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Streams of stars from captured dwarf galaxies and dissolved globular clusters are identifiable through the similarity of their orbital parameters, a fact that remains true long after the streams have dispersed spatially. We calculate the…

星系天体物理 · 物理学 2020-01-08 Nicholas W. Borsato , Sarah L. Martell , Jeffrey D. Simpson

Recent dynamical analysis based on Gaia data have revealed major accretion events in Milky Way's history. Nevertheless, our understanding of the primordial Galaxy is hindered because the bona fide identification of the most metal-poor and…

The overlap between the spectroscopic Galactic Archaeology with HERMES (GALAH) survey & $Gaia$ provides a high-dimensional chemodynamical space of unprecedented size. We present a first analysis of a subset of this overlap, of 7066 dwarf,…

The Milky Way accreted several smaller satellite galaxies in its history. These mergers added stars and gas to the Galaxy and affected the properties of the pre-existing stellar populations. Stellar chemical abundances and ages are needed…

星系天体物理 · 物理学 2023-04-26 Riano E. Giribaldi , Rodolfo Smiljanic

We have extended our chemical and cosmological galaxy evolution model to calculate the abundance evolution for altogether 16 different elements in spiral galaxies in a chemically consistent way which is a considerable step towards a more…

天体物理学 · 物理学 2007-05-23 Ulrich Lindner , Uta Fritze -- von Alvensleben , Klaus J. Fricke

A direct observation of the spiral structure of the Galaxy is hindered by our position in the middle of the Galactic plane. We propose a method based on the analysis of the birthplaces of high Galactic latitude runaway stars to map the…

星系天体物理 · 物理学 2015-06-12 M. D. V. Silva , R. Napiwotzki

The organization of the interstellar medium in disk galaxies obeys the large scale dynamics set by kpc-size structures. Improving our knowledge of how the dense, molecular gas is distributed in a disk is an important step in our…

星系天体物理 · 物理学 2013-10-02 F. Renaud , F. Bournaud , E. Emsellem , B. Elmegreen , R. Teyssier

Previous studies have found that the elemental abundances of a star correlate directly with its age and metallicity. Using this knowledge, we derive ages for a sample of 250,000 stars taken from GALAH DR3 using only their overall…

Decoding the key dynamical processes that shape the Galactic disk structure is crucial for reconstructing the Milky Way's evolution history. The second Gaia data release unveils a novel wave pattern in the $L_Z-\langle V_R\rangle$ space,…

星系天体物理 · 物理学 2024-11-19 Chengye Cao , Zhao-Yu Li , Ralph Schönrich , Teresa Antoja

The present study of the two-stream instability in stellar disks with counter-rotating components of stars and/or gas is stimulated by recently discovered counter-rotating spiral and S0 galaxies. Strong linear two-stream instability of…

天体物理学 · 物理学 2009-10-28 R. V. E. Lovelace , K. P. Jore , M. P. Haynes

The formation of planetary systems has historically been considered in isolation, decoupled from processes on galactic scales. Recent findings employing data from ESA's Gaia mission challenge this narrative, identifying trends in planet…

地球与行星天体物理 · 物理学 2024-09-17 Sarah Ballard

The ``galactic shocks'' \citep{fujimoto68,roberts69} is investigated using a full three-dimensional hydrodynamic simulations, taking into account self-gravity of the ISM, radiative cooling, and star formation followed by energy feedback…

天体物理学 · 物理学 2009-11-13 Keiichi Wada

The radial profiles of the Hb, Mg, and Fe line-strength indices are presented for a sample of eight spiral galaxies with a low surface-brightness stellar disc and a bulge. The correlations between the central values of the line-strength…

宇宙学与河外天体物理 · 物理学 2015-06-04 L. Morelli , E. M. Corsini , A. Pizzella , E. Dalla Bontà , L. Coccato , J. Méndez-Abreu , M. Cesetti

We derive stellar metallicities, light-weighted ages and stellar masses for a magnitude-limited sample of 175,128 galaxies drawn from the Sloan Digital Sky Survey Data Release Two (SDSS DR2). We compute median-likelihood estimates of these…

天体物理学 · 物理学 2008-11-26 Anna Gallazzi , Stephane Charlot , Jarle Brinchmann , Simon D. M. White , Christy A. Tremonti

Taking advantage of the recent Gaia Data Release 3 (DR3), we map chemical inhomogeneities in the Milky Way's disc out to a distance of $\sim$ 4 kpc from the Sun, using different samples of bright giant stars. The samples are selected using…

Mergers and tidal interactions between massive galaxies and their dwarf satellites are a fundamental prediction of the Lambda-Cold Dark Matter cosmology. These events are thought to provide important observational diagnostics of nonlinear…

Determination of chemical abundances for elements produced mainly by Type I SNae and intermediate mass stars in high redshift DLAs probes the early chemical build-up on time-scales comparable with their production. Nitrogen shows a peculiar…

天体物理学 · 物理学 2007-05-23 P. Molaro , M. Centurion , V. D'Odorico , C. Peroux

We present a new method for inferring the gravitational potential of the Galactic disk, using the time-varying structure of a phase-space spiral in the $(z,w)$-plane (where $z$ and $w$ represent vertical position and vertical velocity). Our…

星系天体物理 · 物理学 2021-11-30 Axel Widmark , Chervin F. P. Laporte , Pablo F. de Salas

[ABRIDGED] Galaxy evolution is shaped by internal and external mechanisms that regulate the baryon cycle and star formation activity. We present a theoretical framework based on the GAlaxy Evolution and Assembly (GAEA) semi-analytic model.…

Stellar abundances and ages afford the means to link chemical enrichment to galactic formation. In the Milky Way, individual element abundances show tight correlations with age, which vary in slope across ([Fe/H]-[$\alpha$/Fe]). Here, we…