3D structure of the H ii region Sh2-235 from tunable-filter optical observations. Issue 1 (10th July 2020)

• Record Type: Journal Article
• Authors: Kirsanova, M S; Boley, P A; Moiseev, A V; Wiebe, D S; Uklein, R I
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 497:Issue 1(2020)
• Page Start: 1050
• Page End: 1058
• Publication Date: 2020-07-10
• Subjects: techniques: imaging spectroscopy -- stars: massive -- ISM: dust, extinction -- ISM: H II regions -- ISM: photodissociation region (PDR); Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa2004
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present observations of the H α, H β, [S ii ] λλ6716, 6731 and [N ii ] λ6583 emission lines in the galactic H ii region Sh2-235 with the Mapper of Narrow Galaxy Lines (MaNGaL), a tunable filter at the 1-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We show that the H ii region is obscured by neutral material with A V ≈ 2−4 mag. The area with the highest A V is situated to the south-west from the ionizing star and coincides with a maximum detected electron density of ≳300 cm −3 . The combination of these results with archive AKARI far-infrared data allows us to estimate the contribution of the front and rear walls to the total column density of neutral material in S235 and explain the 3D structure of the region. The H ii region consist of a denser, more compact portion deeply embedded in the neutral medium and the less dense and obscured gas. The front and rear walls of the H ii region are inhomogeneous, with the material in the rear wall having a higher column density. We find a two-sided photodissociation region in the dense clump S235 East 1, illuminated by a UV field with G 0 = 50−70 and 200 Habing units in the western and eastern parts, respectively.