相关论文: Galactic abundance gradients from deep spectra of …

We present spectra obtained with the 10.4 m Gran Telescopio Canarias telescope of 13 Galactic HII regions, most of them of very low ionisation degree. The objects are located along the Galactic disc, with R_G from 5.7 to 16.1 kpc. We…

We present a reassessment of the radial abundance gradients of C, N, O, Ne, S, Cl and Ar in the Milky Way using deep spectra of 33 H II regions gathered from the literature, covering Galactocentric distances from 6 to 17 kpc. The distances…

We present deep optical spectroscopy of eight HII regions located in the anticentre of the Milky Way. The spectra were obtained at the 10.4m GTC and 8.2m VLT. We determined Te([NII]) for all objects and Te([OIII]) for six of them. We also…

We present preliminary results of the O, Ne, S and Cl abundance gradients of the Milky Way. We analyze in a homogenous way the physical conditions and chemical abundances of a sample of 35 H II regions with deep spectra observed mainly with…

We present results of deep echelle spectrophotometry of eight Galactic HII regions located at Galactocentric distances between 6.3 and 10.4 kpc. The data have been taken with the Very Large Telescope (VLT) Ultraviolet Echelle Spectrograph…

We present a reassessment of the radial abundance gradients of He, C, N, O, Ne, S, Cl, and Ar in the Milky Way using the deep optical spectra of 42 HII regions presented in Arellano-C\'ordova et al. (2020, 2021) and M\'endez-Delgado et al.…

We determine the radial abundance gradient of helium in the disc of the Galaxy from published spectra of 19 $\text{H}\thinspace \text{II}$ regions and ring nebulae surrounding massive O stars. We revise the Galactocentric distances of the…

We derive the electron temperature gradient in the Galactic disk using a sample of HII regions that spans Galactocentric distances 0--17 kpc. The electron temperature was calculated using high precision radio recombination line and…

The distribution of metals in the Galaxy provides important information about galaxy formation and evolution. HII regions are the most luminous objects in the Milky Way at mid-infrared to radio wavelengths and can be seen across the entire…

We study the physical and chemical properties of a sample of HII regions located at RG >11 kpc and present the radial distribution of abundances towards the Galaxy anticentre. We carried out optical spectroscopic observations of nine HII…

We investigate the electron temperature gradient in the galactic disk as measured by young HII regions on the basis of radio recombination lines and the corresponding gradient in planetary nebulae (PN) based on [OIII] electron temperatures.…

We have obtained spectrophotometric observations of 41 anticenter planetary nebulae (PNe) located in the disk of the Milky Way. Electron temperatures and densities, as well as chemical abundances for He, N, O, Ne, S, Cl, and Ar were…

We present optical spectra of nine Galactic H II regions observed with the 10.4 m Gran Telescopio Canarias telescope and located at Galactocentric distances (RG) from 4 to 8 kpc. The distances of the objects have been revised using Gaia DR2…

We present deep echelle spectrophotometry of the Galactic HII region NGC 2579. The data have been taken with the Very Large Telescope Ultraviolet-Visual Echelle Spectrograph in the 3550--10400 \AA\ range. This object, which has been largely…

Elemental abundance patterns in the Galactic disk constrain theories of the formation and evolution of the Milky Way. HII region abundances are the result of billions of years of chemical evolution. We made radio recombination line and…

We present spectroscopic observations of a sample of 72 emission-line objects, including mainly HII regions, in the spiral galaxy M 33. Spectra were obtained with the multi-object, wide field spectrograph AF2/WYFFOS at the 4.2m WHT…

We present very deep spectrophotometry of 14 bright extragalactic HII regions belonging to spiral, irregular, and blue compact galaxies. The data for 13 objects were taken with the HIRES echelle spectrograph on the Keck I telescope. We have…

Radial O/H abundance gradients derived from HII regions, hot stars and planetary nebulae are combined with [Fe/H] gradients from open cluster stars in order to derive an independent [O/Fe] x [Fe/H] relation for the galactic disk. A…

We present deep spectrophotometry of 18 HII regions in the nearby massive spiral galaxies M101 and M31. We have obtained direct determinations of electron temperature in all the nebulae. We detect the CII 4267 line in several HII regions,…

We determine the radial abundance gradient of Cl in the Milky Way from HII regions spectra. For the first time, the Cl/H ratios are computed by simply adding ionic abundances and not using an ionization correction factor (ICF). We use a…