We present GECKOS (Generalising Edge-on galaxies and their Chemical bimodalities, Kinematics, and Outflows out to Solar environments), a new ESO VLT/MUSE large program. The main aim of GECKOS is to reveal the variation in key physical processes of disk formation by connecting Galactic Archaeology with integral field spectroscopic observations of nearby galaxies. Edge-on galaxies are ideal for this task: they allow us to disentangle the assembly history imprinted in thick disks and provide the greatest insights into outflows. The GECKOS sample of 35 nearby edge-on disk galaxies is designed to trace the assembly histories and properties of galaxies across a large range of star formation rates, bulge-to-total ratios, and boxy and non-boxy bulges. GECKOS will deliver spatially resolved measurements of stellar abundances, ages, and kinematics, as well as ionised gas metallicities, ionisation param- eters, pressure, and inflow and outflow kinematics; all key parameters for building a complete chemodynamical picture of disk galaxies. With these data, we aim to extend Galactic analysis methods to the wider galaxy population, reaping the benefits of detailed Milky Way studies, while probing the diverse mechanisms of galaxy evolution.

The cornerstone mission of the European Space Agency, Gaia, has revealed properties of 260 000 white dwarfs in the Galaxy, allowing us for the first time to constrain the evolution of white dwarfs with a large sample. Complementary surveys (CoRoT, Kepler, K2, APOGEE and Gaia-ESO), will revolutionize our understanding of the formation and history of our Galaxy, providing accurate stellar masses, radii, ages, distances, and chemical properties for very large samples of stars across different Galactic stellar populations. To exploit the potential of the combination of spectroscopic, seismic and astrometric observations, the population synthesis approach is a very crucial and efficient tool. We develop the Besançon Galaxy model (BGM, Lagarde et al.2017) for which stellar evolution predictions are included, providing the global asteroseismic properties and the surface chemical abundances along the evolution of low- and intermediate-mass stars. For the first time, the BGM can explore the effects of an extra-mixing occurring in red-giant stars Lagarde et al.2019, changing their stellar properties. The next step is to model a consistent treatment of giant stars and their remnants (e.g., white dwarfs). This kind of improvement would help us to constrain stellar and Galactic evolutions.

We employ Pan-STARRS photometry, Gaia trigonometric parallaxes, modern stellar evolution and atmosphere models, and our Bayesian fitting approach to determine cooling and total ages for 159,238 white dwarfs. In many cases we are able to derive precise ages (better than 5%) for individual white dwarfs. These results are meant for broad use within the white dwarf and stellar astrophysics communities and we plan to make available on-line the posterior distributions for cooling age, total age, initial stellar mass, and other parameters.

Dynamical models will be key to exploitation of the incoming flood data for our Galaxy. Modelling techniques are reviewed with an emphasis on f(J) modelling.

The BAaDE (Bulge Asymmetries and Dynamical Evolution) project is an SiO maser survey of the Galactic Plane. About 19,000 sources have been observed at 43 GHz with the VLA, and the production of spectra for each of these sources is well underway. The primary goal of the project is to collect line-of-sight velocities for all the detected masers in the sample to probe Galactic dynamics. With an expected detection rate of over 60% we should collect over 11,000 velocities to probe the Galactic potential. The survey is also a large sample of infrared sources to explore the different evolved stellar populations within the Milky Way. So far we discern three distinct groups in the BAaDE sample: the main group containing oxygen-rich, evolved stars with a high SiO maser detection rate, a much smaller population of carbon-rich evolved stars, and finally a group of likely young stellar objects with no maser emission. These populations are separated using 2MASS and MSX color-color diagrams, and we find a particularly useful cut between the young and evolved objects using the MSX [D] –[E] color. Identification of these populations will isolate BAaDE’s evolved star sample, and will more tightly define the region in IR color-color diagrams where SiO masers occur yielding a better understanding of these kinematical probes. Using our color-divisions we can also study the distribution of each of the populations within the Galactic Plane.

A major uncertainty in the determination of the mass profile of the Milky Way using stellar kinematics in the halo is the poorly determined anisotropy parameter, , where σr is the Galactocentric radial velocity dispersion, and σθ and σφ are the tangential components of the velocity dispersion. We have used a sample of over 24,000 Galactic halo K giant and blue horizontal branch stars from the LAMOST stellar spectroscopic survey and SDSS/SEGUE, combined with proper motions from Gaia Data Release 2, to measure β(rgc) over a wide range of Galactocentric distances rgc from 5 to 80 kpc. Kinematic substructures have been carefully removed to reveal the underlying diffuse stellar halo prior to measuring β. We find that orbits are generally radial (β > 0) and β is constant out to distances of about 40 kpc, with a dependence on metallicity of the stars, such that β declines with lower metallicity. Similar behavior is seen in both the K giant and BHB samples.

