CN 2-1 and CS 5-4 observations toward Arp 299 with the SMA

TL;DR

This study uses high-resolution SMA observations of dense gas tracers CN 2-1 and CS 5-4 in Arp 299 to analyze dense gas distribution and star formation efficiency across different regions of the merging galaxy system.

Contribution

It provides new high-resolution observations of dense gas tracers in Arp 299, revealing spatial variations and implications for starburst activity during galaxy mergers.

Findings

Dense gas tracers are spatially consistent with each other and with HCN 1-0.

Line ratios vary across regions, highest in B.

Dense gas fraction decreases from nucleus to overlap region.

Abstract

Dense gas is the key for understanding star formation in galaxies. We present high resolution ($\sim3''$) observations of CN 2-1 and CS 5-4 as dense gas tracers toward Arp 299, a mid stage major merger of galaxies, with the Submillimeter Array (SMA). The spatial distribution of CN 2-1 and CS 5-4 are generally consistent with each other, as well as HCN 1-0 in literature. However, different line ratios of CS 5-4 and CN 2-1 are found in A, B, and C regions, with highest value in B. Dense gas fraction decreases from IC 694 (A), to NGC 3690 (B) and the overlap starburst region (C and C$'$), which indicates that circum-nuclear upcoming starburst in A and B will be more efficient than that in the overlap region of Arp 299.