Infrared emission from interstellar dust cloud with two embedded sources: IRAS 19181 + 1349

Abstract

Mid-and far-infrared maps of many Galactic star forming regions show multiple peaks in close proximity, implying more than one embedded energy source. With the aim of understanding such interstellar clouds better, the present study models the case of two embedded sources. A radiative transfer scheme has been developed to deal with a uniform density dust cloud in a cylindrical geometry, which includes isotropic scattering in addition to the emission and absorption processes. This scheme has been applied to the Galactic star forming region associated with IRAS 19181 + 1349, which shows observational evidence for two embedded energy sources. Two independent modelling approaches have been adopted, viz., to fit the observed spectral energy distribution (SED) best; or to fit the various radial profiles best, as a function of wavelength. Both the models imply remarkably similar physical parameters.