Feeding and feedback in the inner kiloparsec of the active galaxy NGC 2110

Abstract

We present two-dimensional gaseous kinematics of the inner 1.1 × 1.6 kpc 2 of the Seyfert 2 galaxy NGC 2110, from optical spectra (5600-7000Å) obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈ 100 pc. Gas emission is observed over the whole field-of-view, with complex -and frequently double -emissionline profiles. We have identified four components in the emitting gas, according to their velocity dispersion (σ), which we refer to as: (1) warm gas disk (σ = 100-220 km s −1 ); (2) cold gas disk (σ = 60-90 km s −1 ); (3) nuclear component (σ = 220-600 km s −1 ); and (4) northern cloud (σ = 60-80 km s −1 ). Both the cold and warm disk components are dominated by rotation and have similar gas densities, but the cold gas disk has lower velocity dispersions and reaches higher rotation velocities. We attribute the warm gas disk to a thick gas layer which encompasses the cold disk as observed in some edge-on spiral galaxies. After subtraction of a rotation model from the cold disk velocity field, we observe excess blueshifts of ≈ 50 km s −1 in the far side of the galaxy (NE) as well as similar excess redshifts in the near side (SW). These residuals can be interpreted as due to nuclear inflow in the cold gas, with an estimated ionized gas mass inflow rate of φ ≈ 2.2 × 10 −2 M ⊙ yr −1 . We have also subtracted a rotating model from the warm disk velocity field and found excess blueshifts of ≈ 100 km s −1 to the SW of the nucleus and excess redshifts of ≈ 40 km s −1 to the NE, which we attribute to gas disturbed by an interaction with a nuclear spherical outflow. This nuclear outflow is the origin of the nuclear component observed within the inner 300 pc and it has a mass outflow rate of 0.9 M ⊙ yr −1 . In a region between 1 ′′ and 4 ′′ north of the nucleus, which shows strong X-ray and [O III] λ5007Å emission, we find a new low σ component of ionized gas which we attribute to a high latitude cloud photoionized by the nuclear source. The identification of the 4 distinct kinematic components has clarified the nature of the apparent asymmetry in the rotation curve of the galaxy pointed out in previous studies: it results from the dominance of different components to the south and north of the nucleus. We conclude that a comprehensive two-dimensional coverage of the kinematics and geometry of the nuclear gas around the AGN is necessary to reveal the different processes at play, such as its feeding -via the cold inflowing gas -and the feedback, via the warm gas outflows.

The origin of double-peaked narrow lines in active galactic nuclei – III. Feedback from biconical AGN outflows

“…Our galaxies span a wide range of AGN bolometric luminosities, overlapping with low-luminosity local Seyfert galaxies (e.g., Müller-Sánchez et al 2011;Schnorr-Müller et al 2014) as well as high-luminosity quasars (e.g., Liu et al 2013a;Mcelroy et al 2015). The average mass outflow rate for the 18 galaxies modeled in this work is ∼10 2.7 M yr −1 .…”

Unravelling the Complex Structure of Agn-Driven Outflows. Ii. Photoionization and Energetics

“…We typically use the maximum velocity and velocity dispersion reported in the respective papers. For studies using different emission lines (i.e., Schnorr-Müller et al 2016;Riffel et al 2015;Schönell et al 2014;Schnorr-Müller et al 2014;Riffel et al 2013;Riffel & Storchi-Bergmann 2011b,a;Müller-Sánchez et al 2011;Storchi-Bergmann et al 2010), we adopt the values of mass outflow rates reported in the respective papers. We underline here that by adopting the simplest prescription for the calculation of the mass outflow rate and due to the effects discussed above, the values shown in Fig.…”

Observational Constraints on the Influence of Active Galactic Nuclei on the Evolution of Galaxies

“…This relationship between the observed line-emitting gas mass, n e and L Hβ (or an equivalent using L Hα ) is commonly adopted in studies of outflows (e.g., Holt et al 2006;Genzel et al 2011;Rodríguez Zaurín et al 2013;Liu et al 2013b;Schnorr-Müller et al 2014) with normalisation factors that vary within a factor of a few, depending on the exact assumptions. Using our extinction un-corrected L Hβ values (Table 4.2), we obtain total observed ionised gas masses of M gas = (2-40) ×10 7 M ⊙ , assuming the commonly adopted n e = 100 cm −3 (e.g., Liu et al 2013b), or M gas = (0.4-8) ×10 7 M ⊙ assuming our median value of n e = 500 cm −3 .…”