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X-ray measurements find systematically lower Fe abundances in the X-ray emitting haloes pervading groups ($kT\lesssim1.7$ keV) than in clusters of galaxies. These results have been difficult to reconcile with theoretical predictions.…

We present updated stellar population models appropriate for old ages (>1 Gyr) and covering a wide range in metallicities (-1.5<[Fe/H]<0.3). These models predict the full spectral variation associated with individual element abundance…

Astrophysics of Galaxies · Physics 2018-02-28 Charlie Conroy , Alexa Villaume , Pieter van Dokkum , Karin Lind

We describe a new method for determining total gas-phase abundances for the Galactic ISM with minimal ionization uncertainties. For sight lines toward globular clusters containing both UV-bright stars and radio pulsars, one can measure…

Astrophysics · Physics 2009-11-13 J. Christopher Howk , Kenneth R. Sembach , Blair D. Savage

State-of-the-art spectral analysis of hot stars by means of non-LTE model-atmosphere techniques has arrived at a high level of sophistication. The analysis of high-resolution and high-S/N spectra, however, is strongly restricted by the lack…

Solar and Stellar Astrophysics · Physics 2015-06-11 T. Rauch , K. Werner , E. Biemont , P. Quinet , J. W. Kruk

When using Fe as a surrogate for ``metallicity'', the metallicity is best represented by the dominant species of Fe. Accordingly, we have derived a new globular cluster metallicity scale based on the equivalent widths of FeII lines measured…

Astrophysics · Physics 2007-05-23 R. P. Kraft , I. I. Ivans

We present a new direct spectroscopic calibration for a fast estimation of the stellar metallicity [Fe/H]. These calibrations were computed using a large sample of 451 solar-type stars for which we have precise spectroscopic parameters…

Solar and Stellar Astrophysics · Physics 2012-09-04 Sérgio G. Sousa , Nuno C. Santos , Garik Israelian

Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of…

Solar and Stellar Astrophysics · Physics 2020-03-11 Neda Hejazi , Sebastien Lepine , Derek Homeier , R. Michael Rich , Michael M. Shara

We present a new calibration of the Calcium II Triplet equivalent widths versus [Fe/H], constructed upon K giant stars in the Galactic bulge. This calibration will be used to derive iron abundances for the targets of the GIBS survey, and in…

Astrophysics of Galaxies · Physics 2015-08-19 S. Vasquez , M. Zoccali , V. Hill , O. A. Gonzalez , I. Saviane , M. Rejkuba , G. Battaglia

Parameters and abundances have been derived for 435 Cepheids based on an analysis of 1127 spectra. Results from five or more phases are available for 52 of the program stars. The latter set of stars span periods between 1.5 and 68 days. The…

Solar and Stellar Astrophysics · Physics 2018-10-17 R. Earle Luck

Parameters and abundances for 1002 stars of spectral types F, G, and K of luminosity class IV and V have been derived. After culling the sample for rotational velocity and effective temperature, 867 stars remain for discussion. Twenty-eight…

Solar and Stellar Astrophysics · Physics 2016-12-28 R. Earle Luck

Context. With the aid of stellar abundance analysis, it is possible to study the galactic formation and evolution. Magnesium is an important element to trace the alpha-element evolution in our Galaxy. For chemical abundance analysis, such…

Instrumentation and Methods for Astrophysics · Physics 2017-02-08 A. Pehlivan Rhodin , H. Hartman , H. Nilsson , P. Jonsson

The iron abundance relative to alpha-elements in the circumnuclear region of quasars is regarded as a clock of the star formation history and, more specifically, of the enrichment by SNIa. We investigate the iron abundance in a sample of 22…

Astrophysics · Physics 2009-11-10 R. Maiolino , Y. Juarez , R. Mujica , N. Nagar , E. Oliva

The goal of the Gemini Deep Deep Survey (GDDS) is to study an unbiased sample of K<20.6 galaxies in the redshift range 0.8<z<2.0. Here we determine the statistical properties of the heavy element enrichment in the interstellar medium (ISM)…

The abundance of alpha-process elements such as magnesium and carbon relative to iron measured from the broad emission lines of QSOs can serve as a diagnostic of the star formation and chemical enrichment histories of their host galaxies.…

Astrophysics · Physics 2009-11-10 Michael R. Corbin , Kirk T. Korista , Nalaka Kodituwakku , Wolfram Freduling

We report empirical determinations of atomic oscillator strengths, or f-values, for 11 ground-state transitions of Fe II in the wavelength range 1050 to 1150 Ang. We use ultraviolet absorption line observations of interstellar material…

Astrophysics · Physics 2009-10-31 J. Christopher Howk , Kenneth R. Sembach , Katherine C. Roth , Jeffrey W. Kruk

From an analysis of the spectrum (4000\AA to 8800\AA) of HD~101584 it is found that most of the neutral and single ionized metallic lines are in emission. The forbidden emission lines of [OI] 6300\AA and 6363\AA and [CI] 8727\AA are…

Astrophysics · Physics 2009-10-31 T. Sivarani , M. Parthasarathy , P. Garcia-Lario , A. Manchado , S. R. Pottasch

We derived Lick narrow-band indices for 139 candidate super metal-rich stars of different luminosity class previously studied in Malagnini et al. (2000). Indices include Iron Fe50, Fe52, Fe53, and Magnesium Mgb and Mg2 features. By…

Astrophysics · Physics 2016-01-27 A. Buzzoni , M. Chavez , M. L. Malagnini , C. Morossi

We have performed a differential, line-by-line, chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main sequence halo stars, near [Fe/H]=$-$2 dex. Our abundances range from…

Solar and Stellar Astrophysics · Physics 2017-04-05 Erin O'Malley , Andrew McWilliam , Brian Chaboyer , Ian Thompson

We present results from analysis of spectra from a sample of ~900 quasars from the Sloan Digital Sky Survey. These objects were selected for their intermediate redshift (1.2<z<1.8), placing MgII and UV FeII in the optical band pass,…

Astrophysics · Physics 2009-11-10 Karen M. Leighly , John R. Moore

In the current era of large spectroscopic surveys of the Milky Way, reference stars for calibrating astrophysical parameters and chemical abundances are of paramount importance. We determine elemental abundances of Mg, Si, Ca, Sc, Ti, V,…

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