NOTE: This week in NOIRLab Room 27 !

Aafaque Raza Khan (UA/Steward)
Mapping the Emission from the CGM of Large Magellanic Cloud with SmallSats: Aspera Extended Mission Concept and Beyond

This talk introduces an example of an Aspera extended mission science concept focused on mapping OVI emission around the Large and Small Magellanic Clouds (LMC/SMC) and the Milky Way (MW). Recent background quasar absorption line studies have detected multiphase gas trailing the LMC, containing ionized species like CIV, SIV, and OVI. The origin of this gas remains unclear, with two potential explanations: it could either be the primordial CGM of the LMC or a mixture of recent stellar outflows from the LMC and MW CGM, which have been entrained by the LMC due to its high-speed motion through the MW halo. To differentiate between these scenarios, it is essential to understand the spatial extent of this gas ahead of the LMC, an area where data is sparse. The two scenarios predict different gas distributions—one that is truncated (LMC CGM) due to shock interactions, and another that is extended (primordial LMC CGM).

We explore how Aspera, a NASA astrophysics pioneer mission, could detect emission from the warm-hot phase of the LMC and MW CGM. Aspera is designed to map OVI emission from CGM of nearby galaxies. After completion of its primary mission,  we intend to do several pointings along the direction of the LMC's tangential velocity over several months. Aspera would be able to sample the radial profile of OVI emission ahead of the LMC providing insight into the distribution of warm hot gas at the interface of LMC and MW CGM. Determining the origin of this OVI emission is crucial for understanding the evolution of the LMC and SMC system and the role mergers play in shaping the CGM of galaxies like the MW. These observations would act as a proof of concept for future missions aimed at mapping the morphology and distribution of ionized gas surrounding the LMC. We briefly discuss how small satellites provide a unique proposition in enabling a comprehensive multi-wavelength map (OVI, CVI, SiIV) of the CGM around the LMC and probe its interaction with the Milky Way. 

Myoungwon Jeon (Kyung Hee University)
Challenges in Simulating Ultra-Faint Dwarf Galaxies: Discrepancies in Metallicity and Size
Ultra-faint dwarf galaxies (UFDs) present significant challenges in cosmological simulations, especially in accurately reproducing stellar metallicity and galaxy size. Even with advancements in simulation resolution that allow for more detailed sub-grid physics, discrepancies between simulated and observed UFD properties remain. A notable issue is the stellar mass-metallicity relation (MZR), which shows a strong correlation in the classical dwarf regime, aligning observations with simulations. However, for UFD galaxies that formed most of their stars before reionization (z ~ 6), this correlation diminishes, displaying a plateau. Simulations often predict metallicities that are 2-3 dex lower than those observed in the UFD regime. Furthermore, predicting the size of observed UFDs accurately is challenging, as current high-resolution simulations tend to predict larger half-light radii than those observed. In this talk, I will present some results from cosmological simulations of UFD analogs and explore potential causes for these discrepancies between observations and simulations.