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Symposium 2024 (New Orleans, LA)

Symposium Guest Speakers

Guest Speakers

Keynote: How Astronomers Can Help Solve Climate Change
Travis Rector, University of Alaska Anchorage
Climate change is the most important topic of our time. It is an existential threat that requires our immediate attention. The good news is that we can still avoid the worst consequences, but only if we take swift action over the next decade. The severity of the problem calls for everyone to do their part, including astronomers. Fortunately, we are in a position to make a positive impact. Through the classes we teach and our public outreach we can– and should– take the opportunity to help people understand the causes and consequences of, and solutions to, climate change. Astronomy offers a unique and important perspective on the problem. Indeed, there is no Planet B. We also need to address that astronomy as a profession is a contributor to climate change. From supercomputing, air travel, and operations we are responsible for an outsized carbon footprint. Astronomy is also being affected by climate change, from the increased risk of forest fires to the stability of the atmospheric conditions at our observatories. How should astronomers change how we work in order to reduce our carbon footprint? How should we adapt to the impacts of climate change and proposed mitigation efforts? And how can we make changes that improve the equity and productivity of our profession? In my talk I will discuss the roles that astronomers can play in addressing the climate crisis.

Keynote: Transformative Discoveries with Machine Learning
Michelle Ntampaka, STScI
The Astro2020 Decadal Report makes a bold claim about machine learning’s role in astronomy: ML “could lead to transformative discoveries from the new data sets available in the 2020s.” But are the newest tools enough to make a transformative discovery with machine learning? In this talk, I will describe how the application of ML in astronomy has evolved over the past decade, I will show how new learners of ML can try out state-of-the-art tools, and I will describe best practices for using ML tools in an ethical way to usher in the discoveries of the next decade.

Workshop: Strategies to Improve Mentorship
Joshua Brown, University of Wisconsin-Madison
Dr. Joshua Brown (UW-Madison, School of Human Ecology) will facilitate a workshop focusing on strategies to improve mentorship. Strategies include maintaining effective communication, inclusive practices for mentorship, and the mentor/mentee pathway dialog. Attendees will be provided materials and practices to integrate into their mentorship practice. Session length: 1.5 hrs.

Panel Discussion: Job Hunting in Industry & Academia
Claire Murray, Faculty UW
Michelle Ntampaka, Research scientist STScI
Justin Ellis, Software engineer / Data scientist

Symposium Schedule

Schedule

Saturday, January 6
9:00 – 9:10 Welcome and Opening Remarks
9:10 – 9:30 Welcome Mixer
9:30 – 10:00 NSF Introduction, Q&A
Andrea Prestwich
10:00 – 10:30 Coffee Break
10:30 – 12:00 Workshop: Strategies to Improve Mentorship
Joshua Brown
12:00 – 1:00 Lunch
1:00 – 2:00 Keynote: How Astronomers Can Help Solve Climate Change
Travis Rector
2:00 – 3:00 Talks by Fellows
Devontae Baxter: Empowering Community College Transfer Students Through Coding and Mentorship Workshops
Aaron Stemo: The EMIT Program: Establishing Multimessenger astronomy Inclusive Training
Emily Griffith: The Access Network: A Near-Peer Mentorship Program Starter Kit
Loren Matilsky: Towards a Permanent Peer-Mentoring Program at the University of California, Santa Cruz.
Dominique Segura-Cox: AstroCore: Modules for High School Classrooms
3:00 – 3:30 Coffee Break
3:30 – 5:00 Talks by Fellows
Matthew De Furio: From Dense Clusters to OB Associations: Tracing the Impact of Environment on Multiplicity beyond 10 AU in the Orion Complex
Rebecca Levy: A JWST View of Massive Star Clusters in the Central Starburst of M82
Francisco Mercado: Nature vs. Nurture: Understanding how internal and external processes shape galactic interiors
Michael Busch: Dark Molecular Gas as traced by 18cm OH in M31
Ruby Byrne: Probing the Cosmic Dawn with the OVRO-LWA Stage III
Dan Rybarczyk: Studying the earliest stages of molecule formation in the diffuse ISM: insights from 21cm and 3mm absorption
6:30 – 8:30 Social Time @ Urban South Brewery
Sunday, January 7
9:00 – 9:15 Welcome and Opening Remarks
9:15 – 10:30 Talks by Fellows
Fatemeh Bagheri: Exoplanets Magnetosphere Interactions with Stellar Winds
Steven Giacalone: Uncovering the Landscape of Close-In Planets Orbiting Hot Stars with TESS
Colin Burke: Intermediate-mass black holes in the era of Rubin Observatory
Josh Forer: Theoretical dissociative recombination rate coefficients for diffuse interstallar cloud models
Ronald A Lopez: The Development of an MKID High Resolution Multi-Object Spectrometer
10:30 – 11:00 Coffee Break
11:00 – 12:00 Panel Discussion: Job Hunting in Industry & Academia
12:00 – 1:00 Lunch
1:00 – 2:00 Keynote: Transformative Discoveries with Machine Learning
Michelle Ntampaka
2:00 – 3:00 Talks by Fellows
Stephanie Ho: Multiphase Circumgalactic Gas Flow
Devontae Baxter: Investigating the Halo Mass Dependence of Environmental Quenching at z~1
Nora Shipp: Near-Field Cosmology with Stellar Streams
Loren Matilsky: The importance of oblateness in the solar equator-to-pole temperature difference
3:00 – 3:30 Coffee Break
3:30 – 4:45 Talks by Fellows
Erin Cox: Using Magnetic Field Signatures to Probe Protobinary Formation
Sanjana Curtis: Blue kilonovae from neutron star merger remnants
Kaley Brauer: Simulating Early Chemical Enrichment and Formation of the First Galaxies
Maddie Lucey: Constraining First Star Nucleosynthesis and the Early Universe with the Inner Milky Way
Emily Griffith: KPM: A flexible and data-driven K-process model for nucleosynthesis
4:45 – 5:00 Closing Remarks
Symposium Talk Details