We summarise recent results from analysis of APOGEE/Gaia data for stellar populations in the Galactic halo, disk, and bulge, leading to constraints on the contribution of dwarf galaxies and globular clusters to the stellar content of the Milky Way halo. Intepretation of the extant data in light of cosmological numerical simulations suggests that the Milky Way has been subject to an unusually intense accretion history at z ≳ 1.5.

We serendipitously found an intriguing Extended Emission Line Region (EELR) near the quiescent and massive early-type Mrk 1172, with a projected extension of approximately 14 × 14 kpc. Its irregular shape, high gas content, strong emission lines and proximity to an isolated possible faded quasar raise questions about the ionization of this gas and the nature of this object. Analyzing the stellar population in both objects we observe that the EELR has a dominance of young-intermediate and intermediate stellar populations (200 Myr < t < 1 Gyr) with significant star formation activity, while Mrk 1172 is dominated by old stellar population (t > 5 Gyr). BPT diagnostic diagrams indicate that the gas in the EELR is photoionized by hot massive stars rather than by a hard radiation field or by shocks. Further analysis on abundances of the gas and its kinematics shall be performed to better comprehend the nature of this object and how it is interacting with Mrk 1172.

Binary interactions can alter the intrinsic properties of stars (such as: pulsation, mass-loss, photospheric chemistry, dust-formation, circumstellar envelope morphology etc.) and can even play a dominant role in determining its ultimate fate. While past studies have shown that binarity can end the AGB life of a star, recent studies have revealed that in specific cases binarity also pre-maturely terminate the RGB evolution. A characteristic feature of evolved binaries is the presence of a Keplerian circumbinary disc of gas and dust which plays a lead role in the evolution of the systems. In this article, I will review our advances in the research landscape of post-RGB and post-AGB binary stars, focussing on their observational properties, spectral energy distribution, photospheric chemistry, the evolution of their stable circumbinary discs, and the evolutionary connection between the enigmatic post-AGB/post-RGB binaries, and other systems whose primary component is a white dwarf.

I use SkyMapper DR1.1 to explore the quality of its uvgriz photometry, and zero-points. I introduce a formalism to derive photometric zero-points across the sky by benchmarking against stars with well known effective temperatures, bypassing the need for absolute spectrophotometry.

Dwarf galaxies in the Local Group (LG) represent a distinct as well as diverse family of tracers of the earliest phases of galaxy assembly and the processing resulting from galactic harrassment. Their stellar populations can be resolved and used as probes of the evolution of their host galaxy. In this regard, we present the first reconstruction of the star formation history (SFH) of them using the most evolved AGB stars that are long period variable (LPV). LPV stars trace stellar populations as young as ∼ 30 Myr to as old as the oldest globular clusters. For the nearby, relatively massive and interacting gas-rich dwarf galaxies, the Magellanic Clouds, we found that the bulk of the stars formed ∼ 10 Gyr ago for the LMC, while the strongest episode of star formation in the SMC occurred a few Gyr later. A peak in star formation around 0.7 Gyr ago in both Clouds is likely linked to their recent interaction. The Andromeda satellite pair NGC147/185 show different histories; the main epoch of star formation for NGC 185 occurred 8.3 Gyr ago, followed by a much lower, but relatively constant star formation rate (SFR). In the case of NGC 147, the SFR peaked only 6.9 Gyr ago, staying intense until ∼ 3 Gyr ago. Star formation in the isolated gas-rich dwarf galaxy IC 1613 has proceeded at a steady rate over the past 5 Gyr, without any particular dominant epoch. Due to lack of sufficient data, we have conducted an optical monitoring survey at the Isaac Newton Telescope (INT) of 55 dwarf galaxies in the LG to reconstruct the SFH of them uniformly. The observations are made over ten epochs, spaced approximately three months apart, as the luminosity of LPV stars varies on timescales of months to years. The system of galactic satellites of the large Andromeda spiral galaxy (M31) forms one of the key targets of our monitoring survey. We present the first results in the And I dwarf galaxy, where we discovered 116 LPVs among over 10,000 stars.

The time evolution of the radial metallicity gradient is one of the most important constraints for Milky Way chemical and chemo-dynamical models. In this talk we reviewed the status of the observational debate and presented a new measurement of the age dependence of the radial abundance gradients, using combined asteroseismic and spectroscopic observations of red giant stars. We compared our results to state-of-the-art chemo-dynamical Milky Way models and recent literature results obtained with open clusters and planetary nebulae, and propose a new method to infer the past history of the Galactic radial abundance profile.

