A Near-Infrared Imaging Survey of Coalsack Globule 2

Abstract

We describe a near-infrared imaging survey of Globule 2 in the Coalsack. This Bok globule is the highest density region of this southern hemisphere molecular cloud and is the most likely location for young stars in this complex. The survey is complete for K < 14.0, H < 14.5, and J < 15.5, several magnitudes more sensitive than previous observations of this globule. From the large number of background stars, we derive an accurate near-infrared extinction law for the cloud. Our result, E_{J-H}/E_{H-K} = 2.08 \pm 0.03, is significantly steeper than results for other southern clouds. We use the J-H/H-K color-color diagram to identify two potential young stars with K < 14.0 in the region. We apply H-band star counts to derive the density profile of the Coalsack Globule 2 and use a polytropic model to describe the internal structure of this small cloud. For a gas temperature T \sim 15 K, this globule is moderately unstable.

19 pages, manuscript format; 6 figures -- Accepted by AJ

Cited by in corpus (27)

• The Wavelength Dependence of Interstellar Extinction from 1.25 to 8.0 microns Using GLIMPSE Data
• The UKIDSS Galactic Plane Survey
• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• Infrared Extinction Toward Nearby Star-Forming Regions
• Line derived infrared extinction towards the Galactic Center
• Near Infrared Imaging Survey of Bok Globules: Density Structure
• Fragmentation of a Molecular Cloud Core versus Fragmentation of the Massive Protoplanetary Disk in the Main Accretion Phase
• The Virial Balance of Clumps and Cores in Molecular Clouds
• Evidence for Environmental Changes in the Submillimeter Dust Opacity
• The Slope of the Near Infrared Extinction Law
• Galactic cold cores V. Dust opacity
• Observational Constraints on Interstellar Grain Alignment
• Extinction law in the range 0.4-4.8 $\mu$m and the 8620 $\mathring{A}$ DIB towards the stellar cluster Westerlund 1
• From Dusty Filaments to Cores to Stars: An Infrared Extinction Study of Lupus 3
• The Mid-Infrared Extinction Law and its Variation in the Coalsack Nebula
• The Formation and Evolution of Protostellar Disks; 3D AMR Hydro-Simulations of Collapsing, Rotating Bonnor-Ebert-Spheres
• Alignment of Outflows with Magnetic Fields in Cloud Cores
• Discovery of a Dusty Ring in the Coalsack: A Dense Core Caught in the Act of Formation?
• The Near-Infrared Extinction Law in Regions of High Av
• A Galactic Plane Relative Extinction Map from 2MASS
• Impact of distance determinations on Galactic structure. I. Young and intermediate-age tracers
• A Near-Infrared (JHK) Survey of the Vicinity of the HII region NGC 7538: Evidence for a Young Embedded Cluster
• Near-Infrared Extinction in The Coalsack Globule 2
• A 2MASS Analysis of the Stability of Southern Bok Globules
• Dust extinction map of the Galactic plane based on the VVV survey data
• The dense ring in the Coalsack: the merging of two subsonic flows
• Chemical chronology of the Southern Coalsack