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NGC 5139 ($\omega$ Cen), is the closest candidate of a Nuclear Star Cluster that has been stripped of its host galaxy in the Milky Way. Despite extensive studies through the last decades, many open questions about the cluster remain, including the properties of the binary population. In this study we use MUSE multi-epoch spectroscopy to identify binary systems in $\omega$ Cen. The observations span 8 years, with a total of 312 248 radial velocity measurements for 37 225 stars. Following the removal of known photometric variables, we identify 275 stars that show RV variations, corresponding to a discovery fraction of 1.4$\pm$0.1%. Using dedicated simulations, we find that our data is sensitive to 70$\pm$10% of the binaries expected in the sample, resulting in a completeness-corrected binary fraction of 2.1$\pm$0.4% in the central region of $\omega$ Cen. We find similar binary fractions for all stellar evolutionary stages covered by our data, the only notable exception being the blue straggler stars, which show an enhanced binary fraction. We also find no distinct correlation with distance from the cluster centre, indicating a limited amount of mass segregation within the half-light radius of $\omega$ Cen., Comment: 13 pages, 9 figures, 1 Table; Published by Monthly Notices of the Royal Astronomical Society (MNRAS)

The vertical evolution of galactic discs is governed by the sub-structures within them. We examine the diversity of kinematic sub-structure present in the first 12 galaxies observed from the GECKOS survey, a VLT/MUSE large programme providing a systematic study of 35 edge-on, Milky Way-mass disc galaxies. Employing the nGIST analysis pipeline, we derive the mean line-of-sight stellar velocity ($V_{\star}$), velocity dispersion ($\sigma_{\star}$), skew ($h_{3}$), and kurtosis ($h_{4}$) for the sample, and examine 2D maps and 1D line profiles. Visually, the majority of this sample (8/12) are found to possess boxy-peanut bulges and host the corresponding kinematic structure predicted for stellar bars viewed in projection. Four galaxies exhibit strong evidence for the presence of nuclear discs, including central $h_{3}$-$V_{\star}$ anti-correlations, `croissant'-shaped central depressions in $\sigma_{\star}$ maps, strong gradients in $h_{3}$, and positive $h_{4}$ plateaus over the expected nuclear disc extent. The strength of the $h_{3}$ feature corresponds to the size of the nuclear disc, measured from the $h_{3}$ turnover radius. We can explain the features within the kinematic maps of all sample galaxies via disc structure(s) alone. We do not find any need to invoke the existence of dispersion-dominated bulges. Obtaining the specialised data products for this paper and the broader GECKOS survey required significant development of existing integral field spectroscopic (IFS) analysis tools. Therefore, we also present the nGIST pipeline: a modern, sophisticated, and easy-to-use pipeline for the analysis of galaxy IFS data. We conclude that the variety of kinematic sub-structures seen in GECKOS galaxies requires a contemporary view of galaxy morphology, expanding on the traditional view of galaxy structure, and uniting the kinematic complexity observed in the Milky Way with the extragalactic., Comment: 32 pages (9 of which are appendix), 26 figures, submitted to A&A. Comments welcome!

We present age estimates for over 8100 sub-giant branch (SGB) stars in Omega Centauri ($\omega$ Cen) to study its star formation history. Our large data set, which combines multi-wavelength HST photometry with MUSE metallicities, provides an unprecedented opportunity to measure individual stellar ages. We do this by fitting each star's photometry and metallicity with theoretical isochrones, that are embedded with an empirical [C+N+O]-[Fe/H] relation specifically for $\omega$ Cen. The bulk of the stars have ages between 13 and 10 Gyr, with the mean stellar age being 12.08$\pm$0.01 Gyrs and the median age uncertainty being 0.68 Gyrs. From these ages we construct the most complete age-metallicity relation (AMR) for $\omega$ Cen to date. We find that the mean age of stars decreases with increasing metallicity and find two distinct streams in the age-metallicity plane, hinting at different star formation pathways. We derive an intrinsic spread in the ages of 0.75$\pm$0.01 Gyr for the whole cluster, with the age spread showing a clear increase with metallicity. We verify the robustness of our age estimations by varying isochrone parameters and constraining our systematics. We find the C+N+O relation to be the most critical consideration for constraining the AMR. We also present the SGB chromosome map with age information. In the future, these stellar ages could be combined with chemical abundances to study age differences in subpopulations, and uncover the chemical evolution history of this massive nuclear star cluster., Comment: 23 pages, 11 figures

Star formation rates (SFRs), gas-phase metallicities, and stellar masses are crucial for studying galaxy evolution. The different relations resulting from these properties give insights into the complex interplay of gas inside galaxies and their evolutionary trajectory and current characteristics. We aim to characterize these relations at $z\sim 0.3$, corresponding to a 3-4 Gyr lookback time. We utilized optical integral field spectroscopy of 65 emission-line galaxies from the MAGPI survey at a redshift of $0.28

$\omega$ Centauri, the most massive globular cluster in the Milky Way, has long been suspected to be the stripped nucleus of a dwarf galaxy that fell into the Galaxy a long time ago. There is considerable evidence for this scenario including a large spread in metallicity and an unusually large number of distinct sub-populations seen in photometric studies. In this work, we use new MUSE spectroscopic and HST photometric catalogs to investigate the underlying metallicity distributions as well as the spatial variations of the populations within the cluster up to its half-light radius. Based on 11,050 member stars, the [M/H] distribution has a median of $ (-1.614 \pm 0.003)$ dex and a large spread of $\sim$ 1.37 dex reaching from $ -0.67$ dex to $ -2.04$ dex for 99.7 % of the stars. In addition, we show the chromosome map of the cluster, which separates the red giant branch stars into different sub-populations, and analyze the sub-populations of the metal-poorest component. Finally, we do not find any metallicity gradient within the half-light radius, and the different sub-populations are well mixed., Comment: 22 pages, 18 figures, and 3 tables. Accepted for publication in ApJ

The kinematics and chemical composition of stellar populations of different ages provide crucial information about the evolution of a galaxy. We aim to provide such information for IC 1613, an isolated, gas-rich, star-forming dwarf galaxy in the Local Group. We present here the results of a new spectroscopic study performed with MUSE, an integral-field spectrograph on the Very Large Telescope. We extracted from the data cubes more than 2000 sources from which we separated stellar objects for further spectroscopic analysis. The quality of the data set allowed us to obtain accurate classifications and line-of-sight velocities for about 800 stars. Our sample includes not only Red Giant Branch (RGB) and Main Sequence (MS) stars, but also a number of probable Be and C stars. We also obtained reliable metallicities for about 300 RGB stars. The kinematic analysis revealed for the first time the presence of stellar rotation with high significance. We found general agreement with the rotation velocity of the neutral gas component. Examining the kinematics of stars as a function of broad age ranges, we find that the velocity dispersion increases as a function of age, with the behaviour being very clear in the outermost pointings, while the rotation-to-velocity dispersion support decreases. On timescales shorter than a Gyr, the stellar kinematics still follow very closely that of the neutral gas, while the two components decouple on longer timescales. The chemical analysis of the RGB stars revealed average properties comparable to other Local Group dwarf galaxies. We also provide a new estimation of the inclination angle using only independent stellar tracers. Our work provides the largest spectroscopic sample of an isolated LG dwarf galaxy. The results obtained seem to support the scenario in which the stars of a dwarf galaxy are born from a less turbulent gas over time., Comment: Accepted for publication in A&A. Changes from previous version include: a more structured text, updated figures and the addition of a discussion section (incl. a new figure). Previous results remain unchanged, but are now contextualised with respect to similar dwarf galaxies. A new estimate of the inclination angle has been added. References updated. 18 pages (10 figures, 5 tables) + appendices

