2MASS wide field extinction maps

II. The Ophiuchus and the Lupus cloud complexes

¹ European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching bei München, Germany e-mail: mlombard@eso.org
² University of Milan, Department of Physics, via Celoria 16, 20133 Milan, Italy (on leave)
³ Harvard-Smithsonian Center for Astrophysics, Mail Stop 42, 60 Garden Street, Cambridge, MA 02138, USA
⁴ Calar Alto Observatory – Centro Astronómico Hispano Alemán, C/Jesús Durbán Remón 2-2, 04004 Almeria, Spain

Received: 26 April 2008
Accepted: 30 June 2008

Abstract

We present an extinction map of a ~1700 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, 
A&A, 377, 1023) allow us to detect extinction as low as A_K = 0.05 mag with a 2-σ 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.