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Niusha Ahvazi : The role of dwarf galaxies as progenitors of the intra-cluster light in galaxy groups and clusters

Deep observations by JWST and Euclid will be fundamental to constrain the properties of the diffuse intra-cluster light, offering a window to extend stellar-halo science into the more massive and active environments of groups and clusters. These results have the potential to constrain cosmology and galaxy formation models, which are currently not tuned to reproduce observables of this type. We use the cosmological hydrodynamical simulation TNG50 complemented with a globular cluster catalog to explore the predicted amount of light, age/metallicity and radial distribution of the stars and globular clusters in the intra-cluster and intra-group component. Contrary to what is expected, we find that dwarf galaxies have a wide range of relevance as builders of the intra-cluster and intra-group component, with some systems showing negligible contribution from galaxies with M⋆ < 10^9 M⊙ , while in others they contribute about half of the intra-group material. We determine which observables can be used to reconstruct this feature of the assembly history that might be applicable to upcoming deep observations.


Refath Bari : Detecting Molecular Nitrogen in Water World Atmospheres

Exoplanets with a few percent water mass fraction may have a high-pressure ice mantle, separating the rocky interior from the atmosphere. We investigate the role played by this layer in the transport of molecular Nitrogen between the interior and atmosphere. We find that molecular nitrogen has a negative free energy of mixing with water at 2.5 GPa and 383.5 K, consistent with pressure-temperature domains of small water worlds. We present various means of validating our findings by observation via ELTs. 


James Bullock : The physics of disk galaxy formation over cosmic time

Using FIRE-2 cosmological simulations, I discuss the physical drivers of disk galaxy formation and the emergence of thin disk galaxies over cosmic time.  We see three phases of growth for Milky-Way size disk galaxies: 1) an early, chaotic pre-disk phase, where bursty star formation is dominant; 2) a clumpy, bursty, thick-disk phase where angular momentum begins to build up; and 3) a steady, highly coherent thin-disk phase, ushered in by the emergence of a virialized CGM.  The physics that enables disk formation can be tested with JWST and ELTs in concert and this will inform modern theories of feedback and galaxy formation. 


Jeff Cooke : The high utility of z ~ 2 - 20 supernovae

Core-collapse supernovae are very luminous in the rest-frame UV and can be detected to very high redshift (z ~ 2 - 20) with deep optical and infrared surveys (e.g., HSC, Roman, JWST, including long-term programs). The rest-frame UV is probed in the observed-frame optical and even out to long IR wavelengths for the highest redshift events. The class of superluminous supernovae can be detected to z ~ 20, probing the deaths of the very first stars formed after the Big Bang, and include the long sought-after pair instability supernovae. I will discuss high utility of high-redshift supernovae in many areas of stellar and galaxy formation and evolution research, reionization, IGM and CGM absorption-line studies, cosmology, high energy and compact object physics, and other areas. In addition, I will also describe the necessary roles of ELTs and JWST in confirmation, classification, and characterization of supernovae, including the need for z ~ 2-6 events to inform detections at z > 7.


Tuan Do : Envisioning the next decade of Galactic center science with JWST and ELTs

As the closest example of a galactic nucleus, the Galactic center (GC) presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environment. I will describe several exciting new research directions that, over the next 10 years, hold the potential to answer some of the biggest scientific questions raised in recent decades: Is General Relativity (GR) the correct description for supermassive black holes? What is the nature of star formation in extreme environments? How do stars and compact objects dynamically interact with the supermassive black hole? What physical processes drive gas accretion in low-luminosity black holes? I will discuss how the current observations of the Galactic center with Keck and JWST will address these questions and how the increased sensitivity, angular resolution, and astrometric precision offered by ELTs with adaptive optics will transform Galactic center science. 


René Doyon : Atmospheric Characterization of Temperate Rocky Exoplanets – A JWST and ELT Perspective

The first year of JWST observations have confirmed the incredible power of this observatory for probing the atmosphere of exoplanets of all types, from hot Jupiters to temperate rocky planets, through emission and transmission spectroscopy. These results also underscore the challenge of stellar activity that can severely contaminate transmission spectra of K and M dwarfs. I will share recent results from a reconnaissance transmission spectroscopy program with JWST focused on some Trappist-1 planets and discuss their implications for subsequent in-depth characterization efforts. Additionally, I will briefly present detailed simulations of the ANDES instrument on the upcoming European Extremely Large Telescope, more specifically its bio-signature detection capability for the nearest non-transiting habitable worlds observed in reflected light through a combination of high-contrast imaging and high-dispersion spectroscopy.


Christophe Dumas : JWST/TMT synergy and complementarity for solar system observations

The large number of accepted JWST solar system programs, and the breadth of their investigation, from the composition and/or activity of small bodies to the composition, dynamics and monitoring of giant planet atmospheres, illustrate the formidable advances expected in these fields, thanks to the remarkable sensitivity and image quality provided by a large space telescope operating at near/mid-infrared wavelengths.  In this talk, I’ll review some of the anticipated/early results from these programs and will present the complementary and advanced capabilities that an Extremely Large Telescope such as the Thirty Meter Telescope, equipped with state-of-the-art diffraction limited instrumentation as early as “first light”, will offer to the community of planetary scientists for studying, with unequaled details, the bodies of our solar system. 


Ryan Endsley : Building a Detailed Picture of Reionization by Targeting UV-bright z>6 Galaxies with ELTs

The first year of JWST has completely revolutionized our understanding of UV-bright reionization-era galaxies, opening the door for continued advancements with upcoming ELTs. UV-bright (Muv < -20) z~6-9 galaxies are now known to power much higher EW rest-optical nebular emission lines (e.g., [OIII] and H-alpha) relative to their fainter counterparts. This result implies that UV-bright systems at z>6 are often in a burst phase of star formation, meaning their light is dominated by O stars which greatly boost their UV-light to mass ratios and ionizing photon production efficiencies. In this talk, we will discuss how targeted ELT follow-up of early UV-bright galaxies will be crucial to building a detailed understanding of cosmic hydrogen reionization, particularly as Roman delivers much larger samples of these systems. We will discuss how rest-UV absorption line spectroscopy with ELTs will provide much-needed statistical constraints on the ionizing photon escape fractions (f_esc) of UV-bright z>6 galaxies, and hence their average contribution to reionization. Combined constraints on f_esc for individual UV-bright z>6 galaxies in known ionized bubbles (from Lyman-alpha and 21cm results) will also enable detailed studies on how these systems modulate the morphology and residual neutral hydrogen content within their host bubbles. Moreover, because the light from early UV-bright galaxies is often heavily dominated by recently-formed O stars, they are ideal laboratories to characterize the ionizing spectra of early star-forming systems. Deep rest-UV spectroscopy with ELTs will probe several nebular emission lines spanning low (~10 eV) to very high (~75 eV) ionization potentials, thereby revealing the shape of the ionizing spectra from metal-poor massive stars that are often thought to be the source of reionization.


Wen-fai Fong : The Race to Find Photons from Gravitational Wave Sources and Gamma-ray Bursts in the ELT Era

I will briefly review how JWST has been used to study gamma-ray bursts and multi-messenger gravitational wave sources (e.g., neutron star mergers), largely enabled largely by Target-of-Opportunity observations. I will then discuss how Target-of-Opportunity is a critical piece to incorporate in ELT operations, and present some of the exciting multi-messenger science enabled by being able to re-point these facilities on a variety of timescales.


