Symposium 347 - Abstracts


Theoretical physics and cosmology with ELTs

Martins, Carlos

The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete (or possibly incorrect) and that new physics is out there, waiting to be discovered. A crucial task for the next generation of astrophysical facilities is to search for, identify and ultimately characterize this new physics. I will outline the theoretical arguments pointing to this new physics, and then discuss some unique contributions of the ELTs towards this endeavour, including tests of the stability of nature’s fundamental couplings, tests of the behaviour of gravity in the strong-field regime, and mapping the expansion history of the universe in the deep matter era, by both direct and indirect means. I will also briefly highlight how the ELTs can optimally complement other planned ground and space facilities.

Quantitative Spectroscopy of the Young Stellar population of Star Forming Galaxies

Kudritzki, Rolf

The determination of the chemical composition of galaxies is crucial for investigating the formation and evolution of star forming galaxies and provides a powerful tool to constrain the effects of galactic winds and accretion from the cosmic web. In this regard stellar absorption line studies provide an attractive alternative to the standard techniques using the strong emission lines of HII regions. I will introduce a number of newly developed methods - multi-object spectroscopy of individual blue and red supergiant stars, the brightest stars in the universe at visual and NIR wavelengths, - NIR spectroscopy of super star clusters, - optical spectroscopy of the integrated light of stellar populations in the disks of star forming galaxies, and present results accumulated in the last two years. I will then discuss the scientific perspectives and potential of these methods for the use of ELTs.


Maguire, Kate

Extremely Large Telescopes (ELTs) will provide the ability to study supernovae at higher redshifts than currently possible. These observations will be crucial for precision cosmological measurements using Type Ia supernovae, as well as for dramatically increasing our understanding of massive star formation in the early Universe through the study of stellar explosions. In this talk, I will discuss the latest predictions for studies of  both thermonuclear and core-collapse supernovae at high redshifts with ELTs. I will also highlight how future observations will target the explosions of the first generation of stars, and provide key constraints on star formation at high redshift.

Formation and evolution of galaxies in clusters revealed with ELTs

Kodama, Tadayuki

I will review what we can learn on the formation and evolution of galaxy clusters and galaxies therein with ELTs.

Gaia & ELTs: quantitative stellar astrophysics

Thévenin, Frédéric

Gaia is delivering the second release this year producing 1.3 billion star measurements in particular parallaxes and proper motions. This represents a great progress for astrophysical knowledges mainly for the galactic structure and the stellar physics which are tied together. At the end of the nominal mission, the release of 2022 Gaia DR4 will definitively change our understanding of the Universe and it will represent a very important basis for future stellar astrophysics understanding based on ELTs, JWST and PLATO collect of data. The present status of the satellite, of the published Gaia DR2 and of the foreseen Gaia DR3 will be discussed. Links with asteroseismology and interferometry will be presented, but the talk will focus more on the synergy with ELTs in this important phase of preparation of ELTs instruments in the context of stellar physics.

Astrobiology with the ELTs: Searching for bio-signatures in exoplanet atmospheres

Palle, Enric

The advances in high-precision instrumentation and dedicated space missions over the past two decades have produced a revolution in the field of exoplanet research, leading to the discovery of a wealth of earth-sized worlds, several of them within the habitable zone of their star. In the coming years, the efforts will concentrate in the characterization of these planets and their atmospheres, specially those transiting and orbiting around low mass stars. The final goal will be the detection of bio-signatures (clues for wide-spread life affecting the atmospheric composition of these planets). Here I will review the possibilities that the new generation of ELT's and their associated instrumentation will offer in this quest for life around our neighbor stars. 

ELTs for complex populations of evolved stars around the Galactic center, a few parsecs to a few kilo-parsecs

Matsunaga, Noriyuki

The Galactic center is comprised of complex systems of stars and interstellar matter (gas and dust), and possibly dark matter, which are distributed on different scales. With the super-massive black hole and the highest density of stars/inter stellar matter, this region is important for galaxy-scale evolution and stellar populations therein have such imprints. The severe foreground extinction, however, requires observations in the infrared (rather than in the optical), and current observations are limited to bright tracers such as massive stars, bright pulsating stars, and bright red giants in relatively low extinction fields. An obvious advantage of ELTs is the deeper limiting magnitudes which will allow us to observe tracers with lower luminosity and/or higher foreground extinction. There are other merits of ELTs' larger collecting areas: One can, for example, obtain spectra with higher spectral resolution and/or higher signal-to-noise ratio. The purpose of my talk is to give some perspectives of future observations for various information like stellar kinematics and chemical abundances which can be explored with ELTs in the future and to discuss their impacts on our understanding of populations traced mainly by evolved stars in this region.

