The Physical Characteristics of Interstellar Medium in NGC 3665 with Herschel Observations
Abstract
We present the analysis of the physical properties of the interstellar medium in the nearby early-type galaxy NGC 3665, based on the far-infrared photometric and spectroscopic data as observed by the Herschel Space Observatory. The fit to the spectral energy distribution reveals a high dust content in the galaxy, with a dust-to-stellar mass ratio of {M}dust}/M * ∼ 1.1 × 10-4 that is nearly three times larger than the mean value of local S0+S0a galaxies. For the ionized regions (H II regions), the electron density (n e ) is around 49.5 ± 11.9 cm-3 based on the [N II] 122 μm/[N II] 205 μm ratio. For the photodissociation regions, the heating efficiency ranges from 1.26 × 10-3 to 1.37 × 10-3 based on the ([C II]+[O I] 63 μm)/{L}TIR}, which is slightly lower than other local galaxies; the hydrogen nucleus density and the strength of the far-UV radiation field are n ∼ 104 cm-3 and G 0 ∼ 10-0.25, respectively. The above results are consistent with the presence of weak active galactic nuclei and a low level of star-forming activity in NGC 3665. Our results give strong support to the “morphological quenching” scenario, where a compact, massive bulge can stabilize the amount of cool gas against star formation.
Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2018
- DOI:
- 10.3847/1538-4357/aaa895
- arXiv:
- arXiv:1801.05110
- Bibcode:
- 2018ApJ...854..111X
- Keywords:
-
- galaxies: elliptical and lenticular;
- cD;
- galaxies: individual: NGC 3665;
- galaxies: ISM;
- infrared: ISM;
- ISM: lines and bands;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 31 pages, 6 figures, accepted to ApJ