An Observed Lack of Substructure in Starless Cores

TL;DR

This study used high-resolution radio observations to investigate the internal structure of starless cores in Perseus, finding most lack substructure and suggesting their density profiles are shallower than r^-2.

Contribution

It provides the first high-resolution survey of starless cores in Perseus, showing most cores are single structures and challenging assumptions about core blending effects.

Findings

Only 2 of 11 cores detected at 3mm

Non-detections imply cores are mostly single structures

Supports that starless cores have shallow density profiles

Abstract

In this paper we present the results of a high resolution (5") CARMA and SZA survey of the 3mm continuum emission from 11 of the brightest (at 1.1mm) starless cores in the Perseus molecular cloud. We detect 2 of the 11 cores, both of which are composed of single structures, and the median 3 sigma upper limit for the non-detections is 0.2 M_sun in a 5" beam. These results are consisent with, and as stringent as, the low detection rate of compact 3mm continuum emission in dense cores in Perseus reported by Olmi et al. (2005). From the non-detection of multiple components in any of the eleven cores we conclude that starless core mass functions derived from bolometer maps at resolutions from 10"-30" (e.g. with MAMBO, SCUBA or Bolocam) are unlikely to be significantly biased by the blending of lower mass cores with small separations. These observations provide additional evidence that the majority of starless cores in Perseus have inner density profiles shallower than r^-2.