Machine learning has rapidly become a tool of choice for the astronomical community. It is being applied across a wide range of wavelengths and problems, from the classification of transients to neural network emulators of cosmological simulations, and is shifting paradigms about how we generate and report scientific results. At the same time, this class of method comes with its own set of best practices, challenges, and drawbacks, which, at present, are often reported on incompletely in the astrophysical literature. With this paper, we aim to provide a primer to the astronomical community, including authors, reviewers, and editors, on how to implement machine learning models and report their results in a way that ensures the accuracy of the results, reproducibility of the findings, and usefulness of the method., Comment: 14 pages, 3 figures; submitted to the Bulletin of the American Astronomical Society

We present an observational study of the dark matter fraction in star-forming disk-like galaxies up to redshift $z \sim 2.5$, selected from publicly available integral field spectroscropic surveys: KMOS$^{\rm 3D}$, KGES, and KROSS. To model the $H\alpha$ kinematics of these galaxies, we employ 3D forward-modelling, which incorporates beam-smearing and inclination corrections, and yields rotation curves. Subsequently, these rotation curves are corrected for gas pressure gradients, resulting in circular velocity curves or `intrinsic' rotation curves. Our final sample comprises of 263 rotationally supported main sequence star-forming galaxies with redshifts ranging from $0.6 \leq z < 2.5$. We estimate the dark matter fraction of these galaxies by subtracting the baryonic mass from the total mass, where the total mass is derived from the intrinsic rotation curves. We provide novel observational evidence, suggesting that at a fixed redshift, the dark matter fraction gradually increases with radius such that the outskirts of galaxies are dark matter dominated, similarly to local star-forming disk galaxies. This observed dark matter fraction exhibits a decreasing trend with increasing redshift and, on average, the fraction within the effective radius (upto outskirts) remains above 50\%, similar to locals. We investigate the relationships between dark matter, baryon surface density, and circular velocity of galaxies. We observe that low stellar mass galaxies, with $\log(M_{\rm star}\ [\mathrm{M_\odot}]) \leq 10.0$, undergo a higher degree of evolution, which may be attributed to the hierarchical merging of galaxies. Most importantly, we discuss several sources of uncertainties and current limitations in the field, as well as their impact on the measurements of dark matter fraction and its trend across galactic scales and cosmic time., Comment: Comments are welcome

Omega Centauri ($\omega$ Cen) is the most massive globular cluster of the Milky Way and has been the focus of many studies that reveal the complexity of its stellar populations and kinematics. However, most previous studies have used photometric and spectroscopic datasets with limited spatial or magnitude coverage, while we aim to investigate it having full spatial coverage out to its half-light radius and stars ranging from the main sequence to the tip of the red giant branch. This is the first paper in a new survey of $\omega$ Cen that combines uniform imaging and spectroscopic data out to its half-light radius to study its stellar populations, kinematics, and formation history. In this paper, we present an unprecedented MUSE spectroscopic dataset combining 87 new MUSE pointings with previous observations collected from guaranteed time observations. We extract spectra of more than 300,000 stars reaching more than two magnitudes below the main sequence turn-off. We use these spectra to derive metallicity and line-of-sight velocity measurements and determine robust uncertainties on these quantities using repeat measurements. Applying quality cuts we achieve signal-to-noise ratios of 16.47/73.51 and mean metallicity errors of 0.174/0.031 dex for the main sequence stars (18 mag $\rm < mag_{F625W}<$22 mag) and red giant branch stars (16 mag $<\rm mag_{F625W}<$10 mag), respectively. We correct the metallicities for atomic diffusion and identify foreground stars. This massive spectroscopic dataset will enable future studies that will transform our understanding of $\omega$ Cen, allowing us to investigate the stellar populations, ages, and kinematics in great detail., Comment: 27 pages, 18 figures, 3 tables, published in ApJ, the catalog is available in the online material of the published article; typos corrected in this version

We present the first results from the Revealing Low-Luminosity Active Galactic Nuclei (ReveaLLAGN) survey, a JWST survey of seven nearby LLAGN. We focus on two observations with the Mid-Infrared Instrument's (MIRI) Medium Resolution Spectrograph (MRS) of the nuclei of NGC 1052 and Sombrero (NGC 4594 / M104). We also compare these data to public JWST data of a higher-luminosity AGN, NGC 7319 and NGC 7469. JWST clearly separates the AGN spectrum from the galaxy light even in Sombrero, the faintest target in our survey; the AGN components have very red spectra. We find that the emission-line widths in both NGC 1052 and Sombrero increase with increasing ionization potential, with FWHM > 1000 km/s for lines with ionization potential > 50 eV. These lines are also significantly blue-shifted in both LLAGN. The high ionization potential lines in NGC 7319 show neither broad widths or significant blue shifts. Many of the lower ionization potential emission lines in Sombrero show significant blue wings extending > 1000 km/s. These features and the emission-line maps in both galaxies are consistent with outflows along the jet direction. Sombrero has the lowest luminosity high-ionization potential lines ([Ne V] and [O IV]) ever measured in the mid-IR, but the relative strengths of these lines are consistent with higher luminosity AGN. On the other hand, the [Ne V] emission is much weaker relative to the [Ne III] and [Ne II] lines of higher-luminosity AGN. These initial results show the great promise that JWST holds for identifying and studying the physical nature of LLAGN., Comment: Accepted to ApJ Feb 28, 2024

We present a unified approach to (bi-)orthogonal basis sets for gravitating systems. Central to our discussion is the notion of mutual gravitational energy, which gives rise to the self-energy inner product on mass densities. We consider a first-order differential operator that is self-adjoint with respect to this inner product, and prove a general theorem that gives the conditions under which a (bi-)orthogonal basis set arises by repeated application of this differential operator. We then show that these conditions are fulfilled by all the families of analytical basis sets with infinite extent that have been discovered to date. The new theoretical framework turns out to be closely connected to Fourier-Mellin transforms, and it is a powerful tool for constructing general basis sets. We demonstrate this by deriving a basis set for the isochrone model and demonstrating its numerical reliability by reproducing a known result concerning unstable radial modes., Comment: to be published in Astronomy & Astrophysics

We apply a population-orbit superposition method to 16 galaxies in the Fornax cluster observed with MUSE/VLT in the context of the Fornax3D project. By fitting the luminosity distribution, stellar kinematics, and age and metallicity maps simultaneously, we obtained the internal stellar orbit distribution, as well as the age and metallicity distribution of stars on different orbits for each galaxy. Based on the model, we decompose each galaxy into a dynamically cold disk (orbital circularity $\lambda_z\ge0.8$) and a dynamically hot non-disk component (orbital circularity $\lambda_z<0.8$), and obtain the surface-brightness, age, and metallicity radial profiles of each component. The galaxy infall time into the cluster is strongly correlated with galaxy cold-disk age with older cold disks in ancient infallers. We quantify the infall time $t_{\rm infall}$ of each galaxy with its cold-disk age using a correlation calibrated with TNG50 cosmological simulations. For galaxies in the Fornax cluster, we found that the luminosity fraction of cold disk in galaxies with $t_{\rm infall}>8$ Gyr are a factor of $\sim 4$ lower than in more recent infallers while controlling for total stellar mass. Nine of the 16 galaxies have spatially extended cold disks, and most of them show positive or zero age gradients; stars in the inner disk are $\sim 2-5$ Gyr younger than that in the outer disk, in contrast to the expectation of inside-out growth. Our results indicate that the assembly of cold disks in galaxies is strongly affected by their infall into clusters, by either removal of gas in outer regions or even tidally stripping or heating part of the pre-existing disks. Star formation in outer disks can stop quickly after the galaxy falls into the cluster, while star formation in the inner disks can last for a few Gyrs more, building the positive age gradient measured in cold disks., Comment: 31 pages, 32 figures, Accepted to A&A

