相关论文: Interstellar chemistry of nitrogen hydrides in dar…

Nitrogen bearing species are common tracers of the physical conditions in a wide variety of objects, and most remarkably in dark clouds. The reservoir of gaseous nitrogen is expected to be atomic or molecular, but none of the two species…

Nitrogen is the fifth most abundant element in the Universe, yet the gas-phase chemistry of N-bearing species remains poorly understood. Nitrogen hydrides are key molecules of nitrogen chemistry. Their abundance ratios place strong…

The HIFI instrument on board the Herschel Space Observatory has been used to observe interstellar nitrogen hydrides along the sight-line towards G10.6-0.4 in order to improve our understanding of the interstellar chemistry of nitrogen. We…

We have used the Herschel-HIFI instrument to observe interstellar nitrogen hydrides along the sight-lines towards W49N and G10.6-0.4 in order to elucidate the production pathways leading to nitrogen-bearing species in diffuse gas. All…

Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N2, with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear…

Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low density lines of sight towards G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models. In this paper we…

The nuclear-spin chemistry of interstellar water is investigated using the University of Grenoble Alpes Astrochemical Network (UGAN). This network includes reactions involving the different nuclear-spin states of the hydrides of carbon,…

Chemistry plays an important role in the interstellar medium (ISM), regulating heating and cooling of the gas, and determining abundances of molecular species that trace gas properties in observations. Although solving the time-dependent…

We review the reactions involving HCN and HNC in dark molecular clouds to elucidate new chemical sources and sinks of these isomers. We find that the most important reactions for the HCN-HNC system are Dissociative Recombination (DR)…

We investigated the chemistry of nitrogen--containing species, principally isotopomers of CN, HCN, and HNC, in a sample of pre-protostellar cores. We used the IRAM 30 m telescope to measure the emission in rotational and hyperfine…

We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes…

Although ammonia is an abundant molecule commonly observed towards the dense interstellar medium, it has not yet been established whether its main formation route is from gas-phase ion-molecule reactions or grain-surface hydrogen additions…

We present long slit optical spectroscopy of 67 HII regions in 21 dwarf irregular galaxies to investigate the enrichment of oxygen, nitrogen, neon, sulfur, and argon in low mass galaxies. Oxygen abundances are obtained via direct detection…

Context. The abundances of many observed compounds in interstellar molecular clouds still lack an explanation, despite extensive research that includes both gas and solid (dust-grain surface) phase reactions. Aims. We aim to qualitatively…

Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of…

Sulphur-bearing species are often used to probe the physical structure of star forming regions of the interstellar medium, but the chemistry of sulphur in these regions is still poorly understood. In dark clouds, sulphur is supposed to be…

Nitrogen-bearing molecules in cold molecular clouds exhibit a range of isotopic fractionation ratios and these molecules may be the precursors of $^{15}$N enrichments found in comets and meteorites. Chemical model calculations indicate that…

The chemistry in the diffuse interstellar medium initiates the gradual increase of molecular complexity during the life cycle of matter. A key molecule that enables build-up of new molecular bonds and new molecules via proton-donation is…

Using the HST Goddard High Resolution Spectrograph (GHRS), we have obtained high S/N echelle observations of the weak interstellar N I 1160, 1161 A absorption doublet toward the stars Gamma Cas, Lambda Ori, Iota Ori, Kappa Ori, Delta Sco,…

Nitrogen-bearing molecules display variable isotopic fractionation levels in different astronomical environments such as in the interstellar medium or in the Solar System. Models of interstellar chemistry are unable to induce nitrogen…