Dwarf Galaxy Integral-field Survey (DGIS): survey overview and the result of global mass-metallicity relation

TL;DR

The DGIS survey provides high-resolution spatial data on dwarf galaxies, revealing that their mass-metallicity relation extends from larger galaxies without reduced dispersion, independent of star formation rate.

Contribution

This study presents the first detailed overview of the DGIS survey and its initial results on the mass-metallicity relation in dwarf galaxies.

Findings

Mass-metallicity relation extends to dwarf galaxies.

Dispersion in metallicity does not decrease with SFR.

High-resolution integral-field data enables detailed galactic studies.

Abstract

Low-mass galaxies are the building blocks of massive galaxies in the framework of hierarchical structure formation. To enable detailed studies of galactic ecosystems in dwarf galaxies by spatially resolving different galactic components, we have carried out the Dwarf Galaxy Integral-field Survey (DGIS). This survey aims to acquire observations with spatial resolutions as high as 10 to 100 pc while maintaining reasonably high signal-to-noise ratios with VLT/MUSE and ANU-2.3m/WiFeS. The whole sample will be composed of 65 dwarf galaxies with $M_{\rm \ast}$ $<$ 10$^{9}$ $\rm M_{\odot}$, selected from the Spitzer Local Volume Legacy Survey. The overall scientific goals include studying baryonic cycles in dwarf galaxies, searching for off-nuclear (intermediate)-massive black holes, and quantifying the inner density profiles of dark matter. In this work, we describe the sample selection, data reduction, and high-level data products. By integrating the spectra over the field of view for each galaxy, we obtained the integrated gas-phase metallicity and discussed its dependence on stellar mass and SFR. We find that the overall relation between metallicity and stellar mass of our DGIS nearly follows the extrapolation from the higher mass end. Its dispersion does not decrease by invoking the dependence on SFR.