In the ALMA era of observational astronomy, we are availed of a plethora of spatially resolved images of protoplanetary discs, the site of exoplanet formation. Significant substructure, such as spirals and ring-like gaps, has proved to be the norm, rather than the exception, in these systems. There is now a consensus that much of this substructure is caused by forming gas-giant exoplanets. However, this is problematic for our understanding of planet formation. These protoplanetary discs are typically a factor of 10 too young to have formed such massive planets in the standard core accretion paradigm, but it is also understood that planets do not form directly through gravitational collapse. When protoplanetary discs are very young, they are very massive relative to their host star, and therefore pass through a period of gravitational instability. This instability may accelerate the earliest stages of planet formation in the standard core accretion paradigm, offering a solution to the planet formation timescale problem. I discuss my research into gravitational instability and detection of substructure, and discuss future research plans which will explore the formation of exoplanets in dynamically evolving protoplanetary discs.

Core collapse supernovae (CCSNe) represent the final evolutionary stage of stars more massive than 8 M☉. Just like their massive star progenitors, CCSN explosions are far from homogenous. The photometric and spectral evolution zoo of CCSNe can be better understood when the mass-loss histories of their progenitors are taken into context. We can now reconstruct the mass-loss history and physical parameters of the massive star progenitor with observations of SNe in the hours to years after explosion, without the need for rare pre-explosion Hubble Space Telescope imaging. Mass-loss rates and eruptive events in evolved massive stars impact the behavior of the terminal CCSN, including red supergiants, yellow hypergiants, and luminous blue variables. Red supergiants and yellow hypergiants have slower wind velocities and lower mass-loss rates than luminous blue variables, creating very different explosion environments, and by extension, very different observational characteristics of the supernova. I will present how I use these extremely bright and violent explosions to understand more about the final years of massive star evolution, and what tools are being used and developed to discover these SNe so rapidly in what is becoming the golden age of transient astronomy.

A powerful tool for understanding the Universe is the distribution of matter on very large scales, and a number of upcoming surveys will map the large-scale structure at radio wavelengths using the 21 cm line from neutral hydrogen. I will describe the Canadian Hydrogen Intensity Mapping Experiment (CHIME), which will make the largest-ever three-dimensional map of the Universe. This map will enable precise measurements of the expansion of the Universe to understand its anomalous acceleration and the dark energy hypothesized to be driving it. In addition, I will show how the digital design of the CHIME telescope allows it to simultaneously search for a new class of radio transient, fast radio bursts, which provide another probe of the Universe. CHIME belongs to a new class of radio telescope which are remarkably scalable, opening a new frontier in observational cosmology to understand both the evolution of the Universe and fundamental physics.

Understanding how massive galaxies form and grow is important to galaxy evolution and cosmology. In this talk, I will present the stellar population study of massive galaxies and their surrounding environments in nearby galaxy clusters, with particular focus on the scaling relations between stellar mass and galaxy central stellar population properties, as well as the radial profiles where their stellar population bear the imprint of the assembly history. I will begin by introducing the `coordinated assembly` picture for massive galaxies with a case study of an ongoing brightest cluster galaxy assembly at z=0.1. I will then present our `Deep Coma` project in the SDSS IV/MaNGA collaboration. The deep integral field spectroscopy and full spectral modeling method enabled detailed analysis at the low surface brightness regime. We are therefore able to demonstrate the stellar populations of various types of targets in the Coma Cluster. Last, I will briefly discuss the `coordinated assembly` picture in the IllustrisTNG simulations.

Abstract: Massive galaxies are valuable targets for studying cosmology and galaxy-halo connection as they help us locate massive dark matter halos across the history of the universe. Although the general behavior of stellar-halo mass relation (SHMR) is reasonably constrained at low-redshift, there is still much to learn about the connection between the assembly of massive galaxies to the growth of their host dark matter halos. Using deep images from the Hyper Suprime-Cam (HSC) survey and taking advantage of its unprecedented weak lensing capabilities, we reveal a remarkably tight connection between the stellar mass distribution of massive central galaxies and their host dark matter halo mass. Massive galaxies with more extended stellar mass distributions tend to live in more massive dark matter haloes. We explain this connection with a phenomenological model, showing that halo mass varies significantly at fixed total stellar mass (as much as 0.4 dex) with a clear dependence on stellar mass within 10 kpc. This two-parameter model provides a more accurate picture of the galaxy–halo connection at the high-mass end than the simple SHMR and opens a new window to connect the assembly history of halos with those of central galaxies. I will also discuss potential applications of our model on topics from the assembly of massive galaxies to cosmology using massive clusters.