Kevin Hardegree-Ullman : Bioverse and the Prospects for Observing Biosignatures with JWST and the ELTs

JWST is enabling exoplanet atmospheric study in unprecedented detail, and it will tell us which, if any, nearby transiting rocky planets have atmospheres. Systems with habitable zone planets, like TRAPPIST-1, are of particular interest due to the prospect of biosignatures. Detection of several different biosignatures will be crucial to rule out the possibility of abiotic production. Recent studies have concluded JWST should be able to detect certain biosignatures such as CO2 and CH4 under the right exoplanet atmospheric conditions, but key biosignatures such as O2 will not be detectable. The collecting area, sensitivity, and wavelength coverage afforded by the ELTs make them the perfect platform to complement observations with JWST and can significantly increase our ability to detect biosignatures. We developed Bioverse, an open-source modular framework to simulate surveys, test hypotheses, and perform trade studies to assess the capabilities of upcoming and future facilities to detect exoplanet features such as biosignatures and address population-level questions. Our recent Bioverse simulations for both transmission and reflected light spectroscopy with the ELTs go beyond previous studies and account for constraints such as planet occurrence rates, relative system velocities, and target observability. I will present our new simulations, which predict whether or not Earth-like levels of O2 could be probed on Earth-sized exoplanets within 20 pc of the Sun, including the TRAPPIST-1 system. Bioverse, and the new capabilities added by our project, now enables realistic, systematic assessment of which hypotheses about habitable exoplanet atmospheres will be testable by joint constraints from JWST and the ELTs.


Santosh Harish : First look at the 7.7um JWST/MIRI sources in the COSMOS-Web

COSMOS-Web is the largest JWST Cycle 1 Guest Observer program, both in terms of contiguous area on the sky and total prime time allocation, which will image the COSMOS field at near- and mid-infrared wavelengths, adding on to the existing rich, multi-wavelength observations in this region. Roughly half of the program has been observed to date and here we present an overview of the MIRI F770W observations and reductions using the JWST Science Calibration Pipeline including additional steps for an improved reduction. We also present 5-sigma depths as well as number count estimates based on the current MIRI coverage, and a comparison with the Spitzer/IRAC CH4 observations for bright sources in the field. Owing to a wide area coverage, we also identify several candidate MIRI-only sources across the field. In addition, preliminary efforts on the selection and characterization of extreme emission line galaxies at high redshifts (z>6) will also be presented.


Matthew Hosek : "Star Formation in Extreme Environments: The Stellar Initial Mass Function at the Galactic Center with JWST and Future ELTs "

The Milky Way Galactic Center (GC) offers a unique opportunity to study star formation at high resolution within a galactic nucleus. One fundamental question is how the stellar Initial Mass Function (IMF) behaves in the starburst-like environment of the region, offering key insight into star formation physics as well as our understanding of stellar populations and their by-products. We present preliminary results from JWST observations of young star clusters near the GC, which build upon previous studies indicating that the IMFs of these clusters are systematically different than those in the galactic disk. We also discuss tremendous potential of ELTs in studying the IMF at the GC (and beyond!), as these facilities may allow us to resolve sources in these young clusters down to the brown dwarf regime.


Yuzo Ishikawa : Advancing dual quasars science at cosmic noon and beyond with ELTs: spatially resolved observations with JWST and ALMA

Galaxy mergers play a crucial role in the buildup of galaxies and their supermassive black holes (SMBHs), yet the merger-connection to the galaxy-SMBH co-evolution model remain elusive. There has been long interest in understanding the evolution and fate of two SMBHs in a galaxy merger. And mergers are often invoked as an important path to fuel and form SMBH pairs, which eventually further spiral into the center of the merger remnant to form a binary until coalescence. Actively accreting SMBH pairs are observed as a dual quasar, yet the properties of dual quasars and their host galaxies during the inspiral process are poorly understood. For example, it is unknown how dual quasars are activated and whether they contribute to the feedback observed in massive hosts. Furthermore, critical observations of the different evolutionary stages, marked by their separation distances, are scarce; only over the past decade, dual quasars have been detected at kpc-/galaxy-scale separations, mostly at low redshifts. One of the biggest challenge in identifying and characterizing close-separation quasars at even higher redshifts is the ability to detect and spatially resolve the pairs. Using a novel astrometric selection technique, we have identified several dual quasar candidates at sub-arcsec separations at cosmic noon, yet follow-up studies remain a challenge, requiring the best space-based (HST and JWST) and ground-based (Keck and ALMA) facilities to detect the quasars and their hosts. The unprecedented NIR sensitivity, spatial resolution, and spectral coverage of JWST allows us for the first time to determine the properties of dual quasars and their hosts at cosmic noon. With JWST IFU, we measure the kinematics and ionization of the gas in the host galaxy and refine the quasar spectra. We discover that some dual quasars have very similar SMBH accretion properties, suggesting a possible symbiotic growth, and that some may be hosted by a single disk galaxy, which calls into question the conventional idea of a merger-driven formation of dual quasars. Finally, ALMA reveals large reservoirs of molecular gas that fuel the quasar and galaxy. These discoveries were only possible with the sensitivity and angular resolution of JWST and ALMA. However, we require many more follow-ups known candidates. ELTs will be groundbreaking in uncovering the properties close-separation dual quasars to better understand their formation and evolution.


Joseph Jensen : Building an Independent Distance Ladder for Early-type Galaxies with HST, JWST, and ELT

The persistent discrepancy between the Hubble constant as measured using luminosity distances and that inferred from the cosmic microwave background and CDM cosmological model requires multiple tests using independent techniques to determine where our understanding is incomplete. Our team is establishing an independent distance ladder based on the tip of the red giant branch (TRGB) and surface brightness fluctuations (SBF) to compare to the current gold-standard Cepheid and type Ia supernova (SN) ladder. Our new ladder is based entirely on old stellar populations in early-type galaxies and has comparable precision to the SN measurements. Cycle 2 JWST observations of 14 nearby elliptical galaxies will be used to establish a direct link between TRGB and SBF, and will set the zero point of the SBF distance scale. More than 100 SBF distances good to <5% per galaxy are being efficiently measured out to 100 Mpc using HST, and JWST can be used to triple that distance limit. Next-generation Multi-conjugate Adaptive Optics (MCAO) on an ELT will make SBF distance measurements possible that can be directly compared to the SN and independently determine the Hubble constant without any reliance on Cepheids or SN. 


