Spiral arms are common features in low-redshift disc galaxies, and areprominent sites of star-formation and dust obscuration. However, spiralstructure can take many forms: from galaxies displaying two strong `granddesign' arms, to those with many `flocculent' arms. We investigate how thesedifferent arm types are related to a galaxy's star-formation and gas propertiesby making use of visual spiral arm number measurements from Galaxy Zoo 2. Wecombine UV and mid-IR photometry from GALEX and WISE to measure the rates andrelative fractions of obscured and unobscured star formation in a sample oflow-redshift SDSS spirals. Total star formation rate has little dependence onspiral arm multiplicity, but two-armed spirals convert their gas to stars moreefficiently. We find significant differences in the fraction of obscuredstar-formation: an additional $\sim 10$ per cent of star-formation in two-armedgalaxies is identified via mid-IR dust emission, compared to that in many-armedgalaxies. The latter are also significantly offset below the IRX-$\beta$relation for low-redshift star-forming galaxies. We present severalexplanations for these differences versus arm number: variations in the spatialdistribution, sizes or clearing timescales of star-forming regions (i.e.,molecular clouds), or contrasting recent star-formation histories.

We study the effect of angular momentum on the surface density profiles ofdisc galaxies, using high resolution simulations of major mergers whoseremnants have downbending radial density profiles (type II). As described inthe previous papers of this series, in this scenario, most of the disc mass isacquired after the collision via accretion from a hot gaseous halo. We findthat the inner and outer disc scalelengths, as well as the break radius,correlate with the total angular momentum of the initial merging system, andare larger for high angular momentum systems. We follow the angular momentumredistribution in our simulated galaxies, and find that, like the mass, thedisc angular momentum is acquired via accretion, i.e. to the detriment of thegaseous halo. Furthermore, high angular momentum systems give more angularmomentum to their discs, which affects directly their radial density profile.Adding simulations of isolated galaxies to our sample, we find that thecorrelations are valid also for disc galaxies evolved in isolation. We showthat the outer part of the disc at the end of the simulation is populatedmainly by inside-out stellar migration, and that in galaxies with higherangular momentum, stars travel radially further out. This, however, does notmean that outer disc stars (in type II discs) were mostly born in the innerdisc. Indeed, generally the break radius increases over time, and not takingthis into account leads to overestimating the number of stars born in the innerdisc.

We use ALMA to detect and image CO (1-0) emission from Minkowski's Object, adwarf galaxy that is interacting with a radio jet from a nearby ellipticalgalaxy. These observations are the first to detect molecular gas in Minkowski'sObject. We estimate the range in the mass of molecular gas in Minkowski'sObject assuming two different values of the ratio of the molecular gas mass tothe CO luminosity, $\alpha_{\rm CO}$. For the Milky Way value of $\alpha_{\rmCO}=4.6~M_{\odot}{\rm (K~km~s^{-1}~pc^2)^{-1}}$ we obtain a molecular gas massof $M_{\rm H_2} =3.0 \times 10^7~M_{\odot}$, 6% of the HI gas mass. We also usethe prescription of Narayanan et al. (2012) to estimate an $\alpha_{\rmCO}=27~M_{\odot}{\rm (K~km~s^{-1}~pc^2)^{-1}}$, in which case we obtain $M_{\rmH_2} =1.8 \times 10^8~M_{\odot}$, 36% of the HI mass. The observations areconsistent with previous claims of star formation being induced in Minkowski'sObject via the passage of the radio jet, and it therefore being a rare localexample of positive feedback from an AGN. In particular, we find highlyefficient star formation, with gas depletion timescales $\sim 5\times 10^7 -3\times 10^8$yr (for assumed values of $\alpha_{\rm CO}=4.6$ and$27~M_{\odot}{\rm (K~km~s^{-1}~pc^2)^{-1}}$, respectively) in the upstreamregions of Minkowski's Object that were struck first by the jet, and lessefficient star formation downstream. We discuss the implications of thisobservation for models of jet induced star formation and radio mode feedback inmassive galaxies.

