An extensive library of 2500–10 500 Å synthetic spectra

Munari, U.; Sordo, R.; Castelli, F.; Zwitter, T.

doi:10.1051/0004-6361:20042490

Cited by 371 publications

(551 citation statements)

References 30 publications

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“…The reference spectra are either a grid of theoretical models (e.g. Munari et al 2005;Coelho et al 2005) or a set of observed stars whose parameters are known from the analysis of individual high resolution spectra (e.g. Soubiran et al 1998).…”

Section: Determination Of Stellar Atmospheric Parametersmentioning

confidence: 99%

ULySS: a full spectrum fitting package

Koleva

Prugniel

Bouchard

et al. 2009

A&A

470

526

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Aims. We provide an easy-to-use full-spectrum fitting package and explore its applications to (i) the determination of the stellar atmospheric parameters and (ii) the study of the history of stellar populations. Methods. We developed ULySS, a package to fit spectroscopic observations against a linear combination of non-linear model components convolved with a parametric line-of-sight velocity distribution. The minimization can be either local or global, and determines all the parameters in a single fit. We use χ 2 maps, convergence maps and Monte-Carlo simulations to study the degeneracies, local minima and to estimate the errors. Results. We show the importance of determining the shape of the continuum simultaneously to the other parameters by including a multiplicative polynomial in the model (without prior pseudo-continuum determination, or rectification of the spectrum). We also stress the usefulness of using an accurate line-spread function, depending on the wavelength, so that the line-shape of the models properly matches the observation. For simple models, i.e., to measure the atmospheric parameters or the age/metallicity of a singleage stellar population, there is often a unique minimum, or when local minima exist they can be recognized unambiguously. For more complex models, Monte-Carlo simulations are required to assess the validity of the solution. Conclusions. The ULySS package is public, simple to use and flexible. The full spectrum fitting makes optimal use of the signal.

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Section: Determination Of Stellar Atmospheric Parametersmentioning

confidence: 99%

ULySS: a full spectrum fitting package

Koleva

Prugniel

Bouchard

et al. 2009

A&A

470

526

View full text Add to dashboard Cite

show abstract

“…The temperature and surface gravity of each star were determined in Paper I and are used to select an appropriate spectral model atmosphere, from which the absorption line strengths are measured. In this work the Munari set of Kurucz-Castelli models, KC-models, are used for lines with λ < 10050Å, due to their 1Å sampling (Munari et al 2005); a metalicity of [M/H]=0 is adopted. For longer wavelengths additional models are required, the older KC-models are used here computed by Kurucz (1993); Castelli & Kurucz (2004).…”

Section: Measuring Emission Line Strengthsmentioning

confidence: 99%

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Fairlamb

Oudmaijer

Mendigutía

et al. 2016

Mon. Not. R. Astron. Soc.

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The Herbig Ae/Be stars (HAeBes) allow an exploration of the properties of PreMain Sequence(PMS) stars above the low-mass range (< 2 M ⊙ ) and those bordering the high-mass range (> 8 M ⊙ ). This paper is the second in a series exploring accretion in 91 HAeBes with Very Large Telescope/X-shooter spectra. Equivalent width measurements are carried out on 32 different lines, spanning the UV to NIR, in order to obtain their line luminosities. The line luminosities were compared to accretion luminosities, which were determined directly from measurements of an UV-excess. When detected, emission lines always demonstrate a correlation with the accretion luminosity, regardless of detection frequency. The average relationship between accretion luminosity and line luminosity is found to be L acc ∝ L line 1.16±0.15 . This is in agreement with the findings in Classical T Tauri stars, although the HAeBe relationship is generally steeper, particularly towards the Herbig Be mass range. Since all observed lines display a correlation with the accretion luminosity, all of them can be used as accretion tracers. This has increased the number of accretion diagnostic lines in HAeBes tenfold. However, questions still remain on the physical origin of each line, which may not be due to accretion.

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“…These authors also stated that for larger numbers of repetitions (five or six measurements) the binary fraction for SB1 increases to about 10−15%, which they referred to as the lower limit for the binary fraction in RAVE. Matijevič et al (2010), on the other hand, investigated the cross-correlation function of observed to template spectra (Munari et al 2005) in DR2. They identified 123 doublelined spectroscopic binaries (SB2), indicated either by more than one peak or an asymmetric central peak.…”

Section: Radial Velocity Experimentsmentioning

confidence: 99%