VERTICO III: The Kennicutt-Schmidt relation in Virgo cluster galaxies by M. J. Jiménez-Donaire et al. on Wednesday 30 November

In this VERTICO science paper we aim to study how the star formation process

depends on galactic environment and gravitational interactions in the context

of galaxy evolution. We explore the scaling relation between the star formation

rate (SFR) surface density and the molecular gas surface density, also known as

the Kennicutt-Schmidt (KS) relation, in a subsample of Virgo cluster spiral

galaxies. We use new ACA and TP observations from the VERTICO-ALMA Large

Program at 720pc resolution to resolve the molecular gas content, as traced by

the 12CO(2-1) transition, across the disks of 37 spiral galaxies in the Virgo

cluster. In combination with archival observations, we estimate the parameters

of the KS relation for the entire ensemble of galaxies, and within individual

galaxies. We find the KS slope for the entire population to be N=0.97+/-0.07,

with a characteristic molecular gas depletion time of 1.86Gyr for our full

sample, in agreement with previous work in isolated star-forming galaxies. In

individual galaxies, we find KS slopes ranging between 0.69 and 1.40, and

typical star formation efficiencies (SFE) that can vary from galaxy to galaxy

by a factor of ~4. These galaxy-to-galaxy variations account for ~0.20dex in

scatter in the ensemble KS relation, which is characterized by a 0.42dex

scatter. We find that the HI-deficient galaxies in the Virgo cluster show a

steeper resolved KS relation and lower molecular gas efficiencies than

HI-normal cluster galaxies. While the molecular gas content in Virgo cluster

galaxies appears to behave similarly to that in isolated galaxies, our VERTICO

sample shows that cluster environments play a key role in regulating star

formation. The environmental mechanisms affecting the HI galaxy content also

have a direct impact in the SFE of molecular gas in cluster galaxies, leading

to longer depletion times in HI-deficient members.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16521v1