Circumgalactic medium (CGM), the interface between the interstellar medium and the intergalactic medium (IGM), is a complicated site of entwined gas from the IGM accretion and galactic outflows. QSO absorption line systems are unique tools to probe such gas phases that still remains undetected in emission. Combining the morpho-kinematics of the host galaxy absorber extracted from IFU observations and absorption lines kinematics lead us unraveling the nature of the CGM gas. Here, I present the results of our recent CGM studies using MUSE observations and discuss the possible scenarios for the origin of the gas seen in absorption.

The chemical enrichment of the Universe is considerably affected by the contributions of Giant stars. Giant and supergiant stars are surrounded by a hot layer called the chromosphere, which could likely powers Magneto-Hydrodynamic Alfven waves that drive their mass loss. Toward the end of their life, on the Asymptotic Giant Branch (AGB), stars produce heavy chemical elements, molecules, and dust, which, through the mass loss provided via their stellar winds, are placed into the interstellar medium.

This talk will explore ongoing work modeling high-resolution spectroscopic observations with Hubble Space Telescope instruments (Rau et al. 2018, subm.), to reveal the role of the chromosphere in driving K-M giant and supergiant winds. Our results include estimates of wind and chromospheric parameters, mass-loss rates, and fundamental stellar parameters.

In addition, ground-based interferometric measurements with high-angular resolution instruments from VLTI, such as MIDI (Rau et al. 2015, Rau et al. 2017), GRAVITY (Wittkowski et al. 2018), help to test geometrical and dynamical models describing the behavior of the outer AGB atmospheres at various spatial scales. In this way we are able to unravel the role of molecules and dust in their extended atmospheres.Future plans include the use of high-angular resolution instruments such as VEGA at CHARA, and MATISSE at VLTI, to better understand the behavior of cool stars outer atmospheres at various spatial scales.

Feedback from AGN is often invoked within galaxy formation models to restrict star formation and prevent simulated galaxies from becoming too large. However, directly observing this feedback has proven to be non-trivial, and indeed the sphere of influence of the AGN with respect to the host galaxy is not well understood. I present some recent observational work that connects activity within the AGN engine to observational signatures throughout the host galaxy, showing that the influence of nuclear activity can indeed extend beyond the central environment.

A high fraction of dwarf galaxies host a nuclear star cluster (NSC), which shows characteristics similar to the high-mass and metal complex globular clusters (GCs). This suggests that these type of GCs could be former NSCs, stripped remnants of dwarf galaxies accreted by the Milky Way.

M54 is the closest extragalactic NSC and it lies at the center of its host - the Sagittarius dwarf spheroidal galaxy (Sgr dSph) - in a privileged position where we can resolve its stellar populations. This high-mass and chemically complex cluster offers the opportunity to understand low-mass galaxy nuclei in the unique stage preceding the total disruption of the host galaxy. I will present a large MUSE data set covering out to ∼2.5 effective radii of M54 from which we extracted ∼6600 member stars. With metallicity and age estimates on this data, we have been able to disentangle the star formation history of this NSC in unprecedented detail, detecting at least three stellar sub-populations. I will explain how these findings might be an evidence of the concurrent action of the two proposed NSC formation scenarios: (i) infall and accretion of GCs by dynamical friction effects, and (ii) in-situ star formation from enriched gas.

Dome A, Antarctica is a unique site for astronomical observations. It is a site with a median temperature of -70 degree centigrade in the winter time. The atmospheric turbulence layer has a height of only around 14 meters. The preceptible water vapor is the lowest on the surface of Earth. The austral winter lasts over 3 months with low sky background in the optical and the near IR. These properties enable a broad range of astronomical observations. Both ongoing astronomical activities and future potentials will be discussed. 

