Ionized Gas in the Irr Galaxy IC 10: The Emission Spectrum and Ionization Sources

TL;DR

This study analyzes the ionized gas spectrum in the star-forming galaxy IC 10, refining metallicity estimates and characterizing ionization sources, electron density, and star cluster properties using advanced models and spectroscopic data.

Contribution

It provides new detailed measurements of gas ionization parameters, electron density, and star cluster characteristics in IC 10 using improved ionization models and spectroscopic observations.

Findings

Ionization models fit the observed spectra well.

Star cluster age estimated at 2.5-5 Myr.

Cluster mass estimated at (0.2-1)×10^5 solar masses.

Abstract

We present the results of observations of the Irr galaxy IC 10 at the 6-m SAO telescope with the panoramic Multi-Pupil Fiber Spectrograph (MPFS). Based on the results of these observations and our long-slit spectroscopy performed previously, we have investigated the ionized-gas emission spectrum in the region of intense star formation and refined the gas metallicity estimates. We show that the "diagnostic diagrams" constructed from our observations agree best with the new improved ionization models by Martin-Manjon et al. Using these models, we have determined the electron density and gas ionization parameter and ionizing-cluster characteristics, the age and mass, from the spectra of the investigated HII regions. The cluster age and mass are shown to be within the ranges 2.5 - 5 Myr and (0.2 - 1)*10^5 M(sun), respectively.