A WISE Survey of New Star Clusters in the Central Plane Region of the Milky Way

TL;DR

This study uses WISE infrared data to discover 923 new star clusters in the Milky Way's central plane, overcoming previous survey limitations and revealing their distribution and ages.

Contribution

The paper introduces a new infrared survey method that significantly increases the known star cluster count in the Milky Way's central region.

Findings

923 new clusters discovered, including 202 embedded clusters.

Embedded clusters are more concentrated toward the Galactic plane.

Distribution of clusters is symmetric with respect to Galactic longitude.

Abstract

We present the discovery of new star clusters in the central plane region ($|l|<30\deg$ and $|b|<6\deg$) of the Milky Way. In order to overcome the extinction problem and the spatial limit of previous surveys, we use the Wide-field Infrared Survey Explorer (WISE) data to find clusters. We also use other infrared survey data in the archive for additional analysis. We find 923 new clusters, of which 202 clusters are embedded clusters. These clusters are concentrated toward the Galactic plane and show a symmetric distribution with respect to the Galactic latitude. The embedded clusters show a stronger concentration to the Galactic plane than the non-embedded clusters. The new clusters are found more in the first Galactic quadrant, while previously known clusters are found more in the fourth Galactic quadrant. The spatial distribution of the combined sample of known clusters and new clusters is approximately symmetric with respect to the Galactic longitude. We estimate reddenings, distances, and relative ages of the 15 class A clusters using theoretical isochrones. Ten of them are relatively old (age $>800$ Myr) and five are young (age $\approx4$ Myr).