arXiv subjects

Gabriel R. Hauschild-Roier

Publications and source records attributed to Gabriel R. Hauschild-Roier.

3 recordsLinked to original sources

arXiv2026

The differences in the Narrow Line Region of nearby QSOs 1 and QSOs 2: II - Signatures of kinetic feedback

We compare the integrated kinematic properties of the Narrow-Line Region (NLR) of ~1500 type 1 and ~700 type 2 QSOs at 0.4 < z < 0.5 using emission-line profiles from SDSS-IV spectra. The NLR [OIII] 5007 and Hbeta emission lines are fitted using a two-component model comprising a narrow (v_n, sigma_n) and a broad component (v_b, sigma_b), while fainter lines are fitted with a single Gaussian component. Both QSO types exhibit similar median narrow-component velocities (v_n ~ 0) and velocity dispersions (sigma < 200 km s^-1), consistent with motion driven by the host galaxy's gravitational potential. However, parameters associated with the broad, high-velocity gas component (v_b, v_05, v_10, v_[NeV], sigma_b, W80 and W90) differ: QSOs 1 display larger blueshifts and broader emission lines than QSOs 2. This suggests that these components trace Active Galactic Nuclei (AGN) outflows, that appear stronger in QSOs 1, leading to higher estimated mass-outflow rates (\dot{M}_out) and kinetic powers (\dot{{E}_out). Rather than offering absolute determinations of \dot{M}_out and \dot{E}_out -- which remain subject to physical uncertainties -- this statistical study supports the higher NLR excitation found for QSOs 1 in Paper I, as an orientation effect: in QSOs 1, we observe gas closer to the AGN core, where velocities and velocity dispersions are intrinsically higher. Nevertheless, the trend of QSOs 2 exhibiting higher average [OIII] luminosities than QSOs 1 suggests an evolutionary contribution, where QSOs 2 represent an early obscured AGN phase followed by a blowout phase that reveals the central core as a QSO 1.

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arXiv2025

The differences in the Narrow Line Region of nearby QSOs 1 and 2 -- I: higher excitation and contribution of shocks in type 1's

We compare the excitation of the Narrow-Line Region (NLR) of type 1 and type 2 QSOs for redshifts $0.4 \le z \le 0.5$ via the analysis of their emission line properties in Sloan Digital Sky Survey (SDSS) near-UV/optical spectra. We fit the continuum and emission lines, using two kinematic components for \oiii$λ$5007 and \hb\ (narrow and broad) and a single component for the weaker lines. We find two main differences in the NLR excitation of type 1 and 2 QSOs: (i) QSOs 2 have higher \oiii/\hb\ than QSOs 1 in both narrow and broad components; (ii) QSOs 1 present higher \nev, \neiii\ and \oiii$\lambda4363$ luminosities, higher \nev/\neiii\ and \neiii/\oii\ ratios and higher temperatures than QSOs 2. These differences support more highly excited regions, higher temperature gas and prevalence of shocks in type 1 relative to type 2 QSOs. We suggest two possible scenarios: (i) type 1 QSOs are seen more pole-on, allowing the observation of more highly excited gas closer to the nucleus, supporting the Unified Model scenario; (ii) evolution from type 2 to type 1 QSOs, with highest excitation regions obscured in type 2's and cleared up in a ``blow-out phase". Support for the evolutionary scenario is given by the usually higher L\oiii\ in QSOs 2, in the sense that these sources host a more powerful AGN that, in its evolution, clears up the excess dust and gas to reveal a lower-luminosity but more highly excited type 1 AGN.

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arXiv2022

Gas inflows in the polar ring of NGC 4111: the birth of an AGN

We have used Hubble Space Telescope (HST) images, SAURON Integral Field Spectroscopy (IFS) and adaptative optics assisted Gemini NIFS near-infrared K-band IFS to map the stellar and gas distribution, excitation and kinematics of the inner few kpc of the nearby edge-on S0 galaxy NGC 4111. The HST images map its $\approx$ 450 pc diameter dusty polar ring, with an estimated gas mass $\ge10^7$ M$_\odot$. The NIFS datacube maps the inner 110 pc radius at $\approx$ 7 pc spatial resolution revealing a $\approx$ 220 pc diameter polar ring in hot ($2267\pm166$ K) molecular H$_2$ 1-0 S(1) gas embedded in the polar ring. The stellar velocity field shows disk-dominated kinematics along the galaxy plane both in the SAURON large-scale and in the NIFS nuclear-scale data. The large-scale [O III] $\lambda5007$ Åvelocity field shows a superposition of two disk kinematics: one similar to that of the stars and another along the polar ring, showing non-circular motions that seem to connect with the velocity field of the nuclear H$_2$ ring, whose kinematics indicate accelerated inflow to the nucleus. The estimated mass inflow rate is enough not only to feed an Active Galactic Nucleus (AGN) but also to trigger circumnuclear star formation in the near future. We propose a scenario in which gas from the polar ring, which probably originated from the capture of a dwarf galaxy, is moving inwards and triggering an AGN, as supported by the local X-ray emission, which seems to be the source of the H$_2$ 1-0 S(1) excitation. The fact that we see neither near-UV nor Br$γ$ emission suggests that the nascent AGN is still deeply buried under the optically thick dust of the polar ring.

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