We study galactic outflows of star-forming galaxies at $z\sim$0-2 based onoptical spectra with absorption lines of NaID, MgI, MgII, CII, and CIV. Thespectra of galaxies at $z\sim$0, 1, and 2 are taken from the large-survey datasets of SDSS DR7, DEEP2 DR4, and Erb et al. (2006), respectively. We carefullyconstruct large and homogeneous galaxy samples with similar stellar massdistributions. We stack the galaxy spectra in our samples and perform themulti-component fitting of model absorption lines to the stacked spectra. Weobtain the central ($v_\rm{out}$) and maximum ($v_\rm{max}$) outflowvelocities, and estimate the mass loading factors ($\eta$) that are defined bythe ratio of the mass outflow rate to the star formation rate (SFR). Becauseour optical spectra do not cover all of the absorption lines at each redshift,for investigating the redshift evolution, we compare outflow velocities atdifferent redshifts with the absorption lines whose depths and ionizationenergies are similar. We identify, for the first time, that the average valueof $v_\rm{out}$ ($v_\rm{max}$) monotonically increases by 0.1-0.4 dex from$z\sim$0 to 2 at the $\gtrsim5\sigma$ significance levels at a given SFR.Moreover, based on the absorption lines of NaID at $z\sim0$, MgI at $z\sim1$,and CII at $z\sim2$, we find that $\eta$ increases from $z\sim0$ to 2 by$\eta\propto(1+z)^{1.8\pm0.5}$ at a given halo circular velocity $v_\rm{cir}$,albeit with a potential systematics caused by model parameter choices. Theredshift evolution of $v_\rm{out}$ ($v_\rm{max}$) and $\eta$ are probablyexplained by high gas fractions in high-redshift massive galaxies, which issupported by recent radio observations. We obtain a scaling relation of$\eta\propto v_\rm{cir}^a$ for $a=-0.5\pm1.1$ in our $z\sim0$ galaxies. Thisscaling relation agrees well with the momentum-driven outflow model ($a=-1$)within the uncertainty.

Among the Milky Way satellites discovered in the past three years, TriangulumII has presented the most difficulty in revealing its dynamical status. Kirbyet al. (2015a) identified it as the most dark matter-dominated galaxy known,with a mass-to-light ratio within the half-light radius of 3600 +3500 -2100M_sun/L_sun. On the other hand, Martin et al. (2016) measured an outer velocitydispersion that is 3.5 +/- 2.1 times larger than the central velocitydispersion, suggesting that the system might not be in equilibrium. From newmulti-epoch Keck/DEIMOS measurements of 13 member stars in Triangulum II, weconstrain the velocity dispersion to be sigma_v < 3.4 km/s (90% C.L.). Ourprevious measurement of sigma_v, based on six stars, was inflated by thepresence of a binary star with variable radial velocity. We find no evidencethat the velocity dispersion increases with radius. The stars display a widerange of metallicities, indicating that Triangulum II retained supernova ejectaand therefore possesses or once possessed a massive dark matter halo. However,the detection of a metallicity dispersion hinges on the membership of the twomost metal-rich stars. The stellar mass is lower than galaxies of similar meanstellar metallicity, which might indicate that Triangulum II is either a starcluster or a tidally stripped dwarf galaxy. Detailed abundances of one starshow heavily depressed neutron-capture abundances, similar to stars in mostother ultra-faint dwarf galaxies but unlike stars in globular clusters.