Planetary Nebulae in the nearby Universe

Pena, Miriam

In the past years there has been a rapidly growing of observational data on planetary nebulae (PNe) in different galaxies, in particular in the nearby ones. This is due to PNe provide important clues to analyze several aspects of galaxies. Differently to  HII  regions, PNe can be studied in any kind of galaxies: ellipticals, spirals and irregulars. Thus they give information on the stellar evolution of post-AGB stars and the distribution and kinematics of low-intermediate mass stars in parental galaxies. They help  to determine the distances of galaxies through the PN luminosity function; they allow to perform the chemical analysis of the old population through the determination of the elements not modified by the stellar nucleosynthesis, to determine the effect of nucleosynthesis of low-intermediate mass stars in the chemical evolution of galaxies, to analyze the old chemical gradient in disk galaxies, and many others.PNe are easily detected in external galaxies by using on-band off-band images, mainly in the Halpha and [OIII] ?5007 lines, which are usually the brightest lines in PNe. However a positive detection does not guarantee the discovery of a PN, as also compact HII regions can be detected with such a technique, therefore spectroscopic confirmation is usually required. For such a confirmation, it is found that 4-m telescopes are in the limit of what is achievable in a reasonable exposure time. Thus, larger telescopes are needed.In this talk I will present some results coming from the analysis of PNe the in nearby Universe. And I will emphasize  the importance of analyzing these faint objects with ELTs, in order to improve our understanding of this important population.

ISM conditions in distant galaxies

Kewley, Lisa

The conditions in the ISM are critical for star formation, the evolution of HII regions, for the fuelling of supermassive black holes, and the propagation of galactic outflows throughout galaxies.  I will present an overview of the ISM conditions in distant galaxies.  I will describe the latest methods for measuring ISM conditions in the high redshift universe, utilizing stellar evolutionary synthesis and photoionisation and shock models.  I will discuss new self-consistent UV - optical - IR diagnostics for measuring the ISM conditions in galaxies across cosmic time.  I will finish by presenting a summary of how this field will be dramatically opened in the ELT era.

Stars and exoplanets in full Stokes IQUV

Strassmeier, Klaus

The new step forward with HIRES at the ELT would be to apply high spectral resolution polarimetry to stars with planets. It is generally known, and particularly true for the Sun, that linear polarization is much more prominent in individual spectral lines than in the continuous spectrum. An exoplanet transit breaks spherical symmetry over the projected stellar disk. It blocks the inherent (stellar) limb polarization and results in a non-vanishing linear polarization that is related to the planet’s size and orbit.  Spectropolarimetry is also at hand for all out-of-eclipse situations where we can expect starlight reflected off the planet in the direction of the observer. Polarized spectral line observations at orbital quadrature of both stellar and planetary atmospheric constituents may show up strong linear polarization amplitudes, e.g., in water lines due to its molecular properties. In the search for life, time resolved linear spectropolarimetry can be used to seek evidence of special features such as a strongly polarized specular reflection, dubbed the glint that would arise from the liquid surface of an extrasolar ocean. We have proposed that the European ELT will be equipped with a high-precision polarimeter in its only rotationally symmetric focus (the intermediate focus) that is capable of feeding its High Resolution Spectrograph HIRES.

The reionization epoch: latest results and future prospects with the ELT

Pentericci, Laura

One of the principal science goals for the E-ELT is to find the very first galaxies, that probably reionized the universe and probe their physical properties, which may well be very different from those of their lower redshift counterparts, as they are forming from pristine gas, with very low metal abundances. Current results show that the Lyalpha line coming from young, dust free stellar populations is not only a powerful redshift indicator but its demographics can also be used to constrain the neutral hydrogen fraction at the various epochs, and thus trace the reionization history. In my talk I I will review the latest results in the studies of the earliest galaxies, maily from deep spectroscopic observations and discuss out future prospects with the  ELT 

Living with an Adolescent: The Quasar Phase

Gallagher, Sarah

The centre of every massive galaxy hosts a supermassive black hole that likely grew through accretion as a luminous quasar when the universe was a quarter to a half of its current age.  Quasar activity is thus a phase in the evolution of every massive galaxy much like adolescence: transformative (perhaps violently so) though relatively brief.  This epoch also coincides roughly with the build-up of stellar mass as a consequence of active star formation.  Though these two transformational activities occur close in time and are likely related, their relationship has not been rigourously explored because to date, studying quasar host galaxies at z~2 has proven extremely difficult.  The light from the quasar point source swamps the much fainter stellar emission from the host, and the samples of quasar hosts amenable to adaptive optics on 8-m class telescopes are small.  Extremely Large Telescopes will break open this field with high resolution imaging and high signal-to-noise spectroscopy of much larger samples of quasar hosts than have been accessible to date.  I'll review the overall science cases for the ELTs related to quasars, and offer my subjective view of the most exciting opportunities for major advances in understanding the quasar phase in galaxy evolution.

Large Radio Facilities (SKA, FAST, MeerKAT) in the era of ELTs.