Talk Details

Exoplanets Magnetosphere Interactions with Stellar Winds
Fatemeh Bagheri – University of Texas at Arlington
Numerous numerical studies have been carried out in recent years that simulate different aspects of star-planet interactions. These studies focus mostly on hot Jupiters with sun-like stars. However, more realistic simulations require including a wide range of stellar types in studying stellar-planetary interactions. In this study, I use MHD simulations to model star-planet interactions assuming different stellar types.

Empowering Community College Transfer Students Through Coding and Mentorship Workshops
Devontae Baxter – University of California, San Diego
Community college remains a viable entry point into higher education for many Americans, especially those from historically underrepresented backgrounds. However, the transition from a 2-year college to a 4-year university is often quite challenging, and transfer students often report feeling lost, alone, and unprepared for academic research. In this talk, I will share with you updates on the Computational Astrophysics Research Preparation (CARP) program, which is an in-person coding and mentorship workshop series that seeks to improve the transfer outcomes for community college students in San Diego County.

Investigating the Halo Mass Dependence of Environmental Quenching at z~1
Devontae Baxter – University of California, San Diego
Galaxies that dwell in dense regions of the cosmos, such as groups and clusters, predominantly exhibit elliptical morphologies, reduced cold gas fractions, and suppressed star-formation activity. Despite these observations, the underlying physical mechanisms driving these trends remain elusive. This presentation will detail ongoing modeling efforts dedicated to inferring the timescales governing the suppression of star formation in galaxy populations within groups and clusters. Emphasis will be placed on utilizing this timescale to identify the dominant physical mechanism driving observed trends, and exploring its dependence on host halo mass.

Simulating Early Chemical Enrichment and Formation of the First Galaxies
Kaley Brauer – Harvard-Smithsonian Center for Astrophysics
The first galaxies formed 200-300 million years after the Big Bang. The smallest of these early galaxies, the ultra-faint dwarfs, were quenched by reionization, so those that survived until now are composed of ancient stars from 13 billion years ago. Stars from these tiny galaxies thus are relics from the era of the first stars and galaxies, preserving clean signatures of early chemical enrichment. Previously, though, simulations have been unable to explain observed stellar chemical abundances in these galaxies. To fully utilize the available chemical abundance data on stars from ultra-faint dwarfs, we have run new high-resolution cosmological simulations of early dwarf galaxy formation with individual stars, detailed chemical yields, and highly-resolved metal mixing. These simulations, the Aeos simulations, allow us to explore complex galaxy formation processes including source-dependent metal mixing, hierarchical galaxy merging, bursty star formation, and variations across different galaxies to learn how early galaxies evolved. We present the methodology and initial results from this new simulation suite.

