相关论文: Deep spectroscopy of the emission-line populations…

NGC3201 is a globular cluster (GC) which shows very peculiar kinematic characteristics including an extreme radial velocity and a highly retrograde orbit, strongly suggesting an extraGalactic origin. Our aims are to study NGC3201 in the…

The recent discovery of a new population of stars exhibiting unusual elemental abundance patterns characterized by enhanced Ti to Ga elements and low alpha and n-capture elements suggests the contribution of a new class of supernovae,…

Aims. The aim of this work is to compare the detailed chemical composition of the field N-rich dwarf stars to the second generation stars of globular clusters (GC) in order to investigate the hypothesis that they originated in GCs. Methods.…

We present an abundance analysis based on high resolution spectra of 8 stars selected to span the full range in metallicity in the Draco dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.5 to -3.0 dex. Combining…

We present spectroscopy of nine planetary nebulae (PNe) in the outskirts of M31, all but one obtained with the 10.4m GTC telescope. These sources extend our previous study of the oxygen abundance gradient of M31 to galactocentric radii as…

Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been…

Given the complex nature of galaxies' interstellar medium (ISM), multi-wavelength data are required to probe the interplay among gas, dust, and stellar populations. Spiral galaxies are ideal laboratories for such a goal as they are rich in…

We present an analysis of the X-ray properties of the Magellanic-type galaxy NGC 55 based on two contiguous XMM-Newton observations. We detect a total of 137 X-ray sources in the field of view, 42 of which are located within the optical…

NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution…

Recent JWST observations of the z=10.6 galaxy GN-z11 have revealed a very high gas-phase nitrogen abundance (higher than four times the solar value), a very small half-light radius(~ 60 pc), and a large stellar mass (M_s ~ 10^9 M_sun) for…

We have previously reported on chemical abundance trends with evolutionary state in the globular cluster NGC 6397 discovered in analyses of spectra taken with FLAMES at the VLT. Here, we reinvestigate the FLAMES-UVES sample of 18 stars,…

The isolated elliptical (IE) NGC 7796 is accompanied by an interesting early-type dwarf galaxy, named NGC7796-DW1. It exhibits a tidal tail, very boxy isophotes, and multiple nuclei or regions (A, B, and C) that are bluer than the bulk…

We review the properties of globular clusters which make them useful for studying the Galactic halo, Galactic chemical evolution, and the early stages of the formation of the Milky Way. We review the evidence that GCs have a chemical…

This study presents a comparative analysis of mass-loss and dust-production rates in the dwarf galaxies NGC 147 and NGC 185, focusing on long-period variables (LPVs) and pulsating asymptotic giant branch (AGB) stars as primary indicators of…

We propose a new chemical evolution model aimed at explaining the chemical properties of globular clusters (GC) stars. Our model depends upon the existence of (i) a peculiar pre-enrichment phase in the GC's parent galaxy associated with…

We assess the morphology-density relation, H-alpha linewidth-density relation, and the effects of nearby companions for 300 galaxies selected from low-density environments of the Center for Astrophysics Redshift Survey. Both the…

In previous works, we computed abundances for the red giant in nearly four dozen S-type symbiotic systems (SySt). The abundances provide information about metallicity, evolutionary status, and possible memberships in Galactic stellar…

We study the chemical abundances of a wide sample of 142 Galactic planetary nebulae (PNe) with good quality observations, for which the abundances have been derived more or less homogeneously, thus allowing a reasonable comparison with…

We introduce the first results from an ongoing, systematic survey for new symbiotic stars selected from the AAO/UKST SuperCOSMOS H$\alpha$ Survey (SHS). The survey aims to identify and characterise the fainter population of symbiotic stars…

We present BVRI CCD surface photometry for the central (6'.35 X 6'.35) regions of the dwarf elliptical galaxies NGC 185 and NGC 205 in the Local Group. Surface brightness profiles of NGC 185 (R < 225") and NGC 205 (R < 186") show excess…