We study the evolution of kinematically-defined stellar discs in 10 Fornax-like clusters identified in the TNG50 run from the IllustrisTNG suite of cosmological simulations. We considered disc galaxies with present-day stellar mass $M_{\star}\geq 3 \times 10^{8} M_{\odot}$ and follow their evolution since first entering their host cluster. Very few stellar discs survive since falling in such dense environments, ranging from 40% surviving to all being disrupted. Such survival rates are consistent with what reported earlier for the two more massive, Virgo-like clusters in TNG50. In absolute terms, however, the low number of present-day disc galaxies in Fornax-like clusters could be at odds with the presence of three edge-on disc galaxies in the central regions of the actual Fornax cluster, as delineated by the Fornax3D survey. When looking at the Fornax analogues from random directions and with the same selection function of Fornax3D, the probability of finding three edge-on disc galaxies in any one Fornax-like cluster in TNG50 is rather low, albeit not impossible. We also compared the stellar-population properties near the equatorial plane derived from integral-field spectroscopy for the three edge-ons in Fornax to similar line-of-sight integrated values for present-day disc galaxies in TNG50. For one of these, the very old and metal-rich stellar population of its disc cannot be matched by any the disc galaxies in TNG50, including objects in the field. We discuss possible interpretations of these findings, while pointing to future studies on passive cluster spirals as a way to further test state-of-the-art cosmological simulations., Comment: 12 pages, 7 figures. Accepted on 21 of October, published on 25 of October

This work is based on high quality integral-field spectroscopic data obtained with the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT). The 21 brightest ($m_B\leq 15$ mag) early-type galaxies (ETGs) inside the virial radius of the Fornax cluster are observed out to distances of $\sim2-3\ R_{\rm e}$. Deep imaging from the VLT Survey Telescope (VST) is also available for the sample ETGs. We investigate the variation of the galaxy structural properties as a function of the total stellar mass and cluster environment. Moreover, we correlate the size scales of the luminous components derived from a multi-component decomposition of the VST surface-brightness radial profiles of the sample ETGs with the MUSE radial profiles of stellar kinematic and population properties. The results are compared with both theoretical predictions and previous observational studies and used to address the assembly history of the massive ETGs of the Fornax cluster. We find that galaxies in the core and north-south clump of the cluster, which have the highest accreted mass fraction, show milder metallicity gradients in their outskirts than the galaxies infalling into the cluster. We also find a segregation in both age and metallicity between the galaxies belonging to the core and north-south clump and the infalling galaxies. The new findings fit well within the general framework for the assembly history of the Fornax cluster., Comment: 23 pages, 7 figures, 3 tables. Accepted for publication in A&A

[arXiv Abridged] In this work, we explore new spatially-resolved measurements of the IMF for three edge-on lenticular galaxies in the Fornax cluster. Specifically, we utilise existing orbit-based dynamical models, which re-produce the measured stellar kinematics, in order to fit the new IMF maps within this orbital framework. We then investigate correlations between intrinsic orbital properties and the local IMF. We find that, within each galaxy, the high-angular-momentum, disk-like stars exhibit an IMF which is rich in dwarf stars. The centrally-concentrated pressure-supported orbits have IMF which are similarly rich in dwarf stars. Conversely, orbits at large radius which have intermediate angular momentum exhibit IMF which are markedly less dwarf-rich relative to the other regions of the same galaxy. Assuming that the stars which, in the present-day, reside on dynamically-hot orbits at large radii are dominated by accreted populations, we can interpret these findings as a correlation between the dwarf-richness of a population of stars, and the mass of the host in which it formed. Specifically, deeper gravitational potentials would produce more dwarf-rich populations, resulting in the relative deficiency of dwarf stars which originated in the lower-mass accreted satellites. Conversely, the central and high angular-momentum populations are likely dominated by in-situ stars, which were formed in the more massive host itself. There are also global differences between the three galaxies studied here, of up to $\sim 0.3\ \mathrm{dex}$ in the IMF parameter $\xi$. We find no local dynamical or chemical property which alone can fully account for the IMF variations., Comment: 11 pages. Accepted to MNRAS

The role played by environment in galaxy evolution is a current debate in astronomy. The degree to which environment can alter, re-shape, or drive galaxy evolution is a topic of discussion in both fronts, observations and simulations. This paper analyses the gas metallicity gradients for a sample of 10 Fornax cluster galaxies observed with MUSE as part of the Fornax3D project. Detailed maps of emission lines allowed a precise determination of gas metallicity and metallicity gradients. The integrated gas metallicity of our Fornax cluster galaxies show slightly higher metallicities (~0.045 dex) in comparison to a control sample. In addition, we find signs of a mass and metallicity segregation from the center to the outskirts of the cluster. By comparing our Fornax cluster metallicity gradients with a control sample we find a general median offset of ~0.04 dex/Re, with 8 of our galaxies showing flatter or more positive gradients. We find no systematic difference between the gradients of recent and intermediate infallers when considering the projected distance of each galaxy to the cluster center. To identify the origin of the observed offset in the metallicity gradients, we perform a similar analysis with data from the TNG50 simulation. We identify 12 subhalos in Fornax-like clusters and compare their metallicity gradients with a control sample of field subhalos. This exercise also shows a flattening in the metallicity gradients for galaxies in Fornax-like halos, with a median offset of ~0.05 dex/Re We also analyse the merger history, Mach numbers (M), and ram pressure stripping of our TNG50 sample. We conclude that the observed flattening in metallicity gradients is likely due to a combination of galaxies traveling at supersonic velocities (M>1) that are experiencing high ram pressure stripping and flybys., Comment: Accepted by A&A

The stellar initial mass function (IMF) is central to our interpretation of astronomical observables and to our understanding of most baryonic processes within galaxies. The universality of the IMF, suggested by observations in our own Milky Way, has been thoroughly revisited due to the apparent excess of low-mass stars in the central regions of massive quiescent galaxies. As part of the efforts within the Fornax 3D project, we aim to characterize the two-dimensional IMF variations in a sample of 23 quiescent galaxies within the Fornax cluster. For each galaxy in the sample, we measured the mean age, metallicity, [Mg/Fe], and IMF slope maps from spatially resolved integrated spectra. The IMF maps show a variety of behaviors and internal substructures, roughly following metallicity variations. However, metallicity alone is not able to fully explain the complexity exhibited by the IMF maps. In particular, for relatively metal-poor stellar populations, the slope of the IMF seems to depend on the (specific) star formation rate at which stars were formed. Moreover, metallicity maps have systematically higher ellipticities than IMF slope ones. At the same time, both metallicity and IMF slope maps have at the same time higher ellipticities than the stellar light distribution in our sample of galaxies. In addition we find that, regardless of the stellar mass, every galaxy in our sample shows a positive radial [Mg/Fe] gradient. This results in a strong [Fe/H]-[Mg/Fe] relation, similar to what is observed in nearby, resolved galaxies. Since the formation history and chemical enrichment of galaxies are causally driven by changes in the IMF, our findings call for a physically motivated interpretation of stellar population measurements based on integrated spectra that take into account any possible time evolution of the stellar populations., Comment: 14 pages and 10 figures (plus Appendix including all the stellar population maps). Accepted for publication in Astronomy and Astrophysics

Extragalactic planetary nebulae (PNe) offer a way to determine the distance to their host galaxies thanks to the nearly universal shape of the planetary nebulae luminosity function (PNLF). Accurate PNe distance measurements rely on obtaining well-sampled PNLFs and the number of observed PNe scales with the encompassed stellar mass. This means either disposing of wide-field observations or focusing on the bright central regions of galaxies. In this work we take this second approach and conduct a census of the PNe population in the central regions of galaxies in the Fornax cluster, using VLT/MUSE data for the early-type galaxies observed over the course of the Fornax3D survey. Using such integral-field spectroscopic observations to carefully separate the nebular emission from the stellar continuum, we isolated [OIII] 5007 {\AA} sources of interest, filtered out unresolved impostor sources or kinematic outliers, and present a catalogue of 1350 unique PNe sources across 21 early-type galaxies, which includes their positions, [OIII] 5007 {\AA} line magnitudes, and line-of-sight velocities. Using the PNe catalogued within each galaxy, we present independently derived distance estimates based on the fit to the entire observed PNLF observed while carefully accounting for the PNe detection incompleteness. With these individual measurements, we arrive at an average distance to the Fornax cluster itself of 19.86 $\pm$ 0.32 Mpc ($\mu_{PNLF}$ = 31.49 $\pm$ 0.04 mag). Our PNLF distance measurements agree well with previous distances based on surface brightness fluctuations, finding no significant systematic offsets between the two methods as otherwise reported in previous studies., Comment: 26 pages, 16 figures, 3 tables. Accepted for publication in Astronomy and Astrophysics Journal. Corrected Fig. 7 legend