Intermediate-mass black holes in the era of Rubin Observatory
Colin Burke – Yale University
Despite their ubiquity in massive galaxies in the local Universe, little is known about how supermassive black holes were seeded at high redshift and subsequently grew over cosmic time. The relic population of intermediate-mass black holes (IMBHs) in the centers of dwarf galaxies is sensitive to these conditions and will be observable with the Vera C. Rubin Observatory and the Laser Interferometer Space Antenna (LISA). In order to make inferences about black hole seeding from these observations, I have developed forward modeling tools to predict the detectible black hole populations from semi-analytic models of black hole seeding and growth. By coupling these multi-wavelength observational constraints to semi-analytic models that track black hole growth and mergers over cosmic time, we can place observationally-constrained expectations for the populations of IMBHs detectable by Rubin and LISA.

Dark Molecular Gas as traced by 18cm OH in M31
Michael Busch – University of California, San Diego
The most abundant interstellar molecule, molecular Hydrogen (H2), is practically invisible in cold molecular clouds. Astronomers typically use carbon monoxide (CO) to trace the bulk distribution and mass of H2 in our galaxy and many others. CO observations alone fail to trace a massive component of molecular gas known as “CO-dark” gas. We present for the first detection of thermal 18cm hydroxyl (OH) in another galaxy for the first time. This pilot search was completed using the 100m Green Bank Telescope in West Virginia. We successfully detected the 1667 and 1665 MHz OH line in faint thermal emission, as it appears in the characteristic LTE ratio of 5:9. OH is an optically thin radio tracer of molecular gas, unfortunately it is very faint. In the future we will be able to map out faint signals using phased-array feeds on single dish telescopes.

Probing the Cosmic Dawn with the OVRO-LWA Stage III
Ruby Byrne – California Institute of Technology
The most abundant interstellar molecule, molecular Hydrogen (H2), is practically invisible in cold molecular clouds. The highly redshifted 21 cm emission line from neutral hydrogen has the potential to reveal the temperature, density, and ionization fraction of the intergalactic medium (IGM) during the Cosmic Dawn, when the first stars and galaxies illuminated the universe. The upgraded Long Wavelength Array at the Owens Valley Radio Observatory (OVRO-LWA) is sensitive to this cosmological signal at redshifts z ≈ 16-100. We describe preliminary results toward deep limits on the 21 cm power spectrum from the Cosmic Dawn using the upgraded OVRO-LWA Stage III. We discuss the impact of the array upgrade on 21 cm cosmology systematics, including reduction of signal crosstalk and reflections. We then present a data analysis strategy that focuses on precision calibration and power spectrum estimation with an imaging-style analysis. Calibration is performed with DWCal, a direction-independent interferometric calibration technique that reduces spectral calibration error and is robust to sky model error. We use the FHD/εppsilon pipeline for imaging and power spectrum estimation. A fully polarized simulated beam model is used to capture direction-dependent effects in calibration and imaging. We discuss the role of quality metrics, validation, and repeatability in our analysis.

Using Magnetic Field Signatures to Probe Protobinary Formation
Erin Cox – Northwestern University
Stars form in the hearts of molecular clouds, collapsing over 10 orders in spatial magnitude. This collapse is dominated by gravity, turbulence, magnetic fields, and stellar feedback. While gravity ultimately wins, these other dynamical effects can either hinder or aid the collapse at various scales. The initial conditions of the earliest evolutionary phase of a protostar are essential in constraining the architecture of the stellar system (e.g., the number of stars that will form or the mass budget for planets). Arguably the magnetic field is one of the more difficult dynamical effects to constrain observationally. In this talk, I will present new research showing multi-wavelength polarization observations that probe the multi-scale magnetic field morphology of a young stellar system in an isolated Bok globule where we believe the collapse is magnetically regulated. I will show how the observed magnetic field signature of the protostellar envelope may provide a new way to probe binary star formation. Since most stars form in multiple systems, understanding the system’s formation is crucial in understanding how the protostar and its planets evolve.