Justin Kader : Mapping Multi-scale AGN Outflows with Keck+JWST

It is now widely understood that energetic feedback from starbursts and active galactic nuclei (AGN) has a significant impact on galaxy evolution by removing star-forming gas from the galaxy and by preventing gas from cooling to form stars. AGN are of particular interest because of the high incidence of active galaxies at cosmic noon, and their ability to drive large-scale feedback over long timescales. However, it is still not clear which properties of the central engine and host galaxy control the feedback efficiency to couple energetically to the ISM, prompting a need for wide-field, multi-wavelength observations of AGN-driven outflows. Our program combines integral field unit observations in the optical from Keck/KCWI and in the mid-infrared from JWST, as well as archival multi-wavelength datasets, to map the full extent of multi-phase (ionized, neutral, and molecular gas) AGN outflows from the central kpc region out to tens of kpc in a sample of local (ultra-)luminous infrared galaxies (ULIRGs), which are likely local analogues of star-forming active galaxies at cosmic noon. Here we present the first results from our program, showcasing the stunning activity discovered in the nearby LIRG, VV 340N. The JWST mid-infrared spectroscopy reveals an extraordinarily elongated and collimated, high velocity coronal line outflow, extending at least 3 kpc beyond the central AGN. Ground-based Keck optical spectroscopy unveils a pair of galactic-scale filamentary nebulae, aligned with the coronal line outflow but extending much farther into the galactic halo. VLA radio continuum imaging shows for the first time a pair of narrow kpc-scale synchrotron jets emanating from the AGN and forming a symmetric S-shape, strongly indicating AGN jet precession. The multi-wavelength observations, when taken together, suggest a galactic-scale ionized outflow driven by the precessing radio jet, removing star forming gas, heating the ISM to prevent the formation of molecular clumps, and possibly suppressing cooling flows from the CGM. This pilot study is especially timely in the era leading up to the advent of ELTs, and highlights their unique potential to provide diffraction-limited observations of unrivaled sensitivity to uncover galactic-scale outflows that bridge the central supermassive black hole to the cosmic web.


Jeyhan Kartaltepe : Lessons in Galaxy Evolution from the First Year of JWST Observations

One of the stunning surprises from JWST's first year of observations of the extragalactic sky is that not only are we detecting large numbers of galaxies in the early universe but that many of these galaxies are resolved and show great structural detail.  In this presentation, I will highlight some of the first (often surprising) results from JWST in the area of galaxy evolution, including the detection of galaxies in the early universe, the evolution of their luminosity functions, and what we know about their structures. These findings have important implications for the role that ELTs will play in unraveling how galaxies have evolved over cosmic time.


Shawn Knabel : Cosmology through spatially resolved stellar kinematics of strong lensing galaxies: from Keck to JWST to ELTs

We present dynamical analyses of strong lensing galaxies utilizing spatially resolved stellar kinematics measured with state-of-the-art ground-based optical integral field unit (IFU) spectroscopy from Keck Cosmic Web Imager (KCWI). We demonstrate the remarkable capability of spatially resolved kinematics to constrain the mass profiles and orbital anisotropy of early-type galaxies and the power it lends to cosmological measurements using time-delay cosmography of quadruply lensed quasars, particularly the Hubble constant. We show first results from a JWST NIRSPEC-IFU program. In the next decade orders of magnitude increases in the sample of lensed quasars and supernovae are expected from Euclid, Rubin, Roman. We argue that ELTs will be transformative by obtaining stellar kinematics of those systems and enabling high precision and accuracy in cosmological measurements.


Danial Langeroodi : Correlation between compactness and metal-deficiency in high-redshift galaxies

Recent NIRSpec observations indicate that z > 4 galaxies are more metal deficient than expected for their stellar masses and star-formation rates if the local Universe calibration of the fundamental metallicity relation (FMR) is adopted. There is growing evidence that this metal deficiency correlates with galaxy compactness: the most compact galaxies are also the most metal-poor. In this talk, I share our results based on the largest compilation of NIRSpec prism data consisting of 600+ galaxies at z > 4. I present the gas-phase metallicity measurements of this sample, showing their redshift-evolving offset from the local Universe calibration of the FMR: the higher redshift galaxies are on average more offset from the FMR, and hence more metal-poor than expected. I present the mass-size relation and its redshift evolution as inferred from the NIRCam imaging of this spectroscopically confirmed sample, and show that compactness can be used as a strong tracer of metal deficiency. I discuss how these findings provide evidence for the inside-out growth of galaxies as well as the stochastic star formation in higher redshift/lower stellar mass systems. The smallest galaxies in this sample remain spatially unresolved even in the high spatial resolution NIRCam short-wavelength filters. The upcoming class of ELTs will allow size measurements of lower stellar mass and higher redshift galaxies, and probe a more nascent stage of early gas-infall, star formation, and galaxy evolution. 


Zhaoran Liu : JWST, Subaru and the ELT Era

In this presentation, I will present two individual studies conducted by space telescope JWST and ground-based Subaru Telescope, to discuss about the how to prepare for the ELT era. Our target for Subaru Telescope is a z=0.9 supercluster, this large-scale structure could be efficiently observed thanks to the large FoV of Subaru, we conduct pair narrow-band survey across this LSSs to catch the Hα + Hβ  emission line, which enables us to measure the Balmer Decrement with only imaging. With ~ 30 hours exposure time in total, we discovered more than 100 emitters in this 50-Mpc scale structure, those emitters and the Balmer Decrement based dust extinction value provide us with valuable insight about the physical processes that determine the properties of the galaxy populations as a function of environment.  Notably, this study underscores the unique advantages of specialized narrow-band techniques in expediting scientific endeavors, highlighting the critical role such methods will play in the ELT era. In parallel, with the public available JWST data in SMACS0723 field, we develop a new algorithm to decompose the dust and stellar components of individual galaxies. Utilizing MIRI and NIRCam imaging, we probed the fine-scale morphologies of these components, revealing intriguing phenomena that shed light on bulge growth and the complex dynamics underlying the inside-out quenching process. These in-depth galaxy studies offer essential insights into the 'inside' story of galaxy evolution. These studies provide a glimpse of the possibilities the ELT era holds. ELTs, as ground-based telescope, are poised to redefine observational astronomy. Offering the flexibility to customize narrow and medium filters to suit a range of scientific objectives anytime, combined with the AO systems that deliver space telescope-level resolution, ELT promise to bridge the gap between the panoramic view of the cosmic web and the intricate narratives embedded within individual galaxies.


Christian Marois : Toward Imaging Rocky Exoplanets with TMT, From Validating Focal Plane WFS technologies on 8-m telescopes, to the Development of “Ultra Fast” Adaptive Optics Systems

Facility-class high-contrast exoplanet imaging systems are currently limited by non-common path quasi-static speckles. Due to these aberrations, the raw contrast saturates after a few seconds. Several active wavefront correction techniques have been developed to remove this noise, with limited successes, with existing ExAO systems currently relying mostly on clever observing techniques and post-processing methods to gain contrast with integration time. To prepare the development of facility-class extreme of systems for TMT, the NRC Canada is funding two projects, the SPIDERS pathfinder at the Subaru telescope (ETA 2024), and the CAL2 upgrade of the Gemini Planet Imager-2 (ETA 2025), to deploy a modified self-coherent camera (SCC, based on the FAST coronagraph) to measure the focal plane electric field, and to apply wavefront corrections in closed loop down to 10s of ms in a narrow band. The CAL2 project will focus at developing a facility-class focal plane & Lyot-based low-order sensors using a CRED2 and a SAPHIRA-based camera, reaching up to a gain of 100x in contrast for bright stars. The SPIDERS pathfinder will have a similar configuration with the addition of an imaging Fourier Transform spectrograph, allowing the acquisition of a 3.5” diagonal FOV to up to R-20,000 in the NIR to perform advanced spectral differential imaging at high-spectral resolution to search and characterize exoplanets. These projects will serve as the foundation to develop similar systems for TMT, and be an important step toward the development of instruments to search for life signatures in the atmosphere of rocky exoplanets. In this presentation, I will showcase both projects, their scope, their timeline, and simulations of expected performances. I will also showcase NEW EARTH Laboratory results to demonstrate working prototypes. Finally, I will discuss our new concept, STARLITE, that can overcome the star photon noise limit, by using a constellation of a few orbiting space lasers on high eccentric orbits that surround a science target for up to a few hours per transit to generate bright guide stars. The concept will open up a new regime for ground-based adaptive optics, and allow the development of Ultra Fast Adaptive Optics (UFAO) systems. STARLITE will allow >10KHz high SNR WFS systems to possibly reach 10E10 contrast in a few hours of integration in a <1% narrowband on/off the 760nm Oxygen line on the nearest Sun-like stars. STARLITE and TMT will be able to perform an initial campaign to find rocky exoplanets with O2 detections for future broadband follow-ups from space.


