Lenticular galaxies (S0s) are more likely to host anti-truncated (Type III) stellar discs than galaxies of later Hubble types. Previous work on Type-III S0s at z = 0 revealed that the characteristic parameters of the breaks obey tight scaling relations (Borlaff et al. 2014). These relation are similar in both S0’s and spirals, in optical and NIR, and for barred and non-barred galaxies (Eliche-Moral et al. 2015). We have analysed 3DHST images (Brammer et al. 2012) of S0 galaxies from the SHARDS survey (Pérez-González et al. 2013) in order to investigate if E/S0 and S0 galaxies with anti-truncated stellar profiles up to z ~ 0.6 follow similar scaling relations compared to the local sample. We find that the characteristic photometric parameters of Type-III S0s at 0.4 < z < 0.6 obey analogous scaling relations to those observed in their local counterparts, lying on top of the extrapolations of the local trends towards brighter magnitudes in several photometric diagrams and sharing similar trends and values in the hi – RbrkIII, ho – RbrkIII and hi – ho diagrams. We have measured the offsets in magnitudes between two subsets of the z ~ 0.5 and z = 0 samples with similar masses (log 10M/M⊙ ~ 10.7). The median offsets are: ΔμbrkIII = − 2.23+0.46−0.62, Δμ0, i = − 2.61+0.31−0.26 and Δμ0, o = − 2.31+0.57−0.78 mag arcsec-2. We find that PSF corrections in our images do not significantly affect the scaling relations obtained in our 0.2 < z < 0.6 sample. In conclusion, the existence of similar scaling relations in Type-III S0 discs since z ~ 0.6 implies that the structures of the inner and outer discs in anti-truncated S0s have been similarly linked in the last ~ 6 Gyr, posing strong constraints to the processes proposed to explain their formation.

We use 3.6 μm photometry for 1154 disk galaxies (i < 65°) in the S4G (Sheth et al. 2010). We obtain the average stellar component of the circular velocity (Vdisk) and the mean (dark matter) halo-to-stellar mass ratio (Mhalo/M*) inside the optical radius (Ropt) in bins of total stellar mass (M*, from Muñoz-Mateos et al. 2015), providing observational constraints for galaxy formation models to be tested against. We find the Mhalo/M* − M* relation in good agreement with the best-fit model at z ≈ 0 in ΛCDM cosmological simulations (e.g. Moster 2010), assuming that the dark matter halo within Ropt comprises a constant fraction (~ 4%) of its total mass.

The star formation histories and evolution of 28 dwarf irregular galaxies (dIs) that reside in differing local and global environments are investigated. The shallow gravitational potentials of dwarf galaxies make these objects highly susceptible to changes in morphology or dynamics by external perturbations. Additionally, the lack of more complicated structures such as spiral arms makes environmental effects more easily discernible. Therefore, dIs are ideal candidates for a study of the role of environment in galaxy evolution. The local environment is defined by the local galaxy number density, where high indicates at least one neighbor within 200 kpc and low indicates no neighbors within 1 Mpc. The global environment is classified as either the field or a galaxy group / cluster.

Absolute magnitudes, colors, central surface brightnesses, star formation rates and color profiles were compared using photometry from UBVR and Hα imaging. While some environmental trends are noted (galaxies in local high density environments have brighter central and effective surface brightnesses, while those in global high density environments have brighter absolute magnitudes, central and effective surface brightnesses, and higher star formation rates), no systematic environmental trends are seen in the shape of the color profiles or spatial distribution of recent star formation. A lack of environmental trend in star formation and galaxy color indicates that either internal processes dominate the formation and subsequent evolution of the outskirts of dIs, or there is no systematic environmental effect on such. The appearance of environmental effects should be more noticeable at the outermost edges of these systems. The lack of a trend in such implies that the exact nature of the environmental influence varies greatly depending on the exact nature of the interaction occurring.

We present results on luminous and dark matter mass distributions in disk galaxies from the DiskMass Survey. As expected for normal disk galaxies, stars dominate the baryonic mass budget in the inner region of the disk; however, at about four optical scale lengths (hR) the atomic gas starts to become the dominant contributor. Unexpectedly, we find the total baryon to dark-matter fraction within a galaxy stays nearly constant with radius from 1hR out to at least 6hR, with a baryon fraction of 15–50% among galaxies. On average, only one third of the mass within 2.2hR in a disk galaxy is baryonic and these baryons appear to have had only a minor effect on the distribution of the dark matter.

We revisit the well known H i size-mass relation of galaxies with an unprecedented large sample of over 500 galaxies (Wang et al. 2016). We find that the relation and the scatter about the relation do not depend on the galaxy type, optical luminosity or H i richness. It indicates a fundamental unrecognised mechanism that drives the distribution of H i in different galaxies.

Ultra-Compact dwarf galaxies, which inhabit the outskirts of galaxies, may conceal a significant population of hitherto overlooked super-massive black holes.

We have studied a small sample of star-forming outer rings in unbarred lenticular galaxies by means of long-slit spectroscopy. We have determined metallicities of the outer stellar disks and of the ionized gas in the rings. While the stellar disks of the S0s are metal-poor, [Z/H] < −0.4, the gas has strictly solar oxygen abundance in all the cases.

Accretion of metal-poor gas via cold accretion flows has been recently proposed as a means to trigger/sustain star formation in extremely metal-poor dwarf galaxies (XMPs), a scenario in agreement with theoretical predictions. We report on the tentative detection of CaII absorption used to trace the conditions of the gas clouds in the halo of the XMP UGCA 20.

