Title: The Pairing Mechanism of Short Range Correlations and the impact of Nuclear Structure

Abstract: At very short distances inside nuclei, protons and neutrons can form fleeting pairs with large relative momentum, known as short-range correlations (SRCs). These SRC pairs dominate the high-momentum component of nuclear wave functions and provide a unique window into the short-distance structure of nuclear matter. Due to overlapping quark distributions and strong interactions, SRC pairs also play a crucial role in linking nucleon structure to the underlying dynamics of the strong force and the behavior of dense nuclear systems. Although many properties of SRCs have been investigated, the fundamental mechanism by which nucleons form correlated pairs remains an open question. In this talk, I will provide a brief overview of what we have learned about SRCs and present new results that probe the nucleon-pairing mechanism and its connection to nuclear structure.

Title: From massive gravity to RATs: ultra-light dark matter phenomenology with atom interferometers

Abstract: Atom interferometers offer exceptional sensitivity to ultra-light dark matter (ULDM)  through their precise measurement of phenomena acting on atoms. Previous work has established their capability to detect scalar and vector ULDM, but their potential for detecting spin-2 ULDM has until recently remained unexplored. In this talk I will introduce the sensitivity of atom interferometers to ULDM and focus on novel research for spin-2 models derived from several frameworks for massive gravity: a Lorentz-invariant Fierz-Pauli case and two Lorentz-violating scenarios. Coherent oscillations of the spin-2 ULDM field induce a measurable phase shift through three distinct channels: coupling of the scalar mode to atomic energy levels, and vector and tensor effects that modify the propagation of atoms and light. Atom interferometers uniquely probe all of these effects, while providing sensitivity to a different mass range from laser interferometers. These results demonstrate an exciting new theory target for atom interferometers and other quantum sensors to explore. I will also discuss challenges faced by these experiments from environmental noise, including atmospheric phenomena and local human and animal activity.

Title: A novel view of the Milky Way disk and outer Solar system

Abstract: Combining big survey data with advanced statistical analysis is a fruitful approach to new discoveries. I will present two examples.   (1) One is a new mapping technique to provide for the first time a clear and flat view of the phase space of Milky Way disk. Applying it to Gaia data, we found sharp new structures with order-of-unity contrast in number density and metallicity. It opens a new window to study galactic dynamics, calling for theoretical explanation and observational search for similar structures in other disk galaxies.  (2) Another example is a new algorithm searching for moving objects from imaging survey. Applying it to cosmological surveys, I found a dwarf planet with the widest orbit in the Solar system, which places an interesting challenge to the Planet Nine / Planet X hypothesis.

Title: Warm ionized gas filaments in non-central early-type galaxies

Abstract: Filamentary multiphase gas is nearly ubiquitous within the brightest cluster galaxies (BCGs) of cool-core clusters and is likely related to the feeding and feedback of their supermassive black holes. Determining how such filaments form is crucial to understanding the interplay between baryon cycling, active galactic nucleus (AGN) feedback, and the evolution of early-type galaxies (ETGs). However, BCGs account for only a small fraction of all ETGs and their gaseous atmospheres are thought to be strongly influenced by the extreme, dense cluster environments in which they reside. In this talk, I will present the results of our multiwavelength analysis of 126 nearby ETGs that sit outside of the immediate cores of galaxy groups and clusters (hereafter “non-central” ETGs) - with the aim of connecting our current understanding of filamentary multiphase gas formation to the greater ETG population. Using archival VLT-MUSE observations, we detect warm ionized gas in 54 of the 126 non-central ETGs. Most of these systems (35/54) host ordered, rotating gas disks, while the remainder (19/54) show extended filamentary structures that resemble the multiphase filaments seen in BCGs. I will discuss how the MUSE data, in tandem with archival Chandra X-ray observations, support an interpretation in which the warm filaments condense out of cooling, thermally unstable hot halos. Furthermore, I will present emission-line diagnostics that test the ionization mechanisms capable of powering the filaments.

Title: Reading Between the Bumps: Unexplained Features in Optical Extinction Curves

Abstract: The features of interstellar extinction curves serve as powerful diagnostics for interstellar dust, revealing information about its composition, size distribution and the physical and chemical processes that shape it. Extinction features tend to be categorized based on width as they probe different carriers. 

These extinction features include narrow interstellar absorption features from Na, Ca and K and diffuse interstellar bands (DIBs) with widths on the scale of ~0.1-1.0 nm. On the intermediate scale, the well-known 2175A with a width of ~427A is thought to originate from carbonaceous grains. Massa et al 2020, reported three new intermediate-scale structures (ISS). Their analysis found that strength two of the three of these ISS features correlate with the 2175A bump strength, but none were correlated with the total-to-selective extinction ratio, R(V). \

Since then, three additional candidate ISS features were identified in the literature at 0.770, 0.540, 0.850 micron, all with widths greater than any known DIB. To help identify their carriers, I used 74 different lines-of-sight to study the three original ISS features as well as the candidate features. Furthermore, in this study I identified 10 more candidate ISS features observed in these sightlines. Lastly, I present an analysis of all these ISS features on how they relate to the extinction curve parameters, to each other and to the 2175A bump feature.

Title: TBA

Abstract: TBA

Title: Using the Metallicity of Simulated Galaxies to Understand Galaxy Evolution

Abstract: Numerical simulations are an invaluable tool for understanding how galaxies form and evolve. Yet, the current generation of simulations suffers from significant modeling uncertainties, rooted in divergent predictions from different codes using similar prescriptions and in a lack systematic comparisons between qualitatively different models. In this talk, I will highlight the oftentimes underappreciated differences between popular cosmological simulations (e.g., IllustrisTNG, EAGLE, FIRE) through examining their metal content. Metals serve as powerful observational tracers of the galactic baryon cycle and are highly sensitive to the details of feedback physics. I will show that even for nominally similar simulation models (e.g., IllustrisTNG and EAGLE), the overall metal budget of the galaxy can be significantly different. Moreover, distinct physical implementations (e.g., IllustrisTNG and FIRE) make very different predictions for the spatial distribution of metals within galaxies. Together, these predictions provide a theoretical framework through which we can leverage the wealth of observational data on metals to gain deeper insight into the processes driving galaxy evolution.

Zoom Link: https://uky.zoom.us/j/82910452708

Title: Where the hot universe meets the energetic universe

Abstract: The hot circumgalactic medium (CGM), a reservoir of missing baryons, metals and energy, plays a key role in our understanding of galaxy evolution. Extraordinary observational challenges, however, make the hot CGM one of the least understood components of galaxies. 

Studying the hot CGM was not the objective of current X-ray or mm facilities during the design phase. As an excellent byproduct, however, observing the hot CGM has emerged as a promising field over the last two decades, coming at the forefront of priority science goals for the current and upcoming decades. 

I will discuss three snippets of our recent efforts to detect and characterize the hot CGM: 

1. X-raying the Milky Way: Investigating thermal and chemical anomalies.
2. Is CGM detectable? Conducting deep searches in individual external galaxies using X-ray,
3. Test for self-similarity: stacking thousands of galaxies in mm (Sunyaev-Zeldovich Effect). 

I will highlight how our findings provide insights into the impact of galactic feedback on the hot CGM, establish our confidence in leveraging current telescopes to inform theoretical simulations and set a benchmark for designing experiments with next-generation X-ray and mm facilities.