Infrared and Radio Study of Star‐forming Regions Associated with IRAS 19111+1048 and IRAS 19110+1045

Abstract

A multiwavelength study of the star-forming regions associated with IRAS 19111+1048 and IRAS 19110+1045 has been carried out. These have been simultaneously mapped in two far-infrared bands at k eA ¼ 130 and 200 m with $1 0 angular resolution using the TIFR 1 m balloon-borne telescope. The radio emission from the ionized gas of these regions has been imaged at 1280, 610, and 325 MHz using the Giant Metrewave Radio Telescope, India. Assuming the detected compact sources to represent exciting zero-age main sequence ( ZAMS) stars, the initial mass function [(m) / m Àa ] for the IRAS 19111+1048 region is found to be quite steep, with a ¼ 5:3 AE 0:5 for the mass range 14 < m/M < 33. The near-infrared ( NIR) source coincident with the IRAS 19111+1048 peak is likely to be an embedded pre-main-sequence star. The spectral types of the ZAMS stars inferred independently from the radio and NIR measurements match very well for a good fraction of the radio sources having NIR counterparts. The best-fit radiative transfer models of the two IRAS sources are in good agreement with the observed spectral energy distributions. A uniform density distribution of dust and gas is implied for both the sources. The extents of ionized gas, number of ZAMS stars, presence of deeply embedded sources, and lower value of L/M for the cloud support the youth of IRAS 19110+1045 vis-à-vis its neighbor, IRAS 19111+1048, consistent with earlier studies.

A Multiwavelength Study of M17: The Spectral Energy Distribution and PAH Emission Morphology of a Massive Star Formation Region

“…It is qualitatively similar to the SED of a dust cocoon surrounding a single newly formed early type star (Churchwell et al 1990;Vig et al 2006). The underlying shape of the global IR SED resembles a blackbody curve that peaks near 60 m. This is a ''graybody'' composite of many underlying dust blackbodies, representing a large range of grain temperatures and sizes found throughout the M17 region.…”

Stellar population in two star-forming regions

“…Both regions contain type I OH masers (Argon et al, 2000) Churchwell, 1996) and methanol maser emissions (Breen et al, 2019, Hernández-Hernández et al, 2019. The NIR data, as well as high-resolution radio measurements, enabled Vig et al (2006) and Rivera-Ingraham et al (2010) to conclude that IRAS 19111+1048 region contains a larger number of ZAMS stars energizing compact and evolved HII region.…”

“…We adopt a distance of ∼7.8 kpc in our study. Many multi-wavelength studies suggest that both UC HII regions are sites of active massive star formation, at that IRAS 19111+1048 is a more advanced (Hunter et al, 1997, Vig et al, 2006. Both regions contain type I OH masers (Argon et al, 2000) Churchwell, 1996) and methanol maser emissions (Breen et al, 2019, Hernández-Hernández et al, 2019.…”

Interstellar Medium and Star Formation Studies with the Square Kilometre Array

“…Here, we discuss a few diverse results obtained. The radio morphology of the star forming region IRAS 19111+1048 investigated by Vig et al (2006) shows the presence of a highly inhomogeneous ionized medium in the neighbourhood of an ultracompact HII region. Twenty compact sources including one non-thermal source were identified.…”