MASCOT -- An ESO-ARO legacy survey of molecular gas in nearby SDSS-MaNGA galaxies: I. first data release, and global and resolved relations between H_2 and stellar content

TL;DR

This paper presents the first data release of the MASCOT survey, measuring molecular gas in 187 nearby galaxies using CO(1-0) emission, revealing relations between gas content, star formation, and stellar populations.

Contribution

It provides integrated CO(1-0) measurements across multiple radii for a large galaxy sample, linking molecular gas properties with stellar and star formation characteristics.

Findings

Star formation decline correlates with reduced molecular gas and efficiency.

Galaxies with less molecular gas have older central stellar populations.

Evidence suggests inside-out quenching related to molecular gas distribution.

Abstract

We present the first data release of the MaNGA-ARO Survey of CO Targets (MASCOT), an ESO Public Spectroscopic Survey conducted at the Arizona Radio Observatory (ARO). We measure the CO(1-0) line emission in a sample of 187 nearby galaxies selected from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey that has obtained integral field unit (IFU) spectroscopy for a sample of ~ 10,000 galaxies at low redshift. The main goal of MASCOT is to probe the molecular gas content of star-forming galaxies with stellar masses > 10^9.5 M_solar and with associated MaNGA IFU observations and well-constrained quantities like stellar masses, star formation rates and metallicities. In this paper we present the first results of the MASCOT survey, providing integrated CO(1-0) measurements that cover several effective radii of the galaxy and present CO luminosities, CO kinematics, and estimated H2 gas masses. We observe that the decline of galaxy star formation rate with respect to the star formation main sequence (SFMS) increases with the decrease of molecular gas and with a reduced star formation efficiency, in agreement with results of other integrated studies. Relating the molecular gas mass fractions with the slope of the stellar age gradients inferred from the MaNGA observations, we find that galaxies with lower molecular gas mass fractions tend to show older stellar populations close to the galactic center, while the opposite is true for galaxies with higher molecular gas mass fractions, providing tentative evidence for inside-out quenching.