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We have analyzed long-slit spectra of 12 dwarf irregular galaxies from the Arecibo Dual Beam Survey (ADBS). These galaxies represent a heterogeneous sample of objects detected by ADBS, but on average are relatively gas-rich,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Nathalie C. Haurberg , Jessica Rosenberg , John J. Salzer

We have used Hubble Space Telescope Wide Field Planetary Camera 2 observations to construct a color-magnitude diagram (CMD) for the bulge of M31 at a location ~1.6 kpc from the galaxy's center. Using scaled-solar abundance theoretical red…

Astrophysics · Physics 2008-11-26 Ata Sarajedini , Pascale Jablonka

In this work we present and discuss the observations of the Mn abundances for 247 FGK dwarfs, located in the Galactic disc with metallicity -1<Fe/H]<+0.3. The observed stars belong to the substructures of the Galaxy thick and thin discs,…

Astrophysics of Galaxies · Physics 2015-10-14 T. Mishenina , T. Gorbaneva , M. Pignatari , F. -K. Thielemann , S. A. Korotin

We study the photometric parameters of the bulges of galaxies of different Hubble types including ellipticals, lenticulars, early and late type spirals and early type dwarf galaxies. Analyzing the distributions of various photometric…

Based on the medium-high resolution (R~ 20,000), modest signal-to-noise ratio (S/N > 70) FLAMES-GIRAFFE spectra, we investigated the copper abundances of 129 red giant branch stars in the Galactic bulge with [Fe/H] from -1.14 to 0.46 dex.…

Solar and Stellar Astrophysics · Physics 2019-11-26 X. D. Xu , J. R. Shi , H. L Yan

With the steady increase of the sample size of observed microlenses towards the central regions of the Galaxy, the main source of the uncertainty in the lens mass will shift from the simple Poisson noise to the intrinsic non-uniqueness of…

Astrophysics · Physics 2009-10-30 HongSheng Zhao , P. Tim de Zeeuw

The Galactic bulge of the Milky Way is made up of stars with a broad range of metallicity, -3.0 < [Fe/H] < 1 dex. The mean of the Metallicity Distribution Function (MDF) decreases as a function of height z from the plane and, more weakly,…

Astrophysics of Galaxies · Physics 2016-07-06 M. Ness , K. Freeman

We present the first comprehensive chemical study of a representative sample of 27 luminous red giant branch (RGB) stars belonging to Liller 1, a complex stellar system in the Galactic bulge. This study is based on medium-resolution…

The effect of stars on the lensing properties of the supermassive black hole in the Galactic Center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around SgrA* increases by factors of a…

Astrophysics · Physics 2009-10-31 Tal Alexander , Abraham Loeb

Despite the huge amount of photometric and spectroscopic efforts targetting the Galactic bulge over the past few years, its age distribution remains controversial owing to both the complexity of determining the age of individual stars and…

Astrophysics of Galaxies · Physics 2018-05-02 Edouard J. Bernard , Mathias Schultheis , Paola Di Matteo , Vanessa Hill , Misha Haywood , Annalisa Calamida

The distribution in color and absolute magnitude is presented for 55,158 galaxies taken from the Sloan Digital Sky Survey in the redshift range $0.08<z<0.12$, as a function of galaxy number overdensity in a line-of-sight cylinder of…

We present an analysis of the large set of microlensing events detected so far toward the Galactic center with the purpose of investigating whether some of the dark lenses are located in Galactic globular clusters. We find that in four…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-12 Philippe Jetzer

One of the most important problems in astrophysics concerns the nature of the dark matter in galactic halos, whose presence is implied mainly by the observed flat rotation curves in spiral galaxies. In the framework of a baryonic scenario…

Astrophysics · Physics 2007-05-23 Philippe Jetzer

We report the first high resolution, detailed abundances of 21 elements for giants in the Galactic bulge/bar within $1^\circ$ of the Galactic plane, where high extinction has rendered such studies challenging. Our high S/N and…

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) provides spectroscopic information of regions of the inner Milky Way inaccessible to optical surveys. We present the first large study of the metallicity distribution of…

Microlensing maps -- that is, contours of equal numbers of events per $10^6$ source stars -- are provided for the inner Galaxy under two alternative hypotheses : (1) the bulge is an oblate axisymmetric spheroid or (2) the bulge is a prolate…

Astrophysics · Physics 2009-10-22 N. W. Evans

The microlensing of background stars by compact objects in globular clusters is analyzed. The main strength of the proposed search is the direct relationship between the lens mass and the time scale of the microlensing event. The main…

Astrophysics · Physics 2007-05-23 Bohdan Paczynski

Due to its proximity, the stellar populations of the Galactic bulge (GB) can be resolved and can be studied in detail. This allows tracing the bulge metallicity distribution function (MDF) for different spatial regions within the bulge,…

Astrophysics of Galaxies · Physics 2023-02-08 Oscar Cavichia , Mercedes Mollá , Juanjo J. Bazán

We present the first results of a detailed abundance analysis, based on VLT observations, of giant stars in the very metal-rich globular cluster NGC 6528. We will be able to tie the horizontal branch abundances (see e.g. Carretta et al.…

Astrophysics · Physics 2007-05-23 Sofia Feltzing , Francesca Primas , Rachel Johnson

(ABRIDGED) Globular clusters trace the formation and evolution of the Milky Way and surrounding galaxies, and outline their chemical enrichment history. To accomplish these tasks it is important to have large samples of clusters with…

Astrophysics of Galaxies · Physics 2016-05-04 Bruno Dias , Beatriz Barbuy , Ivo Saviane , Enrico Held , Gary Da Costa , Sergio Ortolani , Marco Gullieuszik , Sergio Vasquez