The PDR fronts in M17-SW localized with FIFI-LS onboard SOFIA

TL;DR

This study uses SOFIA's FIFI-LS instrument to map the PDR in M17-SW, revealing a sharp density change and providing insights into star formation feedback mechanisms.

Contribution

It presents detailed FIR line observations of M17-SW's PDR and develops a density and UV field map using a one-dimensional model, advancing understanding of star formation feedback.

Findings

Detected a sudden change in gas density across the PDR

Mapped the ionization and photo-dissociation fronts

Provided a detailed physical picture of the PDR structure

Abstract

To understand star formation rates, studying feedback mechanisms that regulate star formation is necessary. The radiation emitted by nascent massive stars play a significant role in feedback by photo-dissociating and ionizing their parental molecular clouds. To gain a detailed picture of the physical processes, we mapped the photo-dissociation region (PDR) M17-SW in several fine structure and high-J CO lines with FIFI-LS, the far-infrared imaging spectrometer aboard SOFIA. An analysis of the CO and [O I]146$\mu$m line intensities, combined with the far infrared intensity, allows us to create a density and UV intensity map using a one dimensional model. The density map reveals a sudden change in the gas density crossing the PDR. The strengths and limits of the model and the locations of the ionization and photo-dissociation front of the edge-on PDR are discussed.