Herschel/HIFI Observations of Molecular Lines Toward G10.47+0.03

TL;DR

This study uses Herschel/HIFI archival data to analyze molecular lines in the hot core G10.47+0.03, revealing complex temperature structures, outflow activity, and dense gas conditions through spectral analysis and modeling.

Contribution

First comprehensive spectral analysis of G10.47+0.03 using Herschel data, employing MCMC modeling to determine molecular abundances and excitation conditions.

Findings

Detection of high-excitation molecular lines indicating hot, dense gas.

Identification of outflow signatures through velocity profiles.

Determination of two distinct temperature components in the core.

Abstract

We present a spectral line analysis of the hot molecular core G10.47+0.03 (hereafter, G10). Our aim is to determine molecular abundances and excitation conditions across a wide spectral range inaccessible to ground-based observatories. We utilize archival data from the Herschel Space Observatory, obtained with the Heterodyne Instrument for the Far-Infrared (HIFI). We report here the detection of high-excitation CO, 13CO, and C18O, H2O isotopologues, HCO+, HCN, HNC, CS, C34S, SO, SO2, H2CS, and CH3OH. CO, p-H2O, CS, and HCN show similar velocity profiles with a narrow, blueshifted component, which may be linked to the outer outflow layer. Redshifted wings may indicate inner outflow activity. A Markov Chain Monte Carlo framework is employed to infer column densities and temperatures accurately. We also performed spectral energy distribution fitting to constrain the global physical parameters of G10, providing essential context for interpreting the molecular emission. The MCMC analysis revealed two excitation temperature components: a warm component (30-65 K) and a hot component (90-250 K). The higher temperatures indicate dense, hot gas typical of massive hot cores. The lower temperatures correspond to the warm, less dense envelope around the core. Transitions of H2O, high-excitation CO, and HCN indicate outflowing gas and high-density shocked regions. These findings highlight G10's complex dynamical environment.