She derives the metallicity from averaging the Mg and Fe equivalent widths. Figure 11 - An empirical check of the expected relationship among the three popular Mg indices sampled by the Lick system. Our values, plotted as index versus temperature diagrams, have been compared with observations of M67 stars and field stars, the latter mostly being objects whose atmospheric parameters are similar to the isochrone values. W e provide linear correction. Macul, Santiago, Chile; tpuzia astro. Equation 5 can be applied, only if the second and higher-order derivatives are negligible.
She derives the metallicity from averaging the Mg and Fe equivalent widths. The high metallicities and supersolar abundances shown by these galaxies imply a rapid, high efficiency star formation. The models are based on the evolutionary synthesis technique described in Maraston See Figure 3 for an illustration of the corresponding Lick index corrections that are being used in Equations 5 a n d 6. Estimates of the accuracies of the A-values are provided. Note that for instrument setup B the spectral. Interestingly, Ca is the only index besides CN 1 and CN 2 that is considerably affected by changes of carbon and nitrogen abundances.
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To better characterize the global star formation activity in a galaxy, one needs to know not only the star formation rate SFR but also the rest-frame, far-infrared color e. We split the presentation in four different figures: This method has been applied to observations of a sample of nine S0s in the Fornax Cluster in order to obtain clean high-quality spectra of their individual bulge and disc components. Calibration of the Balmer line indices. Some indices are given in magnitudes , and some in equivalent width units. For the first time we provide statistical errors for each model prediction.
The paper concludes with Section 5. We also discuss stellar populations in field and c Indeed, there is the clear trend that the clusters in the sample that are closer to the Galactic plane have higher NaD relative to their Mg b indices. We apply the models to various stellar clusters and galaxies with high-quality spectra, for which independent studies are available, obtaining excellent results. On these model atmospheres they assess the impact on Lick indices from element abundance variations. In Paper II we present the full analysis of these element abundance variations and show that the globular cluster data can be recovered very well. Apart from constant resolution as a function of wavelength, the system is also based on flux-calibrated spectra.