Yiting’s Title: Resolved Orbits around Accelerating Stars with RV, Direct Imaging and Astrometry

Astrometry, a time-honored planet detection technique, has thus far revealed only one gas giant planet while holding untapped potential for both ground- and space-based telescopes. This talk explores the use of Hipparcos and Gaia catalog data as an astrometry method to determine exoplanet masses. I discuss how integrating astrometry with direct imaging and radial velocity measurements can disentangle orbital curvatures, constrain precise dynamical masses, and improve target selection for direct imaging surveys focused on young, accelerating stars. Our ongoing direct imaging survey, conducted with the Keck/Subaru/SCAxAO and Keck/NIRC2 instruments, has unveiled a plethora of newly discovered substellar companions. These discoveries are contributing to the refinement of substellar evolutionary models and the rigorous testing of atmospheric models for giant planets and brown dwarfs. I will also briefly discuss future research interests, including TOLIMAN, a NASA-JPL astrometry mission to search for earth analog around the nearest binary stars, new ground-based observations and JWST initiatives, and exoplanet demographic studies.

Behzad’s Title: Do Massive Black Holes Come in Small Packages?

The mass function of black holes (BH) at lower masses remains poorly constrained in the local universe due to observational challenges. The occupation fraction of BHs within low-mass galaxy hosts, like compact stellar systems (CSSs), is essential for competing theories on supermassive BH (SMBH) formation. Stellar dynamical modeling has been successful in constraining the masses of central BHs in the cores of CSSs. I will discuss the power and limitations of our dynamical modeling approach to determine the black hole masses for CSSs in the Virgo cluster by JWST NIRSpec. We obtained JWST+NIRSpec/IFU data cubes to derive spatially resolved stellar kinematics of 18 selected CSSs in the Virgo Cluster. We will apply our method to determine the black hole masses in these CSSs, which is the first-ever census of CSS BHs in the Virgo galaxy cluster.