Allsky NICER and NICEST extinction maps based on the 2MASS near-infrared survey

TL;DR

This paper presents all-sky extinction maps derived from the 2MASS near-infrared survey using NICER and NICEST methods, providing a valuable resource for studying Galactic interstellar clouds with resolution-dependent bias correction.

Contribution

The study produces high-resolution all-sky extinction maps with improved bias correction, demonstrating the effectiveness of NICEST over NICER for large-scale Galactic cloud analysis.

Findings

Good correspondence with previous maps but with resolution-dependent bias.

NICEST reduces bias compared to NICER.

Maps are useful for global and initial cloud studies.

Abstract

Extinction remains one of the most reliable methods of measuring column density of nearby Galactic interstellar clouds. The current and ongoing near-infrared surveys enable the mapping of extinction over large sky areas. We produce allsky extinction maps using the 2MASS near-infrared survey. We use the NICER and NICEST methods to convert the near-infrared colour excesses to extinction estimates. The results are presented in Healpix format at the resolutions of 3.0, 4.5, and 12.0 arcmin. The main results of this study are the calculated J-band extinction maps. The comparison with earlier large-scale extinction mappings shows good correspondence but also demonstrates the presence of resolution-dependent bias. A large fraction of the bias can be corrected by using the NICEST method. For individual regions, best extinction estimates are obtained by careful analysis of the local stellar population and the use of the highest resolution afforded by the stellar density. However, the uniform allsky maps should still be useful for many global studies and as the first step into the investigation of individual clouds.