Blue kilonovae from neutron star merger remnants
Sanjana Curtis – University of California, Berkeley
Kilonovae are the only direct observational evidence of r-process nucleosynthesis in situ and thus hold great promise for uncovering how and where heavy elements are produced. The landmark detection of AT2017gfo, the kilonova counterpart to GW170817, confirmed that neutron star mergers are a site of the r-process. However, several open questions remain when it comes to the details of nucleosynthesis in merger ejecta, and the origin of the red and blue components of the observed kilonova. In this talk, I will focus on the origin of the blue component of AT2017gfo. I will present our latest predictions of heavy element abundances and kilonova emission produced by ejecta from a short-lived neutron-star merger remnant. These calculations are based on three-dimensional general-relativistic magnetohydrodynamic simulations. I will show that magnetized outflows from neutron-star merger remnants can produce blue emission, and if the remnant survives long enough, a blue kilonova compatible with AT2017gfo.

Theoretical dissociative recombination rate coefficients for diffuse interstallar cloud models
Josh Forer – Columbia Astrophysics Lab
Star formation is an important process to understand in order to determine the structure and evolution of galaxies. A crucial early step in star formation is the atomic-to-molecular transition of diffuse molecular clouds. Three key molecular ions that can be used to map diffuse cloud properties during this transition are OH+, H2O+, and H2Cl+. However, these ions are all easily destroyed by dissociative recombination (DR) — a major destruction mechanism in molecular plasmas. Reliable DR data for these ions is needed to infer the molecular fraction, constrain the cosmic ray ionization rate of atomic hydrogen, and place constraints on the interstellar radiation field; but such data for these ions is not yet available in the literature. Experimental and theoretical challenges in obtaining accurate low-energy DR rates for diffuse cloud models will be presented, as will recent developments in the current study to develop a method capable of obtaining low-energy DR rates for several molecular ions, including OH+, H2O+, and H2Cl+.

From Dense Clusters to OB Associations: Tracing the Impact of Environment on Multiplicity beyond 10 AU in the Orion Complex
Matthew De Furio – University of Texas at Austin
The stellar and sub-stellar multiple populations of young star-forming regions contain crucial information about the formation and evolution of multiples, the Galactic field star population, and the history of star-forming regions. Previous multiplicity surveys in Taurus, a low-density association, identify a companion frequency to low-mass stars twice that of the Galactic field. In my dissertation work, I utilized archival Hubble Space Telescope data obtained with the Advanced Camera for Surveys to investigate the multiplicity of low-mass stars in the Orion Nebula Cluster (ONC), a high-mass high-density star-forming region, and found no excess of companions relative to the Galactic field indicative of an environmental effect on multiplicity. With these results, I was awarded time on the Keck and Gemini Observatories to explore the multiplicity of different environments, OB associations, which are present-day low density regions but may have emerged from previously dense, embedded clusters. Using Keck imaging and non-redundant masking as well as Gemini speckle interferometry, I will characterize the multiplicity of these two OB associations, Orion OB1a and OB1b, as an exploration of the effect of environment on the formation of multiple systems. In this talk, I will describe our approach to characterize the multiplicity of a star-forming region and present the newly acquired observations.

Uncovering the Landscape of Close-In Planets Orbiting Hot Stars with TESS
Steven Giacalone – California Institute of Technology
The Kepler mission revolutionized our understanding of planetary systems by enabling the discovery of thousands of exoplanets orbiting close to their stars. However, because Kepler primarily observed Sun-like (FGK) stars, it provided a biased picture of exoplanet demographics. Indeed, studies of relatively cool and low-mass M dwarfs have revealed that the statistics of close-in planets depend on stellar mass, indicating that the conditions under which planets form and evolve change with the properties of the host star. The Transiting Exoplanet Survey Satellite (TESS), which launched in 2018 and continues to search for transiting planets across nearly the entire sky, has allowed us to explore these trends even further. Because TESS observes stars of all types, it provides the best opportunity yet to probe the landscape of close-in planets orbiting stars hotter and more massive than the Sun. In this talk, I will present the results of recent planet occurrence rate calculations, which suggest a drop-off in the frequency of close-in planets around A-type stars. In addition, I will discuss what this trend teaches us about planet formation and evolution, and explain how we can gain new insight by studying the orbital architectures of hot Jupiters and brown dwarfs discovered by TESS.

The Access Network: A Near-Peer Mentorship Program Starter Kit
Emily Griffith – University of Colorado Boulder
The Access Network is a consortium of nine university-based programs co-working with graduate and undergraduate students across the country to create a more diverse, equitable, inclusive, and accessible STEM community. To realize this vision, Access and its member programs empower students as co-leaders, giving them voice and ownership over local and national efforts. Access sites focus on fostering supportive learning communities and engaging students in authentic science practices by running near-peer mentorship programs, early arrival summer programs, academic courses, and more. In this talk, I will give an overview of the Access Network and the types of programs that network sites run, focusing on near-peer mentorship. I will discuss my current work with the Access Network to write and distribute a mentorship program starter kit.