This general overview of our understanding of the Galaxy followed the lines of its main structures (halo, disc, bulge/bar) and emphasized some time-domain astronomy contributions. On the one hand the distance and tangential motions of the stars are essential to that understanding, and are obtained through multi-epoch surveys. On the other hand the chemistry of the stars and their radial velocities are also key elements for mapping the Galactic (sub-)structures, and unravelling their history and evolution. Contemporary surveys are revolutionizing our view of the Milky Way and of galaxies in general. Among those, the Gaia mission excels through its precise astrometry of 1.3 billion stars that populate the Milky Way and beyond, providing the first 3-D view of a major part of the Milky Way.

Stars are the main ingredients of galaxies, and the sites of the creation of most chemical elements in our universe. The knowledge that we gain from studying nearby resolved stellar populations assists directly our ability to measure the properties of distant galaxies. The overall objective of this project is to study galaxy formation and evolution in a complete environment of the dwarf galaxies in the Local Group, by using the same methods for all of them. For that purpose, we used the INT to conduct a monitoring survey of the majority of Local-Group dwarf galaxies in order to identify the most evolved AGB stars that are long-period variables (LPV). LPV stars reach their maximum brightness amplitudes at optical wavelengths, owing to changes in temperature. They trace stellar populations as young as ∼30 Myr up to as old as ∼10 Gyr, and identifying them is one of the best ways of reconstructing star-formation history using a method that we have developed and applied successfully to other Local-Group galaxies. Since the luminosity variations span 100–1000 days, we planned observations over 10 epochs, spaced ∼3 months apart; 9 epochs of data have so far been obtained.

The Square Kilometre Array (SKA) will be sensitive enough to discover all of the pulsars in the Milky Way that are beamed towards Earth. Already in the initial deployment, SKA Phase 1, it will make significant advances in pulsar science. In these proceedings I briefly overview what the SKA is, and describe its pulsar search and timing capabilities.

Stars observed in the field of an open cluster are ideal for a controlled test of chemical tagging. Using chemical tagging, one should identify the cluster members, i.e., those stars of similar chemical composition, if their composition is indeed different from that of all the non-member stars of the field. Moreover, the abundance-based membership can be checked against membership based on radial velocities and proper motions. Here, I report preliminary results of such an experiment using data from the Gaia-ESO Survey. Although the three membership criteria usually agree, a few interesting examples of discrepant membership classification have been found. In addition, the mean composition of each open cluster was compared to a sample of 1 600 Gaia-ESO field stars. Some cases of field stars with abundances matching those of the open clusters were identified. This experiment suggests that open clusters do not necessarily have unique abundance patterns that set them apart from all other clusters.

We describe the DR14 APOGEE-TGAS catalogue, a new SDSS value-added catalogue that provides precise astrophysical parameters, chemical abundances, astro-spectro- photometric distances and extinctions, as well as orbital parameters for ~30, 000 APOGEE-TGAS stars, among them ~5, 000 high-quality giant stars within 1 kpc.

I present examples of how chemo-dynamical N-body simulations can help understanding the structure and evolution of the inner Galaxy. Such simulations reproduce the observed links between kinematics, morphology and chemistry in the bar/bulge region and explain them by the self-consistent cohabitation of a number of components. Galactic archaeology, applied to simulation snapshots, explains the sequence in which the stars of the various components were formed. The thick disc stars form earlier than those of the thin disc and in a much shorter time scale. The bar in the thick disc is horizontally thicker than that of the thin disc and has a different vertical morphology. The Galaxy’s inner disc scalelength is much smaller than what is expected from nearby galaxies of similar stellar mass.

The cornerstone mission of the European Space Agency, Gaia, together with forthcoming complementary surveys (CoRoT, Kepler, K2, APOGEE and Gaia-ESO), will revolutionize our understanding of the formation and history of our Galaxy, providing accurate stellar masses, radii, ages, distances, as well as chemical properties for a very large sample of stars across different Galactic stellar populations. Using improved population synthesis approach and new stellar evolution models we attempt to evaluate the possibility to derive ages of clump stars from their chemical properties. A new version of the Besançon Galaxy models (BGM) is used in which new stellar evolutionary tracks are computed from the stellar evolution code STAREVOL. The effects of mixing on chemical composition of the stellar photosphere has a significant impact on the determined stellar age from the observed [C/N] ratio. We clearly show that transport processes occurring in red-giant stars should be taken into account in the determination of ages for future Galactic archaeology studies.

The SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE) has collected high resolution near-IR spectra for several hundred thousand stars throughout the Milky Way. We review some of the results related to chemistry of stars in the disk, where APOGEE has a particular advantage by virtue of being able to work in more obscured areas. The ability to measure carbon and nitrogen abundances in giants in the near-IR provides insight into stellar ages. We summarize results on the variation of mean metallicity, metallicity distribution functions, and the [α/Fe]–[Fe/H] relation across the Galactic disk, as well as results on the structural parameters in mono-abundance populations. Many of these results suggest that radial migration has played a significant role in the Galactic disk. It may be possible to disentangle radial mixing using multi-element abundance patterns.