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200 papers

Aims: In this paper we aim to study the chemical evolution of sulphur in the galactic disk, using a new optimal abundance indicator: the [SI] line at 10821 A. Similar to the optimal oxygen indicators, the [OI] lines, the [SI] line has the…

Astrophysics · Physics 2009-11-11 Nils Ryde

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

The validity of oxygen and nitrogen abundances derived from the global emission-line spectra of galaxies via the P-method has been investigated using a collection of published spectra of individual HII regions in irregular and spiral…

Astrophysics · Physics 2009-11-10 L. S. Pilyugin , T. Contini , J. M. Vilchez

We present carbon and strontium abundances for 100 metal-poor stars measured from R$\sim $7000 spectra obtained with the Echellette Spectrograph and Imager at the Keck Observatory. Using spectral synthesis of the G-band region, we have…

Astrophysics · Physics 2009-11-13 David K. Lai , Jennifer A. Johnson , Michael Bolte , Sara Lucatello

In most accreting black-hole systems the copious X-rays commonly observed from the inner-most regions are accompanied by a reflection spectrum. The latter is the signature of energetic photons reprocessed by the optically thick material of…

High Energy Astrophysical Phenomena · Physics 2018-05-03 J. A. García , T. R. Kallman , M. Bautista , C. Mendoza , J. Deprince , P. Palmeri , P. Quinet

We measured the emission lines in the spaxel spectra of MaNGA galaxies in order to determine the abundance distributions therein. It has been suggested that the strength of the low-ionization lines, R_2, N_2, and S_2 may be increased…

Astrophysics of Galaxies · Physics 2018-05-23 L. S. Pilyugin , E. K. Grebel , I. A. Zinchenko , Y. A. Nefedyev , V. M. Shulga , Han Wei , P. P. Berczik

The study of stellar parameters of planet-hosting stars, such as metallicity and chemical abundances, help us to understand the theory of planet formation and stellar evolution. Here, we present a catalogue of accurate stellar atmospheric…

Solar and Stellar Astrophysics · Physics 2015-03-11 S. Alves , L. Benamati , N. C. Santos , V. Zh. Adibekyan , S. G. Sousa , G. Israelian , J. R. De Medeiros , C. Lovis , S. Udry

We present atmospheric parameters and iron abundances derived from high-resolution spectra for three samples of dwarf stars: stars which are known to host close-in giant planets (CGP), stars for which radial velocity data exclude the…

Astrophysics · Physics 2009-11-10 U. Heiter , R. E. Luck

We present an up-to-date catalog of intrinsic iron abundance spreads in the 55 Milky Way globular clusters for which sufficiently precise spectroscopic measurements are available. Our method combines multiple datasets when possible to…

Astrophysics of Galaxies · Physics 2020-01-08 Jeremy Bailin

We propose an empirical sulphur abundance determination method based on the strong sulphur emission lines, [S II] 6716, 6731 and [S III] 9069, 9531 in H II regions. From a compilation of literature data we have made a calibration of sulphur…

Astrophysics · Physics 2007-05-23 Tina Christensen , Lars Petersen , Peter Gammelgaard

Planetary Nebulae (PNe) abundance patterns have long been used to note signatures of nuclear processing and to trace the distribution of metals throughout galaxies. We present abundance gradients and heavy element ratios based upon newly…

Astrophysics · Physics 2009-11-11 J. B. Milingo , K. B. Kwitter , R. B. C. Henry , S. P. Souza

Neutral Fe lines in metal-poor stars yield conflicting abundances depending on whether and how deviations from local thermodynamic equilibrium (LTE) are considered. We have collected new high resolution and high signal-to-noise ultraviolet…

Solar and Stellar Astrophysics · Physics 2018-07-04 Ian U. Roederer , Christopher Sneden , James E. Lawler , Jennifer S. Sobeck , John J. Cowan , Ann Merchant Boesgaard

As the field of exoplanetary astronomy has matured, demand has grown for precise stellar abundances to probe subtle correlations between stellar compositions and planetary demographics. However, drawing population-level conclusions from the…

Deriving accurate carbon abundance estimates for a wide variety of stars is still complex due to the difficulties in properly measuring it from atomic and molecular lines. The aim of this paper is to analyse the carbon abundance…

The ideal spectral averaging method depends on one's science goals and the available information about one's data. Including low-quality data in the average can decrease the signal-to-noise ratio (SNR), which may necessitate an optimization…

Instrumentation and Methods for Astrophysics · Physics 2023-10-18 L. D. Anderson , B. Liu , Dana S. Balser , T. M. Bania , L. M. Haffner , Dylan J. Linville , Matteo Luisi , Trey V. Wenger

We present a spectroscopic study of the inner circumstellar ring around SN 1987A. The aim is to determine the elemental abundances and density structure, with particular emphasis on the abundance of iron. We acquired and analysed optical…

Astrophysics · Physics 2007-05-23 S. Mattila , P. Lundqvist , P. Meikle , R. Stathakis , R. Cannon

Accurate relative spectrophotometry is critical for many science applications. Small wavelength scale residuals in the flux calibration can significantly impact the measurements of weak emission and absorption features in the spectra. Using…

Instrumentation and Methods for Astrophysics · Physics 2011-10-14 Renbin Yan

We present a method to determine sodium-abundance ratios ([Na/Fe]) using the Na I D doublet lines in low-resolution ($R \sim$ 2000) stellar spectra. As stellar Na I D lines are blended with those produced by the interstellar medium (ISM),…

Astrophysics of Galaxies · Physics 2022-02-02 Jae-Rim Koo , Young Sun Lee , Hye-Jin Park , Young Kwang Kim , Timothy C. Beers

The surface composition of S-type asteroids can be determined using band parameters extracted from their near-infrared (NIR) spectra (0.7-2.50 $\mu$m) along with spectral calibrations derived from laboratory samples. In the past, these…

Earth and Planetary Astrophysics · Physics 2020-03-18 Juan A. Sanchez , Cristina Thomas , Vishnu Reddy , Noah Frere , Sean S. Lindsay , Adriana Mitchell

*Context: The optimisation of new multiplex spectrographs (resolution, wavelength range,...), their associated surveys (choice of setup), or their parameterisation pipelines require methods that estimate which wavelengths contain useful…

Instrumentation and Methods for Astrophysics · Physics 2023-06-14 Georges Kordopatis , Vanessa Hill , Karin Lind