期刊論文
| 學年 | 110 |
|---|---|
| 學期 | 2 |
| 出版（發表）日期 | 2022-03-01 |
| 作品名稱 | A tale of two DIGs: The relative role of H II regions and low-mass hot evolved stars in powering the diffuse ionised gas (DIG) in PHANGS-MUSE galaxies |
| 作品名稱（其他語言） | |
| 著者 | F. Belfiore, F. Santoro, B. Groves, E. Schinnerer, K. Kreckel, S. C. O. Glover, R. S. Klessen, E. Emsellem, G. A. Blanc, E. Congiu, A. T. Barnes, M. Boquien, M. Chevance, D. A. Dale, J. M. Diederik Kruijssen, A. K. Leroy, H.-A. Pan, I. Pessa, A. Schruba and T. G. Williams |
| 單位 | |
| 出版者 | |
| 著錄名稱、卷期、頁數 | Astronomy & Astrophysics 659, p.29 |
| 摘要 | We use integral field spectroscopy from the PHANGS–MUSE survey, which resolves the ionised interstellar medium structure at ∼50 pc resolution in 19 nearby spiral galaxies, to study the origin of the diffuse ionised gas (DIG). We examine the physical conditions of the diffuse gas by first removing morphologically defined H II regions and then binning the low-surface-brightness areas to achieve significant detections of the key nebular lines in the DIG. A simple model for the leakage and propagation of ionising radiation from H II regions is able to reproduce the observed distribution of Hα in the DIG. This model infers a typical mean free path for the ionising radiation of 1.9 kpc for photons propagating within the disc plane. Leaking radiation from H II regions also explains the observed decrease in line ratios of low-ionisation species ([S II]/Hα, [N II]/Hα, and [O I]/Hα) with increasing Hα surface brightness (ΣHα). Emission from hot low-mass evolved stars, however, is required to explain: (1) the enhanced low-ionisation line ratios observed in the central regions of some of the galaxies in our sample; (2) the observed trends of a flat or decreasing [O III]/Hβ with ΣHα; and (3) the offset of some DIG regions from the typical locus of H II regions in the Baldwin–Phillips–Terlevich (BPT) diagram, extending into the area of low-ionisation (nuclear) emission-line regions (LI[N]ERs). Hot low-mass evolved stars make a small contribution to the energy budget of the DIG (2% of the galaxy-integrated Hα emission), but their harder spectra make them fundamental contributors to [O III] emission. The DIG might result from a superposition of two components, an energetically dominant contribution from young stars and a more diffuse background of harder ionising photons from old stars. This unified framework bridges observations of the Milky Way DIG with LI(N)ER-like emission observed in nearby galaxy bulges. |
| 關鍵字 | galaxies: ISM;galaxies: star formation;HII regions;ISM: structure;ISM: general;Astrophysics - Astrophysics of Galaxies |
| 語言 | en_US |
| ISSN | 2329-1273;2329-1265 |
| 期刊性質 | 國外 |
| 收錄於 | SCI |
| 產學合作 | |
| 通訊作者 | |
| 審稿制度 | 是 |
| 國別 | USA |
| 公開徵稿 | |
| 出版型式 | ,電子版,紙本 |
| 相關連結 |
機構典藏連結 ( http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/123338 ) |