The diagnostic power of IR spectroscopy will be of crucial importance to study the galaxy evolution during the dust-obscured phase at the peak of the star formation and black-hole accretion activity (1 < z < 4). The unique suite of spectral lines and dust features present in the mid- to far-IR range allow us to determine the physical conditions in galaxies (e.g. density, ionisation, metallicity) using robust tracers with a feeble response to both extinction and temperature. The SPace IR telescope for Cosmology and Astrophysics (SPICA), a 2.5m cryogenic (< 8K) IR telescope (12-230 micron) currently in competition for the ESA medium-class mission call M5, has been particularly designed to study the physical processes that govern the formation and evolution of galaxies and black holes through cosmic time. Taking advantage of diagnostic tools in the mid- to far-IR range, SPICA will be able to: i) obtain the first spectroscopic determination of both the star-formation rate and black hole accretion rate histories of galaxies in the last 12 Gyr for large statistically significant samples; ii) unveil the role of feedback in galaxy evolution during the last 10 Gyr and explore the detectability of metal-rich inflows in the local Universe, characterising the duty cycle in galaxies; iii) investigate the chemical evolution of galaxies and the dust composition up to z ~ 4; iv) trace the evolution of dust obscured galaxies back to the epoch of reionisation. Finally, I will also discuss the possible synergies between SPICA (planned for ~2030) and future first-class facilities (JWST, ELTs, Athena, SKA).

The existence of a long-lasting link between the central black hole mass and various physical properties of their host spheroids is now a matter of fact. Studying the correlations between the two at different ages is then the best way to rebuild their cosmic evolution.

Within this scenario, we have built up two complementary AGN samples able to probe the accreting phases at both a) very high luminosity (>10^47 erg/s) and BH masses (10^9-10  Msol), i.e. the WISSH Sample, and b) very low luminosities (~10^43 erg/s) and BH masses (~10^5 Msol), i.e. studying sources extracted from the SWIFT/BAT catalog.

By performing AGN-dedicated SED-fitting procedures we derived the main physical properties of both the nuclear engine and the host galaxy of these sources, i.e. bolometric luminosities, star formation rates and stellar masses. We will present the accreting and star formation properties of these sources, comparing the two classes of objects. 

Moreover, we are able to constrain the BH-galaxy scaling relation over three orders of magnitudes in mass and to follow its evolution from z~3 to z~0. I will show that while the more massive galaxies populate the typical region of the already observed MBH-Mstar relation, the less massive ones are still on their way to reach the MBH-Mstar locus, especially obscured AGN which seem to be hosted in less massive galaxies compared to unobscured ones, given the same BH.

We will also present a new universal hard X-ray bolometric correction, which spans about 7 orders of luminosity thus allowing to derive more accurate predictions on the accretion history of the AGN and their host galaxies.

The JVAS and CLASS surveys discovered 22 gravitational lens systems and hopes were high that many time-delay measurements would follow. However, for only three of the systems was a clear signal of variability detected and a time delay determined. Almost totally overlooked, however, was the possibility of determining the time delay from polarization variability. I have recently performed a reanalysis of archival VLA monitoring data and find that the polarization variability is greater than that in total flux density and can provide a time delay where the total flux density cannot. I will give an overview of my results, including a new time delay.

Systematic searches for galaxy clusters have traditionally been conducted at optical wavelengths. While some optical catalogues still are the largest compilations of galaxy clusters, the inherent biases to the optical selection process, most importantly projection effects, are difficult to correct for in statistical studies of cluster properties. In the last two decades, X-ray and sub-millimetre observations have provided some of the most pure galaxy cluster catalogues, overcoming most of the optical biases. Especially, X-ray observations provide powerful means of selecting galaxy clusters and characterising their properties. Albeit these differences, optical/infrared and X-ray observations of galaxy clusters complement each other. In this talk I will present two of such complementary studies: 1) our findings on the physical properties of high redshift (z > 0.8) cluster samples that have been selected at different wavelengths in a common area of the sky: SpARCS in infrared and XMM-LSS in X-rays, 2) a search for new galaxy groups previously undetected in the ROSAT-All-sky survey, which have been identified in optical observations. These studies can tell us which types of galaxy clusters have been missed in samples constructed in past surveys, and the possible impact they can have on cosmological parameter constraints obtained through cluster counts.

The PAH features detected in the infrared range between ~3 and 20um have been extensively used as reliable indicators for distinguishing the dominant energy source of dusty galaxies, such as starburst or active galactic nucleus (AGN). The 3.3um PAH feature is the only PAH feature that will be observable with the James Webb Space Telescope (JWST) at z > 3.5, because the rest of the features at longer wavelengths fall outside the JWST wavelength coverage. However, detailed studies that compare the most frequently used 3.3um and 6.2um PAH features are still limited, because the former was only observable with the AKARI infrared astronomical satellite and the latter was only observable with the Spitzer Space Telescope. In this talk, I will show a direct comparison between the 3.3um and 6.2 PAH feature detected in ~150 local luminous infrared galaxies, which are the best analogs for star-forming galaxies in the early Universe. Then, I will discuss how to adapt these results based on the rest-frame 2-5um range to observe high-z galaxies with JWST.

