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We investigate the evolution of star-forming gas-rich disks, using a 3D chemodynamical model including a dark halo, stars, and a two-phase interstellar medium with feedback processes from the stars. We show that galaxy evolution proceeds…

Astrophysics · Physics 2009-11-10 Andreas Immeli , Markus Samland , Ortwin Gerhard , Pieter Westera

(Abridged) Recent spectroscopic surveys have begun to explore the Galactic disk system outside the solar neighborhood on the basis of large data samples. In this way, they provide valuable information for testing spatial and temporal…

We compare the star-formation history and dynamics of the Milky Way (MW) with the properties of distant disk galaxies. During the first ~4 Gyr of its evolution, the MW formed stars with a high star-formation intensity (SFI), Sigma_SFR~0.6…

Astrophysics of Galaxies · Physics 2015-06-19 Matthew D. Lehnert , Paola Di Matteo , Misha Haywood , Owain N. Snaith

The origin of thick disks and their evolutionary connection with thin disks are still a matter of debate. We provide new insights into this topic by connecting the stellar populations of thick disks at redshift $z=0$ with their past…

In the current galaxy formation scenarios, two physical phenomena are invoked to build disk galaxies: hierarchical mergers and more quiescent external gas accretion, coming from intergalactic filaments. Although both are thought to play a…

Astrophysics · Physics 2016-01-27 Francoise Combes

We present a uniform study of the chemical abundances of 12 elements (Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Na, Mg, and Al) derived from the spectra of 451 stars observed as part of one of the HARPS GTO planet search programs. Sixty eight of…

Astrophysics of Galaxies · Physics 2009-11-13 V. Neves , N. C. Santos , S. G. Sousa , A. C. M. Correia , G. Israelian

We present theoretical results on the galactic abundance gradients of several chemical species for the Milky Way disk, obtained using an improved version of the two-infall model of Chiappini, Matteucci, & Gratton (1997) that incorporates a…

Astrophysics · Physics 2007-05-23 Cristina Chiappini , Francesca Matteucci , Donatella Romano

In local disk galaxies such as our Milky Way, older stars generally inhabit a thicker disk than their younger counterparts. Two competing models have attempted to explain this result: one in which stars first form in thin disks that…

This paper reports simulations allowing for stochastic accretion and mass loss within closed and open systems modeled using a previously developed multi-population, multi-zone (halo, thick disk, thin disk) treatment. The star formation rate…

Astrophysics · Physics 2009-11-10 G. Valle , S. N. Shore , D. Galli

We present the abundance analysis of 97 nearby metal-poor (-3.3<[Fe/H]<-0.5) stars having kinematics characteristics of the Milky Way (MW) thick disk, inner, and outer stellar halos. The high-resolution, high-signal-to-noise optical spectra…

Astrophysics of Galaxies · Physics 2015-06-05 M. N. Ishigaki , M. Chiba , W. Aoki

The distribution of chemical abundances and their variation in time are important tools to understand the chemical evolution of galaxies: in particular, the study of chemical evolution models can improve our understanding of the basic…

Astrophysics of Galaxies · Physics 2015-05-18 Monica M. Marcon-Uchida , Francesca Matteucci , Roberto D. D. Costa

The Milky Way serves as a template for understanding the formation and evolution of late-type massive disk galaxies since we can obtain detailed chemical and kinematic information for large samples of individual stars. However, the early…

Interstellar dust is a significant component of matter in the galaxies. The dust owns its origin and reprocessing in a wide range of astrophysical environments. In order to understand the origin and evolution of the distinct types of…

Solar and Stellar Astrophysics · Physics 2020-04-24 Anuj Gupta , Sandeep Sahijpal

In chemodynamical evolution models it is usually assumed that the Milky Way galaxy forms from the inside-out implying that gas inflows onto the disk decrease with galactocentric distance. Similarly, to reproduce differences between chemical…

Chemical abundances provide important clues to the evolution of galaxies. Ionized nebulae are one of the main sources of chemical abundance measurements, especially in external galaxies. Studies of H II regions have shown that the overall…

Astrophysics · Physics 2007-05-23 G. A. Shields

We investigate, using the Gaia-ESO Survey internal Data-Release 2, the properties of the double sequence of the Milky Way discs (defined chemically as the high-alpha and low-alpha populations), and discuss their compatibility with discs…

The formation and evolution of disk galaxies in the cosmological context is studied. We consider the observable properties of disk galaxies and treat the disk formation and galactic evolutionary processes in a self-consistent fashion. We…

Astrophysics · Physics 2007-05-23 Claudio Firmani , Vladimir Avila-Reese , Xavier Hernández

We present chemical abundance analyses of sodium, iron-peak and neutron-capture elements for 97 kinematically selected thick disk, inner halo and outer halo stars with metallicities -3.3<[Fe/H]<-0.5. The main aim of this study is to examine…

Astrophysics of Galaxies · Physics 2015-06-16 Miho N. Ishigaki , Wako Aoki , Masashi Chiba

The Milky Way's stellar disk exhibits a bimodality in the [Fe/H] vs. [$\alpha$/Fe] plane, showing a distinct high-$\alpha$ and low-$\alpha$ sequence whose origin is still under debate. We examine the [Fe/H]-[$\alpha$/Fe] abundance plane in…

Astrophysics of Galaxies · Physics 2020-01-28 Tobias Buck

The formation and evolution of galactic disks are complex phenomena, where gas and star dynamics are coupled through star formation and the related feedback. The physical processes are so numerous and intricate that numerical models focus,…

Astrophysics · Physics 2009-11-07 B. Semelin , F. Combes