Carignan, Claude

The 64 antennae SKA precursor MeerKAT is starting its operation as we speak and will start its Large Survey Programs at the end of 2018. FAST, the largest single-dish telescope (500m) has started its observations in “drift scan” mode with CRAFTS (Commensal Radio Astronomy Fast Survey) and should be able to start pointed observations in 2019.  During this talk I will try to update you on those two new facilities and on their synergies. In the near future (2019-20), the best combination to study low column density HI will be to combine the sensitivity of FAST with the spatial resolution of MeerKAT. The combination of the data from those two telescopes will allow, 4-5 years before SKA1-MID, to do "cosmic web" research to levels < 5 X 1017 cm-2, close to 1016 cm-2, densities that would normally only be accessible to the full SKA around 2030. It is at those densities that we expect the galaxies to connect with the surrounding cosmic web. Finally, I will briefly address the synergies between those large radio instruments and the optical ELTs.

Stellar population in Local Group and Local Volume galaxies.

Fiorentino, Giuliana

The era of science driven telescopes is starting. The Extremely Large Telescope is a big technological challenge and, in order to exploit its potential, it will be assisted by sophisticated Adaptive Optics systems (e.g. MAORY). I will review some science cases that will become possible using the power of extreme high resolution imaging offered by a 39-meter telescope working at its diffraction limit, as the search for intermediate mass black hole in dense environments within the Local Group (young compact or globular clusters); the study of the stellar populations of very compact objects as the poorly known Elliptical galaxies in the Local Volume and out to the Virgo cluster. On the basis of updated simulations, I will show that resolved stellar populations in the Local Volume (~10M pc) will experience a new era; we expect to reach details Today only possible in the Local Group.

Evolution of the CMB temperature

Noterdaeme, Pasquier

The adiabatic evolution of the cosmic microwave background temperature (TCMB) with cosmic time is a fundamental prediction of the standard Big-Bang theory. Any deviation from the predicted linear relation between TCMB and redshift (z) would have strong implications, either indicating a violation of the hypothesis of local position invariance (and thus of the equivalence principle) or that the number of photons is not conserved. Direct measurements of the CMB temperature-redshift relation provide therefore a crucial test of fundamental physics and cosmology. I will summarise the constraints obtained so far and discuss the future of the measurements with the next generation of extremely large telescopes, along with those obtainable from other facilities.

Low-metallicity massive stars: Breaking out of the SMC

Garcia, Miriam

Low-metallicity massive stars hold the key to interpret gravitational waves, high-redshift SNe and long-GRBs, and star-formation through Cosmic history. The massive stars community is working to supersede the SMC as reference for metal-poor massive stars, with new observations and analysis of increasingly metal-poorer Local Group dwarf irregular galaxies. However, these objects are at least 1Mpc away and we are meeting the sensitivity and resolution limits of current facilities. I will present my team's recent results on the topic, how far the immediate-future instrumentation can reach (GTC-MEGARA), and discuss the crucial contribution the E-ELT may make to the field.

Hunting for the first stars: Demystifying the mystery of He II with ELTs

Nanayakkara, Themiya

In the quest for identifying pop-III stars, the most sought-after emission line is He II, however, stellar population models are unable to accurately predict the He II features while being consistent with other emission line diagnostics. To produce He II ionizing photons, stellar populations require sources of hard ionizing radiations with energies >= 54.4 eV. Sources such as AGN, shocks, X-Ray binaries, stellar rotation and/or binary stellar evolution, and post-AGB stars may contribute to hard ionizing radiation fields. These effects complicate the classical definition of nebular/stellar origin of He II, which is purely based on the shape of the emission line. To accurately identify relative contributions from these wide variety of sources, high signal-to-noise spectra with rest-frame UV/optical coverage and advanced stellar population/photoionization are required. I will discuss recent results obtained by the VLT/MUSE GTO program, which obtained deep ≈10-30h exposures of the Hubble legacy fields to obtain rest-UV spectra of galaxies at z≈2-6. I will perform photo-ionization modelling of our sample and compare our results with local He II studies to show why our high-redshift ‘analogues’ may fall short in exploring the full parameter space of galaxy systems in the early universe and why it is imperative to obtain spectra of high-redshift systems to perform such studies. Specifically, I will address the necessity to obtain high signal-to-noise spectra of individual galaxies to model rest UV emission and absorption systems along with auxiliary rest-NIR lines, which is very expensive even with the current largest optical/NIR facilities and the benefits of 30-m class telescopes for such studies.

Reverberation mapping and the broad-line region of AGN in the ELT era

Ilic, Dragana

The broad emission lines, seen in the optical spectra of type 1 active galactic nuclei (AGN), are produced in the so-called broad-line region (BLR), i.e. the ionized gas, of sub-parsec dimensions, heated by the central continuum source. For the last several decades, the continuous optical monitoring of type 1 AGNs have shown that the change of the line flux is responding to the change of the continuum flux with the certain time-delay, which can be used to directly estimate the size of the BLR. This is the base of the techniques called "reverberation mapping", used for the study of geometry and kinematics of the BLR of the monitored AGN. This method has also revealed the empirical relation between the BLR radius and the continuum luminosity, i.e. the radius-luminosity relation, which is widely used for single-epoch observations of type 1 AGN. In this contribution, we discuss the usage of the reverberation-mapping techniques in the frame of the large telescopes, presenting some possible results and discussing possible problems and caveats.

