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The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral…

Temperature, surface gravity, and metallicitity are basic stellar atmospheric parameters necessary to characterize a star. We aim to improve the description of the spectroscopic temperatures especially for the cooler stars where the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Tsantaki , S. G. Sousa , V. Zh. Adibekyan , N. C. Santos , A. Mortier , G. Israelian

Aims: We estimate stellar masses of galaxies in the high redshift universe with the intention of determining the influence of newly available Spitzer/IRAC infrared data on the analysis. Based on the results, we probe the mass assembly…

Astrophysics · Physics 2009-11-13 F. Elsner , G. Feulner , U. Hopp

We apply a flexible parametric model, a combination of generalized Plummer profiles, to infer the shapes of the stellar density profiles of the Milky Way's satellite dwarf spheroidal galaxies (dSphs). We apply this model to 40 dSphs using…

Astrophysics of Galaxies · Physics 2020-03-26 A. G. Moskowitz , M. G. Walker

Upcoming large-scale spectroscopic surveys with e.g. WEAVE and 4MOST will provide thousands of spectra of massive stars, which need to be analysed in an efficient and homogeneous way. Usually, studies of massive stars are limited to samples…

Solar and Stellar Astrophysics · Physics 2023-09-14 J. M. Bestenlehner , T. Enßlin , M. Bergemann , P. A. Crowther , M. Greiner , M. Selig

We propose a new method for measuring the spatial density distribution of the stellar halo of the Milky Way. Our method is based on a pairwise statistic of the distribution of stars on the sky, the angular two-point correlation function…

Astrophysics of Galaxies · Physics 2023-08-09 Anda Chen , Zhigang Li , Yougang Wang , Yan Gong , Xuelei Chen , Richard J. Long

In physics, it is sometimes desirable to compute the so-called \emph{Density Of States} (DOS), also known as the \emph{spectral density}, of a real symmetric matrix $A$. The spectral density can be viewed as a probability density…

Numerical Analysis · Mathematics 2014-10-07 Lin Lin , Yousef Saad , Chao Yang

We applied machine learning to the entire data history of ESO's High Accuracy Radial Velocity Planet Searcher (HARPS) instrument. Our primary goal was to recover the physical properties of the observed objects, with a secondary emphasis on…

Solar and Stellar Astrophysics · Physics 2024-12-13 Vojtěch Cvrček , Martino Romaniello , Radim Šára , Wolfram Freudling , Pascal Ballester

In this paper we investigate the power of spectral synthesis as a mean to estimate physical properties of galaxies. Spectral synthesis is nothing more than the decomposition of an observed spectrum in terms of a superposition of a base of…

Astrophysics · Physics 2010-04-06 R. Cid Fernandes , A. Mateus , L. Sodre , G. Stasinska , J. M. Gomes

With a goal toward deriving the physical conditions in external galaxies, we present a survey of the formaldehyde emission in a sample of starburst systems. By extending a technique used to derive the spatial density in star formation…

Astrophysics · Physics 2009-11-13 Jeffrey G. Mangum , Jeremy Darling , Karl M. Menten , Christian Henkel

Fitting spectral distributions of total fluxes or image intensities are two standard methods for estimating the masses of starless cores and protostellar envelopes. These mass estimates, which are the main source and basis of our knowledge…

Instrumentation and Methods for Astrophysics · Physics 2016-09-28 Alexander Men'shchikov

In this paper we present a novel method to identify and characterize stellar clusters deeply embedded in a dark molecular cloud. The method is based on measuring stellar surface density in wide-field infrared images using star counting…

Instrumentation and Methods for Astrophysics · Physics 2017-11-29 Marco Lombardi , Charles J. Lada , Joao Alves

The task of flux calibration for LAMOST (Large sky Area Multi-Object Spectroscopic Telescope) spectra is difficult due to many factors. For example, the lack of standard stars, flat fielding for large field of view, and variation of…

Planetary studies demand precise and accurate stellar parameters as input to infer the planetary properties. Different methods often provide different results that could lead to biases in the planetary parameters. In this work, we present a…

Solar and Stellar Astrophysics · Physics 2014-10-22 M. Tsantaki , S. G. Sousa , N. C. Santos , M. Montalto , E. Delgado-Mena , A. Mortier , V. Adibekyan , G. Israelian

A method is presented for finding anisotropic distribution functions for stellar systems with known, spherically symmetric, densities, which depends only on the two classical integrals of the energy and the magnitude of the angular…

Astrophysics · Physics 2008-12-31 Zhenglu Jiang , Leonid Ossipkov

In this paper we describe the FIT\textit{spec} code, a data mining tool for the automatic fitting of synthetic stellar spectra. The program uses a database of 27\,000 {\sc cmfgen} models of stellar atmospheres arranged in a six-dimensional…

A statistical analysis of the observed perturbations in the density of stellar streams can in principle set stringent contraints on the mass function of dark matter subhaloes, which in turn can be used to constrain the mass of the dark…

Astrophysics of Galaxies · Physics 2021-08-18 Joeri Hermans , Nilanjan Banik , Christoph Weniger , Gianfranco Bertone , Gilles Louppe

Based on the Meso-Structured Magnetic Atmosphere (MESMA) approximation, recently introduced by Carroll & Kopf (2007), we present first results of an inversion of spectropolarimetric observations obtained from solar internetwork regions. To…

Astrophysics · Physics 2007-05-23 T. A. Carroll

An empirical method of modeling the stellar spectrum of galaxies is proposed, based on two successive applications of Principal Component Analysis (PCA). PCA is first applied to the newly available stellar library STELIB, supplemented by…

Astrophysics · Physics 2009-11-10 Cheng Li , Ting-Gui Wang , Hong-Yan Zhou , Xiao-Bo Dong , Fu-Zhen Cheng

We present a simple, largely empirical but physically motivated model, which is designed to interpret consistently multi-wavelength observations from large samples of galaxies in terms of physical parameters, such as star formation rate,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Elisabete da Cunha , Stephane Charlot , David Elbaz