相关论文: New response functions for absorption-line indices…
Inferring stellar parameters and chemical abundances by forward modeling stellar spectra usually requires a spectral synthesis code, or an emulator constructed from a curated training set. In these situations continuum normalization is…
In this paper we analyze the line-strength indices in the Lick-system measured by Longhetti et al. (1998a, b) for a sample of 51 early-type galaxies located in low density environments (LDE) and showing signatures of fine structures and/or…
More than about 50% stars of galaxies are in binaries, but most stellar population studies take single star-stellar population (ss-SSP) models, which do not take binary interactions into account. In fact, the integrated peculiarities of…
Based on the classical Lorentz model of the index of refraction, a new method is presented for the extraction of the complex index of refraction from the extinction efficiency of homogeneous and layered dielectric spheres that…
We present differential stellar population models, which allow improved determinations of the ages, iron and alpha-element abundances of old stellar populations from spectral fitting. These new models are calibrated at solar abundances…
Using evolutionary population synthesis we present integrated colours, integrated spectral energy distributions and absorption-line indices defined by the Lick Observatory image dissector scanner (referred to as Lick/IDS) system, for an…
We present empirical calibrations that estimate stellar metallicity, effective temperature and surface gravity as a function of Lick/IDS indices. These calibrations have been derived from a training set of 261 stars for which (1)…
To determine the physical parameters of a transiting planet and its host star from photometric and spectroscopic analysis, it is essential to independently measure the stellar mass. This is often achieved by the use of evolutionary tracks…
We search the Hubble Space Telescope (HST) archive for previously unanalyzed observations of stellar H I Lyman-alpha emission lines, our primary purpose being to look for new detections of Lyman-alpha absorption from the outer heliosphere,…
We present the first science results from our Hubble Space Telescope Survey for Lyman limit absorption systems (LLS) using the low dispersion spectroscopic modes of the Advanced Camera for Surveys and the Wide Field Camera 3. Through an…
The near-infrared (NIR) wavelength range offers some unique spectral features, and it is less prone to the extinction than the optical one. Recently, the first flux calibrated NIR library of cool stars from the NASA Infrared Telescope…
The determination of chemical composition is crucial for investigating the formation and evolution of star forming galaxies and provides a powerful tool to constrain the effects of galactic winds and accretion from the cosmic web. In this…
We report a method of correcting a near-infrared (0.90-1.35 $\mu$m) high-resolution ($\lambda/\Delta\lambda\sim28,000$) spectrum for telluric absorption using the corresponding spectrum of a telluric standard star. The proposed method uses…
As part of a program to study the relationship between QSO Lyman alpha clouds and galaxies at low redshifts, we have obtained a high signal-to-noise far UV spectrum of H 1821+643 [z(em) = 0.297] with the G140L grating of the GHRS. The…
We investigate the Lyman alpha line transfer in nearby and high redshift starbursting galaxies, where the effect of high optical depths and the role of dust in the scattering medium are expected to be conspicuous and should be treated in a…
Galactic outflows provide important feedback effects to regulate the evolution of host galaxies. Two primary diagnostics of outflows are broad and/or blueshifted emission and absorption lines. Even though well-established methods exist to…
Optical frequency combs have attracted attention as optical frequency rulers due to their tooth-like discrete spectra together with their inherent mode-locking nature and phase-locking control to a frequency standard. Based on this concept,…
We recently found that massive cluster elliptical galaxies have strong Na I 8183,8195 and FeH 9916 Wing-Ford band absorption, indicating the presence of a very large population of stars with masses <~ 0.3 M_sun. Here we test this result by…
(Abridged) We explore the dependence of galaxy stellar population properties derived from broad-band SED-fitting - such as age, stellar mass, dust reddening, etc. - on a variety of parameters, such as SFHs, metallicity, IMF, dust reddening…
While spike trains are obviously not band-limited, the theory of super-resolution tells us that perfect recovery of unknown spike locations and weights from low-pass Fourier transform measurements is possible provided that the minimum…