it has not been imaged yet. Since it is too small to be resolved with single-dish telescopes, one can only make indirect assumptions about its structure using models. Using infrared interferometry, however, we were able to resolve the circum-nuclear dust distributions for several nearby AGNs and achieved constraints on some further two dozen sources. We discovered circum-nuclear dust on parsec scales in all sources and, in two nearby sources, were able to dissect this dust into two distinct components. The compact component, a very thin disk, appears to be connected to the maser disk and the extended one, which is responsible for most of the mid-IR flux, is oriented perpendicularly to the circum-nuclear gas disks. What may come as a surprise when having in mind the standard unification cartoon actually connects well to observations on larger scales. Optically thin dust in the polar region, perhaps driven by a disk wind, could solve both the scale height problem of the torus and explain the missing anisotropy in the mid-IR - X-ray relation.
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