The metallicity of galactic gaseous halos provides insights into accretionand feedback of galaxies. The nearby edge-on galaxy NGC 891 has amulti-component gaseous halo and a background AGN (LQAC 035+042 003) projected5 kpc above the disk near the minor axis. Against the UV continuum of this AGN,we detect lines from 13 ions associated with NGC 891 in new {\it HST}/COSspectra. Most of the absorption is from the warm ionized gas with $\logT=4.22\pm0.04$, $\log n_{\rm H}=-1.26\pm0.51$, and $\log N_{\rm H}=20.81\pm0.20$. The metallicity of volatile elements (i.e., C, N, and S) is about halfsolar ($\rm[X/H] \approx -0.3\pm 0.3$), while Mg, Fe, and Ni show lowermetallicities of $\rm[X/H]\approx-0.9$. The absorption system shows thedepletion pattern seen for warm Galactic diffuse clouds, which is consistentwith a mixture of ejected solar metallicity disk gases and the hot X-rayemitting halo ($Z=0.1-0.2Z_\odot$). The warm ionized gases are about 5 timesmore massive than the cold \ion{H}{1} emitting gases around the galacticcenter, which might lead to accretion with a mean rate of$10^2~M_\odot\rm~yr^{-1}$ for a period of time. We also detect low metallicity($\approx 0.1~Z_\odot$) gases toward LQAC 035+042 003 at $110\rm~km~s^{-1}$ (ahigh velocity cloud) and toward another sight line (3C 66A; 108 kpc projectedfrom NGC 891) at $30\rm~km~s^{-1}$. This low metallicity material could be thecold mode accretion from IGM or the tidal disruption of satellites in the NGC891 halo.

We present IRAM 30m observations of molecular lines of CO and itsisotopologues from the massive spiral galaxy NGC 5908 selected from theCGM-MASS sample. $^{12}$CO $J=1-0$, $^{12}$CO $J=2-1$, and $^{13}$CO $J=1-0$lines have been detected in most of the positions along the galactic disk. Thetotal molecular gas mass of NGC 5908 is $\sim7\times10^9\rm~M_\odot$ and thetotal cool gas mass adding atomic hydrogen is$\sim1.3\times10^{10}\rm~M_\odot$, comparable to the upper limit of the mass ofthe X-ray emitting hot gas in the halo. Modeling the rotation curvesconstructed with all three CO lines indicates that NGC 5908 has a dark matterhalo mass of $M_{\rm vir}\sim10^{13}\rm~M_{\rm \odot}$, putting it among themost massive isolated spiral galaxies. The $^{12}$CO/$^{13}$CO $J=1-0$,$^{12}$CO $J=2-1$/$J=1-0$ line ratios and the estimated molecular gastemperature all indicate normal but non-negligible star formation in thisfairly gas-rich massive isolated spiral galaxy, consistent with the measuredstar formation intensity and surface densities. The galaxy is probably at anearly evolutionary stage after a fast growth stage with mergers and/orstarbursts, with plenty of leftover cool gas, relatively high SFR, low hot CGMcooling rate, and low X-ray emissivity.

We study the frequency and dimensions of inner and outer rings in the localUniverse as a function of disk parameters and the amplitude ofnon-axisymmetries. We use the 1320 not-highly inclined disk galaxies($i<65^{\circ}$) from the S$^4$G survey. The ring fraction increases with barFourier density amplitude: this can be interpreted as evidence for the role ofbars in ring formation. The sizes of inner rings are positively correlated withbar strength: this can be linked to the radial displacement of the 1/4ultra-harmonic resonance while the bar grows and the pattern speed decreases.The ring intrinsic ellipticity is weakly controlled by the non-axisymmetricperturbation strength: this relation is not as strong as expected fromsimulations, especially when we include the dark matter halo in the forcecalculation. The ratio of outer-to-inner ring semi-major axes is uncorrelatedwith bar strength: this questions the manifold origin of rings. In addition, weconfirm that i) $\sim 1/3$ ($\sim 1/4$) of the galaxies hosting inner (outer)rings are not barred; ii) on average, the sizes and shapes of rings are roughlythe same for barred and non-barred galaxies; and iii) the fraction of inner(outer) rings is a factor of $1.2-1.4$ ($1.65-1.9$) larger in barred galaxiesthan in their non-barred counterparts. Finally, we apply unsupervised machinelearning (Self-Organizing Maps, SOMs) to show that, among early-type galaxies,ringed or barred galaxies cannot be univocally distinguished based on 20internal and external fundamental parameters. We confirm, with the aid of SOMs,that rings are mainly hosted by red, massive, gas-deficient, dark-matter poor,and centrally concentrated galaxies. We conclude that the present-day couplingbetween rings and bars is not as robust as predicted by numerical models(Abridged).

We report on the neutral hydrogen gas content (21-cm emission) of eightextremely isolated early-type galaxies (IEGs) using the Green Bank Telescope.Emission is detected in seven of the eight objects. This paper is the third ina series that collectively present new HI observations for 20 IEGs. Among the14 HI detections in our observations, eight exhibit a Gaussian-like HI lineprofile shape, four are double-peaked, one is triple-peaked, and another has aplateaued rectangular shape. Five additional IEGs observed in previous surveyswere added to our analysis, bringing the total number of IEGs with HIobservations to 25. Of these objects, emission is detected in 19 (76%). The 25IEGs in our combined study have gas masses that are systematically larger thantheir luminosity-matched comparison galaxy counterparts. The isolatedearly-type galaxies presented here follow a trend of increasing gas-richnesswith bluer B-V colors. This correlation is also observed in a comparison sampledrawn from the literature composed of loose group and field early-typegalaxies. Two IEGs, KIG164 and KIG870, exhibit properties highly anomalous forspheroidal systems: luminous (M_B = -20.5, -20.1) and blue (B-V = 0.47, 0.48)respectively, with substantial neutral gas, M_HI = 4.1 & 5.5x10^9 M_(sun).Other IEG systems may represent early-type galaxies continuing to assemble viaquiescent HI accretion from the cosmic web or relaxed merged systems.