Study of young stellar objects and associated filamentary structures in the inner Galaxy

Abstract

Young stellar objects in the inner Galactic region 10° < l < 15° and −1° < b < 1° were studied using GLIMPSE images and the GLIMPSE data catalogue. A total of 1107 Class I and 1566 Class II sources were identified in this Galactic region. With the help of GLIMPSE 5.8- and 8-μm images, we identified the presence of 10 major star forming sites in the Galactic mid-plane, 8 of which are filamentary while 2 are possible clusters of Class I and II sources. The length of the identified filaments are estimated as 8–33 arcmin (∼9–56 pc). The occurrence of a hub–filamentary system is observed in many filamentary star forming sites. Most of the Class I sources are found to be aligned along the length of these filamentary structures, while Class II sources have a random distribution. The mass and age distribution of 425 Class I and 241 Class II sources associated with filaments and clusters were studied through analysis of their spectral energy distribution. Most of the Class I sources detected have mass >8 M_⊙, while Class II sources have relatively low masses. Class I sources have ages ≤0.5 Myr, while Class II sources have ages in the range ∼0.1–3 Myr. By combining our results with information from high mass star forming tracers, we demonstrate that large numbers of high-mass stars are being formed in the 10 regions studied here.