Dimitri Mawet : MODHIS (Multi-Objective Diffraction-limited High-resolution Infrared Spectrograph

MODHIS (Multi-Objective Diffraction-limited High-resolution Infrared Spectrograph) is an infrared (0.98 to 2.46 microns) cross-dispersed, R=100,000 single-mode fiber-fed diffraction-limited echellette spectrograph for the Thirty Meter Telescope. MODHIS is optimized for TMT's first-light AO system NFIRAOS and will provide compelling science capabilities from exoplanet atmosphere characterization through both transit and direct high-contrast spectroscopy, to detection and mass measurements through infrared precision radial velocity (RV). The science cases include the precise RV measurements of stars orbiting the Galactic Center, Solar System studies, and the chemodynamical history of nearby dwarf galaxies and the galactic halo. I will discuss complementarities between low/medium-resolution infrared studies of exoplanets with JWST and the unique capabilities brought forth by TMT's exquisite angular resolution and the high resolving power of MODHIS. These include: molecular characterization of minor species even in the presence of clouds/hazes, Doppler measurements, and unprecedented inner working angle.


Kristen McQuinn : Resolved Stellar Populations Studies with the JWST

The study of resolved stellar populations in nearby galaxies was transformed by the high sensitivity and spatial resolution of the Hubble Space Telescope (HST), and is now being transformed again with the more powerful James Webb Space Telescope (JWST). The results have far-reaching implications ranging from providing the most detailed and quantitative measures of the star formation histories of low-mass galaxies and insights into their growth across cosmic timescales, to determining precise distances to galaxies which are essential inputs for measuring the Hubble Constant. In this talk, I will highlight recent results from resolved star studies from these two great space observatories and showcase some of what will become possible in the era of ELTs.


Benjamin Metha : Geostatistics of Galaxies -- Making the most of metallicity maps

The metallicity of a galaxy is set by its gas-phase physics: how is metal-poor gas accreting into a galaxy, how often are stars born, and how well are the products of star-formation mixed into their local environments? With data from high-resolution spectroscopic surveys, we can see that galaxies in the local Universe show significant deviations in metallicity from a simple linear trend, allowing us to directly see local metallicity enrichment and dilution events on scales below 100pc. In this talk, I introduce geostatistics, a family of mathematical tools and techniques that are useful for creating 2D predictive models of a galaxy’s metallicity structure from noisy, incomplete data. I discuss the challenges associated with applying these methods to high-redshift galaxies recently observed by JWST, and introduce a publicly available forward-modelling tool that can be used to overcome these issues, allowing details the baryon cycle at cosmic noon to be revealed.


Pritom Mozumdar : A MUSE-HST synergy to probe galaxy morphology and Hubble constant in the era of ELT-JWST

Investigations of early-type galaxies at intermediate redshift provide valuable insights into galaxy evolution and cosmological parameters such as the Hubble constant. We have used a sample of approximately 200 early-type galaxies within the redshift range 0.25-0.9 to probe the redshift evolution and possible impact of the environment on critical galaxy properties such as total density slope and kinematic anisotropy. For these galaxies we employed Jeans dynamical modeling using resolved kinematics from Multi Unit Spectroscopic Explorer (MUSE) spectroscopy in combination with Hubble Space Telescope (HST) imagery. Besides,  the resulting inferences on the properties of massive galaxies will be incorporated into a Bayesian hierarchical framework to infer the Hubble constant from time-delay gravitational lenses with higher precision. With the advent of the James Webb Space Telescope (JWST) and Extremely Large Telescope (ELT), this sample size could be expanded significantly, with an unprecedented combination of angular resolution and sensitivity. This MUSE-HST synergy provides an excellent precursor for what could be achieved from joint analyses of ELT and JWST data.


Camryn Mullin : Direct Imaging of YSOs: Observing five circumstellar disks to search for forming planets

Planets form in circumstellar disks around young stellar objects (YSOs). Several circumstellar disks have observed substructure such as rings, gaps, and spiral arms, suggesting candidate protoplanet companions. Direct observations of protoplanets are crucial to test fundamental planet formation theories – filling in the gap between disk morphology and exoplanet demographics.  In our Guaranteed Time Observation program “Direct Imaging of YSOs” (PID 1179), we used JWST/NIRCam to gather images of five circumstellar disks. We utilized four filters; two for observing spectral line emission (F187N, F405N), and two for continuum emission (F200W, F410M). These five targets were selected for their compelling evidence of companion-induced morphologies: spiral arms (MWC758 and SAO206462), rings and gaps (HLTau and TWHya), and previous confirmed protoplanet detections (PDS-70). JWST has unparalleled sensitivity when compared to ground-based imaging, which is vital in our observations of outer disk regions where the companions are predicted to lie.  For each target, we resolved disk structures and searched for candidate planets. In our two spiral targets, we resolved the spiral arms and explored the possibility of them being planet driven. We obtained high-resolution images of HLTau’s envelope and outflow, previously observed from a wider field of view with Hubble. With JWST’s exquisite sensitivity, we reached the deepest limits observed for MWC758 and SAO206462, allowing us to probe as low as 1 MJup within the highly obscured circumstellar environment. These results from our five targets further our understanding of planet-driven disk morphology, and planet formation and evolution. 


Anna Nierenberg : Measuring the properties of dark matter with JWST and ELTs

The relative brightnesses of gravitationally lensed quasar images are directly sensitive to the presence of low-mass dark matter halos at cosmological distances. Measurements of these systems have enabled some of the strongest constraints to date on a variety of dark matter models. ELTs and JWST can detect complementary emission regions of different sizes from strongly lensed quasars, making it possible to gain significant additional information by separating lensing mass scales. I will show that by combining information from both ELTs and JWST, we will be able to place new constraints on a broad range of dark matter models including self-interacing, fuzzy, warm, and primordial black hole dark matter.