In this talk I will present pioneering work on the panchromatic emission of some of the most luminous galaxies in the early Universe: star forming galaxies and Active Galactic Nuclei. Using state-of-the-art statistical methods and new-generation radio-to-UV instruments, the presented results expand the parameter space covered by current multi-wavelength studies, pushing three different frontiers: the statistical frontier, the wavelength frontier and the resolution frontier. I will introduce a sophisticated statistical tool to robustly model the multi-wavelength emission of galaxies and AGN to push the statistical frontier. The wavelength frontier is pushed forward by exploring galaxy evolution from a new spectral window at low radio frequencies, opened by the LOFAR instrument. Finally, the resolution frontier will be pushed by exploring the resolved distribution of emission components across the spectrum using a combination of high-resolution ALMA and HST imaging.

The majority of galaxies host a very dense and massive star cluster in their centres. Often these nuclear star clusters (NSC) are the only surviving remnants of tidally disrupted galaxies and are usually classified as very massive globular clusters or ultra-compact dwarfs. At difference with typical globular clusters, however, NSCs often  have extended star formation histories (SFH). In this talk I will present the SFH of M54 (the NSC of the Sgr dwarf galaxy, currently under disruption by the tidal field of the Milky Way) as derived from a large MUSE data set of several thousand spectra of individual stars. I will also present the SFH analysis of the NSCs of several nearby galaxies, based on integrated light spectroscopy from X-Shooter, and argue that we are able to distinguish between the two main mechanisms of NSC formation: in situ star formation at the centre of the galaxy vs. stellar accretion.

Using multi-wavelength data, from UV-optical-near-mid IR, for $\sim$6000 galaxies in the local Universe, we study the dependence of star formation on the morphological T-types for massive galaxies ($\log M_*/M_\odot \geq 10$). We find that, early-type spirals (Sa-Sbc) and S0s predominate in the green valley, which is a transition zone between the star forming and quenched regions. Within the early-type spirals, as we move from Sa to Sbc spirals the fraction of green valley and quenched galaxies decreases, indicating the important role of the bulge in the quenching of galaxies. The fraction of early-type spirals decreases as we enter the green valley from the blue cloud, which coincides with the increase in the fraction of S0s. This points towards the morphological transformation of early-type spiral galaxies into S0s which can happen due to environmental effects such as ram-pressure stripping, galaxy harassment, or tidal interactions. We also find a second population of S0s which are actively star-forming and are present in all environments. Since morphological T-type, specific star formation rate (sSFR), and environmental density are all correlated with each other, we compute the partial correlation coefficient for each pair of parameters while keeping the third parameter as a control variable. We find that morphology most strongly correlates with sSFR, independent of the environment, while the other two correlations (morphology-density and sSFR-environment) are weaker. Thus, we conclude that, for massive galaxies in the local Universe, the physical processes that shape their morphology are also the ones that determine their star-forming state.

We present morphological properties of dusty star-forming galaxies at z = 1-3 determined with the high-resolution (FWHM~0.′′19) ALMA 1-mm band maps of our ASAGAO survey covering a 26-arcmin2 area in GOODS-S and the ALMA archive. The present sample consists of 45 ALMA sources with a wide rest-frame far-infrared (FIR) luminosity L_FIR range of 10^11-13 L⊙. To obtain an average rest-frame FIR profile, we perform individual measurements and careful stacking of the ALMA sources using the uv-visibility method that includes positional-uncertainty and smoothing-effect evaluations through Monte-Carlo simulations. We find that the dusty star-forming galaxies have the average FIR-wavelength Sersic index and effective radius of n_FIR = 1.2+/-0.2 and Re_FIR =1.0-1.3 kpc, respectively, additionally with a point source at the center, indicative of the existence of AGN. The average FIR profile agrees with a morphology of an exponential-disk clearly distinguished from a spheroidal profile (Sersic index of 4), and supports a positive correlation of the FIR size-luminosity relation. We also examine the rest-frame optical Sersic index n_opt and effective radius Re_opt with the deep HST images. Interestingly, we obtain n_opt = 0.9+/-0.3 (~ n_FIR) and Re_opt = 3.2+/-0.6 kpc (> Re_FIR), suggesting that the dusty disk-like structure is embedded within a larger stellar disk. The rest-frame UV and FIR data of HST and ALMA provide us a radial surface density pro le of the total star-formation rate (SFR), where the FIR SFR dominates over the UV SFR at the center. Under the simple assumption of a constant SFR, a compact stellar distribution found in z~1-2 compact quiescent galaxies (cQGs) is well reproduced, while a spheroidal stellar morphology of cQGs (n_opt = 4) cannot, suggestive of other important mechanism(s) such as dynamical dissipation.