2024+: Characterizing Exoplanets in the Era of ESO's 39m ELT

Rodler, Florian

In the next decade, the three extremely large telescopes with diameters from 24m to 39m will dramatically extend our knowledge about the composition, dynamics and the structure of exoplanet atmospheres. The unprecedented size of these telescope will permit high-contrast direct imaging of mature planets around stars in the solar neighborhood at orbital separations closer than 1 AU, and high-dispersion spectrographs will open a window to a detailed study of exoplanet atmospheres including weather patterns and cloud properties therein. The combination of high-contrast direct imaging with high-dispersion spectroscopy, to be realized in the first-generation instrument METIS at ESO's 39m ELT, will allow us to measure thermal emission of terrestrial planets in the habitable zone around nearby M-dwarfs. Being capable of inspecting the atmospheres of rocky worlds, the extremely large telescopes will bring us close to the answer of one of the most fundamental questions: does life exist beyond Earth?In my contribution, I will review the capabilities of the instruments suitable for exoplanet characterization at ESO's 39m ELT, METIS, HARMONI, EPICS and HIRES, and will discuss their huge impact on the research field of exoplanet atmospheres.

Simulating imagery of the near and distant universe with MICADO at the ELT

Leschinski, Kieran

K. Leschinski, O. Czoske, G. Verdoes Kleijn, W. Zeilinger, J. Alves, W. Kausch, R. Köhler, M. Mach, N. PrzybillaSimCADO is the data simulation package for the MICADO near-infrared camera for ESO's Extremely Large Telescope. SimCADO allows the user to "observe" their chosen on-sky target as it would be seen through the MICADO/ELT optical train. The python package has been developed as part of the current instrument design effort for MICADO. It is open source and free to use.SimCADO simulates effects along the full photon path - from the source, through the atmosphere, telescope and instrument, on to the detector - for both of the MICADO imaging modes. The functionality to model MICADO's spectrographic mode will be added in the near future. We have validated the accuracy of the simulated images against archive data from HAWK-I. Images produced by SimCADO will be used internally by the Data Flow team to develop the MICADO data flow architecture, and by the Science team to consolidate the key science drivers for the MICADO project.Here I will present an overview of the SimCADO package as well as a series of examples of how the software can be used to study the feasibility of future observation campaigns with MICADO and the ELT with regards to several of the big open questions in astronomy. Examples include: resolving the structure of the IMF outside the Milky Way, directly observing the proper motions of stars in the cores of globular clusters which may contain intermediate mass black holes; imaging gravitational lensing systems; observing time delays of sub arcsecond multiply imaged quasars, and resolving the structure of high-redshift galaxies.

MOSAIC at the ELT: A Gigantic Step into the Deep Universe

Hammer, Francois

Combined with the unprecedented sensitivity of the E-ELT, MOSAIC will be the most efficient MOS facility having both multiplex and multi-IFU capability. MOSAIC at E-ELT will be unique for follow-up the faintest sources detected by JWST, to probe the reionisation epoch at very high redshifts as well as to evaluate the evolution of the dwarf mass function over most of the Universe age. With its IFUs, MOSAIC will be without competitors for probing an inventory of both dark matter (from realistic rotation curves at early epochs) and cool to warm-hot gas phases in z=3.5 galactic haloes. Galactic archeology as well as evolution of first massive black holes are also targets for which the MOS will be unique. Multi-object adaptive optics and accurate sky subtraction with fibers have been demonstrated on sky. A large consortium has been gathered to support the MOS implementation on the ELT.

Kinematics and Dynamics of Young Star Clusters with TMT

Shah, Priya

Star clusters are evolving n-body systems . We discuss the early dynamics of star clusters, the process of primordial mass segregation and clustering observed in certain young clusters.  We discuss how the dynamics coupled with stellar evolution of a cluster define the radial profile, mass function of and disruption the cluster and compare these parameters with some known clusters. As a member of the Thirty Meter Telescope (TMTD), International Science Driven Team (ISDT),  I shall use these details to help define the science case, requirements  and the expected precision in answering possible questions about the Evolution of Star Clusters in terms of astrometry and high resolution spectroscopy. I shall also report on some of the resolutions made at the recent TMT-Forum held in Mysore, India

Key early science programs with MANIFEST on GMT

Colless, Matthew

The MANIFEST fibre system provides a highly versatile feed for the GMACS and G-CLEF first-light spectrographs on the Giant Magellan Telescope (GMT). Combining these low- and high-resolution optical spectrographs with the wide field of view (up to 20 arcmin), high multiplex, and integral field capabilities provided by MANIFEST enables science programs that are not achievable with other extremely large telescopes. For galactic archaeology and near-field cosmology studies of Local Group galaxies, MANIFEST and G-CLEF can obtain up to 40 simultaneous high-resolution optical spectra over a wide field, and so produce detailed kinematic and chemical maps of the stellar populations out to large radius in galaxies covering a broad range of masses and morphologies. For galaxy evolution studies, MANIFEST and GMACS can combine a survey of galaxies at the epoch of peak star formation with a study of the flows of gas between galaxies and the circumgalactic medium, mapping both the emission from hot gas using integral field spectroscopy and the absorption from cold gas with multi-object spectroscopy of background sources. These programs will feature strongly in the early science goals for GMT.

