A Colour-Excess Extinction Map of the Southern Galactic Disc from the VVV and GLIMPSE Surveys

An improved high-resolution and deep A(Ks) foreground dust extinction map is presented for the Galactic disc area within 295 degrees less than or similar to l less than or similar to 350 degrees, -1.0 degrees less than or similar to b less than or similar to +1.0 degrees. At some longitudes the map reaches up to vertical bar b vertical bar similar to 2.25 degrees, for a total of similar to 148 deg(2). The map was constructed via the Rayleigh-Jeans colour 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 arcmin, and relies on NIR observations from the Two Micron All-Sky Survey (2MASS) and new data from ESO's Vista Variables in the Via Lactea (VVV) survey, in concert with MIR observations from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire. The VVV photometry penetrates similar to 4 mag 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.