Zixuan Peng : Using KCWI to Explore the Chemical Evolution and Feedback in a Reionization-era Spectral Analog J1044+0353

JWST will directly observe the early assembly of dwarf galaxies during the Epoch of Reionization. A significant challenge is understanding how galactic winds develop in these highly irregular dwarf galaxies. These winds are important for understanding the escape of Lyman continuum radiation from ultradense, star-forming regions, reionizing the IGM (intergalactic medium), and the dispersal of heavy metals into the IGM, contributing to the next generations of galaxy formations. We study J1044+0353, a Reionization-era spectral local analog, to shed light on the feedback and chemical evolution in high-redshift dwarf galaxies. We use integral field spectroscopy to trace the propagation of the starburst across this small galaxy using Balmer emission- and absorption-line equivalent widths and find a post-starburst population (~ 15 - 20 Myr) roughly one kpc east of the much younger, compact starburst (~ 3 - 4 Myr). We map the Doppler shift and width of the strong emission lines. Over scales several times the size of the galaxy, we discover a velocity gradient parallel to the galaxy’s minor axis. The steepest gradients (~ 30 km/s/kpc) appear to emanate from the post-starburst population. We identify the velocity gradient as an outflow viewed edge-on based on the increased line width and skew in a biconical region. Notably, even in the immediate vicinity of the youngest clusters (in the compact starburst), we find evidence for supernova feedback: ionized shells (300 - 400 pc across) and broad wings on the [O III] and Hβ emission lines. In the direction of the steepest density gradients, these superbubbles have blown out, and the emission-line spectra show very-broad line wings (FWHM ~ 750 km/s), which we attribute to a nascent galactic wind and compare to models that predict catastrophic cooling rates. In contrast to predictions that supernova feedback comes too late to open pathways for LyC escape, the propagation of the starburst allows supernova from a post-starburst population to contribute to the formation of holes in the surrounding neutral gas reservoir, causing ionizing photons to escape and reionize the intergalactic gas. We discuss how this outflow and the gas inflow necessary to trigger the starburst affect the chemical evolution of J1044+0353. We conclude that a chemical evolution model with a metal-enriched wind requires a more realistic inflow rate than a homogeneous chemical evolution model.


R. Michael Rich : Keck/KCWI studies of Lyman alpha Nebulae at 2<z<3

We present Keck Cosmic Web Imager (KCWI) observations of giant Lyα halos surrounding 9 galaxy group sand clusters at 2 < z < 3.3, including five new detections and one upper limit. We find observational evidence for the cold-stream to hot-accretion transition predicted by theory by measuring a decrease in the ratio between the spatially extended Lyα luminosity and the expected baryonic accretion rate (BAR), with increasing elongation above the transition mass (Mstream). This implies a modulation of the share of BAR that remains cold diminishing quasi-linearly (logarithmic slope of 0.97 ± 0.19, 5σ significance) with the halo to Mstreammass ratio. The integrated star-formation rates (SFRs) and AGN bolometric luminosities display a potentially consistent decrease, albeit significant only at 2.6σ and 1.3σ, respectively. The higher scatter in these tracers suggests the Lyα emission might be mostly a direct product of cold accretion in these structures rather than indirect, mediated by outflows and photo-ionization from SFR and AGNs; this is also supported by energetics considerations. Below M (cold-stream regime) we measure L /BAR = 1040.51±0.16 erg s−1 M−1 yr, stream Lyα ⊙ consistent with predictions, and SFR/BAR= 10−0.54±0.23: on average 30+20% of the cold streams go into stars. −10Above Mstream (hot-accretion regime), LLyα is set by Mstream (within 0.2 dex scatter in our sample), independent of the halo mass but rising tenfold from z = 2 to 3.  


Massimo Ricotti : Resolving star formation into parsec-scale compact star clusters in simulations and observations of strongly lensed galaxies at redshifts 6 to 13: Implications on the origin of old globular clusters and the sources driving cosmic reionization.

I will review theory predictions on the formation of compact star clusters in the first galaxies and JWST observations of strongly lensed galaxies at redshifts >6 showing that star formation indeed appears concentrated in parsec-scale clumps, likely the sites of formation of the progenitors of some old globular clusters. I will discuss the implication on the science enabled by ELT's unprecedented sensitivity and resolution with regard to understanding the physics of star formation in the first galaxies, the origin of old globular clusters and their role as sources of UV radiation driving cosmic reionization.


Laura V. Sales : The origin, evolution and dark matter content of ultradiffuse galaxies

The formation of ultradiffuse galaxies (UDGs) still challenge most theoretical models which seem unable to reconcile the wide range of velocity dispersion and dark matter content inferred for observed UDGs. Deep observations by JWST promise to deliver high-resolution imaging and spectroscopy of these interesting objects, unveiling their stellar populations, chemical compositions, and kinematics. I will summarize the efforts of our team to study the formation of UDGs using the cosmological hydrodynamical simulation Illustris-TNG50. Thanks to the large volume of the simulation, we are able to identify hundreds of UDGs in a wide range of environments, from the field to the core of galaxy clusters. We find that UDGs inhabit dwarf-mass halos and their extended sizes are due to a combination of high spin-parameter and early formation times. I will discuss our theoretical predictions for the stellar populations, star formation history and globular clusters content/kinematics, highlighting a few aspects where models seem in tension with current data.


Peter Senchyna : Intertwined uncertainties in metal-poor massive star populations from z~10 to 0

The first year of JWST data has revolutionized our view of the first luminous galaxies, raising new questions and possibilities in equal measure. The routine detection of high-ionization lines and broad emission components suggests a complex interplay of ionizing radiation from both metal-poor massive stars and accreting black holes; and underscores the difficulty of disentangling these sources. Alongside this, peculiar nebular line ratios in some of these objects suggest early enrichment processes potentially linked to the most ancient structures in the local Universe but that we do not yet fully understand. I will argue that uncertainties in the modeling of massive star populations at extremely low metallicity are likely key to unraveling both of these dilemmas. I will present new results from HST/COS targeting unresolved nearby galaxies dominated by the youngest and most metal-poor stellar populations, which cast new light onto the physical conditions and ionizing sources responsible for prominent line emission at high-redshift. Ultimately, studies of the nearest (semi-)resolved galaxies are crucial for breaking degeneracies and directly calibrating the multiscale physics of massive stars which underlies population synthesis models applied at high-redshift. I will highlight the first results from the HelgI survey, a systematic narrowband search for He II Emission in Local Galaxies with IMACS, which is designed to uncover the sources of the hardest ionizing radiation in resolved metal-poor star-forming galaxies in the Local Group. While much work remains to be done with existing facilities, I will forecast the tremendous potential unlocked by the ELTs with the joint application of AO-assisted IFU observations to star-forming regions in high-redshift galaxies and highly multiplexed spectroscopy to individual stars in our own cosmological backyard.


Warren Skidmore : How Science Cases Influence Observatory Design and Operations

Science cases dictate all design aspects of observatories now in development and dictate the plans for operations. Whether an observatory is developed with a specific goal in mind or is built to be a general purpose facility, science cases guide the technical and operational requirements that design engineers work to fulfill. I describe the processes that are followed to gather science ideas and develop technical and operations requirements, to flow the broad high level requirements down into detailed design requirements, to maintain the traceability from detailed low level requirements through to the original science cases, to manage the requirements when the reality of performance, cost and schedule makes fulfilling those requirements difficult or even impossible. The topic is an important part of Systems Engineering for any major modern science project.


