X3: a high-mass Young Stellar Object close to the supermassive black hole Sgr~A*

Abstract

To date, the proposed observation of Young Stellar Objects (YSOs) in the Galactic center (GC) still raises the question where and how these objects could have formed due to the violent vicinity of Sgr~A*. Here, we report the multi-wavelength detection of a highly dynamic YSO close to Sgr~A* that might be a member of the IRS13 cluster. We observe the beforehand known coreless bow-shock source X3 in the near- and mid-infrared (NIR/MIR) with SINFONI (VLT), NACO (VLT), ISAAC (VLT), VISIR (VLT), SHARP (NTT), and NIRCAM2 (KECK). In the radio domain, we use CO continuum and H30$\alpha$ ALMA observations to identify system components at different temperatures and locations concerning the central stellar source. It is suggested that these radio/submm observations in combination with the NIR Br$\gamma$ line can be associated with a protoplanetary disk of the YSO which is consistent with manifold VISIR observations that reveal complex molecules and elements such as PAH, SIV, NeII and ArIII in a dense and compact region. Based on the photometric multi-wavelength analysis, we infer the mass of $15^{+10}_{-5} M_{\odot}$ for the YSO with a related age of a few $10^4$ yr. Due to this age estimate and the required relaxation time scales for high-mass stars, this finding is an indication for ongoing star formation in the inner parsec. The proper motion and 3d distance imply a relation of X3 and IRS13. We argue that IRS13 may serve as a birthplace for young stars that are ejected due to the evaporation of the cluster.