Context. Extragalactic Planetary Nebulae (PNe) are useful distance indicators and are often used to trace the dark-matter content in external galaxies. At the same time, PNe can also be used as probes of their host galaxy stellar populations and to help understanding the later stages of stellar evolution. Previous works have indicated that specific number of PNe per stellar luminosity can vary across different galaxies and as a function of stellar-population properties, for instance increasing with decreasing stellar metallicity. Aims. In this study we further explore the importance of stellar metallicity in driving the properties of the PNe population in early-type galaxies, using three edge-on galaxies in the Fornax cluster offering a clear view into their predominantly metal-rich and metal-poor regions near the equatorial plane or both below and above it, respectively . Methods. Using VLT-MUSE integral-field observations and dedicated PNe detection procedures, we construct the PNe luminosity function and compute the luminosity-specific number of PNe alpha in both in- and off-plane regions of our edge-on systems. Results. Comparing these alpha values with metallicity measurements also based on the same MUSE data, we find no evidence for an increase in the specific abundance of PNe when transitioning between metal-rich and metal-poor regions. Conclusions. Our analysis highlights the importance of ensuring spatial consistency to avoid misleading results when investigating the link between PNe and their parent stellar populations and suggest that in passively-evolving systems variations in the specific number of PNe may pertain to rather extreme metallicity regimes found either in the innermost or outermost regions of galaxies.

Nuclear star clusters (NSCs) are the densest stellar systems in the Universe and are found in the centres of all types of galaxies. They are thought to form via mergers of star clusters such as ancient globular clusters (GCs) that spiral to the centre as a result of dynamical friction or through in-situ star formation directly at the galaxy centre. There is evidence that both paths occur, but the relative contribution of either channel and their correlation with galaxy properties are not yet constrained observationally. We aim to derive the dominant NSC formation channel for a sample of 25 nucleated galaxies, mostly in the Fornax galaxy cluster, with stellar masses between $M_\rm{gal} \sim 10^8$ and $10^{10.5} M_\odot$ and NSC masses between $M_\rm{NSC} \sim 10^5$ and $10^{8.5} M_\odot$. Using Multi-Unit Spectroscopic Explorer (MUSE) data from the Fornax 3D survey and the ESO archive, we derive star formation histories, mean ages and metallicities of NSCs, and compare them to the host galaxies. In many low-mass galaxies, the NSCs are significantly more metal-poor than the hosts with properties similar to GCs. In contrast, in the massive galaxies, we find diverse star formation histories and cases of ongoing or recent in-situ star formation. Massive NSCs ($> 10^7 M_\odot$) occupy a different region in the mass-metallicity diagram than lower mass NSCs and GCs, indicating a different enrichment history. We find a clear transition of the dominant NSC formation channel with both galaxy and NSC mass. We hypothesise that while GC-accretion forms the NSCs of the dwarf galaxies, central star formation is responsible for the efficient mass build up in the most massive NSCs in our sample. At intermediate masses, both channels can contribute. The transition between these formation channels seems to occur at galaxy masses $M_\rm{gal} \sim 10^9 M_\odot$ and NSC masses $M_\rm{NSC} \sim 10^7 M_\odot$., Comment: accepted for publication in Astronomy & Astrophysics, 18 pages, 10 figures (including appendix)

Abridged for arXiv: In this work, we apply a powerful new technique in order to observationally derive accurate assembly histories through a self-consistent combined stellar dynamical and population galaxy model. We present this approach for three edge-on lenticular galaxies from the Fornax3D project -- FCC 153, FCC 170, and FCC 177 -- in order to infer their mass assembly histories individually and in the context of the Fornax cluster. The method was tested on mock data from simulations to quantify its reliability. We find that the galaxies studied here have all been able to form dynamically-cold (intrinsic vertical velocity dispersion $\sigma_z \lesssim 50\ {\rm km}\ {\rm s}^{-1}$) stellar disks after cluster infall. Moreover, the pre-existing (old) high angular momentum components have retained their angular momentum (orbital circularity $\lambda_z > 0.8$) through to the present day. Comparing the derived assembly histories with a comparable galaxy in a low-density environment -- NGC 3115 -- we find evidence for cluster-driven suppression of stellar accretion and merging. We measured the intrinsic stellar age--velocity-dispersion relation and find that the shape of the relation is consistent with galaxies in the literature across redshift. There is tentative evidence for enhancement in the luminosity-weighted intrinsic vertical velocity dispersion due to the cluster environment. But importantly, there is an indication that metallicity may be a key driver of this relation. We finally speculate that the cluster environment is responsible for the S0 morphology of these galaxies via the gradual external perturbations, or `harassment', generated within the cluster., Comment: Accepted for publication in A&A

Studying the stellar kinematics of galaxies is a key tool in the reconstruction of their evolution. However, the current measurements of the stellar kinematics are complicated by several factors, including dust extinction and the presence of multiple stellar populations. We use integral field spectroscopic data of four galaxies from the TIMER survey to explore and compare the kinematics measured in different spectral regions that are sensitive to distinct stellar populations. We derive the line-of-sight velocity and velocity dispersion of both a young (<2 Gyr) and an old stellar population from the spectral regions around the H$\beta$ line and the Ca II Triplet. In addition we obtain colour excess, mean age, and metallicity. We report a correlation of the colour excess with the difference in the kinematic parameters of the H$\beta$ line and the Ca II Triplet range, which are dominated by young and old stellar populations, respectively. Young stellar populations, located primarily in nuclear rings, have higher velocity dispersions than old ones. These differences in the rings are typically 10 km/s in velocity dispersion, but up to a mean value of 24 km/s in the most extreme case. Trends with age exist in the nuclear rings but are less significant than those with dust extinction. We report different degrees of correlation of these trends among the galaxies in the sample, which are related to the size of the Voronoi bins in their rings. No clear trends for the difference of line-of-sight velocity are observed. The absence of these trends can be explained as a consequence of the masking process of the H$\beta$ line during the kinematic extraction, as confirmed by dedicated simulations. Our study demonstrates that kinematic differences caused by different stellar populations can be identified in the central regions of nearby galaxies even from intermediate resolution spectroscopy., Comment: 22 pages, 24 figures

We present the study of the south-west group in the Fornax cluster centred on the brightest group galaxy (BGG) Fornax A, observed as part of the Fornax Deep Survey (FDS). This includes the analysis of the bright group members (mB < 16 mag) and the intra-group light (IGL). The main objective of this work is to investigate the assembly history of the Fornax A group and to compare its physical quantities as a function of the environment to that of the Fornax cluster core. For all galaxies, we extract the azimuthally averaged surface brightness profiles in three optical bands (g, r, i) by modelling the galaxy's isophotes. We derive their colour profiles and structural parameters in all respective bands. The long integration time and large covered area of the FDS allow us to also estimate the amount of IGL. The majority of galaxies in the Fornax A group are late-type galaxies (LTGs), spanning a range of stellar mass of $8 < log (M_* M_{\odot}) < 10.5$. Six out of nine LTGs show a Type III (up-bending) break in their light profiles, which is either suggestive of strangulation halting star-formation in their outskirts or their HI-richness causing enhanced star-formation in their outer-discs. The estimated luminosity of the IGL is $6 \pm 2 \times 10^{10} L_{\odot}$ in g-band, which corresponds to about 16% of the total light in the group. The Fornax A group appears to be in an early stage of assembly with respect to the cluster core. The environment of the Fornax A group is not as dense as that of the cluster core, with all galaxies except the BGG showing similar morphology, comparable colours and stellar masses, and Type III disc-breaks, without any clear trend of these properties with group-centric distances. The main contribution to the IGL is from the minor merging in the outskirts of the BGG NGC1316 and, probably, the disrupted dwarf galaxies close to the group centre., Comment: Published in A&A. Replaced version: corrected typos and title (series number X)