Peter Smith : Stronger Together: Using Synergies Between Ground-Based Telescopes and JWST to Understand Exoplanet Atmospheres

Through spectroscopy of exoplanet atmospheres, we can unlock information about composition, climate, and formation pathways. The two main avenues for this - space-based, low resolution transit spectroscopy and ground-based, high resolution cross-correlation spectroscopy - can provide different, complementary information to each other. By combining the two data types into a joint atmospheric retrieval analysis, we can study exoplanet atmospheres with more inference power and precision than either method could provide alone. Here, I present the first ever combined JWST and ground-based retrieval analyses in two studies of the dayside thermal emission of hot Jupiter WASP-77A b and ultra-hot Jupiter WASP-18 b. Combining NIRSpec/G395 for WASP-77A b or NIRISS/SOSS for WASP-18 b with Gemini South/IGRINS data of both planets improves the constraints on both gas abundances and vertical thermal structure. Given these results, I discuss the power of and potential for joint low and high resolution studies in the era of JWST and eventually the ELT's.


Matt Taylor : Detecting Massive BlackHoles

Globular clusters, nuclear star clusters, ultra-compact dwarfs, and compact elliptical galaxies represent some of the most extreme environments in the universe in terms of central stellar densities. As such, they are valuable laboratories in which to study non-accreting – and thus otherwise invisible – massive black holes (BHs) via their dynamical influence on stars falling within their spheres of influence. To date, only a handful of positive BH detections have been made in similar systems largely due to technical limitations, but their presence (or lack thereof) has important implications for the formation and growth of super-massive BHs over cosmic time. In this talk I will summarize early results from a Cycle 1 JWST program using NIRSpec+IFU to better understand the demographics of such BHs in these systems. Our results represent a pilot program that will significantly expand the sample of known BHs in compact stellar systems in the Virgo galaxy cluster and will inform future large-scale searches in yet further environments not accessible even with JWST. The planned integral-field spectrographs on ground-based ELTs – including that on TMT’s first-light IRIS instrument – thus naturally represents the exciting next step forward in this field.


Quang Tran : The March to Younger Planets through High-Precision Radial Velocities

The presence of close-in giant planets indicates that inward orbital migration is likely a regular phenomenon. However, the processes by which these gas giants arrived at their locations are poorly constrained as radial velocity (RV) surveys have largely avoided young stars. Young stars exhibit intrinsic astrophysical RV "jitter" primarily driven by rotationally-modulated starspots which can overwhelm planetary signals at visible wavelengths. Moving into the near-infrared (NIR) has been shown to reduce this variability. We are carrying out a large precision RV survey of intermediate-age (20-200 Myr) GK dwarfs in young moving groups with the Habitable-zone Planet Finder (HPF), a stabilized high resolution, NIR spectrograph located at the Hobby-Eberly Telescope. The primary goal of this program is to determine the timescale and dominant physical mechanism of giant planet migration by measuring the occurrence rate of warm Jupiters at young ages and comparing this to established frequencies at older ages. In this talk, I will summarize the survey design and initial results, including the first candidate young planets to emerge from this program. Ultimately, the results of this survey will inform multi-wavelength, high cadence, high-precision RV strategies to study planets around young stars with the ELTs.


Hiroya Umeda : First JWST Constraints on the Key Cosmic Reionization Parameters with Lyα Damping Wing Absorptions of Galaxies at z=7-12: Towards the JWSTxELT Era

Lyα damping wing absorption measurement is a useful tool to constrain the key cosmic reionization parameters including volume averaged neutral hydrogen fraction xHI, but the measurement had been limited only to the small number of extremely UV-continuum bright sources such as QSO/GRBs. For the first time, we constrain xHI and ionized bubble radii Rb by measuring Lyα damping wing absorptions using bright galaxy spectra detected in JWST observations. We combine JWST/NIRSpec spectra taken by CEERS, GO-1433, DDT-2750, and JADES programs, and obtain 26 bright (M_UV<-18.5) UV-continuum galaxies at 7 < z < 12. We construct 4 composite spectra binned by redshift and find the clear transition from sharp to soft spectral break towards high redshift at the restframe 1216 Å suggesting the increase of Lyα damping wing absorption. We estimate Lyα damping wing absorption in the galaxy spectra with a state-of-art stellar population synthesis model including Lyα emission and host HI absorptions. Assuming the standard inside-out reionization picture having an ionized bubble with Rb around a galaxy in the inter-galactic medium of xHI, we obtain xHI (Rb) values monotonically increasing (decreasing) trend from xHI = 0.54^{+0.13}_{−0.54} to {0.94}^{+0.06}_{−0.41} (log Rb = {1.89}^{+0.49}_{−1.54} to{−0.72}^{+1.57}_{−0.28} comoving Mpc) at redshift {7.122}^{+0.057}_{−0.077} to {10.28}^{+1.123}_{−1.404}. The redshift evolution of xHI indicates late reionization history consistent with the one suggested from the electron scattering of cosmic microwave background and the evolution of UV luminosity function with an escape fraction correlating with star-formation rate surface density and shallow faint-end slope (α>-2). Our Rb measurements are up to a few dex larger than the cosmic average values estimated by analytic calculations for a given xHI, while our Rb measurements are comparable with the values for merged ionized bubbles around bright galaxies predicted by recent numerical simulations. We discuss the strategy for the future Lyα damping wing research using upcoming JWST and ELT observations. 


Bingjie Wang : Finding the first galaxies behind the lensing cluster Abell 2744

The recent UNCOVER survey with JWST exploits the nearby cluster Abell 2744 to create the deepest view of our universe to date by leveraging strong gravitational lensing. This talk will first present the photometric modeling of more than 50,000 sources, in which redshifts and key stellar population metrics are jointly inferred. This allows us, for the first time, to have a robust inference of the redshift evolution of stellar ages, star formation rates, and rest-frame colors across the full range of 0.2 < z < 15. The new model used, Prospector-beta, and its other scientific applications (e.g., massive galaxies, HST-dark galaxies, and high-z quiescent galaxies) will also be briefly discussed. The second part of the talk will highlight the UNCOVER NIRSpec/Prism observations of two galaxies at z > 12. Detailed stellar population modeling is performed, and the results corroborate the primeval characteristics of these galaxies: low mass (~10^8 solar masses), young, rapidly assembling, metal-poor, and star-forming. Interestingly, both galaxies are spatially resolved, with lensing-corrected rest-UV effective radii on the order of 300–400 pc, which are notably larger than those of many other spectroscopically confirmed z > 10 systems. The observed dynamic range of size at z > 10 spans over an order of magnitude, implying a significant scatter in the size–mass relation at early times. These early data from JWST mark only the beginning of a new census of the early phases of galaxy evolution.


Claire Williams : Lighting up early galaxies through the stream velocity

The James Webb Space Telescope and future ELTs are capable of probing our Universe at extremely high redshift (z>10), when the supersonic relative motions between dark matter and baryonic overdensities modulate structure formation. This “stream velocity” has important implications for early stars and dwarf galaxies, but has remained challenging to incorporate numerically. I will describe our study of low-mass galaxy formation including the stream velocity using high resolution AREPO hydrodynamics simulations, and present theoretical predictions of the UV luminosity function (UVLF) and galaxy stellar mass function (GSMF) for extremely faint and low mass galaxies. I will discuss the mechanisms by which the stream velocity suppresses early star formation while inducing rapid star formation in some larger dwarfs, leading to an enhancement in the faint-end of the UVLF at z = 12. We may be nearing an era where high-z observations can probe the stream velocity as a test of baryonic physics within Lambda-CDM, enabling more robust comparisons with alternative models.