Much progress has been made in recent years towards understanding how early-type galaxies (ETGs) form and evolve. SAURON (Bacon et al. 2001) integral-field spectroscopy from the ATLAS3D survey (Cappellari et al. 2011) has suggested that less massive ETGs are linked directly to spirals, whereas the most massive objects appear to form from a series of merging and accretion events (Cappellari et al. 2013). However, the ATLAS3D data typically only extends to about one half-light radius (or effective radius, Re), making it unclear if this picture is truly complete.

We combine high-quality IFU data with a new set of numerical simulations to study low-mass early type galaxies (dEs) in dense environments. Our earlier study of dEs in the Virgo cluster has produced the first large-scale maps of kinematic and stellar population properties of dEs in those environments (Ryś et al. 2013, 2014, 2015). A quantitative discrimination between various (trans)formation processes proposed for these objects is, however, a complex issue, requiring a priori assumptions about the progenitors of galaxies we observe and study today. To bridge this gap between observations and theoretical predictions, we use the expertise gained in the IFU data analysis to look “through the eye of SAURON” at our new suite of high-resolution N-body simulations of dEs in the Virgo cluster. Mimicking the observers perspective as closely as possible, we can also indicate the existing instrumental and viewer limitations regarding what we are/are not able to detect as observers.

The stellar kinematics of the discs of S0 galaxies (as obtained using planetary nebulae, PNe, and integrated stellar light data) is comparable to that of spiral galaxies, with similar flat rotation curves and falling velocity dispersion profiles, but they present a larger amount of random motions. The only other tracer available to probe the kinematics of individual early-type galaxies are globular clusters (GCs). GCs’ formation is intimately connected to a galaxy major star forming event(s) and GCs are, therefore, good proofs of galaxy formation histories. We directly compare a sample of PNe, GCs, and stellar velocities out to 4 effective radii, in the S0 galaxies NGC 2768 and NGC 1023. In particular, we test a new method for studying GC properties and we find that these two lenticular galaxies are consistent with being formed through different formation mechanisms.

Smith’s Cloud is a large few × 106 Solar Mass cloud which will impact the Milk Way disk in about 35 Million Years (Lockman et al., 2008). Green Bank Telescope OH observations indicate that there are no molecules present in Smith’s Cloud, and thus there is no active ongoing chemistry in Smith’s Cloud.

The AMIGA project carries out a multiwavelength study of the largest catalogue of isolated galaxies from the Local Universe (CIG, Karachentseva 1973). Compared to any other sample —field galaxies included— and using highly strict isolation criteria (unperturbed for at least ~3 Gyr, Verdes-Montenegro et al. 2005), all the results show that these galaxies have the lowest values of the physical magnitudes expected to be enhanced by interactions. This strongly supports isolated galaxies as ideal laboratories for the study of galaxy formation and evolution. Despite CIG galaxies show the lowest HI integrated profile asymmetry level when compared to any other sample, some cases present up to 50% HI asymmetry (Espada et al. 2011b). We aim to shed light over the causes and sources of such asymmetries with our deep radiointerferometric and optical observations of CIG targets. Since major mergers are ruled out by the isolation criteria, in this work we are addressing whether minor mergers, internal processes or primordial gas accretion are responsible for such asymmetries.

We present the first results from a survey of deep imaging of edge-on galaxies, with the goal of testing the growth-by-accretion of galaxies proposed by ΛCDM. The data were obtained with a new telescope at the Wise Observatory. Our images show previously unreported extensions of the disk, tidal distortions, and streams at the level of 27-28 mag arcsec−2.

In the base of our studies of star-forming processes are the data provided by panoramic spectroscopy of galaxies composing our SBS subsample. Observations with multi-pupil spectrographs are organized in a way to obtain the spectral range centered in permitted hydrogen Hα Balmer line, by capturing at least the forbidden doublets of nitrogen [NII]6548,6583 and sulfur [SII]6716,6731. The results obtained are the spatial distributions across the targets of emission intensities and derived properties from line parameters such as radial velocities, which give us the possibility to explore gas kinematics and physical characteristics of HII regions.

We report about an ongoing study of the evolution of 24 S0s with UV-bright ring/arm-like structures observed with SWIFT-UVOT and interpreted via SPH simulations with chemo-photometric implementation.

This project is aimed at understanding the dependence of star formation on the environment by analysing young stellar populations in two very different positions in disk galaxies: circumnuclear and outer disk giant regions. Integral field spectroscopy (IFS) provide an ideal means to achieve these goals providing simultaneous spatial and spectral resolution. Here we present the characterization of the work sample, composed by 671 outer regions and 725 inner regions from 263 isolated spirals galaxies observed by the CALIFA survey. The wide number of regions in both samples allows us to obtain statistically relevant results about the influence of metallicity, density and environment on star formation, and how it disseminates over the galaxy, to obtain evolutionary stories for the star-forming regions and to compare our results with models of massive star formation and galactic chemical evolution.

We have developed a new technique using a novel approach to analyze unresolved stellar populations of spatially-resolved galaxies based on large sky multi-filter surveys. We have successfully applied this technique to 42 early-type galaxies in the ALHAMBRA survey. In agreement with some previous work, we find the gradients of early-type galaxies to be on average slightly positive in age and negative in metallicity at large radii (R > Reff). These mildly negative metallicity gradients support a merging scenario. The positive/flat age gradients could support a more uniformly distributed star formation or even secondary burst triggered by mergers.

Initial efforts to identify extended UV disk (XUV-disk) galaxies were confined to nearby targets using image products from early in the GALEX mission. We developed a beta Zooniverse-based citizen science project to address this issue, specifically (1) allowing a dramatically larger galaxy sample by crowd-sourcing blink comparison UV-optical image inspection to volunteers, and (2) incorporating all archived GALEX data for each target considered. We aim to widely deploy this project to the public within the upcoming year.