From the inner Milky Way to Local Volume galaxies: resolved stellar populations with ELT-HARMONI

Gonzalez, Oscar

I will discuss the predicted performance of the HARMONI spectrograph and the ELT in the context of two specific science cases: resolved stellar populations of Local Volume galaxies and Galactic archaeology in dense environments. We have produced and analysed a set of simulated data-cubes using the HSIM software, mocking observations across the giant elliptical galaxy Centaurus A and in the nuclear bulge of the Milky Way.  I will use our results to demonstrate the instrument’s capabilities to perform stellar absorption line spectroscopy in a large number of stars which will allow us to study the detailed kinematics and stellar population characteristics of these dense systems.

Fundamental physics constraints from testing the stability of the fine-structure constant with the ELTs

Leite, Ana Catarina

The increased collecting area of the ELTs will bring fainter high-z targets within the reach of high-resolution ultra-stable spectrographs, thus enabling a new generation of precision consistency tests, including tests of the stability of nature's fundamental couplings. For example, the stability of the fine-structure constant can be tested by looking into metal absorption lines produced by the intervening clouds along the line of sight of distant quasars.I will discuss the performance that can be expected from the ELTs in testing the stability of the fine-structure constant, based on the early ESPRESSO observations, and present some comparative forecasts of the impact of these measurements for representative models of fundamental physics and cosmology.

Time-delays of gravitationally lensed quasars with MICADO at the ELT

Leschinski, Kieran

K. Leschinski, G Verdoes KleijnOnly a handful of known gravitational lensed systems contain quasars with luminosity variations strong enough to accurately determine the Hubble constant based on the geometric time delay method. However with the vast increase in resolving power and sensitivity, MICADO at the ELT will be able to greatly expand on the current number of these systems. MICADO will be able to resolve lensed systems over 10x smaller than HST, allowing both smaller and less well aligned systems to be studied.In this talk we will describe how we used the MICADO instrument simulator, SimCADO, to determine the size and sensitivity limits for future MICADO observation of lensed systems with variable quasars. We will also show the limits of quasar variability that MICADO should be able to detect for different lensing system configurations.

ELT/MOSAIC survey of dynamical and stellar properties of galaxies at z=1

Ziegler, Bodo

I will make the case for a 3D-spectroscopy survey of galaxies at z=1 with ELT/MOSAIC to derive comprehensively the main physical properties of the stellar component. Similar to CALIFA's IFU observations of local galaxies encompassing the whole variety of Hubble types and spanning a wide range in masses that enabled many different detailed studies we need to build up a statistically significant sample of galaxies at z=1 comprising different types with a wide range in masses, star formation rates, and gas fractions. Due to the surface brightness dimming ELT/MOSAIC is mandatory to achieve the required S/N needed to derive stellar population parameters (from absorption lines in contrast to gas emission lines) and stellar kinematics across ~3 disk scale lengths. Only this will allow the determination of dynamical masses via Jeans and Schwarzschild modelling of the velocity fields out to the turn-over radius where dark matter becomes dominant.

The Near-Infrared Cepheid distance scale based on VMC and Gaia data: a baseline for ELT observations

Ripepi, Vincenzo

We present new accurate Period-Luminosity (PL) and Period-Wesenheit (PW) relations in the J,Ks bands, based on a sample of more than 4000 Classical Cepheids in the Large Magellanic Cloud (LMC) in the context of the VISTA Magellanic Cloud (VMC) Survey. The extreme precision of these data allows us to study the geometry of the LMC and to establish a firm baseline for extragalactic Cepheid distance scale studies. The zero points of the PL and PW relations will be calibrated with great accuracy by using the parallaxes that will be released on April in the context of  the Gaia Data Release 2.These relationships will be of fundamental importance in the ELT Era. Indeed, we plan to useE-ELT+MAORY+MICADO  to extend the extragalactic distance scale of Classical Cepheids, with crucial impacts on the calibration of secondary distance indicators and on our knowledge of Ho. To this aim, we discuss the prospects to observe bright Classical Cepheids in a sample of galaxies with distances ranging from Virgo to Coma, possibly containing SNIa or other secondary distance indicators. These data would allow us not only to constrain, for the first time in one step, the Hubble constant, but also to provide an independent test of the accuracy of various types of secondary distance indicators.

