相关论文: Including All the Lines
Can expressiveness of a drawing be traced with a computer? In this study a neural network (perceptron) and a support vector machine are used to classify line drawings. To do this the line drawings are attributed values according to a…
Calculations are performed for the spectral line profiles and images of astrophysical maser radiation that emerges from isolated spheres and thin disks viewed edge-on. In contrast to previous investigations where various approximations are…
We develop a method of analyzing radio frequency spectral line observations to derive data on the temperature, density, velocity, and molecular abundance of the emitting gas. The method incorporates a radiative transfer code with a new…
The lines of lithium at 6708 A, and 6103 A, are analyzed in high resolution spectra of some sharp-lined and slowly rotating roAp stars. Three spectral synthesis codes - STARSP, ZEEMAN2 and SYNTHM were used. New lines of the rare earth…
We present tests carried out on optical and infrared stellar spectra to evaluate the accuracy of different types of interpolation. Both model atmospheres and continuum normalized fluxes were interpolated. In the first case we used linear…
The absorption lines observed in quasar spectra have given us a detailed picture of the intergalactic medium and the metal abundance and kinematics of high redshift galaxies. In this review, we present an introduction to the field, starting…
This paper sumarizes research on abundances in RR Lyrae stars that one of us (GW) has been engaged in with various astronomers. In addition we report on preliminary analysis of the abundances of C, Si, S and Fe in 24 RR Lyrae stars. Our…
We present a new approach to multi-frequency synthesis in radio astronomy. Using Bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. In principle, the bandwidth of a wide-band…
Fossil record methods based on spectral synthesis techniques have matured over the past decade, and their application to integrated galaxy spectra fostered substantial advances on the understanding of galaxies and their evolution. Yet,…
A non-Hermitean random matrix model proposed a few years ago has a remarkably intricate spectrum. Various attempts have been made to understand the spectrum, but even its dimension is not known. Using the Dyson-Schmidt equation, we show…
We present a systematic study of the intensity mapping technique using updated models for the different emission lines from galaxies and identify which ones are more promising for cosmological studies of the post reionization epoch. We…
This is the first of three papers that present a detailed guide for working with the codes {\sc tlusty} and {\sc synspec} to generate model stellar atmospheres or accretion disks, and to produce detailed synthetic spectra. In this paper, we…
Using the Cloudy_3D code (Morisset, this conference), we run a set of models to build a catalog of emission line profiles of PNe. The goal is to cover the main morphologies (spherical, ellipsoidal, bipolar, thin or thick shells) and to…
Opacity calculations are basic ingredients of stellar modelling. They play a crucial role in the interpretation of acoustic modes detected by SoHO, COROT and KEPLER. In this review we present our activities on both theoretical and…
Earth's atmosphere imprints a large number of telluric absorption and emission lines on astronomical spectra, especially in the near infrared, that need to be removed before analysing the affected wavelength regions. These lines are…
Context: Line asymmetries are generated by convective Doppler shifts in stellar atmospheres, especially in metal-poor stars, where convective motions penetrate to higher atmospheric levels. Such asymmetries are usually neglected in…
Blend lines form an integral part of the theoretical analysis and modeling of the polarized spectrum of the Sun. Their interaction with other spectral lines needs to be explored and understood before we can properly use the main spectral…
Line intensity mapping (LIM) is a rapidly emerging technique for constraining cosmology and galaxy formation using multi-frequency, low angular resolution maps. Many LIM applications crucially rely on cross-correlations of two line…
Most observations of absorption lines from interstellar and intergalactic matter have sufficient resolution to show most of the structure at differing radial velocities of the absorber. In analyzing the lines, however, it is important to…
New numerical models of line-driven stellar winds of late O stars are presented. Statistical equilibrium (NLTE) equations of the most abundant elements are solved. Properly obtained occupation numbers are used to calculate consistent…