Related papers: The emergence of galactic thin and thick discs acr…
The vertical structure of stellar discs provides key constraints on their formation and evolution. Nearby spirals, including the Milky Way, host thin and thick components that may arise either from an early turbulent phase or from the…
We report the first robust measurement of the Milky Way star formation history using the imprint left on chemical abundances of long-lived stars. The formation of the Galactic thick disc occurs during an intense star formation phase between…
We trace the evolution of eight edge-on star-forming disk galaxies by analyzing stellar population properties of their thin and thick disks. These galaxies have relatively low stellar masses (4~$\times$~10$^9$ to…
Although thick disk is a structure prevalent in local disk galaxies and also present in our home Galaxy, its formation and evolution is still unclear. Whether the thick disk is born thick and/or gradually heated to be thick after formation…
Ever since a thick disk was proposed to explain the vertical distribution of the Milky Way disk stars, its origin has been a recurrent question. We aim to answer this question by inspecting 19 disk galaxies with stellar mass greater than…
We investigate thin and thick stellar disc formation in Milky-Way-mass galaxies using twelve FIRE-2 cosmological zoom-in simulations. All simulated galaxies experience an early period of bursty star formation that transitions to a late-time…
Breaks in the radial luminosity profiles of galaxies have been until now mostly studied averaged over discs. Here we study separately breaks in thin and thick discs in 70 edge-on galaxies using imaging from the Spitzer Survey of Stellar…
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…
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 adopt a scenario in which the Galactic thick disk was formed by minor merging between the first generation of the Galactic thin disk (FGTD) and a dwarf galaxy about 9 Gyr ago and thereby investigate chemical and dynamical properties of…
Giant bulgeless disk galaxies, theoretically expected to be rare in the early Universe, have been confirmed by the James Webb Space Telescope (JWST) to exist as early as 2 billion years after the Big Bang. These morphologically extreme…
One of the suggested thick disc formation mechanisms is that they were born quickly and in situ from a turbulent clumpy disc. Subsequently, thin discs formed slowly within them from leftovers of the turbulent phase and from material…
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…
We study the growth of stellar discs of Milky Way-sized galaxies using a suite of cosmological simulations. We calculate the half-mass axis lengths and axis ratios of stellar populations split by age in isolated galaxies with stellar mass…
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…
The separation of the Milky Way disk into a thin and thick component is supported by differences in the spatial, kinematic and metallicity distributions of their stars. These differences have led to the view that the thick disk formed early…
The formation of thick stellar disks in spiral galaxies is studied. Simulations of gas-rich young galaxies show formation of internal clumps by gravitational instabilities, clump coalescence into a bulge, and disk thickening by strong…
Observational studies showed that galaxy disks are already in place in the first few billion years of the universe. The early disks detected so far, with typical half-light radii of 3 kiloparsecs at stellar masses around 10^11 M_sun for…
Within a cosmological hydrodynamical simulation, we form a disc galaxy with sub- components which can be assigned to a thin stellar disc, thick disk, and a low mass stellar halo via a chemical decomposition. The thin and thick disc…
Disc galaxies show a large morphological diversity with varying contribution of three major structural components; thin discs, thick discs, and central bulges. Dominance of bulges increases with the galaxy mass (Hubble sequence) whereas…