Cepheids with MICADO@E-ELT: A 2-steps cosmic distance scale

Inno, Laura

The Hubble constant (H0) provides independent constraints on the spatial curvature of the Universe, its dark energy content, and neutrino physics. Thus, a measurement of H0 to 1% accuracy is crucial to improve our current knowledge of the fundamental physics. Cepheids play a prominent role in understanding the uncertainties on H0, since they contribute to the majority of  the total error budget. By using the largest near-infrared (NIR) dataset to-date for almost 7,000 Cepheids in the Magellanic Clouds (MCs), we showed that Cepheids NIR Period-Luminosity (PL) relations are universal, linear and independent of the metal content. Distances based on NIR PL relations are affected by random error at less than 1% level and by systematics at 5% level, where the systematics mostly concern the zero-point calibration and will be addressed by using a new independent calibration from Gaia. By using MICADO@E-ELT, we will be able to identify and characterise Cepheids down to a limiting magnitude of ~26 mag (J band) with 1hr exposure, and, in turn, to accurately measure the distances of spiral galaxies in the Local Group and beyond (> 4Mpc), from which H0 can be directly derived. Moreover, by adopting NIR PL relation and applying light-curve templates to estimate the mean magnitude from single epoch measurements, we derived accurate individual distances to all the Cepheids in the MCs and obtained their 3D mapping. The adopted approach has proved very efficient to uncover the spatial distribution of the young stellar population in nearby galaxies. E-ELT will allow us to export this analysis to farther and more complex systems such as e.g. the closest merging galaxy, Cen A.

The theoretical scenario to interpret RR Lyrae observed by E-ELT

Marconi, Marcella

We developed a new theoretical scenario for RR Lyrae stars, the most popularlow-mass primary distance indicators. Hydrodynamical calculations cover a widerange of metallicities and both canonical and helium enhanced chemicalcompositions to investigate the dependence of the pulsation observableson chemical composition. To further constrain the possible occurrence ofsystematics in the RR Lyrae distance scale we also investigated the topologyof the instability strip, the bolometric light curves and the most populardiagnostics (Period-Luminosity, Period-Luminosity-Color, Period-Wesenheit relations)used for distance determination. The quoted theoretical framework is going tobe validated with trigonometric distances provided by Gaia. Thanks to theunprecedented accuracy in both relative and absolute distances we also developednew theoretical tools to constrain the metal abundance and the helium content forRR Lyrae stars. This means the opportunity to investigate the metallicity distributionfunction of old stellar populations in Local Group and in Local Volume galaxies, and in turnto constrain their early chemical enrichment. In this context ELT and in particular MICAD/MAORYare going to play a crucial role, since they will allow us to collect accurate NIR (J,H,K) magnitudesthat together with the optical magnitudes (V,I) will allow us to estimate, the metallicity, the reddeningand the distance.  Finally, let us mention that the ELT IFS (HARMONI) will allow us to validatewith medium and high resolution spectra the metallicity scale based on photometric indices.

Resolving the dusty torus of active galactic nuclei with ELTs

Lopez Rodriguez, Enrique

The obscuring material surrounding the central engine of active galaxies is the cornerstone of the unified model. Until now, interferometric observations have been the sole technique to resolve the dusty ‘torus’ of the nearest AGN.  These observations have provided crucial information about the size (< 10 pc) and the emission and distribution of dust at infrared and (sub-)mm wavelengths. The achievable milli-arcsecons (< 1pc) resolution observations in the 2-13 µm wavelength range by the ELTs will for the first time produce single-dish resolved images of the dust emission in the torus of AGN. We present HyperCube of AGN Torus models (HyperCAT), and tools to simulate images of the torus emission as they will be observed by the next generation of ELTs. Our model images are based on the CLUMPY torus models. HyperCAT produces 2D images of torus emission in the range of 1-1000 µm for a given set of telescope and instrument configurations and AGN properties. It takes into account the telescope’s PSF, detector pixelisation, and desired noise characteristics. We will present the tool and our analysis of the resolvability and dust emission morphologies of nearby AGN Tori with ELTs.

Observing the CGM with ELT/HARMONI

Augustin, Ramona

Gas flows in and out of galaxies are poorly constrained and understanding these processes is crucial to studies of galaxy evolution.Observations of the Circum-Galactic Medium (CGM), where these processes take place, are therefore essential for making progress in understanding gas flows but remain challenging as this medium is intrinsically thin and very faint.The next milestone in this research area will be the access to the ELT with its large collective area, increasing the sensitivity to faint extended emission. Its first light IFU HARMONI will give both spatial and spectral information on the CGM.We use dedicated zoom-in cosmological RAMSES simulations and post-process galaxy halos with emission predictions from photoionisation modelling to estimate the typical fluxes from the CGM. Those are used as input into the HARMONI Simulator (HSIM) to predict the expected signal from the CGM with HARMONI observations and to optimise observing strategies.We also compare the outcome with the signal that we would get from existing IFUs, such as MUSE and SINFONI on the VLT, to estimate the improvement over those for CGM studies.