With the rise of large-scale spectroscopy surveys, the amount of self-consistent data has reach unprecedented magnitudes. This data can be used to derive a multitude of parameters for the targeted galaxies, which allowed us to apply various redshift-independent distance indicators to them. We also took the opportunity to further improve established tools, such as the fundamental plane, using additional insights gained by the multitude of data. In combination with redshift-data, we are able to derive the peculiar motion field for a large area of the observable universe. Additionally, we provide a comparison to the peculiar motion data derived using other distance indicators.

Damped Lyman-alpha absorbing systems (DLAs) in the sight line ofbackground quasars and gamma-ray bursts (GRB) offer a unique way tostudy the conditions of star forming regions in high redshift galaxies.Now, for the first time, we are able to use a large and complete sample of 22 GRBsat redshift z > 2 observed with X-shooter to measure the abundances of metals,molecules, and dust, in order to study effects of metallicity, dust depletion andnucleosythesis in the high redshift interstellar medium. To do so, we developednew, state-of-the-art methods, based on the Python Bayesian inferencepackage PyMC, to fit absorption lines in order measure the columndensities of 10 different elements as well as neutral and molecular hydrogen.The measured relative abundances are further used to fit depletion sequencesand determine the dust-to-metals ratio and the host intrinsic visual extinction.In this talk, I want demonstrate our new methods, present the results, and discuss theirimplication for the nature of high-redshift GRB DLAs.

A stellar cusp in a dense stellar system around a massive black hole is a firm prediction of stellar dynamics. Nevertheless, observational evidence from the nuclear cluster of the Milky Way appeared to contradict the theoretical expectations. In this talk we will review the topic and present the latest observational work that provides evidence, from multiple tracers, that the cusp exists.  Its existence implies that we can expect to observe a significant amount of EMRIs with future space based gravitational wave observatories. We confirm previous findings that the cusp is not observed in the bright giants. The “missing cusp” problem is thus a “hidden cusp” problem and some mechanism must have altered the appearance of the giants near  Sagittarius A*.

There are massive galaxies that remain untouched since the high-z Universe. These objects, the so-called relic galaxies, are massive (M_stellar > 8x10^10 M_Sun), very small (effective radius < 2 kpc) and display old (>10 Gyr) stellar populations (thus being red nuggets but at low-z!). For the very few of them already found and analysed, they seem to host übermassive black holes, to show a bottom-heavy IMF and to retain early disk morphologies and kinematics. How did they survive until the present day? Simulations predict that they live in galaxy overdensities whose large velocity dispersions prevent galaxies from merging. However, we have not yet determined observationally neither the environments these galaxies inhabit nor their number densities. The large area and spectroscopic completeness of the GAMA survey allows us to conduct a complete census of this elusive galaxy population, and also to analyse their structural parameters. After inspecting ~150 deg^2 of ancillary KiDS and VIKING photometric data, we have identified 21 of these objects at 0.02 < z < 0.3, that are true windows to the primeval Universe. I will present the first paper introducing this exceptional sample, describing its properties and highlighting the fact that while some of galaxies seem to be satellites of bigger objects, others live in the field, at odds with the theoretical expectations.

We present a new universal star formation law based on the probability density function (PDF) and sonic Mach number of the turbulence in star-forming clouds. In our relation the star formation rate (SFR) correlates with the molecular gas mass per multi-freefall time. We show that the actual SFR is only about 0.45% of the maximum possible SFR, confirming the observed low efficiency of star formation. We show that placing observations in the framework of our developed relation yields a significantly improved correlation with 3-4 times reduced scatter compared to previous star formation relations, such as the Kennicutt-Schmidt or the Krumholz-Dekel-McKee relation. We use this new relation to develop a new method for estimating the column density of cold molecular gas (Σgas) using integral field spectroscopy. We utilise the spatially resolved Hα maps of flux and velocity dispersion from the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) Galaxy Survey to make our estimates. Finally, we present and utilise data from the Combined Array from Research in Millimeter Astronomy (CARMA) and Herschel Space Telescope to measure the star formation efficiency across the face-on Hickson Compact Group galaxy NCG7214. We find that this galaxy is extremely inefficient and cannot be described by star formation relations developed in previous literature. We therefore extend our multi-freefall star formation relation to take into account the virial parameter of the turbulent clouds, which yields significantly improved predictions of the SFR compared to any previous star formation law.