KPM: A flexible and data-driven K-process model for nucleosynthesis
Emily Griffith – University of Colorado Boulder
The element abundance pattern found in Milky Way disk stars is close to two-dimensional, dominated by production from one prompt process and one delayed process. This simplicity is remarkable, since the elements are produced by a multitude of nucleosynthesis mechanisms operating in stars with a wide range of progenitor masses. In this talk I will present a flexible, data-driven K-process model–dubbed \name–and its fit to the abundances of 14 elements for 48,659 red-giant stars from APOGEE DR17. In my fiducial model, with K=2, each abundance in each star is described as the sum of a prompt and a delayed process contribution. I find that KPM with K=2 is able to explain the abundances well, recover the observed abundance bimodality, and detect the bimodality over a greater range in metallicity than previously has been possible. The model fixes the relative contribution of the prompt and delayed process to two elements to break degeneracies and improve interpretability; I find that some of the nucleosynthetic implications are dependent upon these detailed choices. I find that moving to four processes adds flexibility and improves the model’s ability to predict the stellar abundances, but doesn’t qualitatively change the story.

Multiphase Circumgalactic Gas Flow
Stephanie Ho – New Mexico State University
The reservoir of baryons and metals surrounding galaxies is known as the circumgalactic medium (CGM). The CGM plays a crucial role in the growth of galaxies; galaxies require a continuous gas supply to sustain star formation, and this gas accretion process is regulated by feedback from newly formed stars. However, observational analysis of the CGM is challenging. Not only because the low gas density makes the CGM difficult to image directly, but the CGM also consists of gas structures of different temperatures and densities, i.e., the CGM is multiphase. We will present our work on studying the kinematics of the cool (~10^4 K) and warm-hot (~10^5.5 K) CGM of low-redshift, star-forming galaxies. In particular, we will focus on the kinematics of the warm-hot CGM traced by the highly ionized O VI absorption detected in sightlines of background quasars. We will compare our results with analyses from cosmological simulations and explain the observational bias that potentially affects the interpretation of observational data.

A JWST View of Massive Star Clusters in the Central Starburst of M82
Rebecca Levy – University of Arizona
In their earliest evolutionary stages, star clusters are obscured by their dusty natal gas clouds. However, many of their properties, such as the star formation efficiency, are set during this early phase before feedback disperses the gas. While the Hubble Space Telescope has been revolutionary to study more evolved clusters in the local Universe, longer wavelengths are required to probe the youngest (age ≲ 5 Myr) star clusters. JWST offers a new window to study these earliest phases of young massive star cluster evolution at high spatial resolution. M82 is the prototypical starburst galaxy in the local Universe. Located at a distance of 3.6 Mpc, it is an ideal laboratory in which to study the starburst lifecycle, from the young embedded star clusters to its supernova feedback-driven multiphase superwind. We present new images obtained with NIRCam onboard JWST of the central kiloparsec of M82. These images reveal the massive star clusters and the base of the superwind in stunning detail. We identify ~100 clusters with stellar masses > 104 M☉ and radii ~1 pc. We estimate stellar masses for these clusters and investigate the cluster mass function. Upcoming observations of this region with MIRI imaging and spectroscopy will further illuminate the properties of these dusty, dynamic star clusters, their environment, and their relation to the superwind.

The Development of an MKID High Resolution Multi-Object Spectrometer
Ronald A Lopez – University of California, Santa Barbara
Conventional high-resolution spectrographs are typically designed to take detailed spectra of single targets or of a very limited field of view. On the other hand, multi-object spectrographs are designed to acquire spectra of multiple targets simultaneously at the expense of spectral resolution, wavelength coverage, and/or instrument cost. The inherent energy resolution of microwave kinetic inductance detectors (MKIDs) can be used to eliminate the need for a cross-dispersing element in a high-resolution spectrograph, freeing up valuable detector space that can be allocated to the spectra of multiple objects. This work lays the foundation for the development of a new class of high-resolution multi-object spectrographs (HRMOS) without the need to compromise resolution or coverage. A future, fiber-fed MKID HRMOS for the extremely large class of telescopes will be able to sample a comprehensive region around a star with an R~100,000 to detect and characterize exoplanet atmospheres using high-dispersion coronagraphy.

