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Our unified chemical and spectrophotometric evolution code allows to simultaneously study the ISM abundances of a series of elements and the spectral properties of the stellar population in our model galaxies. We use stellar evolutionary…

Astrophysics · Physics 2007-05-23 Uta Fritze - v. Alvensleben

Correlations between stellar kinematics and chemical abundances are fossil evidence for evolutionary connections between Galactic structural components. Extensive stellar surveys show that the only tolerably clear distinction between…

Astrophysics · Physics 2009-10-22 Gerard Gilmore

Beyond the main sequence solar type stars undergo extensive mass loss, providing an environment where planet and brown dwarf companions interact with the surrounding material. To examine the interaction of substellar mass objects embedded…

Solar and Stellar Astrophysics · Physics 2015-05-20 Hyosun Kim , Ronald E. Taam

From a detailed elemental abundance analysis of 102 F and G dwarf stars we present abundance trends in the Galactic thin and thick disks for 14 elements (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba, and Eu). Stellar parameters and…

Astrophysics · Physics 2007-05-23 T. Bensby , S. Feltzing , I. Lundström , I. Ilyin

Large spectroscopic surveys aim to consistently compute stellar parameters of very diverse stars while minimizing systematic errors. We explore the use of stellar clusters as benchmarks to verify the precision of spectroscopic parameters in…

It is often assumed that galaxies cannot generate large-scale coherent star- forming activity without some organizing agent, such as spiral density waves, bars, large-scale instabilities, or external perturbations due to encounters with…

Astrophysics · Physics 2009-09-25 David Chappell , John Scalo

While mergers between massive galaxies and their dwarf satellites are well studied, the properties of dwarf - dwarf satellite mergers are not well constrained. Stellar streams trace satellite disruption and, in the dwarf galaxy regime, are…

Using the method that was developed in the first paper of this series, we measure the vertical gravitational potential of the Galactic disk from the time-varying structure of the phase-space spiral, using data from Gaia as well as…

Astrophysics of Galaxies · Physics 2021-12-01 Axel Widmark , Chervin F. P. Laporte , Pablo F. de Salas , Giacomo Monari

Context. Protoplanetary disks are known to host spiral features that are observed in scattered light, ALMA continuum and more recently in CO gas emission and gas dynamics. It is however unknown if spirals in gas and dust trace the same…

Earth and Planetary Astrophysics · Physics 2020-11-11 Ardjan Sturm , Giovanni Rosotti , Carsten Dominik

We investigate the properties and evolution of star particles in two simulations of isolated spiral galaxies, and two galaxies from cosmological simulations. Unlike previous numerical work, where typically each star particle represents one…

In this review, I discuss just three aspects of the stability and evolution of galactic discs. (1) I first review our understanding of the bar instability and how it can be controlled. Disc galaxies in which the orbital speed does not…

Astrophysics · Physics 2007-05-23 J. A. Sellwood

We present absorption line-strength maps for a sample of 18 Sb-Sd galaxies observed using the integral-field spectrograph SAURON. The SAURON spectral range allows the measurement of the Lick/IDS indices Hbeta, Fe5015 and Mgb, which can be…

The study of the Milky Way stellar discs in the context of galaxy formation is discussed. In particular we explore the properties of the Milky Way disc using a new sample of about 550 dwarf stars for which we have recently obtained…

Astrophysics · Physics 2009-11-13 S. Feltzing , T. Bensby

Stable periodic orbits in spiral galactic models that form families of precessing ellipses can create spiral density waves similar to those that are observed in real grand-design galaxies. We study the range in parameter space for which the…

Chaotic Dynamics · Physics 2021-12-01 M. Harsoula , K. Zouloumi , C. Efthymiopoulos , G. Contopoulos

All stars in the Kepler field brighter than 12.5 magnitude have been classified according to variability type. A catalogue of {\delta} Scuti and {\gamma} Doradus stars is presented. The problem of low frequencies in {\delta} Sct stars,…

Solar and Stellar Astrophysics · Physics 2018-06-13 Luis A. Balona

Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and the high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Marina Trevisan , Ignacio Ferreras , Ignacio de la Rosa , Francesco La Barbera , Reinaldo de Carvalho

We report preliminary results of the characterization of bulge and inner disk stellar populations for 8 nearby spiral galaxies using Gemini/GMOS. The long-slit spectra extend out to 1-2 disk scale lengths with S/N/Ang > 50. Two different…

Astrophysics · Physics 2009-11-13 Lauren A. MacArthur , Jesus Gonzalez , Stephane Courteau

Spiral density wave theory attempts to describe the spiral pattern in spiral galaxies in terms of a long-lived wave structure with a constant pattern speed in order to avoid the winding dilemma. The pattern is consequently a rigidly…

Astrophysics of Galaxies · Physics 2015-06-03 Robert J. J. Grand , Daisuke Kawata , Mark Cropper

We investigate the stellar populations of passive spiral galaxies as a function of mass and environment, using integral field spectroscopy data from the Sydney-AAO Multi-object Integral field spectrograph Galaxy Survey. Our sample consists…

Spirals in galaxies have long been thought to be caused by gravitational instability in the stellar component of the disk, but discerning the precise mechanism had proved elusive. Tidal interactions, and perhaps bars, may provoke some…

Astrophysics of Galaxies · Physics 2022-09-28 J. A. Sellwood , Karen L. Masters