Related papers: Good Abundances from Bad Spectra: I. Techniques
context : Unlike silicon and calcium, sulphur is an alpha-element which does not form dust. Some of the available observations of the evolution of sulphur with metallicity indicate an increased scatter of sulphur to iron ratios at low…
A detailed spectroscopic study, from lambda 3700 A to 1 um, was performed for a sample of 34 HII galaxies in order to derive fundamental parameters for their HII regions and ionizing sources, as well as gaseous metal abundances. All the…
With the dual aims of enlarging the list of extremely metal-poor stars identified in the Galaxy, and boosting the numbers of moderately metal-deficient stars in directions that sample the rotational properties of the thick disk, we have…
We present new, high resolution, infrared spectra of the T dwarf Gliese 229B in the J, H, and K bandpasses. We analyze each of these as well as previously published spectra to determine its metallicity and the abundances of NH3 and CO in…
As the multiplexing power of spectroscopic instruments increases, so does the need for automated analysis. In practice, the bottleneck for speed is the calculation of model spectra to evaluate the likelihood of candidate parameters. This…
Observations with the ACS Wide Field Camera and G800L grism can produce thousands of spectra within a single WFC field producing a potentially rich treasure trove of information. However, the data are complicated to deal with. Here we…
The statistical equilibrium of neutral and ionised silicon in the solar photosphere is investigated. Line formation is discussed and the solar silicon abundance determined. High-resolution solar spectra were used to determine solar $\log…
In this paper we present a detailed spectroscopic analysis of the suspected marginal Am star HD\,71297. Our goal is to test the accuracy of two different approaches to determine the atmospheric parameters effective temperature, gravity,…
The determination of chemical abundances from stellar spectra is considered a mature field of astrophysics. Digital spectra of stars are recorded and processed with standard techniques, much like samples in the biological sciences.…
Using a large sample of 38,478 star-forming galaxies selected from the Second Data Release of the Sloan Digital Sky Survey database (SDSS-DR2), we derive analytical calibrations for oxygen abundances from several metallicity-sensitive…
The ability to measure metallicities and {\alpha}-element abundances in individual red giant branch (RGB) stars using medium-resolution spectra ($R \approx 6000$) is a valuable tool for deciphering the nature of Milky Way dwarf satellites…
We present a method for the determination of [alpha/Fe] ratios from low-resolution (R = 2000) SDSS/SEGUE stellar spectra. By means of a star-by-star comparison with degraded spectra from the ELODIE spectral library and with a set of…
We present a near-infrared abundance analysis of 46 solar analogs with known ages, observed with the WINERED WIDE-mode spectrograph at a resolution of $\lambda/\Delta\lambda = 28,000$. Using an empirically calibrated, line-by-line approach…
We study the photometric properties of stars in the data archive of the Sloan Digital Sky Survey (SDSS), the prime aim being to understand the photometric calibration over the entire data set. It is confirmed that the photometric…
We present a technique that applies spectral synthesis to medium resolution spectroscopy (MRS, R ~ 6000) in the red (6300 A < lambda < 9100 A) to measure [Fe/H] and [alpha/Fe] of individual red giant stars over a wide metallicity range. We…
Modern spectroscopic surveys can only target a small fraction of the vast amount of photometrically cataloged sources in wide-field surveys. Here, we report the development of a generative AI method capable of predicting optical galaxy…
The study of the Milky Way relies on our ability to interpret the light from stars correctly. This calls for a reinvestigation of how reliably we can determine, e.g., iron abundances in such stars and how well they reproduce those of dwarf…
We present equivalent widths, improved model atmosphere parameters, and revised abundances for 14 species of 11 elements derived from high resolution optical spectroscopy of 311 metal-poor stars. All of these stars had their parameters…
The enrichment history of galaxy clusters and groups remains far from being fully understood. Recent measurements in massive clusters have revealed remarkably flat iron abundance profiles out to the outskirts, suggesting that similar…
Classical chemical analyses may be affected by systematic errors that would cause observed abundance differences between dwarfs and giants. For some elements, however, the abundance difference could be real. We address the issue by…