This work is based on deep multi-band (g, r, i) data from the Fornax Deep Survey with VST. We analyse the surface brightness profiles of the 19 bright ETGs inside the virial radius of the Fornax cluster. The main aim of this work is to identify signatures of accretion onto galaxies by studying the presence of outer stellar halos, and understand their nature and occurrence. Our analysis also provides a new and accurate estimate of the intra-cluster light inside the virial radius of Fornax. We performed multi-component fits to the azimuthally averaged surface brightness profiles available for all sample galaxies. This allows to quantify the relative weight of all components in the galaxy structure that contribute to the total light. In addition, we derived the average g-i colours in each component identified by the fit, as well as the azimuthally averaged g-i colour profiles, to correlate them with the stellar mass of each galaxy and the location inside the cluster. We find that in the most massive and reddest ETGs the fraction of light in, probably accreted, halos is much larger than in the other galaxies. Less-massive galaxies have an accreted mass fraction lower than 30%, bluer colours and reside in the low-density regions of the cluster. Inside the virial radius of the cluster, the total luminosity of the intra-cluster light, compared with the total luminosity of all cluster members, is about 34%. Inside the Fornax cluster there is a clear correlation between the amount of accreted material in the stellar halos of galaxies and the density of the environment in which those galaxies reside. By comparing this quantity with theoretical predictions and previous observational estimates, there is a clear indication that the driving factor for the accretion process is the total stellar mass of the galaxy, in agreement with the hierarchical accretion scenario., Comment: 18 pages, 10 figures. Accepted for publication in A&A

Globular clusters (GCs) are found ubiquitously in massive galaxies and due to their old ages, they are regarded as fossil records of galaxy evolution. Spectroscopic studies of GC systems are often limited to the outskirts of galaxies, where GCs stand out against the galaxy background and serve as bright tracers of galaxy assembly. In this work, we use the capabilities of the Multi Unit Explorer Spectrograph (MUSE) to extract a spectroscopic sample of 722 GCs in the inner regions ($\lesssim 3 R_\text{eff}$) of 32 galaxies in the Fornax cluster. These galaxies were observed as part of the Fornax 3D project, a MUSE survey that targets early and late-type galaxies within the virial radius of Fornax. After accounting for the galaxy background in the GC spectra, we extracted line-of-sight velocities and determined metallicities of a sub-sample of 238 GCs. We found signatures of rotation within GC systems, and comparing the GC kinematics and that of the stellar body shows that the GCs trace the spheroid of the galaxies. While the red GCs prove to closely follow the metallicity profile of the host galaxy, the blue GCs show a large spread of metallicities but they are generally more metal-poor than the host., Comment: 13 pages + appendix, accepted for publication in A&A, updated to published version

Globular cluster (GC) systems of massive galaxies often show a bimodal colour distribution. This has been interpreted as a metallicity bimodality, created by a two-stage galaxy formation where the red, metal-rich GCs were formed in the parent halo and the blue metal-poor GCs were accreted. This interpretation, however, crucially depends on the assumption that GCs are exclusively old stellar systems with a linear colour-metallicity relation (CZR). The shape of the CZR and range of GC ages are currently under debate, because their study requires high quality spectra to derive reliable stellar population properties. We determined metallicities with full spectral fitting from a sample of 187 GCs with high spectral signal-to-noise ratio in 23 galaxies of the Fornax cluster that were observed as part of the Fornax 3D project. The derived CZR from this sample is non-linear and can be described by a piecewise linear function with a break point at ($g - z$) $\sim$ 1.1 mag. The less massive galaxies in our sample ($M_\ast < 10^{10} M_\odot$) appear to have slightly younger GCs, but the shape of the CZR is insensitive to the GC ages. Although the least massive galaxies lack red, metal-rich GCs, a non-linear CZR is found irrespective of the galaxy mass, even in the most massive galaxies ($M_\ast \geq 10^{11} M_\odot$). Our CZR predicts narrow unimodal GC metallicity distributions for low mass and broad unimodal distributions for very massive galaxies, dominated by a metal-poor and metal-rich peak, respectively, and bimodal distributions for galaxies with intermediate masses (10$^{10}$ $\leq$ $M_\ast < 10^{11} M_\odot$) as a consequence of the relative fraction of red and blue GCs. The diverse metallicity distributions challenge the simple differentiation of GC populations solely based on their colour., Comment: 12 pages + appendix, updated to published version

Extragalactic planetary nebulae (PNe) are detectable through relatively strong nebulous [OIII] emission and act as direct probes into the local stellar population. Because they have an apparently universal invariant magnitude cut-off, PNe are also considered to be a remarkable standard candle for distance estimation. Through detecting PNe within the galaxies, we aim to connect the relative abundances of PNe to the properties of their host galaxy stellar population. By removing the stellar background components from FCC 167 and FCC 219, we aim to produce PN luminosity functions (PNLF) of these galaxies, and thereby also estimate the distance modulus to these two systems. Finally, we test the reliability and robustness of our novel detection and analysis method. It detects unresolved point sources by their [OIII] 5007{\AA} emission within regions that have previously been unexplored. We model the [OIII] emissions in the spatial and spectral dimensions together, as afforded to us by the Multi Unit Spectroscopic Explorer (MUSE), and we draw on data gathered as part of the Fornax3D survey. For each source, we inspect the properties of the nebular emission lines to remove other sources that might hinder the safe construction of the PNLF, such as supernova remnants and HII regions. As a further step, we characterise any potential limitations and draw conclusions about the reliability of our modelling approach through a set of simulations. By applying this novel detection and modelling approach to integral field unit observations, we report for the distance estimates and luminosity-specific PNe frequency values for the two galaxies. Furthermore, we include an overview of source contamination, galaxy differences, and possible effects on the PNe populations in the dense stellar environments., Comment: 16 pages, 17 figures, 3 tables. Accepted for publication in Astronomy and Astrophysics Journal. Replaced with published version

[Abridged] We present the apparent stellar angular momentum of 300 galaxies across the Hubble sequence, using integral-field spectroscopic data from the CALIFA survey. Adopting the same $\lambda_\mathrm{R}$ parameter previously used to distinguish between slow and fast rotating early-type (elliptical and lenticular) galaxies, we show that spiral galaxies as expected are almost all fast rotators. Given the extent of our data, we provide relations for $\lambda_\mathrm{R}$ measured in different apertures, including conversions to long-slit 1D apertures. Our sample displays a wide range of $\lambda_\mathrm{Re}$ values, consistent with previous IFS studies. The fastest rotators are dominated by relatively massive and highly star-forming Sb galaxies, which preferentially reside in the main star-forming sequence. These galaxies reach $\lambda_\mathrm{Re}$ values of $\sim$0.85, are the largest galaxies at a given mass, and display some of the strongest stellar population gradients. Compared to the population of S0 galaxies, our findings suggest that fading may not be the dominant mechanism transforming spirals into lenticulars. Interestingly, we find that $\lambda_\mathrm{Re}$ decreases for late-type Sc and Sd spiral galaxies, with values than in occasions puts them in the slow-rotator regime. While for some of them this can be explained by their irregular morphologies and/or face-on configurations, others are edge-on systems with no signs of significant dust obscuration. The latter are typically at the low-mass end, but this does not explain their location in the classical ($V/\sigma$,$\varepsilon$) and ($\lambda_\mathrm{Re}$,$\varepsilon$) diagrams. Our initial investigations, based on dynamical models, suggest that these are dynamically hot disks, probably influenced by the observed important fraction of dark matter within R$_\mathrm{e}$., Comment: 17 pages, 7 figures, A&A accepted

