Update on Dusty Sources and Candidate Young Stellar Objects in the S-cluster

TL;DR

This paper investigates dusty sources and young stellar objects in the S-cluster near the Galactic Center's SMBH, revealing evidence of a low-mass stellar population and identifying a candidate Class I YSO, G1.

Contribution

It provides new insights into the dusty members of the S-cluster and suggests the presence of a low-mass stellar population orbiting Sgr A* using radiative-transfer modeling.

Findings

Detection of dusty, embedded sources with Doppler-shifted Brγ lines.

Identification of G1 as a potential Class I YSO.

Evidence supporting a low-mass stellar population in the S-cluster.

Abstract

The Galactic Center provides a unique opportunity to observe a galactic core, objects in close proximity to a supermassive black hole (SMBH), and star formation channels that exhibit imprints of this peculiar environment. This habitat hosts, in addition to the SMBH Sgr A*, a surprisingly young cluster with the so-called S-stars. These stars orbit the SMBH on timescales of a few years with thousands of km/s. While the presence of high-velocity stars in the S-cluster already raises a variety of scientific questions, the observation of several bright L-band emission sources has resulted in a rich discussion of their nature. The detection of a prominent Doppler-shifted Br$\gamma$ line accompanies most of these sources that seem to be embedded in a dusty envelope. Using the radiative-transfer model HYPERION, we find strong indications of the presence of a stellar low-mass population embedded in the S-cluster. We revisit this intriguing cluster and its dusty members that orbit the supermassive black hole Sgr A* on bound Keplerian trajectories. Among these cluster members, there is one source that initiated the studies of this analysis: G1. We find that the flux density of G1 in the NIR and MIR resembles a spectral energy distribution of a Class I YSO, which contributes to the "Paradox of Youth".