Results 1 to 10 of about 105,508 (303)
The Galactic Thick Disk Stellar Abundances [PDF]
The Astronomical Journal, 2000 We present first results from a program to measure the chemical abundances of a large (N>30) sample of thick disk stars with the principal goal of investigating the formation history of the Galactic thick disk. Our analysis confirms previous studies of O and Mg in the thick disk stars which reported enhancements in excess of the thin disk population ...
J. X. Prochaska +4 more
arxiv +7 more sources
Chemical constraints on the formation of the Galactic thick disk [PDF]
EPJ Web of Conferences, 2012 We highlight some results from our detailed abundance analysis study of 703 kinematically selected F and G dwarf stars in the solar neighbourhood. The analysis is based on spectra of high-resolution (R = 45000 to 110 000) and high signal-to-noise (S/N ...
Feltzing S., Bensby T.
doaj +7 more sources
Thick Disks of Lenticular Galaxies [PDF]
Astron.Astrophys. 422 (2004) 465-475, 2004 Thick disks are faint and extended stellar components found around several disk galaxies including our Milky Way. The Milky Way thick disk, the only one studied in detail, contains mostly old disk stars (~10 Gyr), so that thick disks are likely to trace the early stages of disk evolution.
Marc Balcells +5 more
arxiv +5 more sources
The Kinematics of Thick Disks in Nine External Galaxies [PDF]
The Astrophysical Journal, 2008 We present kinematic measurements of thin and thick disk components in a sample of nine edge-on galaxies. We extract stellar and ionized gas rotation curves at and above the galaxies' midplanes using the Ca II triplet absorption features and H-alpha emission lines measured with the GMOS spectrographs on Gemini North and South.
Peter Yoachim +2 more
arxiv +7 more sources
Thick-disk evolution induced by the growth of an embedded thin disk [PDF]
Astrophys.J.718:314-330,2010, 2009 We perform collisionless N-body simulations to investigate the evolution of the structural and kinematical properties of simulated thick disks induced by the growth of an embedded thin disk. The thick disks used in the present study originate from cosmologically-common 5:1 encounters between initially-thin primary disk galaxies and infalling satellites.
Stelios Kazantzidis +2 more
arxiv +7 more sources
On the Significance of the Thick Disks of Disk Galaxies
The Astrophysical Journal Supplement SeriesThick disks are a prevalent feature observed in numerous disk galaxies, including our own Milky Way. Their significance has been reported to vary widely, ranging from a few percent to 100% of the disk mass, depending on the galaxy and the measurement ...
Sukyoung K. Yi +10 more
doaj +5 more sources
Lick Indices in the Thin and Thick Disks of Edge-On Disk Galaxies [PDF]
The Astrophysical Journal, 2008 We have measured Lick index equivalent widths to derive luminosity weighted stellar ages and metallicities for thin and thick disk dominated regions of 9 edge-on disk galaxies with the ARC 3.5 meter telescope at Apache Point Observatory. In all cases, the thick disks are confirmed to be old stellar populations, with typical ages between 4 and 10 Gyr ...
Peter Yoachim +2 more
arxiv +7 more sources
The Kinematics of Thick Disks in External Galaxies [PDF]
Astrophys.J. 624 (2005) 701-713, 2005 We present kinematic measurements of the thick and thin disks in two edge-on galaxies. We have derived stellar rotation curves at and above the galaxies' midplanes using Ca II triplet features measured with the GMOS spectrograph on Gemini North. In one galaxy, FGC 1415, the kinematics above the plane show clear rotation that lags that of the midplane ...
Peter Yoachim, Julianne J. Dalcanton
arxiv +3 more sources
The Emergence of the Thick Disk in a CDM Universe II: Colors and Abundance Patterns [PDF]
Astrophys.J. 630 (2005) 298-308, 2005 The recently emerging conviction that thick disks are prevalent in disk galaxies, and their seemingly ubiquitous old ages, means that the formation of the thick disk, perhaps more than any other component, holds the key to unravelling the evolution of the Milky Way, and indeed all disk galaxies. In Paper I, we proposed that the thick disk was formed in
Chris B. Brook +3 more
arxiv +3 more sources
The Galactic thick and thin disks: differences in evolution [PDF]
, 2006 Recent observations demonstrate that the thin and thick disks of the Galaxy have different chemical abundance trends and evolution timescales. The relative abundances of $\alpha$-elements in the thick Galactic disk are increased relative to the thin disk. Our goal is to investigate the cause of such differences in thick and thin disk abundances.
T. V. Nykytyuk, Т. В. Мішеніна
arxiv +3 more sources