3D Interstellar Extinction Map within the Nearest Kiloparsec

TL;DR

This study presents a high-resolution 3D interstellar extinction map within 1 kpc of the Sun, integrating previous reddening and $R_V$ variation maps, and compares it with existing models to analyze dust properties and Galactic structures.

Contribution

It provides a new detailed 3D extinction map with improved accuracy and resolution, and analyzes the spatial variations of reddening and $R_V$ across the nearest kiloparsec.

Findings

Good agreement with existing maps and models except near the Galactic center.

Schlegel et al.'s map saturates at high reddening and has systematic errors.

Dust grain properties vary systematically across different Galactic regions.

Abstract

The product of the previously constructed 3D maps of stellar reddening (Gontcharov 2010) and $R_V$ variations (Gontcharov 2012) has allowed us to produce a 3D interstellar extinction map within the nearest kiloparsec from the Sun with a spatial resolution of 50 pc and an accuracy of $0.2^m$. This map is compared with the 2D reddening map by Schlegel et al. (1998), the 3D extinction map at high latitudes by Jones et al. (2011), and the analytical extinction models by Arenou et al. (1992) and Gontcharov (2009). In all cases, we have found good agreement and show that there are no systematic errors in the new map everywhere except the direction toward the Galactic center. We have found that the map by Schlegel et al. (1998) reaches saturation near the Galactic equator at $E_{(B-V)}>0.8^m$, has a zero-point error and systematic errors gradually increasing with reddening, and among the analytical models those that take into account the extinction in the Gould Belt are more accurate. Our extinction map shows that it is determined by reddening variations at low latitudes and $R_V$ variations at high ones. This naturally explains the contradictory data on the correlation or anticorrelation between reddening and $R_V$ available in the literature. There is a correlation in a thin layer near the Galactic equator, because both reddening and $R_V$ here increase toward the Galactic center. There is an anticorrelation outside this layer, because higher values of $R_V$ correspond to lower reddening at high and middle latitudes. Systematic differences in sizes and other properties of the dust grains in different parts of the Galaxy manifest themselves in this way. The largest structures within the nearest kiloparsec, including the Local Bubble, the Gould Belt, the Great Tunnel, the Scorpius, Perseus, Orion, and other complexes, have manifested themselves in the constructed map.