English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present Herschel observations of six fine-structure lines in 25Ultraluminous Infrared Galaxies at z<0.27. The lines, [O III]52, [N III]57, [OI]63, [N II]122, [O I]145, and [C II]158, are mostly single gaussians withwidths <600 km s-1 and luminosities of 10^7 - 10^9 Solar. There are deficits inthe [O I]63/L_IR, [N II]/L_IR, [O I]145/L_IR, and [C II]/L_IR ratios comparedto lower luminosity systems. The majority of the line deficits are consistentwith dustier H II regions, but part of the [C II] deficit may arise from anadditional mechanism, plausibly charged dust grains. This is consistent withsome of the [C II] originating from PDRs or the ISM. We derive relationsbetween far-IR line luminosities and both IR luminosity and star formationrate. We find that [N II] and both [O I] lines are good tracers of IRluminosity and star formation rate. In contrast, [C II] is a poor tracer of IRluminosity and star formation rate, and does not improve as a tracer of eitherquantity if the [C II] deficit is accounted for. The continuum luminositydensities also correlate with IR luminosity and star formation rate. We deriveranges for the gas density and ultraviolet radiation intensity of 10^1 < n <10^2.5 and 10^2.2 < G_0 < 10^3.6, respectively. These ranges depend on opticaltype, the importance of star formation, and merger stage. We do not findrelationships between far-IR line properties and several other parameters; AGNactivity, merger stage, mid-IR excitation, and SMBH mass. We conclude thatthese far-IR lines arise from gas heated by starlight, and that they are notstrongly influenced by AGN activity.

Far-infrared Fine-Structure Line Diagnostics of Ultraluminous Infrared Galaxies