Galaxies that abruptly interrupt their star formation in < 1.5 Gyr presentrecognizable features in their spectra (no emission and Hd in absorption) andare called post starburst (PSB) galaxies. By studying their stellar populationproperties and their location within the clusters, we obtain valuable insightson the physical processes responsible for star formation quenching. We presentthe first complete characterization of PSB galaxies in clusters at 0.04 < z <0.07, based on WINGS and OmegaWINGS data, and contrast their properties tothose of passive (PAS) and emission line (EML) galaxies. For V < 20, PSBsrepresent 7.2 +/- 0.2% of cluster galaxies within 1.2 virial radii. Theirincidence slightly increases from the outskirts toward the cluster center andfrom the least toward the most luminous and massive clusters, defined in termsof X-ray luminosity and velocity dispersion. The phase-space analysis andvelocity dispersion profile suggest that PSBs represent a combination ofgalaxies with different accretion histories. Moreover, PSBs with the strongestHd are consistent with being recently accreted. PSBs have stellar masses,magnitudes, colors and morphologies intermediate between PAS and EML galaxies,typical of a population in transition from being star forming to passive.Comparing the fraction of PSBs to the fraction of galaxies in transition onlonger timescales, we estimate that the short timescale star-formationquenching channel contributes two times more than the long timescale one to thegrowth of the passive population. Processes like ram-pressure stripping andgalaxy-galaxy interactions are more efficient than strangulation in affectingstar formation.

We present spectra of 5 ultra-diffuse galaxies (UDGs) in the vicinity of theComa Cluster obtained with the Multi-Object Double Spectrograph on the LargeBinocular Telescope. We confirm 4 of these as members of the cluster,quintupling the number of spectroscopically confirmed systems. Like thepreviously confirmed large (projected half light radius $>$ 4.6 kpc) UDG, DF44,the systems we targeted all have projected half light radii $> 2.9$ kpc. Assuch, we spectroscopically confirm a population of physically large UDGs in theComa cluster. The remaining UDG is located in the field, about $45$ Mpc behindthe cluster. We observe Balmer and Ca II H \& K absorption lines in all of ourUDG spectra. By comparing the stacked UDG spectrum against stellar populationsynthesis models, we conclude that, on average, these UDGs are composed ofmetal-poor stars ([Fe/H] $\lesssim -1.5$). We also discover the first UDG with[OII] and [OIII] emission lines within a clustered environment, demonstratingthat not all cluster UDGs are devoid of gas and sources of ionizing radiation.

From a sample of 84 local barred, moderately inclined disc galaxies, wedetermine the fraction which host boxy or peanut-shaped (B/P) bulges (thevertically thickened inner parts of bars). We find that the frequency of B/Pbulges in barred galaxies is a very strong function of stellar mass: 79% of thebars in galaxies with log (M_{star}/M_{sun}) >~ 10.4 have B/P bulges, whileonly 12% of those in lower-mass galaxies do. (We find a similar dependence indata published by Yoshino & Yamauchi 2015 for edge-on galaxies.) There are alsostrong trends with other galaxy parameters -- e.g., Hubble type: 77% of S0-Sbcbars, but only 15% of Sc-Sd bars, have B/P bulges -- but these appear to beside effects of the correlations of these parameters with stellar mass. Inparticular, despite indications from models that a high gas content cansuppress bar buckling, we find no evidence that the (atomic) gas mass ratioM_{atomic}/M_{star} affects the presence of B/P bulges, once the stellar-massdependence is controlled for. The semi-major axes of B/P bulges range from one-quarter to three-quarters ofthe full bar size, with a mean of R_{box}/L_{bar} = 0.42 +/- 0.09 andR_{box}/a_{max} = 0.53 +/- 0.12 (where R_{box} is the size of the B/P bulge anda_{max} and L_{bar} are lower and upper limits on the size of the bar).