Africa is becoming a focus of the world's radio astronomy community. Evidently, South Africa is unveiling the 64-antenna MeerKAT Radio Telescope, the African's precursor to the world's next generation radio telescope, the SKA, on July 13, 2018 at the SKA Losberg site in the Karoo. It is envisaged that the SKA Phase 2 will have arrays extended to the eight SKA African Partner Countries that include Ghana. Prior to this, African VLBI Network (AVN) is being built with the converted and refurbished 32m satellite communication earth station antenna now at the Ghana Radio Astronomy Observatory (GRAO), as the first non-South African radio telescope of the AVN. This facility was commissioned at Kuntunse near Accra on August 24, 2017 as a functional radio astronomy telescope. The strategic location of the Ghana's 32m radio telescope of 5 degrees north of the Equator is attracting much interests especially in the global VLBI community in terms of spatial resolution contributions. Motivated by these developments, we aim at building a strong and vibrant Ghanaian research community in this area to operate and exploit the radio telescope in Ghana, the AVN, the SKA and other global astronomy instruments. In pursuit of this, research and development links are being established globally with pioneers in the field. The enthusiastic and interested young Ghanaian students and researchers are waiting to embrace opportunities to build carriers in this merging field in the country. The UK was first to heed to this call with the Development in Africa with Radio Astronomy (DARA) astronomy training programme with funding from the Royal Society and more recently by its Newton Fund. The DARA programme is highlighting the potential overlaps between the skills required for radio astronomy and those in related industries such as space science, satellite communications, telecommunications and big data applications. ESO joined the race last year with an outreach programme dubbed ESO-ART, which has had great impact on astronomy development in Ghana, and Sweden will probably move in soon.

In this presentation, I will speak about astronomy development in Ghana, the successes chopped so far and the way forward. I will as well, outline opportunities for research and development brought about by the emergence of astronomy in Ghana, and emphasize the impact of ESO-ART in Ghana's astronomy development drives.

The Hobby-Eberly Telescope (HET) is an innovative VLT, located at the McDonald Observatory. We have completed a major upgrade of the HET that has increased the pupil size to 10 meters and the field of view to 22 arcminutes by replacing the corrector, tracker, and prime focus instrument package. The wide field HET feeds a suite of four new and upgraded instruments, including the revolutionary integral field spectrograph, VIRUS, in support of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The HET Wide Field Upgrade has now been commissioned and is back in full science operations since mid 2016. I will discuss the upgrade, VIRUS and the other new instrumentation, and briefly present some early science results.

The potential formation scenarios of early-type galaxies are very varied, from violent merger histories, to secular quenching scenarios. We use extended stellar kinematics (to ~4 effective radii) for ~25 galaxies from the SLUGGS Survey in an attempt to disentangle the effects of these histories on the kinematics of early-type galaxies. Additionally, we conduct JAM dynamical modelling using both radially-extended SLUGGS and central ATLAS3D data to construct the total-mass density profiles for these galaxies. A comparison of these results not only to other observations but also to the EAGLE and Magneticum simulations will be presented, to better understand the processes that are governing mass distributions in early-type galaxies.

The evolution of baryonic gas across redshifts is a powerful probe of several aspects of cosmology, galaxy formation and the epoch of reionization. Using a data-driven halo model to describe the distribution of neutral hydrogen (HI) in the post-reionization universe(z ~ 5 to 0), we obtain the best-fitting parameters from a rich sample of observational data: low redshift 21-cm emission line studies,intermediate redshift intensity mapping experiments, and higher redshift Damped Lyman Alpha (DLA) observations. Our model describes the abundance and clustering of neutral hydrogen across redshifts 0 - 5, and can be used to investigate several aspects of galaxy formation. I will describe extensions to the formalism for probing molecular gas at moderate redshifts and the epoch of reionization.

Planet host stars,  the Sun among them, will eventually evolve into giants to finally end their lives as white dwarfs. Planets will be engulfed along the giant phases, evaporated during the Planetary Nebula phase, and possibly destabilized when the star enters the white dwarf cooling track. A large number of  planets will eventually be destroyed and all  orbital configurations on the main sequences will be modified. Furthermore, the  planet surface conditions of those planets that survive are expected to change as well as the result of the evolution of the star.

