2MASS wide field extinction maps: II. The Ophiuchus and the Lupus cloud complexe

TL;DR

This paper presents detailed near-infrared extinction maps of the Ophiuchus and Lupus molecular clouds using 2MASS data, revealing small-scale structures and deviations from turbulence models.

Contribution

It introduces a robust method for mapping dust extinction and a novel approach to analyze small-scale cloud inhomogeneities.

Findings

Extinction can be detected down to A_K = 0.05 mag with 3 arcmin resolution.

Small-scale inhomogeneities in clouds are characterized statistically.

Cloud structure functions show deviations from turbulent model predictions.

Abstract

We present an extinction map of a ~1,700 deg sq region that encloses the Ophiuchus, the Lupus, and the Pipe dark complexes using 42 million stars from the Two Micron All Sky Survey (2MASS) point source catalog. The use of a robust and optimal near-infrared method to map dust column density (Nicer, described in Lombardi & Alves 2001) allow us to detect extinction as low as A_K = 0.05 mag with a 2-sigma significance, and still to have a resolution of 3 arcmin on our map. We also present a novel, statistically sound method to characterize the small-scale inhomogeneities in molecular clouds. Finally, we investigate the cloud structure function, and show that significant deviations from the results predicted by turbulent models are observed.