Constraining First Star Nucleosynthesis and the Early Universe with the Inner Milky Way
Maddie Lucey – University of Pennsylvania
The chemical composition, and dynamics of the oldest stars in the Milky Way place unique constraints on the properties of the first stars and the nature of the universe in which they formed. Our theory of galaxy formation and evolution predicts that the oldest stars are concentrated in the inner regions of Milky Way-like galaxies. In this talk, I will discuss a number of results on the properties of ancient inner galaxy stars and their impact on our understanding of the first stars and the early universe. First, I will present constraints on first star nucleosynthesis based on the chemical abundances of the most metal-poor stars in the inner Galaxy from the COMBS survey. I will also touch on the distribution of Carbon-Enhanced Metal-Poor (CEMP) stars in the Galaxy, with a new all-sky sample from Gaia data. Furthermore, I test cosmological zoom-in simulations by comparing the observed and predicted dynamical distribution of old stars in the inner Galaxy. Finally, I will discuss prospects for future constraints on first star nucleosynthesis and early galaxy formation from Milky Way observations with SDSS-V, future Gaia releases and Roman.

Towards a Permanent Peer-Mentoring Program at the University of California, Santa Cruz.
Loren Matilsky – University of California, Santa Cruz
Peer-mentoring is known to be a highly effective tool in giving early-career scientists the professional and social support they need to succeed. My plan for NSF Broader Impacts was to collaborate with students and postdocs at the University of California, Santa Cruz (UCSC) to establish a cross-disciplinary peer-mentoring program in the Astronomy and Applied Math Departments. This program would be molded by the latest research-based techniques in peer mentoring and undergo continual reevaluation and modification through input from its participants. The detailed format of the peer-mentoring program was left a bit loose in the proposal, but nominally would consist of undergraduates, graduate students, and postdoctoral researchers. I currently have several grad students in the Applied Math Department who would be interested in such a program and we’ve met several times to discuss structure but haven’t yet “dived in” and gotten the program off the ground. Part of the reason for this delay (apart from everyone just having really busy schedules) is we’re still figuring out the best way to ensure maximal buy-in, and not present the program as “one more chore” for already overworked students/postdocs. Maybe there is a practical “how to launch an effective mentoring program from scratch” handbook that I’ve been missing? (I’m not kidding, actually, but I haven’t found it!) Anyway, I will discuss the steps we’ve taken so far to establish this mentoring program at UCSC and then leave ample time for discussion and feedback from NSF Fellows, who may have valuable insight!

The importance of oblateness in the solar equator-to-pole temperature difference
Loren Matilsky – University of California, Santa Cruz
In many rotating fluids, the lowest-order force balance is between gravity, pressure, and rotational acceleration (“GPR” balance). Terrestrial GPR balance takes the form of geostrophy (balance of the Coriolis force and horizontal pressure gradients) and hydrostasy (balance of the gravitational force and vertical pressure gradients), which together yield the terrestrial “thermal wind” equation. By contrast, stellar GPR balance, and the resultant thermal wind equation, is really an equation of shape, or oblateness. Although similar in form to the terrestrial equation, the stellar thermal wind equation has several distinct properties, the neglect of which has led to some confusion and conflicting results in the estimates of the pole-to-equator temperature difference in the Sun. I performed a new calculation of this temperature difference (using the stellar equation that correctly incorporates the full oblateness) and found that the often-cited “thermal wind” temperature difference is actually ~3-60 times smaller than the other terms in the shape equation. Thus, the anomaly from the “thermal wind” may not be measurable. If measurement were possible, however, this would potentially yield a new way to measure the width of the tachocline (an internal boundary layer of strong shear that is believed to be extremely important for the production of solar magnetic fields).

Nature vs. Nurture: Understanding how internal and external processes shape galactic interiors
Francisco Mercado – Pomona College
Despite the fact that galaxies are incredibly complex systems, they follow remarkably tight scaling relations between their various internal properties (e.g. the Tully-Fisher Relation, the Radial Acceleration Relation, the Mass Metallicity Relation). These relations play a key role in connecting the observable properties of galaxies to the processes that shape them. In this talk I will discuss work in which I use high-resolution, cosmological simulations to understand how internal processes , like star formation feedback, and external processes, such as interactions with environment, shape galactic interiors. I find that the varied dynamical effects of such processes on a galaxy can dictate its position on a given scaling relation. Understanding the connection between these dynamical effects and the resulting scaling relations provides us with a unique opportunity to use scaling relations as the basis for tests that assess our understanding of galaxy formation and dark matter physics.