Galaxies in the epoch of reionization: the high redshift Universe with ELTs and JWST

Bunker, Andrew

I will discuss the importance of follow-up spectroscopy with ELTs on high redshift galaxies, in particular at z>6 - within the first billion years, and spanning the reionization of the Universe. This field has blossomed in the past 15 years, thanks to the advent of the Hubble Ultra Deep Field, GOODS and COSMOS, coupled with improved near-infrared imaging from the ground. However, a key current limitation is the lack of spectroscopic follow-up for most sources. This means that the contamination rates, exact redshifts, and key spectral diagnostics of stellar populations remain highly uncertain, which has potentially huge implications for the inference of luminosity functions which are key to addressing the assembly of stellar mass in galaxies, and to addressing the question of the role of galaxies in reionizing the Universe. Some progress will be made by JWST NIRSpec in pencil-beam surveys (and I will discuss our joint NIRSpec-NIRCam GTO  JWST Advanced Deep Extragalactic Survey, JADES), but a wider-field facility will be more effective in building up the numbers on the rarer brighter sources. Optical/near-IR spectroscopy from the ground on ELTs, working between the sky lines at spectral resolving power R~3000 out to H-band, will be very competitive with JWST sensitivity. ELT MOSAIC, TMT WFOS & IRMS, and GMACS & GMTIFS on GMT, offer great opportunity not only for redshift confirmation, but also for studies of evolution of the ionization state of the IGM with redshift, and the nature of the underlying stellar populations in the most distant galaxies.  In particular, potential population-III signatures such as HeII(1640) can be probed. I will discuss the role of ELT spectroscopy in the context of other upcoming high redshift surveys from JWST, Euclid and LSST.

Characterization of Earth-like planets with the Exoplanet Surface Imaging (EPSI) technique

Berdyugina, Svetlana

We demonstrate an inversion technique to image indirectly exoplanet surfaces using observed unresolved reflected light variations over the course of the exoplanets orbital and axial rotation: ExoPlanet Surface Imaging (EPSI). Under various geometric conditions the reflected light curve contains enough information to detect both longitudinal and latitudinal structures and to map exoplanet surface features. We demonstrate this using examples of Solar system planets and moons as well as simulated planets with Earth-like life. Such albedo maps obtained in different wavelength passbands can provide "photographic" views of distant exoplanets and may lead to unambiguous detection of life. 

Spectroscopy of extragalactic massive stars with the ELT

Evans, Chris

With the 8-10m class observatories we have observed the most luminous supergiant stars in galaxies out to distances of several Mpc. This has provided direct abundance estimates of their host systems for comparisons with nebular diagnostics. However, to improve our understanding of the evolution of massive stars, there is a longstanding desire to also observe main-sequence OB-type stars in systems beyond 1 Mpc. This will give us, for example, the chance to explore the properties of massive stars in very metal-poor galaxies and the broad range of environments in the galaxies of the Sculptor group, and beyond. I will introduce simulations of visible spectroscopy of O-type stars undertaken to investigate the capability of the ELT-MOSAIC concept, but that will also be relevant to future thinking for TMT-WFOS and GMT-GMACS. An even more exciting prospect is if we were also then able to obtain UV spectroscopy of the same indvidual stars beyond 1 Mpc - I will highlight strong synergies of the ELTs in this context with the LUVOIR and HabEx missions being studied by NASA as part of the US Decadal Survey.

A spatially-resolved study of star and planet formation in Local Group galxies

Yasui, Chikako

We are studying environmental effects of star and planet formation. Among them, we have been previously focusing on metallicity dependence. Metallicity is one of the most critical factor for star and planet formation because dust forms planet cores despite of very small mass fraction in disks (~1%) and because metal is sensitive to heating and cooling in star forming processes, and directly related to radiative transfer. For the region where metallicity is different from solar neighborhood, we are focusing on the outer Galaxy, which we defined as the region with Galactocentric distance of >~ 18kpc.  It is known to have as low metallicity as ~-1dex. The environments are similar to that in nearby dwarf galaxies, damped Lyman-alpha systems, and that in the early stage of the formation of the Galactic disk. We have obtained NIR images of young clusters in the outer Galaxy, using the Subaru 8.2-m telescope, and clearly resolved cluster members with mass detection limits of ~0.1 M_solar. Based on the fitting of K-band luminosity functions (KLFs), we found that the initial mass function (IMF) in the outer Galaxy is consistent with that in the solar neighborhood in terms of the high-mass slope and IMF peak. However, we also found that the fraction of stars with a K-band excess (which originates from the inner circumstellar dust disk at radii of r <= 0.1 AU) is significantly lower than those in the solar neighborhood, suggesting a metallicity dependence of the disk lifetime. Upcoming observations with a higher spatial resolution and sensitivity, using ELT, will allow us to extend spatially-resolved studies of the IMF and protoplanetary disk evolution to Local Group galaxies. Using high spatial resolution and sensitivity (0.02 arcsec and K~27 mag with AO), stars with mass of down to ~1M_solar can be detected and can be resolved sufficiently. From this study, we will gain new insights into wider environmental effects of star and planet formation.