Using new long-slit spectroscopy obtained with X-Shooter at ESO-VLT, we study, for the first time, radial gradients of optical and Near-Infrared IMF-sensitive features in a representative sample of galaxies at the very high-mass end of the galaxy population. The sample consists of seven early-type galaxies (ETGs) at $z\sim0.05$, with central velocity dispersion in the range $300<\sigma<350$km/s. Using state-of-art stellar population synthesis models, we fit a number of spectral indices, from different chemical species (including TiO's and Na indices), to constrain the IMF slope (i.e. the fraction of low-mass stars), as a function of galactocentric distance, over a radial range out to $\sim4$kpc. ETGs in our sample show a significant correlation of IMF slope and surface mass density. The bottom-heavy population (i.e. an excess of low-mass stars in the IMF) is confined to central galaxy regions with surface mass density above $\sim 10^{10} M_\odot kpc^{-2}$, or, alternatively, within a characteristic radius of $\sim2$~kpc. Radial distance, in physical units, and surface mass density, are the best correlators to IMF variations, with respect to other dynamical (e.g. velocity dispersion) and stellar population (e.g. metallicity) properties. Our results for the most massive galaxies suggest that there is no single parameter} that fully explains variations in the stellar IMF, but IMF radial profiles at z$\sim$0 rather result from the complex formation and mass accretion history of galaxy inner and outer regions., Comment: 23 pages, 13 figures, accepted for publication in MNRAS

We present the study of a magnitude limited sample (mB < 16.6 mag) of 13 late type galaxies (LTGs), observed inside the virial radius, Rvir 0.7 Mpc, of the Fornax cluster within the Fornax Deep Survey (FDS). The main objective is to use surface brightness (SB) profiles and g-i colour maps to obtain information on the internal structure of these galaxies and find signatures of the mechanisms that drive their evolution in high-density environment, which is inside the virial radius of the cluster. By modelling galaxy isophotes, we extract the azimuthally averaged surface brightness profiles in four optical bands. We also derive g-i colour profiles, and structural parameters like total magnitude and effective radius. For 10 of the galaxies in this sample, we observe a clear discontinuity in their SB profiles, derive their break radius (Br), and classify their disc-breaks into Type-II (down-bending) or Type-III (up-bending). We find that Type-II galaxies have bluer average (g-i) colour in their outer discs while Type-III galaxies are redder. Br increases with stellar mass and molecular gas mass while decreases with molecular gas-fractions. The inner and outer scale-lengths increase monotonically with absolute magnitude, as found in other works. In Fornax, galaxies with morphological type 5< T< 9 (~60 % of the sample) are located beyond the high-density, ETG-dominated regions, but no correlation found between T and the disc-break type. The main results of this work suggest that the disc-breaks of LTGs inside the virial radius of the Fornax cluster seem to have arisen through a variety of mechanisms, which is evident in their outer-disc colours and the absence of molecular gas beyond their break radius in some cases. This can result in a variety of stellar populations inside and outside the break radii., Comment: Accepted for publication in A&A. Replaced version: corrected latex typos. Full resolution pdf file is available at the following link: https://www.dropbox.com/s/7gpk6fg0whsxyye/The_Fornax_Deep_Survey_with_VST.pdf?dl=0

The 31 brightest galaxies (m_B < 15 mag) inside the virial radius of the Fornax cluster were observed from the centres to the outskirts with the Multi Unit Spectroscopic Explorer on the Very Large Telescope. These observations provide detailed high-resolution maps of the line-of-sight kinematics and line strengths of the stars and ionised gas reaching 2-3 Re for 21 early-type galaxies and 1-2 Re for 10 late-type galaxies. The majority of the galaxies are regular rotators, with eight hosting a kinematically distinct core. Only two galaxies are slow rotators. The mean age, total metallicity, and [Mg/Fe] abundance ratio in the bright central region inside 0.5 Re and in the galaxy outskirts are presented. Extended emission-line gas is detected in 13 galaxies, most of them are late-type objects with wide-spread star formation. The measured structural properties are analysed in relation to the galaxies' position in the projected phase space of the cluster. This shows that the Fornax cluster appears to consist of three main groups of galaxies inside the virial radius: the old core; a clump of galaxies, which is aligned with the local large-scale structure and was accreted soon after the formation of the core; and a group of galaxies that fell in more recently., Comment: Accepted for publication in Astronomy and Astrophysics Journal. The high-resolution pdf file, including all maps in the Appendix, is available at the following link: https://www.dropbox.com/s/oukfd56dogf6v9t/F3D_sample_paper.pdf?dl=0

We used deep MUSE observations to perform a stellar-kinematic and population analysis of FCC 153 and FCC 177, two edge-on S0 galaxies in the Fornax cluster. The geometrical definition of the different structural components of these two galaxies allows us to describe the nature of their thick disks. These are both old, relatively metal poor and [Mg/Fe]-enhanced, and their star formation history (SFH) reveals a minor younger component whose chemical properties suggest its later accretion. Moreover, the outer regions of these geometrically defined thick disks show higher values of metallicity and lower values of [Mg/Fe]. These stars probably formed in the thin-disk region and they were dynamically heated to form the flares present in these two galaxies. We propose different formation scenarios for the three populations of these thick disks: in-situ formation, accretion and disk heating. A clear distinction in age is found between the metal poor and [Mg/Fe]-enhanced thick disks (old, $\sim 12-13$ Gyr), and the metal rich and less [Mg/Fe]-enhanced thin disks (young, $\sim 4-5$ Gyr). These two galaxies show signs of relatively recent star formation in their thin disks and nuclear regions. While the thin disks show more continuous SFHs, the nuclei display a rather bursty SFH. These two galaxies are located outside of the densest region of the Fornax cluster where FCC 170 resides. This other edge-on S0 galaxy was studied by \citet{Pinna2019}. We compare and discuss our results with this previous study. The differences between these three galaxies, at different distances from the cluster center, suggest that the environment can have a strong effect on the galaxy evolutionary path., Comment: 24 pages, 18 figures

The stellar initial mass function (IMF) regulates the baryonic cycle within galaxies, and is a key ingredient to translate observations into physical quantities. Although for decades it was assumed to be universal, there is now growing observational evidence showing that the center of massive early-type galaxies host an enhanced population of low-mass stars compared to the expectations from the Milky Way. Moreover, these variations in the IMF have been found to be related to the radial metallicity variations in massive galaxies. We present here a two-dimensional stellar population analysis of the massive lenticular galaxy FCC 167 (NGC 1380) as part of the Fornax3D project. Using a newly developed stellar population fitting scheme, we derive a full two-dimensional IMF map of an early-type galaxy. This two-dimensional analysis allows us go further than a radial analysis, showing how the metallicity changes along a disc-like structure while the IMF follows a distinct, less disky distribution. Thus, our findings indicate that metallicity cannot be the sole driver of the observed radial IMF variations. In addition, a comparison with the orbital decomposition shows suggestive evidence of a coupling between stellar population properties and the internal dynamical structure of FCC 167, where metallicity and IMF maps seem to track the distribution of cold and warm orbits, respectively., Comment: 12 pages, 7 figures. Accepted for publication in Astronomy & Astrophysics

The formation of two stellar bars within a galaxy has proved challenging for numerical studies. It is yet not clear whether the inner bar is born via a star formation process promoted by gas inflow along the outer bar, or whether it is dynamically assembled from instabilities in a small-scale stellar disc. Observational constraints to these scenarios are scarce. We present a thorough study of the stellar content of two double-barred galaxies observed by the MUSE TIMER project, NGC 1291 and NGC 5850, combined with a two-dimensional multi-component photometric decomposition performed on the 3.6{\mu}m images from S4G. Our analysis confirms the presence of {\sigma}-hollows appearing in the stellar velocity dispersion distribution at the ends of the inner bars. Both galaxies host inner discs matching in size with the inner bars, suggestive of a dynamical formation for the inner bars from small-scale discs. The analysis of the star formation histories for the structural components shaping the galaxies provides constraints on the epoch of dynamical assembly of the inner bars, which took place >6.5 Gyr ago for NGC 1291 and >4.5 Gyr ago for NGC 5850. This implies that inner bars are long-lived structures., Comment: 20 pages, 10 figures, accepted for publication in MNRAS. The quality of figures has been greatly degraded to comply with arXiv size requirements, a full resolution version of the paper can be downloaded at: https://adrianadelorenzocaceres.files.wordpress.com/2019/01/papertimerdbs_v5.pdf

