Related papers: Mapping the Asymmetric Thick Disk: II Distance, Si…
The stellar asymmetry of faint thick disk/inner halo stars in the first quadrant first reported by Larsen & Humphreys (1996) and investigated further by Parker et al. (2003, 2004) has been recently confirmed by SDSS (Juric et al. 2008).…
We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The Cloud is centered at a Galactic longitude of about 40 degrees and extends above and below the Galactic plane by at…
We analyse a 10,000 star spectroscopic survey, focused on Galactic thick disk stars typically 2-5 kpc from the Sun, carried out using the AAOmega Spectrograph on the AAT. We develop methods for completeness-correction of the survey based on…
A significant asymmetry in the distribution of faint blue stars in the inner Galaxy, Quadrant 1 (l = 20 to 45 degrees) compared to Quadrant 4 was first reported by Larsen & Humphreys (1996). Parker et al (2003, 2004) greatly expanded the…
Using the MIKE spectrograph, mounted on the 6.5 m Magellan/Clay telescope at the Las Campanas observatory in Chile, we have obtained high-resolution spectra for 60 F and G dwarf stars, all likely members of a density enhancement in the…
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…
Stellar photometry obtained using the Hubble Space Telescope is used to study the distributions of the number densities of stars of various ages in 12 irregular and dwarf spiral galaxies viewed edge-on. Two subsystems can be distinguished…
In the first two papers of this series, Larsen et al (2010a,b) describe our faint CCD survey in the inner Galaxy and map the over-density of Thick Disk stars in Quadrant I (Q1) to 5 kpc or more along the line of sight. The regions showing…
We map the large-scale sub-structure in the Galactic stellar halo using accurate 3D positions of ~14,000 RR Lyrae reported by the Catalina Sky Survey. In the heliocentric distance range of 10-25 kpc, in the region of the sky approximately…
Abridged: We estimate the distances to ~48 million stars detected by the Sloan Digital Sky Survey and map their 3D number density distribution in 100 < D < 20 kpc range over 6,500 deg^2 of sky. The data show strong evidence for a Galaxy…
It has been proposed that the Hercules stream, a group of co-moving stars in the Solar neighborhood offset from the bulk of the velocity distribution, is the result of resonant interactions between stars in the outer disk and the Galactic…
The Galactic bulge, that is the prominent out-of-plane over-density present in the inner few kiloparsecs of the Galaxy, is a complex structure, as the morphology, kinematics, chemistry and ages of its stars indicate. To understand the…
We have carried out a sample survey in UBVR photometry and proper motions in different directions in the Galaxy, as part of an investigation of galactic structure and evolution. Three fields in the direction of galactic anticentre, centre…
We suggest and verify a new photometric method enabling derivation of relative thickness of a galactic disk from two-dimensional surface-brightness distribution of the galaxy in the plane of the sky. The method is applied to images of 45…
Most, if not all, disk galaxies have a thin (classical) disk and a thick disk. In most models thick disks are thought to be a necessary consequence of the disk formation and/or evolution of the galaxy. We present the results of a study of…
A set of twenty late-type (K5-M5) stars were observed with the Herschel Space Observatory at 100 and 160 microns with the goal of searching for far-infrared excesses indicative of the presence of circumstellar disks. Out of this sample,…
This paper presents an investigation of the outer disk structure by using data from a recent release of the 2 micron sky survey (2MASS). This 2MASS data show unambiguously that the stellar disk thickens with increasing distance from the…
Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes we present detailed elemental abundances for 64 red giant stars in the inner and outer Galactic disk. For the inner disk sample (4-7 kpc from…
We analyze the global structure of 34 late-type, edge-on, undisturbed, disk galaxies spanning a wide range of mass. We measure structural parameters for the galaxies using two-dimensional least-squares fitting to our $R$-band photometry.…
We report the detection of vertically extended far-ultraviolet (FUV) and near-UV emissions in an edge-on spiral galaxy NGC 891, which we interpret as being due to dust-scattered starlight. Three-dimensional radiative transfer models are…