Studying the earliest stages of molecule formation in the diffuse ISM: insights from 21cm and 3mm absorption
Dan Rybarczyk – University of Wisconsin-Madison
The diffuse interstellar medium (ISM) plays an important role in the evolution of gas in galaxies, marking an intermediate stage between hot, diffuse ionized gas and cold, dense star-forming molecular clouds. Although the diffuse ISM hosts the first stages of molecule formation in galaxies, the chemistry of the diffuse ISM is surprisingly — in many cases, confoundingly — rich. We present some of the most sensitive observations to date of diffuse molecular gas (including HCO+, HCN, HNC, CCH, CO, and SiO) in absorption. Paired with observations of atomic gas (HI), we set constraints on the conditions necessary for molecule formation and survival in the diffuse ISM. A broad, faint signature in HCO+ absorption reveals that molecular gas exists in warmer and more diffuse environments than previously thought. A similar signature has recently been identified in OH emission; upcoming observations of HCO+ absorption and OH emission will compare these signatures directly along the same lines of sight. Compared to regions where strong, narrow HCO+ absorption lines are observed, the diffuse gas traced by this broad component has a lower CO abundance, higher gas temperature, and lower molecular fraction. We discuss the implications of this diffuse molecular gas for our understanding of the HI-to-H2 transition in diffuse environments.

AstroCore: Modules for High School Classrooms
Dominique Segura-Cox – University of Texas at Austin
I grew up in a rural small town with my blue-collar family, and I want to contribute to the educations of students in similar situations. I’m currently working with Texas teachers to develop modules of worksheets, lesson plans, activities, and teachers’ notes aimed at bringing astronomy into classrooms. The modules will be published online for broad use by any teacher, rural or urban, advantaged or impoverished. We use astronomy themes to convey core math and science concepts required by Texas state education standards for graduation, and focus on making the main modules no-cost and technology light to best serve the needs of rural students and teachers.

Near-Field Cosmology with Stellar Streams
Nora Shipp – Carnegie Mellon University
Stellar streams, the tidal remnants of globular clusters and dwarf galaxies orbiting throughout the Milky Way’s halo, are some of the most powerful tools in the study of near-field cosmology. In particular, they are sensitive probes of the distribution and properties of dark matter across multiple scales, from the smallest subhalos, to the entire dark matter halo, as well as being excellent tracers of the growth and structure of our Galaxy. Thanks to recent large photometric, astrometric, and spectroscopic surveys, the population of stellar streams around the Milky Way is finally being revealed. In this talk, I will present the discovery, characterization, and modeling of the Milky Way stellar streams, as well as the first comparative studies of stream populations in observations and cosmological simulations, which revealed inconsistencies in orbital parameters, as well as a wealth of potentially yet to be detected stellar streams. In addition, I will discuss plans to use upcoming surveys like the Rubin Observatory LSST in order to discover and analyze tidal structures throughout the Milky Way and across the local Universe. These data will further revolutionize the study of near-field cosmology, and reveal the answers to critical questions about the structure and assembly of our Galaxy and the nature of dark matter.

The EMIT Program: Establishing Multimessenger astronomy Inclusive Training
Aaron Stemo – University of Colorado Boulder
The first multimessenger observations of astronomical objects combining simultaneous electromagnetic and gravitational wave signals are less than a decade old and have already begun to address key questions regarding the physics of the universe. Growing infrastructure and scientific efforts point towards multimessenger astronomy (MMA) being the next major subfield of physics and astronomy, and the Establishing Multimessenger astronomy Inclusive Training (EMIT) Program at Vanderbilt University, in partnership with Fisk University, is working to ensure MMA’s future success. EMIT brings together astronomy, physics, engineering, mathematics, and data science, in a transdisciplinary two-year graduate certificate program that centers diversity and inclusion. The goal of the EMIT program is to produce scholars with the skills needed to drive research and expand the STEM workforce, while building true community. As an NSF MPS-Ascend Postdoctoral Fellow at Vanderbilt, I have been an integral member of the EMIT Program since its foundation. Here, I will discuss the goals and aims of the EMIT Program, as well as our efforts over the last two years to ensure the success of its first cohort, welcomed in the Fall of 2023.