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Forthcoming large galaxy cluster surveys will yield tight constraints on cosmological models. It has been shown that in an idealized survey, containing > 10,000 clusters, statistical errors on dark energy and other cosmological parameters…

Astrophysics · Physics 2008-11-26 Joshua D. Younger , Zoltan Haiman , Greg L. Bryan , Sheng Wang

In the current panorama of large surveys, the vast amount of data obtained with different methods, data types, formats, and stellar samples, is making an efficient use of the available information difficult. The Survey of Surveys is a…

We present K-band interferometric and optical spectroscopic observations of Menkar obtained with the instruments VINCI and UVES at Paranal Observatory. Spherically symmetric PHOENIX stellar model atmospheres are constrained by comparison to…

Astrophysics · Physics 2008-11-26 M. Wittkowski , J. P. Aufdenberg , T. Driebe , V. Roccatagliata , T. Szeifert , B. Wolff

The gas that is present in the interstellar medium is usually very far removed from (local) thermodynamic equilibrium, and in some cases may also not be in a steady-state equilibrium with its surroundings. The physics of this material is…

Solar and Stellar Astrophysics · Physics 2020-02-17 P. A. M. van Hoof , G. C. Van de Steene , F. Guzmán , M. Dehghanian , M. Chatzikos , G. J. Ferland

A scheme for estimating atmospheric parameters T$_{eff}$, log$~g$, and [Fe/H] is proposed on the basis of Least Absolute Shrinkage and Selection Operator (LASSO) algorithm and Haar wavelet. The proposed scheme consists of three processes. A…

Solar and Stellar Astrophysics · Physics 2015-08-04 Yu Lu , Xiangru Li

Photometric light curves suffer from fundamental degeneracies that limit surface information recovery. We demonstrate that astrometry enables access to complementary information through photocentre variations induced by rotating surface…

Solar and Stellar Astrophysics · Physics 2026-04-06 Conaire Deagan , Benjamin T. Montet

Spectral analysis by means of NLTE model atmospheres has presently arrived at a high level of sophistication. High-resolution spectra of central stars of planetary nebulae can be reproduced in detail from the infrared to the X-ray…

Astrophysics · Physics 2007-09-04 Thomas Rauch , Klaus Werner , Marc Ziegler , Jeffrey W. Kruk , Cristina M. Oliveira

Context: StePar is an automatic code written in Python 3.X designed to compute the stellar atmospheric parameters Teff, log(g), [Fe/H], and of FGK-type stars by means of the EW method. This code has already been extensively tested in…

Solar and Stellar Astrophysics · Physics 2019-08-21 H. M. Tabernero , E. Marfil , D. Montes , J. I. González Hernández

Multi-connected universe models with space identification scales smaller than the size of the observable universe produce topological images of cosmic sources. We generalise to locally hyperbolic spaces the crystallographic method, aimed to…

Astrophysics · Physics 2011-05-23 Jean-Philippe Uzan , Roland Lehoucq , Jean-Pierre Luminet

We describe a self-consistent spectrum analysis technique employing non-LTE line formation, which allows precise atmospheric parameters of massive stars to be derived: 1sigma-uncertainties as low as ~1% in effective temperature and…

Solar and Stellar Astrophysics · Physics 2015-03-17 Maria-Fernanda Nieva , Norbert Przybilla

One of the biggest problems we can encounter while dealing with the limb-darkening coefficients for stellar atmospheric models with spherical symmetry is the difficulty of adjusting both the limb and the central parts simultaneously. In…

Solar and Stellar Astrophysics · Physics 2018-10-10 Antonio Claret

We explore the relationship between stellar surface density and gas surface density (the star-gas or S-G correlation) in a 20,000 M$_{\odot}$ simulation from the STAR FORmation in Gaseous Environments (STARFORGE) Project. We create…

Astrophysics of Galaxies · Physics 2023-10-19 Samuel Millstone , Robert Gutermuth , Stella S. R. Offner , Riwaj Pokhrel , Michael Y. Grudić

GALA is a freely distributed Fortran code to derive automatically the atmospheric parameters (temperature, gravity, microturbulent velocity and overall metallicity) and abundances for individual species of stellar spectra using the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 A. Mucciarelli , E. Pancino , L. Lovisi , F. R. Ferraro , E. Lapenna

Context: Massive amounts of spectroscopic data obtained by stellar surveys are feeding an ongoing revolution in our knowledge of stellar and Galactic astrophysics. Analysing these data sets to extract the best possible astrophysical…

Instrumentation and Methods for Astrophysics · Physics 2026-01-14 J. E. Martínez Fernández , S. Özdemir , R. Smiljanic , M. L. L. Dantas , A. R. da Silva

This study presents the continuation of the analysis of variations of atmospheric and space weather parameters above Iberian Peninsula along two years near the 24th solar cycle maximum presented in Morozova et al. [2016]. Previously, the…

Atmospheric and Oceanic Physics · Physics 2020-06-14 Anna L. Morozova , Paulo Ribeiro , Juan Jose Blanco , Tatiana V. Barlyaeva

We present K-band interferometric measurements of the limb-darkened intensity profile of the M4 giant star psi Phoenicis obtained with VLTI/VINCI. High-precision squared visibility amplitudes in the second lobe of the visibility function…

Astrophysics · Physics 2007-05-23 M. Wittkowski , J. P. Aufdenberg , P. Kervella

Using the 2MASS Photometric Redshift catalogue we perform a number of statistical tests aimed at detecting possible departures from statistical homogeneity and isotropy in the large-scale structure of the Universe. Making use of the angular…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 David Alonso , Ana Isabel Salvador , Francisco Javier Sánchez , Maciej Bilicki , Juan García-Bellido , Eusebio Sánchez

In this work, we present a new methodology to fit the observed and synthetic spectrum of solar-like stars at millimeter, submillimeter and infrared wavelengths through semiempirical models of the solar chromosphere. We use the…

Solar and Stellar Astrophysics · Physics 2020-01-15 F. Tapia-Vazquez , V. De la Luz

Accurately measuring the atmospheric coherence time is still an important problem despite a variety of applicable methods. The Multi-aperture scintillation sensor (MASS) designed for the vertical profiling of optical turbulence, also…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Victor Kornilov

We present several new sets of grids of model stellar atmospheres computed with modified versions of the ATLAS9 code. Each individual set consists of several grids of models with different metallicities ranging from [M/H] = -2.0 to +1.0…