Photoelectric heating effects on the evolution of luminous disk galaxies

TL;DR

This study investigates how photoelectric heating affects star formation, gas dynamics, and galaxy evolution in Milky Way-like galaxies using advanced SPH simulations, revealing significant suppression of star formation and altered galaxy morphology.

Contribution

It provides the first detailed simulation-based analysis of PEH effects on galaxy evolution, including dust evolution and feedback mechanisms, in Milky Way-like systems.

Findings

PEH suppresses star formation by heating the ISM.

Higher gas fractions lead to greater star formation suppression.

PEH increases gas outflows and SNe feedback effects.

Abstract

Photoelectric heating (PEH) influences the temperature and density of the interstellar medium (ISM), and potentially also affecting star formation. PEH is expected to have a stronger effect on massive galaxies, as they host larger dust reservoirs compared to dwarf systems. Accordingly, in this paper, we study PEH effects in Milky Way-like galaxies using smoothed particle hydrodynamics (SPH) code which self-consistently implements the evolution of the gas, dust, and interstellar radiation field (ISRF). Dust evolution includes dust formation by stars, destruction by SNe, and growth in dense media. We find that PEH suppresses star formation due to the excess heating that reduces the ISM density. This suppression is seen across the entire range of gas fractions, star formation recipes, dust models, and PEH efficiencies investigated by our code. The suppression ranges from negligible values to approximately a factor of five depending on the specific implementation. Galaxy models having higher gas fraction experience higher star formation suppression. The adopted dust model also alters the extent of star formation suppression. Moreover, when PEH is switched on, galaxy models show higher gas outflow rates and have higher loading factors indicative of enhanced SNe feedback. In gas-rich models (i.e. a gas fraction of 0.5), we also find that PEH suppresses the formation of disk clumps via violent disk instabilities, and thus suppresses bulge formation via clumps migration to the central regions.