C2H, HC3N and HNC Observations in OMC-2/3

TL;DR

This study maps the OMC-2/3 region in three molecular lines, revealing filamentary structures and core properties, and suggests C2H as a good tracer for core structures in molecular clouds.

Contribution

First mapping of OMC-2/3 in C2H, HC3N, and HNC lines, demonstrating their spatial distribution and physical properties, and highlighting C2H's potential as a core tracer.

Findings

C2H emission follows 1300 μm condensations

Core masses vary from 6.4 to 49.5 solar masses

Line widths indicate higher turbulence than dark clouds

Abstract

For the first time, the OMC-2/3 region was mapped in C2H(1-0), HC3N(10-9) and HNC(1-0) lines. In general, the emissions from all the three molecular species reveal an extended filamentary structure. The distribution of C2H cores almost follows that of the 1300 $\mu$m condensations, which might suggest that C2H is a good tracer to study the core structure of molecular clouds. The core masses traced by HNC are rather flat, ranging from 18.8 to 49.5 $M_{\odot}$, while present a large span for those from C2H, ranging from 6.4 to 36.0 $M_{\odot}$. The line widths of both HNC and C2H look very similar, and both are wider than that of HC3N. The line widths of the three lines are all wider than those from dark clouds, implying that the former is more active than the latter, and has larger turbulence caused by winds and UV radiation from the surrounding massive stars.