Wide Field Integral Spectroscopy in Nearby Galaxies with the TYPHOON Survey

TL;DR

The TYPHOON survey provides detailed spectroscopic data of nearby galaxies, revealing how local physical conditions and spiral structures influence the distribution and variation of interstellar medium metallicity within galaxy disks.

Contribution

This study presents early results from the TYPHOON survey, highlighting the relationship between local physical conditions, spiral structures, and ISM metallicity variations in nearby galaxies.

Findings

Strong correlation between ionization parameter and local metallicity.

Metallicity variations driven by star formation and spiral density wave mixing.

Spiral pattern influences ISM organization but does not solely determine azimuthal uniformity.

Abstract

The TYPHOON program is producing an atlas of spectroscopic data cubes of 44 large-angular-sized galaxies with complete spatial coverage from 3650-9000 A. This survey provides an unparalleled opportunity to study variations in the interstellar medium (ISM) properties within individual HII regions across the entire star-forming disks of nearby galaxies. This can provide key insights into the spatial distribution and resolved properties of the ISM to understand how efficiently metals are mixed and redistributed across spirals and dwarf galaxies. In this Proceeding, we present early science results from six nearby spiral galaxies as part of the TYPHOON program from Grasha et al. (2022). We use HIIPhot to identify the HII regions within the galaxy based on the surface brightness of the H-alpha emission line and measure variations of the HII region oxygen abundance. In this initial work, we find that while the spiral pattern plays a role in organizing the ISM, it alone does not establish the relatively uniform azimuthal variations we observe across all the galaxies. Differences in the metal abundances are more likely driven by the strong correlations with the local physical conditions. We find a strong and positive correlation between the ionization parameter and the local abundances as measured by the relative metallicity offset $\Delta$(O/H), indicating a tight relationship between local physical conditions and their localized enrichment of the ISM. These variations can be explained by a combination of localized, star formation-driven self-enrichment and large-scale mixing-driven dilution due to the passing of spiral density waves.