相关论文: Eliminating Error in the Chemical Abundance Scale …

We have used a combination of stellar population synthesis and photoionization models to develop a set of ionization parameter and abundance diagnostics based only on the use of the strong optical emission lines. These models are applicable…

(Abridged) We use high S/N spectra of 20 HII regions in the giant spiral galaxy M101 to derive electron temperatures for the HII regions and robust metal abundances over radii R = 0.19-1.25 Ro (6-41 kpc). We compare the consistency of…

Using a sample of 28 HII regions from the literature with measured temperature inhomogeneity parameter, t^2, we present a statistical correction to the chemical abundances determined with the Te(4363/5007) method. We used the t^2 values to…

We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…

Understanding the complex ionization structure and chemical composition of \hii\ regions poses a significant challenge in astrophysics. The abundance discrepancy problem, characterized by inconsistencies between abundances derived from…

The analysis of metal-rich HII regions has a profound impact on the calibration of abundance diagnostics widely used to measure the chemical content of star-forming galaxies, both locally and at high redshift. I review the main difficulties…

We suggest an empirical calibration for determination of oxygen and nitrogen abundances and electron temperature in HII regions where the [OII]3727+3729 line (R_2) is not available. The calibration is based on the strong emission lines of…

We present high signal-to-noise spectrophotometric observations of seven luminous HII galaxies. The observations have been made with the use of a double-arm spectrograph which provides spectra with a wide wavelength coverage, from 3400 to…

HII regions, ionized nebulae where massive star formation has taken place, exhibit a wealth of emission lines that are the fundamental basis for estimating the chemical composition of the Universe. For more than 80 years, a discrepancy of…

We suggest a new way of the determining abundances and electron temperatures in HII regions from strong emission lines. Our approach is based on the standard assumption that HII regions with similar intensities of strong emission lines have…

The determination of the heavy element abundances from giant extragalactic H II regions is based on collisionally excited lines. We argue that in the presence of temperature variations the abundances determined are lower limits to the real…

Using ab-initio photoionization models of giant HII regions, we test methods for abundance determinations based on a direct measurement of the electron temperature, now possible even for moderate to high-metallicity objects. We find that,…

Of the light element abundances capable of testing standard big bang nucleosynthesis, only He4 is measured with an accuracy of a few percent. Thus, it is imperative to establish a comprehensive technique for determining He4 abundances and…

The discrepancy between the oxygen abundances in high-metallicity HII regions determined through the Te-method (and/or through the corresponding "strong lines - oxygen abundance" calibration) and that determined through the model fitting…

We present a new basis for scaling abundances with total metallicity in nebular photoionisation models, based on extensive Milky Way stellar abundance data, to replace the uniform scaling normally used in the analysis of HII regions. Our…

We present a theoretical investigation of the effect of multiple ionisation sources in HII regions on the total elemental abundances derived from the analysis of collisionally excited emission lines. We focus on empirical methods based on…

The compilation of published spectra of Galactic HII regions with available diagnostic [OIII]4363 line has been carried out. Our list contains 71 individual measurements of 13 HII regions in the range of galactocentric distances from 6.6 to…

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 long slit spectrophotometry of two HII regions: TOL2146-391 and TOL0357-3915. We performed a detailed analysis that involves abundance determinations relaxing the assumption of homogeneous temperature. The temperature…

We provide a new method to derive heavy element abundances based on the unique suite of nebular lines in the mid- to far-infrared (IR) range. Using grids of photo-ionisation models that cover a wide range in O/H and N/O abundances, and…