I will discuss the limits that the theoretical studies allow us to set on the survival and habitability of planets as the star runs out of its hydrogen fuel. Finally, I will summarize the consequences that the presence and destruction of these Extreme Solar systems have in the evolution of stars.

Massive stars, by which we mean those stars evolving through all the stable nuclear burning stages and eventually exploding as core collapse supernovae,play a fundamental role in the evolution of the Universe. In particular, a good knowledge of their evolution is required in order to shed light on many topical subjectslike the chemical evolution of the Universe, the UV outputs of the first stars, the properties of the Galactic and the Magellanic Clouds Wolf-Rayet stars, the origin of the Extremely Metal Poor stars, the final fate of massive stars and how they explode as core collapse supernovae of different types, the nature of the progenitors of the long Gamma Ray Bursts, the nature of the sources of gravitational waves.

In this talk I will review our current understanding of the life and death of massive stars, their contribution to the chemical evolution of the Universe and the nature of their remnants as a function of the initial mass, metallicity and rotation velocity.

Significative evidences of the role of the cosmic web in driving galaxy properties have been measured at low redshift from spectroscopic surveys.  They support a picture in which the influence of the geometry of the large-scale environment drives anisotropic tides which impacts the assembly history of galaxies. But extracting the cosmic web from observed datasets is still a challenge, in particular at high redshift where large and complete spectroscopic surveys are extremely costly. At these redshifts, though, we expect a stronger dependency of galaxy properties on the geometry of the accretion, which makes this extraction pivotal to understand galaxy evolution.

I will give a brief overview of the current status of cosmic web analysis from high redshift observations, either photometric data or lyman-alpha surveys. While relying on a pilot study in COSMOS and forecasts from the simulated horizon-AGN lightcone, I will show how the study of the co-evolution of galaxies and the cosmic web would be possible with future probes including LSST, Euclid, PFS and MOSAIC on the ELT.

Despite formidable challenges, comparative studies of exoplanet atmospheres have begun in earnest. Exoplanets caught in transit are particularly well suited for such investigations. I will discuss attempts to probe exoplanet atmospheres using high-precision photometric and spectroscopic observations. Our analysis of Kepler phase curves reveals peak brightness offsets in some cases, possibly indicating inhomogeneous clouds and/or substantial winds. We have also begun to extend studies using high-resolution transit spectroscopy to exoplanets in the sub-Saturn and super-Earth mass regimes. Finally, I will preview plans for using the NIRISS instrument on the James Webb Space Telescope, and other exciting opportunities for the near future.

Supernova driven outflows are thought to play a critical role in regulating the gas and baryonic content of galaxies. Most cosmological simulations rely on various prescriptions to generate these outflows that lack direct observational support due to their low surface brightness. However, these outflows can be constrained using background quasars line of sight passing near star forming galaxies. Using a combination of both MUSE and UVES instruments, we built the MusE GAs FLOw and Wind (MEGAFLOW) survey. We used the strong low-ionization MgII absorption to constrain the ejected mass rate using a bi-conical model. In this talk, I will present the results we have on these outflows from z~1 star-forming galaxies and compare them with simulation predictions.

Disc galaxies at z~1 are known to be more clumpy and turbulent than their local counter parts. However, with the current observing facilitates, we are mostly limited to study these features at 1-2 kpc scales.  A way to overcome this issue before the new generation of telescopes becomes available, is to target strongly lensed objects. In this talk, I will show some of the results we obtained studying a representative sample of 8 strongly lensed galaxies at z~1, where spatial resolutions of a couple hundred parsecs can be reached. Using both MUSE and HST data we analysed the kinematics of these objects, focusing on the velocity dispersion of the ionised gas and their relationship with star-forming regions, providing some clues on local star-formation feedback at z~1.

Examining the chemo-morphological relations of stellar populations in the Milky Way (MW) bulge can provide clues to the formation history of our Galaxy, and of disc galaxies in general. To explore the possible disc origin of the MW bulge we use an N-body simulation in which the bulge forms secularly through the vertical heating of a bar, which in turn forms from a composite thin+thick disc. The simulation is compared to data of the bulge obtained with the near infrared spectroscopic survey APOGEE. As I will show, all the chemo-morphological relations examined are well reproduced by the model, as is the metallicity distribution function (MDF) of the MW bulge as a function of galactic longitude and latitude. These findings show that the chemical composition of the MW bulge is consistent with it being made up of thin+thick disc stellar populations. I will discuss these results in light of the mounting evidence -- from morphology, kinematics and chemistry -- of the MW bulge's pure disc origin.

