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We compute the chemical evolution of the Galactic bulge in the context of an inside-out model for the formation of the Milky Way. The model contains updated stellar yields from massive stars. The main purpose of the paper is to compare the…

Astrophysics · Physics 2009-11-13 Silvia K. Ballero , Francesca Matteucci , Livia Origlia , R. Michael Rich

The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that…

Using the high resolution Milky Way-like model from Auriga simulation we study the chemical properties of the Galactic bulge, focusing on the metallicity difference between stars on the near side (in front of the Galactic center) and the…

Astrophysics of Galaxies · Physics 2022-08-03 Bin-Hui Chen , Zhao-Yu Li

We have done a detailed study on the structural and kinematical properties of lenticular and early- and late-type spiral galaxies with bars, aiming to explore the formation and evolution processes of stellar bars in galaxies, and their…

Astrophysics · Physics 2009-11-10 Dimitri Alexei Gadotti

Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. [ABRIDGED], we now have 58 microlensed bulge dwarfs…

Numerical simulations predict that bars represent a very important agent for triggering gas inflows, which in turn could lead to central star formation. Bars thus are thought to contribute to the formation of the bulge.This changes both,…

Astrophysics of Galaxies · Physics 2014-06-27 Raúl Cacho , Patricia Sánchez-Blázquez , Javier Gorgas , Isabel Pérez

The HST/WFC3 multiband photometry spanning from the UV to the near-IR of four fields in the Galactic bulge, together with that for six template globular and open clusters, are used to photometrically tag the metallicity [Fe/H] of stars in…

We have combined optical and near-infrared data of known RR Lyrae (RRL) stars in the bulge in order to study the spatial distribution of its metal-poor component by measuring precise reddening values and distances of 7663 fundamental-mode…

Astrophysics of Galaxies · Physics 2015-01-21 I. Dékány , D. Minniti , M. Catelan , M. Zoccali , R. K. Saito , M. Hempel , O. A. Gonzalez

Recent analysis of stellar populations in barred galaxies have focused on the spatial distribution of stellar population ages and metallicities. However, barred galaxies are complex objects where dynamical instabilities play a leading role…

Astrophysics · Physics 2009-11-13 Hervé Wozniak

We present detailed abundance results for 9 Galactic bulge stars in Baade's Window, based on HIRES (R=45,000--60,000) spectra taken with the Keck I telescope. The alpha elements show non-uniform enhancements relative to the Solar…

Astrophysics · Physics 2007-05-23 Andrew McWilliam , R. Michael Rich

We have used photometric data on almost 91 000 fundamental-mode RR Lyrae stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way. Based on their metallicity distributions, we demonstrate…

Recent large scale surveys of galactic bulge stars allowed to build a detailed map of the bulge kinematics. The bulge exhibits cylindrical rotation consistent with a disky origin which evolved through bar driven secular evolution. However…

Astrophysics of Galaxies · Physics 2016-07-06 Carine Babusiaux

(Abridge) Bars are very common in the centre of the disc galaxies, and they drive the evolution of their structure. A volume-limited sample of 2106 disc galaxies extracted from the Sloan Digital Sky Survey Data Release 5 was studied to…

Astrophysics of Galaxies · Physics 2009-11-13 J. A. L. Aguerri , J. Mendez-Abreu , E. M. Corsini

The center of our disk galaxy, the Milky Way, is dominated by a boxy/peanut-shaped bulge. Numerous studies of the bulge based on stellar photometry have concluded that the bulge stars are exclusively old. The perceived lack of young stars…

Astrophysics of Galaxies · Physics 2015-06-18 M. Ness , Victor. P. Debattista , T. Bensby , S. Feltzing , R. Roskar , D. R. Cole , J. A. Johnson , K. Freeman

We study a sample of 62 Baade's Window (1,-4) K giants that have published proper motions, radial velocity and metallicity. We construct the velocity ellipsoids for the metal rich stars and metal poor stars. We find a vertex deviation…

Astrophysics · Physics 2019-08-17 HongSheng Zhao , D. N. Spergel , R. M. Rich

The evolution of the Milky Way bulge and its relationship with the other Galactic populations is still poorly understood. The bulge has been suggested to be either a merger-driven classical bulge or the product of a dynamical instability of…

Classical bulges and stellar bars are common features in disk galaxies and serve as key tracers of galactic evolution. Angular momentum exchange at bar resonances drives secular morphological changes throughout the disk, including bar…

The Galactic bulge and bar are critical to our understanding of the Milky Way. However, due to the lack of reliable stellar distances, the structure and kinematics of the bulge/bar beyond the Galactic center have remained largely…

The four main findings about the age and abundance structure of the Milky Way bulge based on microlensed dwarf and subgiant stars are: (1) a wide metallicity distribution with distinct peaks at [Fe/H]=-1.09, -0.63, -0.20, +0.12, +0.41; (2)…

Astrophysics of Galaxies · Physics 2018-08-22 T. Bensby , S. Feltzing , A. Gould , J. C. Yee , J. A. Johnson , M. Asplund , J. Meléndez , S. Lucatello , L. M. Howes

Bar-like structures were investigated in a sample of 186 disk galaxies larger than 0.5 arcsec that are in the I-band image of the Tadpole galaxy taken with the HST ACS. We found 22 clear cases of barred galaxies, 21 galaxies with small bars…

Astrophysics · Physics 2009-11-10 Bruce G. Elmegreen , Debra Meloy Elmegreen , Amelia C. Hirst