Young Stellar Objects in the Massive Star Forming Region W49

TL;DR

This study investigates the young stellar objects in the massive star-forming region W49 using infrared data, identifying hundreds of YSOs, analyzing their distribution, and comparing star formation activity with other regions.

Contribution

The paper provides a comprehensive catalog of YSOs in W49 and analyzes their spatial distribution and clustering, offering new insights into massive star formation in this region.

Findings

Identified 232 Class 0/I YSOs, 907 Class II YSOs, and 74 transition disk candidates.

52% of YSOs are in clusters with more than 7 members.

W49 has the richest YSO population with 7 subclusters compared to similar regions.

Abstract

We present the initial results of our investigation of the star-forming complex W49, one of the youngest and most luminous massive star forming regions in our Galaxy. We used Spitzer/Infrared Array Camera (IRAC) data to investigate massive star formation with the primary objective to locate a representative set of protostars and the clusters of young stars that are forming around them. We present our source catalog with the mosaics from the IRAC data. In this study we used a combination of IRAC, MIPS, Two Micron All Sky Survey (2MASS) and UKIRT Deep Infrared Sky Survey (UKIDSS) data to identify and classify the Young Stellar Objects (YSOs). We identified 232 Class 0/I YSOs, 907 Class II YSOs, and 74 transition disk candidate objects using color-color and color-magnitude diagrams. In addition, to understand the evolution of star formation in W49 we analysed the distribution of YSOs in the region to identify clusters using a minimal spanning tree method. The fraction of YSOs that belong to clusters with >7 members is found to be 52% for a cut-off distance of 96" and the ratio of Class II/I objects is 2.1. We compared the W49 region to the G305 and G333 star forming regions and concluded that the W49 has the richest population with 7 subclusters of YSOs.