Abstract

An investigation of the IRAS 16148−5011 region – a cluster at a distance of 3.6 kpc – is presented here, carried out using multiwavelength data in near-infrared (NIR) from the 1.4 m Infrared Survey Facility telescope, mid-infrared (MIR) from the archival Spitzer GLIMPSE (Galactic Legacy Infrared Midplane Survey Extraordinaire) survey, far-infrared (FIR) from the Herschel archive, and low-frequency radio continuum observations at 1280 and 843 MHz from the Giant Metrewave Radio Telescope and Molonglo Survey archive, respectively. A combination of NIR and MIR data is used to identify 7 Class I and 133 Class II sources in the region. Spectral energy distribution (SED) analysis of selected sources reveals a 9.6 M⊙ high-mass source embedded in nebulosity. However, Lyman continuum luminosity calculation using radio emission – which shows a compact H ii region – indicates the spectral type of the ionizing source to be earlier than B0-O9.5. Free–free emission SED modelling yields the electron density as 138 cm−3, and thus the mass of the ionized hydrogen as ∼16.4 M⊙. Thermal dust emission modelling, using the FIR data from Herschel and performing modified blackbody fits, helped us construct the temperature and column density maps of the region, which show peak values of 30 K and 3.3 × 1022 cm−2, respectively. The column density maps reveal an AV > 20 mag extinction associated with the nebular emission, and weak filamentary structures connecting dense clumps. The clump associated with this IRAS object is found to have dimensions of ∼ 1.1 pc × 0.8 pc, and a mass of 1023 M⊙.

Highlights

  • Most star formation activity is known to take place in clusters (Lada & Lada 2003), and as such, observational studies of young embedded stellar cluster regions are imperative, because they serve as a template to further investigate various associated processes and their signatures

  • Completeness limits were calculated for all three bands by carrying out artificial star experiments using the ADDSTAR package in IRAF

  • From extinction calculations, we find that almost all non-YSO sources had AV ≤ 20 mag, and we specified the range of interstellar visual extinction AV as 1–20 mag

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Summary

INTRODUCTION

Most star formation activity is known to take place in clusters (Lada & Lada 2003), and as such, observational studies of young embedded stellar cluster regions are imperative, because they serve as a template to further investigate various associated processes and their signatures. A high-mass stellar source was detected by Grave & Kumar (2009) with the help of spectral energy distribution (SED) fitting using near-infrared (NIR) to millimetre (mm) data. Analyses of this region at 1.2-mm dust continuum emission and at molecular lines have revealed the presence of dense gas, with a large column density, as well as massive clumps. Taking into account these characteristics, this region makes a good candidate to carry out an investigation for understanding the morphology and stellar population Since this is a possible H II region with an embedded cluster, multiwavelength observations are required to fully discern this region’s various constituents and how they relate to each other.

NIR observations
Radio continuum observations
Spitzer MIR observations
Herschel FIR observations
Identification of YSOs
SED of YSOs
Luminosity function
Mass spectrum
Cluster analysis and extinction mapping
Radio morphology
Central region
Herschel results
Findings
DISCUSSION
CONCLUSIONS
Full Text
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