Becky Arnold Stars, Stats, Software I will present a brief outline of my research to date. I will describe my work using N-body simulations to study the evolution of star clusters with a focus on binary clusters. I will then discuss statistical methods for quantifying and comparing spatial-velocity substructures. Finally I will go into my interest in good software development practice for rigorous and reproducible research. Chris Faesi PHANGs: Connecting cloud-scale star formation to galaxy evolution Star formation drives the secular evolution of galaxies across cosmic time. However it is not yet understood how this key process, which occurs on a localized basis within molecular clouds (10s of pc scales), couples to the kpc scale processes and environments of galaxies. The Physics at High Angular Resolution in Nearby Galaxies (PHANGs) collaboration is undertaking a comprehensive series of observational and modeling efforts to systematically explore the cloud-scale star-forming interstellar medium (ISM) in the nearby universe. With ongoing sub-arcsecond resolution ALMA, VLT/MUSE, and Hubble large programs mapping full disks of dozens of nearby galaxies, we are poised to revolutionize our understanding of molecular clouds, HII regions, star clusters, star formation efficiency, and feedback, as well as to explore their environmental dependences. I will highlight some first PHANGs science results and outline the exciting path forward in the coming years, which includes many opportunities for students to get involved. As one example, I am leveraging the MUSE data to map the Balmer decrement-derived dust extinction at 50 pc scales and comparing to ALMA CO emission to understand the cloud-scale distribution of dust and gas across galaxy disks. Matteo Messa Title: Young Star Cluster and Clumps in the local (and far) Universe Abstract: I will briefly go through what I have done, I am doing, and I would like to do, concerning the optical-NIR study of clumpy star formation. This includes: the effects of galaxy environment on the formation and evolution of star clusters; new machine-learning methods to fully exploit the large set of clusters’ observations; the clumpiness of nearby starburst galaxies and their relation with high-redshift galaxies; the use of lensed galaxies to test resolution-effects on the properties of massive clumps at high-redshift. Basically, I will try to convince you (in ~10 min.) that star clusters and star-forming clumps are powerful tools to study star-formation across space and time. Mimi Song Title: Tracing galaxy growth over cosmic time with galaxy stellar mass functions Abstract: Over the last decade the advent of the Hubble Space Telescope (HST) Wide Field Camera 3 has enabled us to build statistically significant samples of galaxies out to z=8. We have subsequently witnessed remarkable progress in our understanding of galaxy evolution in the early universe. However, our understanding of the galaxy stellar mass growth in this era has been limited due to the lack of rest-frame optical data at a comparable depth as the HST data. In this talk, I will first talk about observationally constraining the galaxy stellar mass function at z = 4–8 using deep Hubble and Spitzer data in the CANDELS GOODS fields. Then, I will present an empirical model for galaxy evolution out to z = 8 by combining the dark matter halo growth history extracted from cosmological simulations with the the observed galaxy stellar mass functions over cosmic time.

A synergetic combination of multi-wavelength astronomical surveys promises to provide an ever more comprehensive view of cosmic structures, by mapping out the distributions of dark matter, gas, stars and black holes in the universe. Such datasets will reveal rich physics of galaxies, clusters and cosmic web and ultimately shed light on the nature of dark matter and dark energy that govern their formation and evolution. However, new astronomical datasets will be large and complex. New way of thinking and problem solving are required. In this talk, I will discuss new opportunities and future challenges at the crossroads of large cosmological surveys, computational astrophysics and data science.

Faculty Research Presentations by: Kate Whitaker, Min Yun, Daniel Wang, Kate Follette, Rob Gutermuth, Houjun Mo, Mauro Giavalisco, Gopal Narayanan

The Neutron Star Interior Composition Explorer (NICER) is NASA’s newest X-ray telescope. A small Mission of Opportunity (about the size of a washing machine), it is perched on the International Space Station, with the main science objective of measuring the equation of state of ultra dense matter in neutron stars. Beyond this prime science goal, NICER is also making groundbreaking measurements of black holes. In this talk, I will highlight two recent and ongoing studies from NICER, one on measuring X-ray reverberation light echoes in the bright X-ray transient MAXI J1820+070, which have allowed us to map out scales closer to the event horizon of a stellar mass black hole than ever before. And second, I will present ongoing work on a multi-wavelength monitoring campaign of a transitioning AGN, 1ES 1927+654, which we observed transitioning from a Type 2 to a Type 1 AGN on timescales of a few months. Both of these observations are shedding light on the evolution of the X-ray emitting corona and its connection to the accretion disc and relativistic jets.

Our own Milky Way Galaxy is a powerful and relatively nearby laboratory in which to study the physical processes that occur throughout the Universe. From the organization of gas on galactic scales to the life cycle of gas and stars under varied environmental conditions, studies of our Milky Way underpin many areas of modern astrophysics. I will present a brief tour of our Milky Way Laboratory, including 1) the connection between long, filamentary molecular clouds and spiral structure, 2) statistical studies of high-mass star formation using surveys of our Galaxy’s disk, and 3) how observing our extreme, turbulent Galactic Center (the Central Molecular Zone) can help us learn more about how gas is converted into stars during the peak epoch of cosmic star formation. I will also briefly discuss the Origins Space Telescope, a NASA mission concept study for the 2020 Decadal survey, opening up about 3 orders of magnitude of discovery space on science from first stars to life.

Over the last few decades, astronomers have progressed from archeological studies of nearby galaxies to direct observations of the early universe. We have uncovered billions of years of cosmic growth that present new challenges to galaxy formation theories. In this talk, I will review the recent innovative techniques developed to probe the distant universe, and the key observations constraining the formation histories of galaxies over the past 11 billion years. We have discovered a population of surprisingly compact and massive “red and dead” (quiescent) galaxies that are no longer actively forming stars. The physical mechanisms responsible for shutting down star formation and the subsequent buildup of this quiescent population at such early times is one of the most outstanding questions in astrophysics today. I will present promising paths forward towards solving this puzzle that leverage strong gravitational lensing and the capabilities of the Hubble Space Telescope, as well as a look toward the future with exciting upcoming public facilities.

We review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts (GRBs) are associated with type Ic Supernovae (SNe). Current estimates of SN and GRB rates show that only a tiny fraction of massive stars, likely less than 3%, are able to pruduce GRBs.