We investigate Lyα, [Oiii] λ5007, Hα, and [Cii]158µm emission from 1,124 low-mass galaxies (typically M* ~ 108 Mʘ) at z = 4.9 - 7.0, composed of 1,092 Lyα emitters (LAEs) at z = 4.9 - 7.0 identified by Subaru/Hyper Suprime-Cam (HSC) narrowband surveys and 34 galaxies at z = 5.148 - 7.508 with deep ALMA [Cii]158µm data in the literature. At z = 4.9, we find that the rest-frame Hα equivalent width positively correlates with the rest-frame Lyα equivalent width EW0Lyα. At z = 5.7 - 7.0, there exists an interesting turn-over trend that the [ Oiii]/ Hα flux ratio increases in EW0Lyα ≃ 0 - 30 Å, and then decreases out to EW0Lyα ≃ 130 Å. We also identify an anti-correlation between a [ Cii] luminosity to star-formation rate ratio (L[CII]/SFR) and EW0Lyα at the >99% confidence level. We carefully investigate physical origins of the correlations, and find that a simple anti-correlation between EW0Lyα and metallicity explains self-consistently all of the relations identified in our study.

The narrow-band Δa photometric system measures the flux depression at λ5200 Å by comparing the flux at the band centre to adjacent regions. It has been shown that virtually all peculiar stars with magnetic fields (mCPs) have significant positive Δa values (of up to +100 mmag), whereas Be/Ae/B[e] and metal weak stars (including lambda Bootis types) exhibit significant negative values of Δa. By using this photometric system we are therefore able to detect chemically peculiar (CP), emission types and metal-weak stars in an efficient way. The poster presented the first results of our survey of the Small Magellanic Cloud. In the selected field we found only 0.5 % of bona fide CP stars against 15 % in our Galaxy.

The present-time Milky Way (MW) radial metallicity gradient is a prime observable for galaxy evolution studies. Yet, a large diversity of measured gradients can be found in the literature, with values ranging from -0.01 to -0.09 dex kpc−1, depending on the tracers used. In order to understand if this diversity comes from Galactic evolution processes or observational biases, stellar probes uniformly distributed across the disc and with accurately known ages and distances are needed. Classical Cepheids fulfil all these requirements and have been used to measure accurate abundance gradients in the MW. Here, I summarise some of the recent results based on Cepheids and on other stellar probes of similar age, and briefly discuss their implication for Galactic evolution.

Infrared spectroscopic observations have shown that complex organics with mixed aromatic-aliphatic structures are synthesized in large quantities during the late stages of stellar evolution. These organics are ejected into the interstellar medium and spread across the Galaxy. Due to the sturdy structures of these organic particles, they can survive through long journeys across the Galaxy under strong UV background and shock conditions. The implications that stellar organics were embedded in the primordial solar nebula is discussed.

The Lambda Cold Dark Matter (LCDM) paradigm makes specific predictions for the abundance, structure, substructure and clustering of dark matter halos, the sites of galaxy formation. These predictions can be directly tested, in the low-mass halo regime, by dark matter-dominated dwarf galaxies. A number of potential challenges to LCDM have been identified when confronting the expected properties of dwarfs with observation. I review our understanding of a few of these issues, including the “missing satellites” and the “too-big-to-fail” problems, and argue that neither poses an insurmountable challenge to LCDM. Solving these problems requires that most dwarf galaxies inhabit halos of similar mass, and that there is a relatively sharp minimum halo mass threshold to form luminous galaxies. These predictions are eminently falsifiable. In particular, LCDM predicts a large number of “dark” low-mass halos, some of which should have retained enough primordial gas to be detectable in deep 21 cm or Hα surveys. Detecting this predicted population of “mini-halos” would be a major discovery and a resounding success for LCDM on small scales.

