[Paper Review] Spatially resolved analysis of neutralwWinds, stars, and ionized gas kinematics with MEGARA/GTC: new insights on the nearby galaxy UGC 10205

C. Catalán-Torrecilla, Á. Castillo-Morales+6 more|arXiv (Cornell University)|Jan 1, 2020

Galaxies: Formation, Evolution, Phenomena137 references9 citations

TL;DR

This study uses high-resolution integral field spectroscopy from MEGARA/GTC to analyze multi-phase kinematics in the nearby edge-on spiral UGC 10205. It reveals complex ionized gas dynamics with up to three kinematic components and detects a cold neutral outflow with a mass outflow rate of 0.78 ± 0.03 M⊙ yr⁻¹, demonstrating the importance of high-resolution IFS for probing galactic winds in quiescent galaxies.

ABSTRACT

We present a comprehensive analysis of the multiphase structure of the interstellar medium (ISM) and the stellar kinematics in the edge-on nearby galaxy UGC 10205 using integral field spectroscopy (IFS) data taken with MultiEspectrógrafo en GTC de Alta Resolución para Astronomía (MEGARA) at the GTC. We explore both the neutral and the ionized gas phases using the interstellar Na I D doublet absorption (LR−V setup, R ∼ 6000) and the Hα emission line (HR−R setup, R ∼ 18000), respectively. The high-resolution data show the complexity of the Hα emission-line profile revealing the detection of up to three kinematically distinct gaseous components. Despite of this fact, a thin-disk model is able to reproduce the bulk of the ionized gas motions in the central regions of UGC 10205. The use of asymmetric drift corrections is needed to reconciliate the ionized and the stellar velocity rotation curves. We also report the detection of outflowing neutral gas material blueshifted by ∼ 87 km s^(−1) . The main physical properties that describe the observed outflow are a total mass M_(out) = (4.55 ± 0.06) × 10^(7) Mʘ and a coldgas mass outflow rate M_(out) = 0.78  0.03 Mʘ yr^(−1) . This work points out the necessity of exploiting highresolution IFS data to understand the multiphase components of the ISM and the multiple kinematical components in the central regions of nearby galaxies.

Motivation & Objective

• To investigate the multi-phase kinematics of the interstellar medium (ISM) in the nearby edge-on spiral galaxy UGC 10205.
• To determine the role of galactic winds in shaping galaxy evolution by analyzing ionized and neutral gas components.
• To assess the necessity of asymmetric drift corrections (ADC) in reconciling stellar and ionized gas rotation curves in early-type spirals.
• To characterize the physical properties of a cold neutral outflow using the thin-shell model and ISM absorption lines.
• To explore the kinematic structure of ionized gas and its relation to dust lanes and stellar dynamics in a spatially resolved manner.

Proposed method

• Acquired high-resolution integral field spectroscopy (IFS) data using MEGARA on the GTC telescope with two setups: LR−V (R ~ 6000) for neutral gas via Na I D absorption and HR−R (R ~ 18,000) for ionized gas via Hα emission.
• Constructed 2D stellar kinematics maps from the stellar velocity dispersion and line-of-sight velocity using Voronoi binning and moment analysis.
• Applied asymmetric drift corrections (ADC) to reconcile the stellar and ionized gas rotation curves, using the equation Vrot(stars) = Vrot(gas) × (1 + ADC).
• Modelled the Hα emission line profile using a thin-disk kinematic model with inclination i = 75° to reproduce the ionized gas dynamics.
• Used the thin-shell model to estimate the total mass and mass outflow rate of the cold neutral wind from Na I D absorption kinematics.
• Analyzed the spatial distribution of ionized gas, neutral gas, and dust lanes to identify distinct kinematic components and their geometric associations.

Experimental results

Research questions

• RQ1 What are the kinematic properties of the ionized gas (Hα) and neutral gas (Na I D) in the central regions of UGC 10205?
• RQ2 How do the ionized gas and stellar rotation curves compare, and what role does asymmetric drift correction play in reconciling them?
• RQ3 What are the physical parameters (mass, mass outflow rate) of the detected cold neutral outflow?
• RQ4 Are there multiple kinematic components in the ionized gas, and how do they relate to the dust lanes and stellar structure?
• RQ5 Can a simple thin-disk model reproduce the complex Hα line profile in the central regions of UGC 10205?

Key findings

• The ionized gas in UGC 10205 exhibits up to three kinematically distinct components, with one component best described by a thin-disk model at i = 75°.
• The stellar and ionized gas rotation curves are reconciled only after applying asymmetric drift corrections, yielding a mean Vrot(stars)/Vrot(gas) ratio of 0.75 ± 0.08.
• A cold neutral outflow is detected blueshifted by ∼87 km s⁻¹, with a total mass of Mout = (4.55 ± 0.06) × 10⁷ M⊙ and a mass outflow rate of ˙Mout = 0.78 ± 0.03 M⊙ yr⁻¹.
• The outflow is likely driven by past minor merger activity, as indicated by the presence of a shell structure and infalling neutral gas components.
• The Na I D absorption reveals a redshifted foreground component with ∆V = (114 ± 5) km s⁻¹, indicating mild inflows toward the inner regions.
• The ionized gas is confined to a rotating disk, while the neutral gas shows complex kinematics, including a blueward-shifted component aligned with the NE semi-minor axis, consistent with a galactic outflow.