Shell galaxies are understood to form through the collision of a dwarf galaxy with an elliptical galaxy. Shell structures and kinematics have been noted to be independent tools to measure the gravitational potential of the shell galaxies. We compare theoretically the formation of shells in Type I shell galaxies in different gravity theories in this work because this is so far missing in the literature.

We include Newtonian plus dark halo gravity, and two non-Newtonian gravity models, MOG and MOND, in identical initial systems. We investigate the effect of dynamical friction, which by slowing down the dwarf galaxy in the dark halo models limits the range of shell radii to low values. Under the same initial conditions, shells appear on a shorter timescale and over a smaller range of distances in the presence of dark matter than in the corresponding non-Newtonian gravity models. If galaxies are embedded in a dark matter halo, then the merging time may be too rapid to allow multi-generation shell formation as required by observed systems because of the large dynamical friction effect. Starting from the same initial state, in the dark halo model the observation of small bright shells should be accompanied by large faint ones, while for the case of MOG, the next shell generation patterns iterate with a specific time delay. The first shell generation pattern shows a degeneracy with the age of the shells and in different theories, but the relative distance of the shells and the shell expansion velocity can break this degeneracy.

Galaxies continuously undergo chemical enrichment. Heavy elements are produced in stars and then dispersed into the interstellar medium by means of stellar winds and supernovae. Gas flows also contribute to regulate the amount of metals in the ISM; therefore, gas-phase metallicity represents a fossil record of the recent star formation history and is strongly sensitive to all the processes that drive the baryon-cycle in galaxies.

In this talk, I will first discuss the method for measuring chemical abundances in star forming galaxies, presenting a re-calibration of the most common metallicity diagnostics based on strong emission lines  by means of stacking galaxy spectra from the Sloan Digital Sky Survey according to their observed line ratios.

I will discuss also the evolution in the excitation properties and chemical abundances for a sample of high-redshift (1.2 < z < 2.5) gravitationally lensed sources, observed in the framework of the ESO Large Program KLEVER. Exploiting KMOS observations in the J, H and K bands we aim to map multiple optical rest-frame nebular diagnostics allowing a full, detailed characterisation of the ISM properties in these objects on a spatially resolved basis.

Fossil systems (FS) are groups or clusters of galaxies whose optical emission is dominated by a single giant galaxy. The lack of bright satellites is thought to be a sign of an evolved system, in which the central galaxy has had enough time to merge all the bright satellite population. At the same time, few interactions are expected within FS and the cosmic web. For these reasons, FS are considered fossil relics of the ancient Universe. However, this formation scenario has been questioned in recent years. In particular, controversial results were presented regarding X-ray and optical scaling relations, formation histories of the brightest central galaxies (BCGs), and the relaxation status of these systems.

In this seminar I will present some of the latest results from the Fossil Group Origins (FOGO) project. In the first part of the talk will be presented results on the satellite population: in particular, the dependence of the LF on the magnitude gap (the key parameter in the definition of FS) and one deep spectroscopic LF of a nearby (z=0.05) fossil group.

In the second part of the seminar, the attention will be focused on the BCGs of the two nearest-known FS (z=0.013 and z=0.025). I will present their resolved stellar populations and discuss their formation histories, trying to highlight the differences with BCGs in non-fossil systems.

When galaxies first form in a turbulent young Universe, they have diverse and complex morphologies. That has changed dramatically over the last 13 Gyr as elliptical and spiral shapes now dominate the bulk of local galaxy morphologies, as depicted by the Hubble diagram. The exact details of how and when these transformations happened still elude astronomers.

On this talk, I will show you a summary of our results on the evolution of galaxy structure across cosmic time (Paulino-Afonso et al. 2017, 2018). I will focus on the evolution of Ha and Lya emitting galaxies from z~0 to z~7 and contextualize this population of galaxies on the global picture of galaxy evolution.