We present and discuss the stellar kinematics and populations of the S0 galaxy FCC 170 (NGC 1381) in the Fornax cluster, using deep MUSE data from the Fornax 3D survey. We show the maps of the first four moments of the stellar line-of-sight velocity distribution and of the mass-weighted mean stellar age, metallicity and [Mg/Fe] abundance ratio. The high-quality MUSE stellar kinematic measurements unveil the structure of this massive galaxy: a nuclear disk, a bar seen as a boxy bulge with a clear higher-velocity-dispersion X shape, a fast-rotating and flaring thin disk and a slower rotating thick disk. Whereas their overall old age makes it difficult to discuss differences in the formation epoch between these components, we find a clear-cut distinction between metal-rich and less [Mg/Fe]-enhanced populations in the thin-disk, boxy-bulge and nuclear disk, and more metal-poor and [Mg/Fe]-enhanced stars in the thick disk. Located in the densest region of the Fornax cluster, where signs of tidal stripping have been recently found, the evolution of FCC 170 might have been seriously affected by its environment. We discuss the possibility of its "pre-processing" in a subgroup before falling into the present-day cluster, which would have shaped this galaxy a long time ago. The thick disk displays a composite star formation history, as a significant fraction of younger stars co-exist with the main older thick-disk population. The former sub-population is characterized by even lower-metallicity and higher-[Mg/Fe] values, suggesting that these stars formed later and faster in a less chemically evolved satellite, which was subsequently accreted. Finally, we discuss evidence that metal-rich and less [Mg/Fe]-enhanced stars were brought in the outer parts of the thick disk by the flaring of the thin disk., Comment: 22 pages, 15 figures

Galaxies continuously reprocess their interstellar material. One can therefore expect changing dust grain properties in galaxies which have followed different evolutionary pathways. Determining the intrinsic dust grain mix of a galaxy helps in reconstructing its evolutionary history. Early-type galaxies occasionally display regular dust lanes in their central regions. Due to the relatively simple geometry and composition of their stellar bodies, these galaxies are ideal to disentangle dust mix variations from geometric effects. We therefore model the various components of such a galaxy (FCC 167). We reconstruct its recent history, and investigate the possible fate of the dust lane. MUSE and ALMA observations reveal a nested ISM structure. An ionised-gas disk pervades the central regions of FCC 167, including those occupied by the main dust lane. Inward of the dust lane, we also find a disk/ring of cold molecular gas where stars are forming and HII regions contribute to the ionised-gas emission. Further in, the gas ionisation points towards an active galactic nucleus and the fuelling of a central supermassive black hole from its surrounding ionised and molecular reservoir. Observational constraints and radiative transfer models suggest the dust and gas are distributed in a ring-like geometry and the dust mix lacks small grains. The derived dust destruction timescales from sputtering in hot gas are short and we conclude that the dust must be strongly self-shielding and clumpy, or will quickly be eroded and disappear. Our findings show how detailed analysis of individual systems can complement statistical studies of dust-lane ETGs., Comment: 14 pages, 9 figures, accepted for publication in Astronomy & Astrophysics

This paper is based on the multi-band (ugri) Fornax Deep Survey (FDS) with the VLT Survey Telescope (VST). We study bright early-type galaxies (m_B<15 mag) in the 9 square degrees around the core of the Fornax cluster, which covers the virial radius. The main goal of the present work is to provide the analysis of the light distribution for all galaxies out to unprecedented limits (in radius and surface brightness) and to release the main products resulting from this analysis in all FDS bands. From the isophote fit, we derive the azimuthally averaged surface brightness profiles, the position angle and ellipticity profiles as a function of the semi-major axis. In each band, we derive the total magnitudes, effective radii, integrated colors and stellar mass-to-light ratios. The long integration times, the arcsec-level angular resolution of OmegaCam@VST and the large covered area of FDS allow us to map the light and color distributions out to large galactocentric distances (up to about 10-15 R_e) and surface brightness levels beyond mu_r = 27 mag/arcsec^2 (mu_B > 28 mag/arcsec^2). Therefore, the new FDS data allow us to explore in great detail the morphology and structure of cluster galaxies out to the region of the stellar halo. The observations suggest that the Fornax cluster is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and GCs) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster., Comment: Accepted for publication in Astronomy & Astrophysics. High-resolution version of paper is available at the following link: https://www.dropbox.com/s/ybe4tg2hbqayteh/FDS_V.ETGs.pdf?dl=0

Double bars are thought to be important features for secular evolution in the central regions of galaxies. However, observational evidence about their origin and evolution is still scarce. We report on the discovery of the first Box-Peanut (B/P) structure in an inner bar detected in the face-on galaxy NGC 1291. We use the integral field data obtained from the MUSE spectrograph within the TIMER project. The B/P structure is detected as bi-symmetric minima of the $h_4$ moment of the line-of-sight velocity distribution along the major axis of the inner bar, as expected from numerical simulations. Our observations demonstrate that inner bars can follow a similar evolutionary path as outer bars, undergoing buckling instabilities. They also suggest that inner bars are long-lived structures, thus imposing tight constraints to their possible formation mechanisms, Comment: 5 pages, 2 figures. Accepted in MNRAS

We used ionized gas and stellar kinematics for 667 spatially resolved galaxies publicly available from the Calar Alto Legacy Integral Field Area survey (CALIFA) 3rd Data Release with the aim of studying kinematic scaling relations as the Tully $\&$ Fisher (TF) relation using rotation velocity, $V_{rot}$, the Faber $\&$ Jackson (FJ) relation using velocity dispersion, $\sigma$, and also a combination of $V_{rot}$ and $\sigma$ through the $S_{K}$ parameter defined as $S_{K}^2 = KV_{rot}^2 + \sigma^2$ with constant $K$. Late-type and early-type galaxies reproduce the TF and FJ relations. Some early-type galaxies also follow the TF relation and some late-type galaxies the FJ relation, but always with larger scatter. On the contrary, when we use the $S_{K}$ parameter, all galaxies, regardless of the morphological type, lie on the same scaling relation, showing a tight correlation with the total stellar mass, $M_\star$. Indeed, we find that the scatter in this relation is smaller or equal to that of the TF and FJ relations. We explore different values of the $K$ parameter without significant differences (slope and scatter) in our final results with respect the case $K=0.5$ besides than a small change in the zero point. We calibrate the kinematic $S_{K}^2$ dynamical mass proxy in order to make it consistent with sophisticated published dynamical models within $0.15\ dex$. We show that the $S_{K}$ proxy is able to reproduce the relation between the dynamical mass and the stellar mass in the inner regions of galaxies. Our result may be useful in order to produce fast estimations of the central dynamical mass in galaxies and to study correlations in large galaxy surveys., Comment: accepted by MNRAS

The Fornax cluster provides a uniquely compact laboratory to study the detailed history of early-type galaxies and the role played by environment in driving their evolution and their transformation from late-type galaxies. Using the superb capabilities of the Multi Unit Spectroscopic Explorer on the Very Large Telescope, high-quality integral-field spectroscopic data were obtained for the inner regions of all the bright ($m_B\leq15$) galaxies within the virial radius of Fornax. The stellar haloes of early-type galaxies are also covered out to about four effective radii. State-of-the-art stellar dynamical and population modelling allows to aim in particular at better characterising the disc components of fast-rotating early-type galaxies, constraining radial variations in the stellar initial-mass functions and measuring the stellar age, metallicity, and $\alpha$-element abundance of stellar haloes in cluster galaxies. This paper describes the sample selection, observations, and overall goals of the survey, and provides initial results based on the spectroscopic data, including the detailed characterisation of stellar kinematics and populations to large radii; decomposition of galaxy components directly via their orbital structure; the ability to identify globular clusters and planetary nebulae, and derivation of high-quality emission-line diagnostics in the presence of complex ionised gas., Comment: Accepted for publication in Astronomy & Astrophysics. An high resolution version is available at the following link: https://www.dropbox.com/s/bext14c5udhln8n/F3D_paper.pdf?dl=0