About 20% of low-redshift galaxies are late-type spirals with a small or nobulge component. Although they are the simplest disk galaxies in terms ofstructure and dynamics, the role of the different physical processes drivingtheir formation and evolution is not yet fully understood. We investigatedwhether small bulges of late-type spirals follow the same scaling relationstraced by ellipticals and large bulges and if they are disk-like or classicalbulges. We derived the photometric and kinematic properties of 9 nearbylate-type spirals. To this aim, we analyzed the surface brightness distributionfrom the i-band images of the Sloan Digital Sky Survey and obtained thestructural parameters of the galaxies from a two-dimensional photometricdecomposition. We measured the line-of-sight stellar velocity distributionwithin the bulge effective radius from the long-slit spectra taken with highspectral resolution at the Telescopio Nazionale Galileo. We used thephotometric and kinematic properties of the sample bulges to study theirlocation in the Fundamental Plane, Kormendy, and Faber-Jackson relationsdefined for ellipticals and large bulges. We found that our sample bulgessatisfy some of the photometric and kinematic prescriptions for beingconsidered disk-like bulges such as small sizes and masses with nearlyexponential light profiles, small bulge-to-total luminosity ratios, low stellarvelocity dispersions, and ongoing star formation. However, each of them followsthe same scaling relations of ellipticals, massive bulges, and compactearly-type galaxies so they cannot be classified as disk-like systems. We finda single population of galaxy spheroids that follow the same scaling relations,where the mass seems to lead to a smooth transition in the photometric andkinematic properties from less massive bulges to more massive bulges andellipticals.

We use deep multi-epoch near-IR images of the VISTA Variables in the V\'iaL\'actea (VVV) Survey to search for RR Lyrae stars towards the SouthernGalactic plane. Here we report the discovery of a group of RR Lyrae stars closetogether in VVV tile d025. Inspection of the VVV images and PSF photometryreveals that most of these stars are likely to belong to a globular cluster,that matches the position of the previously known star cluster FSR\,1716. Thestellar density map of the field yields a $>100$ sigma detection for thiscandidate globular cluster, that is centered at equatorial coordinates$RA_{J2000}=$16:10:30.0, $DEC_{J2000}=-$53:44:56; and galactic coordinates$l=$329.77812, $b=-$1.59227. The color-magnitude diagram of this object revealsa well populated red giant branch, with a prominent red clump at $K_s=13.35 \pm0.05$, and $J-K_s=1.30 \pm 0.05$. We present the cluster RR Lyrae positions,magnitudes, colors, periods and amplitudes. The presence of RR Lyrae indicatesan old globular cluster, with age $>10$ Gyr. We classify this object as anOosterhoff type I globular cluster, based on the mean period of its RR Lyraetype ab, $<P>=0.540$ days, and argue that this is a relatively metal-poorcluster with $[Fe/H] = -1.5 \pm 0.4$ dex. The mean extinction and reddening forthis cluster are $A_{K_s}=0.38 \pm 0.02$, and $E(J-K_s)=0.72 \pm 0.02$ mag,respectively, as measured from the RR Lyrae colors and the near-IRcolor-magnitude diagram. We also measure the cluster distance using the RRLyrae type ab stars. The cluster mean distance modulus is $(m-M)_0 = 14.38 \pm0.03$ mag, implying a distance $D = 7.5 \pm 0.2$ kpc, and a Galactocentricdistance $R_G=4.3$ kpc.

Early type galaxies (ETG) contain most of the stars present in the localUniverse and, above a stellar mass of ~5e10 Msun, vastly outnumber spiralgalaxies like the Milky Way. These massive spheroidal galaxies have, in thepresent day, very little gas or dust, and their stellar populations have beenevolving passively for over 10 billion years. The physical mechanisms that ledto the termination of star formation in these galaxies and depletion of theirinterstellar medium remain largely conjectural. In particular, there arecurrently no direct measurements of the amount of residual gas that might bestill present in newly quiescent spheroids at high redshift. Here we show thatquiescent ETGs at z~1.8, close to their epoch of quenching, contained 2-3orders of magnitude more dust at fixed stellar mass than local ETGs. Thisimplies the presence of substantial amounts of gas (5-10%), which was howeverconsumed less efficiently than in more active galaxies, probably due to theirspheroidal morphology, and consistently with our simulations. This lower starformation efficiency, and an extended hot gas halo possibly maintained bypersistent feedback from an active galactic nucleus (AGN), combine to keep ETGsmostly passive throughout cosmic time.