AFGL 5157 NH$_3$: A new stellar cluster in the forming

TL;DR

This study analyzes infrared observations of AFGL 5157, revealing active star formation, bipolar jets, and a young embedded cluster, indicating ongoing stellar birth in this region.

Contribution

It provides new evidence of bipolar jets and a young embedded cluster in AFGL 5157, supporting a sequential star formation scenario.

Findings

Detection of bipolar jets and their potential driving sources.

Identification of a very young embedded stellar cluster.

Spatial correlation of millimeter emissions with Class 0/I sources.

Abstract

We present the analysis of Spitzer/IRAC and NIR imaging observation of AFGL 5157, an active star forming region. In the IRAC images, this region shows strong PAH emissions in channel 4 and H$_2$ emissions in channel 2. Many of the H$_2$ features are aligned to form jet-like structures. Three bipolar jets in the NH$_3$ core region and a couple of jets northwest of the core have been identified. We identify the possible driving agents of the bipolar jets and show them to be very young. An embedded cluster has been detected in the NH$_3$ core; many members in the cluster show their SEDs increasing from JHK bands toward longer wavelength, indicative of their early evolutionary stages. Millimeter and sub-millimeter continuum emissions are found to coincide spatially with these presumable Class 0/I sources, in the NH$_3$ core and the NW subregion. The existence of H$_2$ bipolar jets and very young stellar objects suggests that star formation is still going on at present epoch in these subregions. Combining the information from previous studies, we propose a sequential star formation scenario in the whole AFGL 5157 region.