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200 papers

We present the results of two-component (disc+bar) and three-component (disc+bar+bulge) multiwavelength 2D photometric decompositions of barred galaxies in five SDSS bands ($ugriz$). This sample of $\sim$3,500 nearby ($z<0.06$) galaxies…

We report the first abundance analysis of 14 M giant stars in the Galactic bulge, based on R=25,000 infrared spectroscopy (1.5-1.8um) using NIRSPEC at the Keck II telescope. Because some of the bulge M giants reach high luminosities and…

Astrophysics · Physics 2009-11-11 R. Michael Rich , Livia Origlia

We continue the analysis of the dataset of our spectroscopic observation campaign of M31, by deriving simple stellar population properties (age metallicity and alpha-elements overabundance) from the measurement of Lick/IDS absorption line…

Astrophysics of Galaxies · Physics 2018-10-31 R. P. Saglia , M. Opitsch , M. H. Fabricius , R. Bender , M. Blana , O. Gerhard

In the present work we analyzed seven globular clusters selected from their location in the Galactic bulge and with metallicity values in the range $-1.30\lesssim\rm{[Fe/H]}\lesssim-0.50$. The aim of this work is first to derive cluster…

Understanding the structure, formation and evolution of the Galactic Bulge requires the proper determination of spatial metallicity gradients in both the radial and vertical directions. RR Lyrae pulsators, known to be excellent distance…

Solar and Stellar Astrophysics · Physics 2015-06-22 Sara Alejandra Sans Fuentes , Joris De Ridder

The chemical abundances measured in stars of the Galactic bulge offer an unique opportunity to test galaxy formation models as well as impose strong constraints on the history of star formation and stellar nucleosynthesis. The aims of this…

Astrophysics of Galaxies · Physics 2015-05-20 Gabriele Cescutti , Francesca Matteucci

We present the first statistical study on the intrinsic three-dimensional (3D) shape of a sample of 83 galactic bars extracted from the CALIFA survey. We use the galaXYZ code to derive the bar intrinsic shape with a statistical approach.…

Astrophysics of Galaxies · Physics 2018-07-11 J. Mendez-Abreu , L. Costantin , J. A. L. Aguerri , A. de Lorenzo-Caceres , E. M. Corsini

The photometric estimate of the metallicity and the age of the Azzopardi et al. (1991, A&AS 88, 265) carbon stars (Ng 1997, A&A 328, 211) is revised to respectively Z~0.004 and ~0.1 Gyr. Under the hypothesis that the carbon stars are…

Astrophysics · Physics 2007-05-23 Y. K. Ng

The Bulge Radial Velocity/Abundance Assay (BRAVA) has accomplished a survey of 10,000 red giants in the Southern Galactic bulge, approximately spanning -8 deg. < l < +8 deg. and -3 deg. <b < -8 deg., a region within roughly 1 kpc from the…

Astrophysics of Galaxies · Physics 2011-08-31 R. Michael Rich

We present a study of the stellar populations within the central regions of four nearby barred galaxies, and use a novel technique to constrain the duration of bar activity. We focus on the star formation 'desert', a region within each of…

Astrophysics of Galaxies · Physics 2016-02-03 Phil A. James , Susan M. Percival

We selected Bulge stars from APOGEE DR17 cross-matched with astrometric data from \textit{Gaia} DR3. Bulge stars were divided into sub-samples with line-of-sight velocity dispersion analyzed and the peaks of MDF were detected by both…

Astrophysics of Galaxies · Physics 2025-10-29 Haoyang Liu , Cuihua Du , Zhongcheng Li , Jian Zhang , Mingji Deng

Bars in galaxies are thought to stimulate both inflow of material and radial mixing along them. Observational evidence for this mixing has been inconclusive so far however, limiting the evaluation of the impact of bars on galaxy evolution.…

I discuss the age and helium abundance of the Galactic bulge stellar population. I present examples as to how age and helium abundance can be degenerate observationally, and thus, how unstated assumptions of the helium-metallicity relation…

Astrophysics of Galaxies · Physics 2013-07-16 David M. Nataf

Barred structures are widespread in a considerable fraction of galactic discs, spanning diverse environments and galaxy luminosities. The environment likely exerts a significant influence on bar formation. It is plausible that the…

Astrophysics of Galaxies · Physics 2023-09-22 J. Alfonso L. Aguerri , Virginia Cuomo , Azahara Rojas-Roncero , Lorenzo Morelli

Recently the search for the oldest stars have started to focus on the Bulge region. The Galactic bulge hosts extremely old stars, with ages compatible with the ages of the oldest halo stars. The data coming from these recent observations…

Astrophysics of Galaxies · Physics 2018-08-22 Gabriele Cescutti , Cristina Chiappini , Raphael Hirschi

The stellar population of the Milky Way bulge is thoroughly studied, with a plethora of measurements from virtually the full suite of instruments available to astronomers. It is thus perhaps surprising that alongside well-established…

Solar and Stellar Astrophysics · Physics 2016-07-06 David M. Nataf

Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this letter is determining if the mass assembly…

We present a comprehensive chemical abundance analysis of five red giants and two horizontal branch (HB) stars towards the southern Galactic bulge, at (l,b)$\sim$(0$^{\rm o}$,-11$^{\rm o}$). Based on high-resolution spectroscopy obtained…

Astrophysics of Galaxies · Physics 2016-03-16 Andreas Koch , Andrew McWilliam , George W. Preston , Ian B. Thompson

Using data from the Two Micron All-Sky Survey (2MASS), we identify a population of infrared carbon (IR C) stars with J-K >= 2 in the Milky Way. These stars are shown to trace the stellar bar previously identified in IR and optical surveys.…

Astrophysics · Physics 2009-11-07 Andrew A. Cole , Martin D. Weinberg

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…