CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud

TL;DR

This study uses N2H+ observations to analyze the structure and kinematics of filaments in the Serpens South molecular cloud, revealing narrower gas filaments and complex velocity patterns that inform star formation processes.

Contribution

It provides high-resolution, large-area N2H+ mapping of Serpens South, highlighting differences between gas and dust filaments and analyzing their velocity structures.

Findings

Gas filaments are narrower than dust filaments, challenging Herschel's resolution.

Some filaments exhibit velocity gradients suggestive of turbulence or mass infall.

Velocity gradients vary along and across filaments, indicating complex dynamics.

Abstract

We present the N2H+(J=1-0) map of the Serpens South molecular cloud obtained as part of the CARMA Large Area Star Formation Survey (CLASSy). The observations cover 250 square arcminutes and fully sample structures from 3000 AU to 3 pc with a velocity resolution of 0.16 km/s, and they can be used to constrain the origin and evolution of molecular cloud filaments. The spatial distribution of the N2H+ emission is characterized by long filaments that resemble those observed in the dust continuum emission by Herschel. However, the gas filaments are typically narrower such that, in some cases, two or three quasi-parallel N2H+ filaments comprise a single observed dust continuum filament. The difference between the dust and gas filament widths casts doubt on Herschel ability to resolve the Serpens South filaments. Some molecular filaments show velocity gradients along their major axis, and two are characterized by a steep velocity gradient in the direction perpendicular to the filament axis. The observed velocity gradient along one of these filaments was previously postulated as evidence for mass infall toward the central cluster, but these kind of gradients can be interpreted as projection of large-scale turbulence.