A Color-Excess Extinction map of the Southern Galactic disk from the VVV and GLIMPSE Surveys

TL;DR

This paper presents a high-resolution, deep extinction map of the Southern Galactic disk using the RJCE technique with combined NIR and MIR data, improving upon previous maps by revealing more accurate dust extinction in heavily obscured regions.

Contribution

The authors develop a new, high-resolution extinction map of the Galactic disk using deep NIR and MIR data, surpassing previous maps in accuracy and resolution.

Findings

The new map covers 148 deg$^2$ with 1' resolution.

It reveals systematic underestimation in prior extinction maps.

The map is publicly available via a web interface.

Abstract

An improved high-resolution and deep A$_{Ks}$ foreground dust extinction map is presented for the Galactic disk area within $295^{\circ} \lesssim l \lesssim 350^{\circ}$, $-1.0^{\circ} \lesssim b \lesssim +1.0^{\circ}$. At some longitudes the map reaches up to $|b|\sim2.25^{\circ}$, for a total of $\sim$148 deg$^2$. The map was constructed via the Rayleigh-Jeans Color Excess (RJCE) technique based on deep near-infrared (NIR) and mid-infrared (MIR) photometry. The new extinction map features a maximum bin size of 1', and relies on NIR observations from the Two Micron All-Sky Survey (2MASS) and new data from ESO's Vista Variables in the V\'ia L\'actea (VVV) survey, in concert with MIR observations from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE). The VVV photometry penetrates $\sim$4 magnitudes fainter than 2MASS, and provides enhanced sampling of the underlying stellar populations in this heavily obscured region. Consequently, the new results supersede existing RJCE maps tied solely to brighter photometry, revealing a systematic underestimation of extinction in prior work that was based on shallower data. The new high-resolution and large-scale extinction map presented here is readily available to the community through a web query interface.