The Initial Mass Function in the ELT era

Alves, João

The stellar initial mass function (IMF) is one of the main pillars of modern astrophysics. Although taken as a universal constant, there has been in the recent literature tantalizing evidence for drastic variations. Is the stellar IMF approximately constant across the local universe? The advent of the ELTs will allow one to probe the local universe for critically needed resolved IMF studies of various stellar populations. Spectroscopy, even from the ELTs, will be observationally inefficient to allow for the characterization of a sufficient number of sources, so our ability to measure the IMF in the local universe depends critically on our ability to constrain masses from photometric data. In a recent paper (Ascenso 2018), we showed that this can be done reliably even with near-infrared data alone, circumventing the need for the wide wavelength coverage typically necessary to build SEDs. In this talk, we will present results from an investigative study for resolved IMFs in the local universe done with SIMCADO (the ELT-MICADO simulator (Leschinski et al. 2018)). Although ELT PSFs make life very difficult, we conclude that  1) ELT-MICADO can get well into the Brown dwarf regime (>0.01Msun) for all clusters within 8kpc of the Sun, 2) It will just miss out on the BD knee in the LMC (>0.1 Msun), but it will catch the true structure of the 0.5 Msun knee, and 3) densities of ~1000 stars/arcsec^2 are easily resolvable while 5000 stars/arcsec^2 is possible only if we have good knowledge of the PSF. The latter is equivalent to every star in an Arches-like cluster at a distance of the LMC. An ONC-like cluster would be fully resolvable (assuming no extinction) in Leo I Dwarf (220kpc). In the LMC, meaning MICADO can basically resolve out all the stars in every YMC listed in Portegies-Zwart 2010. We will end presenting the distance limit for resolved IMFs for a broad range of conditions. 

Crowded field photometry with MCAO systems

monelli, matteo

I will present the photometric analysis of crowded fields in globular clusters based on MCAO data collected with 8-10 m class telescopes (LBT/PISCES, Gemini/GEMS). I will discuss the performance of these instruments, and the improvements with respect to the classical approach. The photometry, reaching Ms~21, allowed us to reach the lower main sequence. In this regime, a well defined bend (main sequence knee) appears in NIR colour-magnitude diagrams. The magnitude difference with respect to the turn-off is a solid absolute age indicator, which provides error bars on average a factor of two smaller than other methods. I will summarize the results of our project, and discuss the impact of the incoming ELTs in this field.

High Redshift Supernova Survey with ELTs

Suzuki, Nao

In the era of ELTs,  one of the holy grails of observational cosmology is to discover the signs of 'First Star’ and their explosions.   It is very important to understand how the first generation of stars were born and ionized the universe, how massive black holes were formed and seeded the formation of the galaxies.   The 'First Star' bridges many area of studies in astrophysics, and the surveys by ELTs would be critical.In 2020s, LSST would discover millions of supernovae, and cosmological parameters would be listed as a table on the back page of your text book.  However, the nature of dark energy still remains as a mystery.   ELTs are capable of probing high-z universe where the expansion is decelerating (z>1).   Also, ELTs can investigate rare events such as gravitationally lensed Type Ia supernovae and test general relativity as well as cosmological parameters.   It’s not only distant universe, but ELTs would revolutionize the view of nearby universe. As of today, we do not have a definitive answer of the progenitor system of Type Ia supernovae, but ELT should be able to reveal the identity of its companion star in the nearby universe.  Cepheid variable measurements can be extended to cosmological distances, and we may be able to find inhomogeneous expansion of the local universe.Reverberation Mapping of AGNs enters new era if we can resolve the dust torus with TMT.   ELTs would advance the era of “High Precision Cosmology”.    New distance indicators, Fast Radio Burst (FRB) and Gravitational Wave as a standard siren could become more common in 2020s.   Time domain science with ELTs has a promising future.   However, it is always true that "the great ocean of truth lay all undiscovered before" us.  The most exciting ELT discovery would be something we have not listed yet, but we should always be well prepared for the new discovery.

Brown dwarfs in the context of ELTs

Bayo, Amelia

Even though substellar objects were first imaged already more than twenty years ago (and theoretically predicted more than 50 years ago), many fundamental questions regarding these objects remain open: their dominant mechanism of formation, their complex atmospheres, etc. In this talk I will summarize the state-of-the-art of some of these open challenges and how the ELTs with their first and second generation instrumentation and the synergies with other developping facilities will pave the way to answers.

A Beacon in the Dark

Dall'Ora, Massimo

MAORY+MICADO will give us the unique opportunity to expand the space volume for which stellar populations studies, on a star-by-star basis, will be feasible. As a matter of fact, in the Local Group we are forced to limit our studies to a couple of giants spirals, a dwarf spiral, a dwarf elliptical, and several dwarf spheroidals and irregulars. Moreover, the fact that the Local Group is a small ensemble of galaxies does not tell us too much on the effects of the environment on the stellar populations, especially in presence of major merging events. This means that, with MAORY+MICADO, we can probe the stellar populations over a variety of galactic morphological types and in a variety of environments. However, the AO loop can be closed only when bright enough stars are close to the area under investigation. This means that, since the expected sky coverage of the MCAO at the typical Galactic coordinates of the Virgo and of the Fornax clusters is of the order of 50%, only ~ 50% of the galaxies have close foreground stars that can be used for the AO loop. The simple idea that we propose is to use possible supernovae (regardless of the type), as bright reference stars to make available the SCAO mode for galaxies where no MCAO is feasible, because of the lack of bright foreground stars.

XXX IAU General Assembly | ACV - Austria Center Vienna  | Bruno-Kreisky-Platz 1  | 1220 Vienna