Devon Williams : The First Quadruply Imaged Quasar Modeled with JWST Imaging: WFI2033 - 4723

While gravitational time delays provide a measurement of H_0 independent of other probes, one limitation of this measurement is the accuracy of the lens models. Many efforts have been made to reduce the computational and investigator time required to model these systems, with the goal being increasing the number of modeled systems to rein in the uncertainty in H_0. However, another way to drop this uncertainty is by using higher resolution imaging to directly increase the accuracy and precision of the modeled parameters while also reducing their systematic uncertainties. Previously this was not something readily obtainable, however the recent launch of JWST allows for unparalleled imaging of these lensed systems. One such system is the gravitationally-lensed quadruply-imaged quasar WFI2033 - 4723, whose updated lens model parameters we present. This study demonstrates techniques and methods that will be crucial to harness the power of ELTs superior sensitivity and angular resolution to further improve the precision and accuracy of time delay cosmography.


Yi Xu : Stellar and AGN Feedback Probed with Outflows in JWST Galaxies at z=3-9: Implications of Frequent Nearly-Spherical Galactic Fountains

We study outflows in 180 galaxies with -16<M_UV<-22 at z=3-9 identified in JWST NIRSpec and NIRCam WFSS data taken by the CEERS, FRESCO, GLASS, and JADES programs. We identify 37 out of the 180 galaxies with broad components of FWHM~150-800 km/s in the emission lines of Hα and [OIII]λ5007 that trace ionized outflows. Four out of the 37 outflowing galaxies are Type 1 AGNs whose Hα emission lines include line profile components as broad as FWHM>1000 km/s. With the velocity shift and line widths of the outflow broad lines, we obtain ~80-500 km/s for the outflow velocities. We find that the outflow velocities as a function of star-formation rate are comparable to or higher than those of galaxies at z~1, accounting for the selection bias raised by the spectral resolutions and signal-to-noise ratios, while the outflow velocities of AGN are large but not significantly different from the others. Interestingly, these outflow velocities are typically not high enough to escape from the galactic potentials, suggestive of fountain-type outflows, which are concluded on the basis of thorough comparisons with recent JWST results. We estimate mass loading factors to be η=0.1-1 that are not particularly large, but comparable with those of z~1 outflows. The large fraction of galaxies with outflows (37 out of 180 galaxies) provides constraints on outflow parameters, suggesting a wide opening angle of >45 deg and a large duty-cycle of >30%, which gives a picture of frequent and nearly-spherical outflows in high-z galaxies.  The upcoming JWST and ELT observations will reveal the details of stellar and AGN feedback in the early universe probed by multiphase outflows with different ionized state gas.


Yongda Zhu : Constraining Cosmic Reionization in the ELT Era: Direct Measurements of Ionizing Photon Mean Free Path

The mean free path of ionizing photons (MFP) is a key indicator of the intergalactic medium during the epoch of reionization. I will present direct measurements of the MFP from QSO spectra over the redshift range 5<z<6, including the first measurements at z~5.3 and 5.6. The sample includes data from the XQR-30 VLT large program, as well as new Keck/ESI observations of QSOs near z~5.5, for which we also acquired new [CII] 158μm redshifts with ALMA. I will discuss the results as well as the implications on the timing of reionization. This study also potentially provides new insights into the formation and evolution of galaxies and neutral hydrogen in the early universe. Finally, I will discuss the robustness of absorption lines in QSO spectra for constraining cosmic reionization as well as the formation and evolution of early galaxies in the ELT era.



David Andersen (George Jacoby) : TMT Instrument Group Leader

The TMT first light instrument suite were chosen to provide a wide range of scientific capabilities.  The InfraRed Imaging Spectrograph (IRIS) will yield near diffraction-limited imaging over a 34 x 34 sq arcsec FOV and integral field spectroscopy with a variety of angular and spectral resolutions from R=3000-10000.  The Multi-Objective High Dispersion Infrared Spectrograph (MODHIS) will provide resolution 100,000 spectroscopy for a single target with an internal velocity resolution better than 30 cm/s from 0.98-2.45 microns.  Both IRIS and MODHIS are fed Multi-Conjugate Adaptive Optics corrected light from the Narrow-Field Infrared Adaptive Optics System (NFIRAOS).  Finally, the Wide Field Optical Spectrograph is capable of imaging or multi-object slit spectroscopy over a 8x3 square arcmin FOV. It is capable of providing 100% spectral coverage from 0.31-1.05 microns at R=1500. Spectral resolutions of up to R=5000 with seeing-limited slits will be achieved with less spectral coverage.  In this paper, I will present the key capabilities and performance budgets for NFIRAOS, IRIS, MODHIS and WFOS.


Wako Aoki : First stars and early chemical evolution explored from Milky Way stars

JWST’s observations of most distant galaxies are revealing formation of the first stars and their impact on the reionization, evolution of galaxies etc. An alternative approach to study the very early stages of star and galaxy formation is to determine chemical composition and kinematics of early generations of stars in the Milky Way and its satellite galaxies. Recent large surveys of metal-deficient stars combined with astrometry with Gaia provide useful constraints on the mass distribution of first stars, early chemical evolution of the universe, and origins of elements heavier than iron. This paper reports on our recent findings from large survey with LAMOST and follow up studies with the Subaru Telescope, and discuss problems to be solved in the ELT era. 


Nuo Chen : Abundance of compact [OIII] emission-line regions (Green Beans) in Hα emitters at z∼2.3 with JWST JADES Observations

We present a rest-frame optical morphological studies of 113 Hα emitters (HAEs) at z = 2.1−2.5 in the ZFOURGE-CDFS field from JADES JWST/NIRCam imaging. The ultra-deep, high-resolution, NIRCam data enable us to take a first look at the emission-line morphology of HAEs from 10^8M⊙  to 10^10 M ⊙ . We have made an emission-line map of each HAEs from flux excess in the F150W filter, and discover a large population of compact [OIII] emission-line regions (“Green beans”), which are similar to so-called “Green Pea” galaxies in the local universe. We have identified 72 Green beans with EW [OIII] > 300A from nearly 50 HAEs and 20 of the green beans have extremely large EW [OIII] > 1000A. Furthermore, we investigate their relationship to the physical properties of their host galaxies, such as the stellar mass (M∗), star formation rate (SFR). We speculate that some of these regions are possibly the original birthplace of global cluster or intermediate-mass black holes (IMBHs).


Daisuke Iono : High Resolution Imaging of Distant Massive Galaxies

The brightest star-forming galaxies are the most probable ancestors of the massive galaxies that dominate the central regions of clusters we see today. Mergers or large-scale gas inflow in isolated disks are possible scenarios explaining the observed large star formation rate, but the exact triggering mechanism is unclear, mainly due to insufficient high-resolution observational data to draw a general conclusion. To address this problem, we are currently studying the spatial distribution of a statistically significant sample of unlensed bright galaxies at < 0.1” resolution using ALMA and JWST. We present the overall science goal of this program and a preliminary analysis of the early and existing data, as well as prospects of synergies with the ELTs.