We present the results of a wide spectroscopic survey aimed at detecting extragalactic globular clusters (GCs) in the core of the Fornax cluster. About 4500 low resolution spectra (from 4800 to 10000 \AA ) were observed in 25 VLT/VIMOS masks covering the central 1 deg$^{2}$ around the dominant galaxy NGC 1399 corresponding to $\sim$175 kpc galactocentric radius. We describe the methodology used for data reduction and data analysis. We found a total of 387 unique physical objects (372 GCs and 15 ultra compact dwarfs) in the field covered by our observations. Most of these objects are associated with NGC 1399, with only 10% likely belonging to other giant galaxies. The new VIMOS dataset is complementary to the many GC catalogues already present in the literature and it brings the total number of tracer particles around NGC 1399 to more than 1130 objects. With this comprehensive radial velocity sample we have found that the velocity dispersion of the GC population (equally for red and blue GC populations) shows a relatively sharp increase from low velocity dispersion ($\sim250$-$350$ kms$^{-1}$) to high velocity dispersion ($\sim300$-$400$ kms$^{-1}$) at projected radius of $\approx10$ arcmin ($\sim60$ kpc) from the galaxy centre. This suggests that at a projected radius of $\approx60$ kpc both blue and red GC populations begin to be governed by the dominating Fornax cluster potential, rather than by the central NGC 1399 galaxy potential. This kinematic evidence corroborates similar results found using surface brightness analysis and planetary nebulae kinematics., Comment: 13 pages, 9 figures, submitted to MNRAS, companion paper FVSS-II (Spiniello et al. 2018, submitted)

The stellar velocity ellipsoid (SVE) in galaxies can provide important information on the processes that participate in the dynamical heating of their disc components (e.g. giant molecular clouds, mergers, spiral density waves, bars). Earlier findings suggested a strong relation between the shape of the disc SVE and Hubble type, with later-type galaxies displaying more anisotropic ellipsoids and early-types being more isotropic. In this paper, we revisit the strength of this relation using an exhaustive compilation of observational results from the literature on this issue. We find no clear correlation between the shape of the disc SVE and morphological type, and show that galaxies with the same Hubble type display a wide range of vertical-to-radial velocity dispersion ratios. The points are distributed around a mean value and scatter of $\sigma_z/\sigma_R=0.7\pm 0.2$. With the aid of numerical simulations, we argue that different mechanisms might influence the shape of the SVE in the same manner and that the same process (e.g. mergers) does not have the same impact in all the galaxies. The complexity of the observational picture is confirmed by these simulations, which suggest that the vertical-to-radial axis ratio of the SVE is not a good indicator of the main source of disc heating. Our analysis of those simulations also indicates that the observed shape of the disc SVE may be affected by several processes simultaneously and that the signatures of some of them (e.g. mergers) fade over time., Comment: Published in MNRAS, 05 January 2018. 17 pages, 9 figures, 4 tables

We determine abundance ratios of 37 dwarf ellipticals (dEs) in the nearby Virgo cluster. This sample is representative of the early-type population of galaxies in the absolute magnitude range -19.0 < Mr < -16.0. We analyze their absorption line-strength indices by means of index-index diagrams and scaling relations and use the stellar population models to interpret them. We present ages, metallicities and abundance ratios obtained from these dEs within an aperture size of Re/8. We calculate [Na/Fe] from NaD, [Ca/Fe] from Ca4227 and [Mg/Fe] from Mgb. We find that [Na/Fe] is under-abundant with respect to solar while [Mg/Fe] is around solar. This is exactly opposite to what is found for giant ellipticals, but follows the trend with metallicity found previously for the Fornax dwarf NGC 1396. We discuss possible formation scenarios that can result in such elemental abundance patterns and we speculate that dEs have disk-like SFH favouring them to originate from late-type dwarfs or small spirals. Na-yields appear to be very metal-dependent, in agreement with studies of giant ellipticals, probably due to the large dependence on the neutron-excess in stars. We conclude that dEs have undergone a considerable amount of chemical evolution, they are therefore not uniformly old, but have extended SFH, similar to many of the Local Group galaxies., Comment: 15 pages, 5 figures; accepted for publication in MNRAS

In the core of the Fornax cluster, on the West side of NGC1399, we have detected a previously unknown region of intra-cluster light (ICL). It is made up by several faint ($\mu_r \simeq 28 - 29$~mag/arcsec$^2$) {\it patches} of diffuse light. The bulk of the ICL is located in between the three bright galaxies in the core, NGC1387, NGC1379 and NGC1381, at $10\leq R \leq40$~arcmin ($\sim 58 - 230$~kpc) from the central galaxy NGC~1399. We show that the ICL is the counterpart in the diffuse light of the known over-density in the population of blue globular clusters (GCs). The total g-band luminosity of the ICL is $L_g\simeq 8.3 \times 10^{9}$ $L_{\odot}$, which is $\sim5\%$ of the total luminosity of NGC1399. This is consistent with the fraction of the blue GCs in the same region of the cluster. The ICL has $g-r \sim 0.7$~mag, which is similar to the colors in the halo of the bright galaxies in the cluster core. The new findings were compared with theoretical predictions for the ICL formation and they support a scenario in which the intra-cluster population detected in the core of the Fornax cluster is build up by the tidal stripping of material (stars and GCs) from galaxy outskirts in a close passage with the cD. Moreover, the diffuse form of the ICL and its location close to the core of the cluster is expected in a dynamically evolved cluster as Fornax., Comment: Accepted for publication in ApJ

We study a sample of 28 S0 galaxies extracted from the integral-field spectroscopic (IFS) survey CALIFA. We combine an accurate two-dimensional (2D) multi-component photometric decomposition with the IFS kinematic properties of their bulges to understand their formation scenario. Our final sample is representative of S0s with high stellar masses ($M_{star}/M_{sun} > 10^{10}$). They lay mainly on the red sequence and live in relatively isolated environments similar to that of the field and loose groups. We use our 2D photometric decomposition to define the size and photometric properties of the bulges, as well as their location within the galaxies. We perform mock spectroscopic simulations mimicking our observed galaxies to quantify the impact of the underlying disc on our bulge kinematic measurements ($\lambda$ and $v/\sigma$). We compare our bulge corrected kinematic measurements with the results from Schwarzschild dynamical modelling. The good agreement confirms the robustness of our results and allows us to use bulge reprojected values of $\lambda$ and $v/\sigma$. We find that the photometric ($n$ and $B/T$) and kinematic ($v/\sigma$ and $\lambda$) properties of our field S0 bulges are not correlated. We demonstrate that this morpho-kinematic decoupling is intrinsic to the bulges and it is not due to projection effects. We conclude that photometric diagnostics to separate different types of bulges (disc-like vs classical) might not be useful for S0 galaxies. The morpho-kinematics properties of S0 bulges derived in this paper suggest that they are mainly formed by dissipation processes happening at high redshift, but dedicated high-resolution simulations are necessary to better identify their origin., Comment: 31 pages, 19 figures. Accepted for publication in MNRAS

Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this letter is determining if the mass assembly of the different components leaves an imprint in their stellar populations allowing to estimate the time of bar formation and its evolution. To this aim we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis shows clearly different SADs for the different bar areas. There is an underlying old (>=12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyrs with a deficit of younger populations. The outer bar region presents a SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas., Comment: Accepted for publication in MNRAS Letters