The Galactic globular cluster system went and is still going through dynamical processes that require to be explored in detail. Here we illustrate how primordial massive globular clusters born in the Milky Way’s disc evolved by stripping material from each other or even merging very early during their lives. These processes might explain the puzzling presence of star-by-star spreads in iron content observed in massive globular clusters and should be taken into account when studying globular cluster stellar populations. In this context, we show how the direct comparison between the predictions provided by our direct N-body simulations and observations can shed light on the origin and chemo-dynamical evolution of globular clusters.

The Space-based, multi-band, astronomical Variable Object Monitor (SVOM) is a collaborative project between China and France dedicated to the detection, localisation and study of about 60 Gamma Ray Bursts per year, and other high-energy transient phenomena. SVOM is planned to be launched in 2021, with a lifetime of 3–5 years. The poster described our construction and testing of a prototype to set up an interface between our data reduction sub-system, the global VOEvent network, and the French science centre.

The paper discusses possible impacts of the interstellar medium (ISM) on processes on Earth, first of all those, which may affect the Earth biosphere.

The study of radial metallicity gradients in the disc of the Milky Way is a powerful tool to understand the mechamisms that have been acting in the formation and evolution of the Galactic disc. In this proceeding, I will put the eye on some problems that should be carefully addressed to obtain precise determinations of the metallicity gradients.

We present evolution calculations from the Asymptotic Giant Branch (AGB) to the Planetary Nebula (PNe) phase for models of mass 1.0 to 2.0 M⊙ over a range of metallicities. The understanding of these objects plays an important role in galactic evolution and composition. Here, we particularly focus on Late Thermal Pulse (LTP) models, which are models that experience an intense helium-shell pulse that occurs just following AGB departure and causes a rapid looping evolution between the AGB and PN phases. The transient phases only last decades and centuries while increasing and decreasing in temperature dramatically. We use our models to make comparisons to V839 Ara (SAO 244567). This star has been observed rapidly heating over more than 50 years. Observations have proven difficult to model because the central star has a small radius, high surface gravity, and low temperature compared to our models.

The combination of sensitivity and large sky coverage of the ALFALFA HI survey has enabled the detection of difficult to observe low mass galaxies in large numbers, including dwarf galaxies overlooked in optical surveys. Three different, but connected, studies of dwarf galaxies from the ALFALFA survey are of particular interest: SHIELD (Survey of HI in Extremely Low-mass Dwarfs), candidate gas-rich ultra-faint dwarf galaxies, and the (Almost) Dark population. SHIELD is a systematic multiwavelength study of all dwarf galaxies from ALFALFA with MHI < 107.2M⊙ and clear optical counterparts. Candidate gas-rich ultra-faint dwarf galaxies extend the dwarf galaxy population to even lower masses. These galaxies are identified as isolated HI clouds with no discernible optical counterpart but subsequent observations reveal that some are extremely faint, gas-dominated galaxies. Leo P, discovered first as an HI detection, and then found to be an actively star-forming galaxy, bridges the gap between these candidate galaxies and the SHIELD sample. The (Almost) Dark sample consists of galaxies whose optical counterparts are overlooked in current optical surveys but which are clear detections in ALFALFA. This sample includes field gas-rich ultra-diffuse galaxies. Coma P, with a peak surface brightness of only ∼26.4 mag arcsec−2 in g’, demonstrates the sort of extreme low surface brightness galaxy that can be discovered in an HI survey.

Stellar magnetic field manifestations such as stellar winds and EUV radiation are the key drivers of planetary atmospheric loss and escape. To understand how the central star influences habitability, it is very important to perform detailed investigation of the star’s magnetic field. We investigate the surface magnetic field geometry and chromospheric activity of 51 sun-like stars. The magnetic geometry is reconstructed using Zeeman Doppler imaging. Chromospheric activity is measured using the Ca II H& K lines. We confirm that the Sun’s large-scale geometry is dominantly poloidal, which is also true for slowly rotating stars. Contrary to the Sun, rapidly rotating stars can have a strong toroidal field and a weak poloidal field. This separation in field geometry appears at Ro=1. Our results show that detailed investigation of stellar magnetic field is important to understand its influence on planetary habitability.