Preethi Karpoor : Advancing Precision RV Reconnaissance Spectroscopy with MODHIS on TMT for Super-Earths around Very-Low-Mass Stars detected by TESS : Prospects

While recent years have seen a significant expansion in our knowledge of exoplanet demographics, numerous fundamental questions persist regarding their formation, evolution, composition, and potential habitability. We also know M dwarfs are the most abundant stars in our Galaxy and have been shown to host the majority of Earth-size planets. However, the peak occurrence rate for such planets as a function of host mass is still an ongoing study requiring larger samples which will enable robust statistical constraints.  The focal point of recent exoplanet research has predominantly encompassed photometric analyses and low-resolution spectroscopic methods. The ascendance of high-resolution spectroscopy, characterized by resolutions of around R∼100,000, has emerged as a transformative tool, enriching our understanding of exoplanets in ways distinct from the observations conducted by space telescopes like Hubble and Spitzer (Konopacky et al. 2023). The Multi-objective Diffraction-limited High Resolution Infrared Spectrograph (MODHIS) on the Thirty Meter Telescope (TMT) is one of the key instruments on a US-ELT (Extremely Large Telescope) that will aid in improving the sensitivity, spectral resolution, and spectral coverage limits necessary for RV follow-up of TESS candidates by manifolds (Mawet et al. 2019). Thus advancing the science goals towards the possibility of “detecting Earth-like biosignatures on rocky exoplanets around nearby stars” (Lopez-Morales et al. 2019). The search for exoplanets, particularly super-Earths orbiting Very-Low-Mass (VLM) stars like M dwarfs, and brown dwarfs, has entered an era of unparalleled precision and efficiency with the advent of Extremely Large Telescopes (ELTs).  Currently, we are carrying out such a study with a specifically curated magnitude limited sample of M dwarfs through an initial search and detection by transit photometry of TESS light curves for this sample. To aid and strengthen our detection/characterization, we explore the possibility of carrying out additional reconnaissance vetting/characterization using Precision Radial velocity (PRV) studies. RV method, being one of the earliest and most pervasive methods for exoplanet detection and characterization, is especially suitable for low-mass stars a.k.a M dwarfs. With promise of high spectral resolution of the order of ~100,000 using MODHIS, RV precision of typically  <30 cm/s can be attained. Considering our magnitude-limited sample of M-dwarfs (Mass range : 0.1 to 0.3 M_sun and Magnitude range ~ 10 to 12), these numbers suggest a very good prospect for accurate RV detection for M- dwarf hosts in our sample for which the expected RV semi-amplitude will be of the order ~100 cm/s (post-correction for variability/rotation). This study explores the advanced capabilities of ELTs in improving the efficiency of transit photometry detections through advanced precision radial velocity and spectroscopic techniques. Thus, enhancing our understanding of the occurrence rate of potentially habitable super-Earths around the smallest stars in our Universe and contributing to a new era of exoplanetary exploration.


Sang Chul Kim : Investigation of the Metal Abundance Distribution of the Milky Way Disk using Old Open Star Clusters

The metallcity distribution of the Galactic plane can be probed by using objects like open clusters, Cepheid variable stars, globular clusters, red clump stars, planetary nebulae, H II regions, field stars, etc. We focus on using old open clusters and on the outer area of the Galactic plane. Since metallicity distribution gets relatively poorer at the outer region of the Galactic plane, old open clusters which are relatively metal-poor are quite useful for the study. There are not many number of old open clusters known or studied at the outer region of the Milky Way, therefore, we try to get observations on the outer region old open clusters finally to study the Galactic plane metalcity gradient. It is anticipated that the extremely large telescopes like the Giant Magellan Telescope will greatly help investigating the relatively distant and faint old open clusters at the outer regions of the Milky Way.


Yen-Ting Lin : Fireworks in the core of a distant cluster: witnessing a short-lived starburst event?

I will report the results of our investigation of a curious system consisting of a blue ring (with a size of 40x60 kpc) encircling a massive red galaxy, and a companion brightest cluster galaxy (BCG), all located at the center of a distant (z=1.06), low-mass cluster. This is a rare discovery enabled by the deep (i~26 AB mag), wide (1100 deg2) Subaru Hyper Suprime-Cam (HSC) survey, and offers an exciting opportunity to study a short-lived but important phase of cluster core formation. Data from archival Spitzer, Herschel, and our own ALMA program reveal an integrated obscured star formation rate (SFR) of ~200 Msun/yr and ample amount of molecular gas. Such a SFR is highest among known clusters at z~1. We further derive the stellar population properties of the ring and two massive galaxies with integral field spectroscopic data obtained from Subaru and Magellan, and discuss the possible origin of the ring, as well as the implications on the initial phase of the formation of BCGs.  Systems like this, to be discovered by Rubin, Euclid, or Roman, can be prime opportunities of a synergy between JWST and ELTs.


Inbal Mizrahi : Spectroscopic Observations of the Galactic Center with Keck, JWST, and ELTs

In the past two decades, spectroscopic observations of the Galactic center have provided many rich science opportunities. These observations have been used to test general relativity, identify and characterize stellar populations, and study star formation history in an extreme environment. Notably, ground-based observations with adaptive optics in the near-infrared provided some of the strongest evidence for a supermassive black hole (SMBH) at the center of the Milky Way. Though ground-based telescopes like Keck can provide high spatial resolution, they are often limited in depth and wavelength coverage. We will discuss how JWST can complement existing ground-based data by providing higher sensitivity and wavelength coverage extending into the mid-infrared. We will present our JWST Cycle 1 observations with the NIRSpec Integral Field Unit (IFU) of the 9”x9” (0.36 x 0.36 parsec) region centered on the SMBH SgrA*. We will also discuss how spectroscopy with future ELTs can advance Galactic center science beyond what we can achieve today.


Yoon Chan Taak : Strong Lensed QSOs with Variability Detectable by LSST: How many are there?

Strong lensed quasi-stellar objects (QSOs) are valuable probes of the Universe in numerous aspects. Two of these applications, reverberation mapping and measuring time delays for determining cosmological parameters, require the source QSOs to be variable with sufficient amplitude. In this paper, we forecast the number of strong lensed QSOs with sufficient variability to be detected by the Vera C. Rubin Telescope Legacy Survey of Space and Time (LSST). The damped random walk model is employed to model the variability amplitude of lensed QSOs taken from a mock catalog by Oguri & Marshall (2010). We expect 30-40% of the mock lensed QSO sample, which corresponds to ~1000, to exhibit variability detectable with LSST. A smaller subsample of 250 lensed QSOs will show larger variability of >0.15~mag for bright lensed images with i<21 mag, allowing for monitoring with smaller telescopes. We discuss systematic uncertainties in the prediction by considering alternative prescriptions for variability and mock lens catalog with respect to our fiducial model. Our study shows that a large-scale survey of lensed QSOs can be conducted for reverberation mapping and time delay measurements following up on LSST. 


Taichi Uyama : Incorporating and fostering early-career researchers in Japan for the next generation extreme large telescopes

We have started a cross-disciplinary science workshop series in Japan (TMT eArly Career Centered, Engineers-Scientists Synergy; TMT-ACCESS) that puts emphasis on discussions to comprehensively explore new science cases for the TMT under the updated construction timeline. That will facilitate interactions among researchers from different fields, leading to the development of innovative science cases at the boundaries of each discipline. Moreover, we intend to offer opportunities that promote mutual understanding between engineers and scientists, providing a platform to foster planning and proposing next-generation instruments based on science cases. We eventually plan to gradually render this workshop series international and seek for opportunities to interact with other communities.