Throughout cosmic history, stars have been destroying deuterium and creating heavier elements. Generally, cosmological simulations include only the most abundant elements, such as oxygen and carbon, but there is much to be learned about our universe from other species. Neutron star mergers are rare, but last year's kilonova observations provided strong evidence that they produce copious amounts of rapid neutron capture (r-process) elements. It is still not clear how such rare events manage to efficiently enrich the interstellar medium, as inferred from observations of abundances in low-metallicity stars. In this talk, I will discuss cosmological zoom-in simulations of Milky Way-mass galaxies with explicit treatment of r-process enrichment via neutron star mergers. I will show that there is sufficient mixing to match current observational constraints and thus that our results are consistent with neutron star mergers being the source of most of the r-process nuclei in the Universe. Our new simulations also include slow neutron capture (s-process) enrichment via asymptotic giant branch stars, which traces mass loss by the old stellar population. I will show preliminary results on the relative importance of these two channels of neutron capture elements. I will end with a discussion on the deuterium abundance in the interstellar and intergalactic medium, which can be used to probe cosmology as well as the importance of stellar mass loss and thus the assembly history of galaxies.

Black holes are a fundamental ingredient in our current understanding of galaxy formation. In the absence of their feedback, state-of-the-art numerical simulations fail to match the observed properties of massive galaxies. Effectively, within a Lambda Cold Dark Matter Universe, black holes reconcile cosmology and galaxy formation theories by regulating baryonic processes. However, despite this widely-accepted and fundamental role, evidence of black hole regulated star formation remains elusive. I will present our observational efforts to characterize and understand the interplay between black hole activity and star formation, based on detailed stellar populations analyses. Our observations show that black hole and stellar population properties are tightly related, calling for a rich and complex observational framework where star formation, black holes, and chemical enrichment evolve coupled in time.

We report new results from our study of the disk structure and evolution in the spiral protoplanetary disk hosting binary, HD 100453. This disk represents the only known “grand-design” (two-armed) spiral protoplanetary disk in which a low-mass companion has also been detected. We present the first constraints on the companion’s orbit, utilizing data from VLT/NACO, VLT/SPHERE, and Magellan/MagAO. We also constrain the disk inclination from ALMA 12CO observations and gas kinematic modeling. We find that the companion’s orbital semi-major axis (105±15 au) is 3-4 times greater than the observed extent of the disk, and that the companion orbits in the same plane of the disk to within measurable limits (±10º) on a low eccentricity orbit (e<0.3), in accordance with a classical disk truncation scenario. We utilized these constraints on the system geometry in combined hydrodynamic and radiative transfer simulations, and find in all cases that the companion generates a prominent two-armed spiral pattern in the simulated disk imaging that is in qualitative agreement with the observed disk structure. This system represents a benchmark in understanding the formation of spiral arms in protoplanetary disks, and has implications for on-going planet searches in the other two similar disks that do not host binary companions, but nevertheless host similar spiral structures.

The most distant galaxies known are at z~10-11, observed 400-500 Myr after the Big Bang. The few z~10-11 candidates discovered to date have been exceptionally small— barely resolved, if at all, by the Hubble Space Telescope. In this talk I will present the discovery of SPT0615-JD, a fortuitous z~10 galaxy candidate stretched into an arc over 2.5” by the effects of strong gravitational lensing. Discovered in the Reionization Lensing Cluster Survey (RELICS) Hubble and Spitzer program, this candidate has a lensed H-band magnitude of 25.7 AB mag and lensing magnification of 4-7. The unprecedented lensed size of this z~10 candidate offers the potential for the James Webb Space Telescope to study the geometric and kinematic properties of a galaxy observed 500 Myr after the Big Bang. I will also present the sample of bright, lensed galaxy candidates at z>6 found in RELICS, that include other rare high-z arcs. Finally, I will discuss how we can improve our estimates of high-z SFRs by constraining the shape of the dust-attenuation law in individual galaxies.

The diversity of low-mass cluster galaxies in terms of their size and stellar content is striking. So-called ultra-diffuse galaxies residing in the core of a massive galaxy cluster appear surprisingly intact and might be protected by a large dark matter content. Ultra-compact objects, on the other hand, were proposed to be remnant nuclei of disrupted dwarf galaxies, but no tidal debris is found in their vicinity. The stellar age gradients of "normal" cluster dwarfs suggest that ram pressure stripping played an important role in their evolution - yet that alone cannot explain the systematically different angular momentum content of late-type and early-type dwarfs. In this talk I am going to present our latest observational efforts to tackle these problems,along with comparisons to simulations that can shed light upon the galaxies' evolutionary history.