Time-domain astronomy is a key theme on research roadmaps worldwide, as was amply demonstrated by the energy which the participants (coming from 33 different countries) brought to this Symposium, as they shared their experience and expertise through various time-domain projects and discussed the challenges and strategies for the road ahead. This short summary is simply a personal view of the many key topics that were discussed.

Stellar metallicity gradients set important constraints on the formation and evolution history of the Milky Way. We present radial and vertical metallicity gradients of the Galactic disc for mono-age stellar populations from the LAMOST Galactic Surveys, and discuss their constraints on the disc assemblage history.

Isotopic ratios are a powerful tool for gaining insights into stellar evolution and nucleosynthesis. The isotopic ratios of the key elements carbon and oxygen are perfectly suited to investigate the pristine composition of red giants, the conditions in their interiors, and the mixing in their extended atmospheres. Of course the dust ejected from red giants in their final evolution also contains isotopically tagged material. This red giant dust is present in the solar system as presolar dust grains. We have measured isotopic ratios of carbon and oxygen in spectra from a large sample of AGB stars including both Miras and semiregular variables. We show how the derived ratios compare with expectations from stellar models and with measurements in presolar grains. Comparison of isotopes that are affected by different types of nucleosynthesis provides insights into galactic evolution.

Several observational and theoretical studies suggest that the initial mass function (IMF) slope for massive stars in globular clusters (GCs) depends on the initial cloud density and metallicity, such that the IMF becomes increasingly top-heavy with decreasing metallicity and increasing the gas density of the forming object. Using N-body simulations of GCs starting with a top-heavy IMF and undergo early gas expulsion within a Milky Way-like potential, we show how such a cluster would evolve. By varying the degree of top-heaviness, we calculate the dissolution time and the minimum cluster mass needed for the cluster to survive after 12 Gyr of evolution.

Raman scattered O VI features at 6825 Å and 7082 Å found in symbiotic stars are important spectroscopic tools to probe the mass transfer process. Adopting a Monte Carlo approach, we perform a profile analysis of Raman O VI features of the yellow SySt AG Draconis and make a comparison with the spectrum obtained with CFHT. It is assumed that the accretion flow is convergent on the entering side with enhanced O VI emission and the flux ratio F(1032)/F(1038)∼1, whereas on the opposite side the flow is divergent with low O VI emission and F(1032/F(1038)∼2. Our best fit to the spectrum is obtained from our model with a mass-loss rate of the giant ∼4 × 10−7 M⊙ yr−1. A slight red wing excess in the spectrum suggests the presence of bipolar neutral components receding in the directions perpendicular to the binary orbital plane with a speed ∼70km s−1

Dwarf galaxies with stellar masses around 109M⊙ can be explored at high and low redshifts and they give a glimpse of the different conditions of galaxy formation at different epochs. Using a large sample of about 300 zoom-in cosmological hydrodynamical simulations of galaxy formation I will briefly describe the formation of dwarfs at this mass scale at 3 different epochs: cosmic dawn (Ceverino, Klessen, Glover 2018), cosmic noon (Ceverino, Primack, Dekel 2015), and today (Ceverino et al. 2017). I will describe the FirstLight simulations of first galaxies at redshifts 5-15. These first dwarfs have extremely high star formation efficiencies due to high gas fractions and high gas accretion rates. These simulations will make predictions that will be tested for the first time with the James Webb Space Telescope (JWST). At cosmic noon, z = 2, galaxy formation is still a very violent and dynamic process. The VELA simulations have generated a set of dispersion-dominated dwarfs that show an elongated morphology due to their prolate dark-matter halos. Between z = 1 and 0, the AGORA simulation shows the formation of a low-mass disc due to slow gas accretion. The disc agrees with many local scaling relations, such as the stellar-mass-halo-mass and the baryonic Tully-Fisher relation.

An overview of the Gaia-ESO Survey project is presented, with focus on open star clusters and their use to trace the radial metallicity gradient in the thin disc.