Related papers: Far-Infrared Line Diagnostics: Improving N/O Abund…
Recent work has demonstrated that widely used strong-line oxygen abundance indicators, such as O3N2, $\rm R23$, and $\widehat{\rm R}$, suffer from large uncertainties when applied to high-redshift galaxies. We show that this loss of…
We present medium resolution (R approx. 1500) ISO-SWS 2.4--45 micron spectra of a sample of 29 galaxies with active nuclei. This data set is rich in fine structure emission lines tracing the narrow line regions and (circum-)nuclear star…
The abundance of carbon relative to oxygen (C/O) is a promising probe of star formation history in the early universe, as the ratio changes with time due to production of these elements by different nucleosynthesis pathways. We present a…
[Abridged] The [OIII]$_{88\mu m}$/[CII]$_{158\mu m}$ and [OIII]$_{88\mu m}$/[NII]$_{122\mu m}$ luminosity ratios have shown to be promising tracers of the ionisation state and gas-phase metallicity of the ISM. Observations of galaxies at…
In the framework of the study of the evolutionary status of galaxies in the nearby Lynx-Cancer void, we present the results of the SAO RAS 6-m telescope spectroscopy for 20 objects in this region. The principal faint line [OIII]4363A, used…
The validity of oxygen and nitrogen abundances derived from the global emission-line spectra of galaxies via the P-method has been investigated using a collection of published spectra of individual HII regions in irregular and spiral…
Infrared OH lines at 1.55 - 1.56 um in the H-band were obtained with the Phoenix high-resolution spectrograph at the 2.1m telescope of the Kitt Peak National Observatory for a sample of 14 metal-poor stars. Detailed analyses of the sample…
Among `empirical' methods of estimating oxygen abundances in extragalactic HII regions, the use of the ratio of nebular lines of [O III] and [N II], first introduced by Alloin et al. in 1979, is reappraised with modern calibration data and…
Oxygen abundances in a sample of ultra-metal-poor subdwarfs have been derived from measurements of the oxygen triplet at 7771--5 A and OH lines in the near UV performed in high-resolution and high signal-to-noise spectra obtained with…
We analyze several key rest-optical emission-line ratios in a sample of 828 galaxies as well as composite spectra from JADES DR3 in the range $1.4 < z < 7$. These emission-line ratios include: [O III]$\lambda5008$/H$\beta$, [N II]$\lambda…
We investigate the systematic variation of the [OII]3727/Halpha flux line ratio as a function of various galaxy properties, i.e., luminosity, metallicity, reddening, and excitation state, for a sample of 1124 emission-line galaxies, with a…
We present deep JWST NIRSpec observations in the sightline of MACS J1149.5+2223, a massive cluster of galaxies at $z=0.54$. We report the spectroscopic redshift of 28 sources at $3<z<9.1$, including 9 sources with the detection of the…
We present a method to estimate the total gas column density, dust-to-gas and dust-to-metal ratios of distant galaxies from rest-frame optical spectra. The technique exploits the sensitivity of certain optical lines to changes in depletion…
Line ratio diagnostics provide valuable clues on the source of ionizing radiation in galaxies with intense black hole accretion and starbursting events, such as local Seyfert or galaxies at the peak of the star formation history. We aim to…
We present an analysis of [OI]63, [OIII]88, [NII]122 and [CII]158 far-infrared (FIR) fine-structure line observations obtained with Herschel/PACS, for ~240 local luminous infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG…
We characterise the relation between the gas and dust content of the interstellar medium towards young stellar objects in the Orion Nebula Cluster. X-ray observations provide estimates of the absorbing equivalent hydrogen column density N_H…
We report new measurements of carbon and oxygen abundances in 34 F and G dwarf and subgiant stars belonging to the halo population and spanning a range of metallicity from [Fe/H] = -0.7 to -3.2 . The survey is based on observations of four…
We study the evolution of nitrogen resulting from a set of spiral and irregular galaxy models computed for a large number of input mass radial distributions and with various star formation efficiencies. We show that our models produce a…
Optical CCD spectra are used to determine the Fe abundances at several positions inside seven bright Galactic HII regions. The observed [FeIII] line ratios are compared with the predictions of different sets of collision strengths and…
We study the direct gas-phase oxygen abundance using the well-detected auroral [OIII]4363 line in the stacked spectra of a sample of local analogs of high-redshift galaxies. These local analogs share the same location as $z\sim2$…