相关论文: AGB Connection and Ultraviolet Luminosity Excess i…

Ultraluminous X-ray sources (ULXs) are some of the brightest phenomena found outside of a galaxy's nucleus, and their explanation typically invokes accretion of material onto a black hole. Here, we perform the largest population study to…

Low-surface-brightness galaxies (LSBs) contribute to a significant fraction of all the galaxies in the Universe. Ultra-diffuse galaxies (UDGs) form a subclass of LSBs that has attracted a lot of attention in recent years (although its…

Based upon a novel paradigm of the galaxy formation under UV background, the evolutionary bifurcation of pregalactic clouds is confronted with observations on elliptical and spiral galaxies. The theory predicts that the dichotomy between…

The sharp change in slope of the ultrahigh-energy cosmic ray spectrum around 10^{9.6} GeV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle which evolves to intermediate/heavy composition…

We present ultraviolet (UV) integrated colors of 44 Galactic globular clusters (GGCs) observed with the Galaxy Evolution Explorer (GALEX) in both FUV and NUV bands. We find for the first time that GCs associated with the Sagittarius dwarf…

Evidence for excess extreme ultraviolet (EUV) emission over a tail of X-ray gas bremsstrahlung emission has been building up recently, but in some cases remains controversial, mostly due to the moderate quality of the EUV data. In order to…

Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to search for hot binary companions to cool AGB…

A major recent development in extragalactic astronomy has been the discovery of a population of galaxies that are luminous at submillimetre wavelengths. Estimates of their spectral energy distributions suggest that these galaxies are the…

The presence of systematic modulations in the colour distributions in composite samples of globular clusters associated with galaxies in the Virgo and Fornax clusters has been reported in a previous work. In this paper we focus on the 27…

In this introduction to the Third Congress of Vienna on AGB stars I first try to highlight why it is so hard to cope with the AGB evolutionary phase. This phase is indeed dominated by three main physical processes concerning bulk motions of…

The most massive Galactic globular cluster, Omega centauri, appears to have multiple populations. Its bluest main sequence and extended horizontal branch stars are suggested to have the common origin, that is, an extremely high helium…

Clusters of galaxies are strong emitters of EUV and soft X-rays substantially in excess of the contribution from the hot intra-cluster medium at X-ray temperatures. After the initial discovery of EUV excess emission in the Virgo cluster,…

This thesis presents observational studies of evolution of dwarf elliptical galaxies. dE's are numerically dominant population in clusters of galaxies, but their origin and evolution is a matter of debate. Several scenarios of gas removal…

To better understand the mixing and mass loss experienced by low-mass stars as they ascend the asymptotic giant branch (AGB), I have gathered from the literature the abundances of CNO and s-process elements in post-AGB stars in Galactic…

We report on intriguing photometric properties of Galactic stars observed in the GALEX satellite's far-UV and near-UV bandbasses as well as from the SDSS survey and the Kepler Input Catalog. First, the FUV-NUV color distribution of stars in…

We have tried to determine the flux of the ultraviolet background radiation field from the column density ratios of various ions in several absorption systems observed in the spectra of QSOs. We find that in most cases the flux is…

Since all of the five clusters of galaxies observed by the Extreme Ultraviolet Explorer deep survey telescope are found to possess a diffuse EUV emitting component which is unrelated to the virial gas at X-ray temperatures, the question…

Many recent estimates of the star formation rate density at high redshift rely on rest-frame ultraviolet (UV) data. These are highly sensitive to dust absorption. Applying a correlation between the far-infrared (FIR) to UV flux ratio and UV…

It is well appreciated that the description of overadiabatic convection affects the structure of the envelopes of luminous asymptotic giant branch (AGB) stars in the phase of ``hot bottom burning '' (HBB). We stress that this important…

Although the majority of known binary Asymptotic Giant Branch (AGB) stars are symbiotic systems (i.e. with a WD as a secondary star), main-sequence companions of AGB stars can be more numerous, even though they are more difficult to find…