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Related papers: Sigma-drop in galaxies and the sigma-metallicity d…

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Energetic feedback from Supernovae and stellar winds can drive galactic winds. Dwarf galaxies, due to their shallower potential wells, are assumed to be more vulnerable to this phenomenon. Metal loss through galactic winds is also commonly…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 S. Recchi , G. Hensler

The formation and evolution of galaxies is imprinted on their stellar population radial gradients. Two recent articles present conflicting results concerning the mass dependence of the metallicity gradients for early-type dwarf galaxies. On…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-11 M. Koleva , Ph. Prugniel , S. De Rijcke , W. W. Zeilinger , D. Michielsen

The stellar metallicity and its gradient pose constraints to the formation and evolution of galaxies. This is a study of the metallicity gradient of the LMC, SMC and M33 galaxies derived from their asymptotic giant branch (AGB) stars. The…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Maria-Rosa L. Cioni

Observations of the line-of-sight component of emitter velocities in galaxies are valuable for reconstructing their 2D velocity fields, albeit requiring certain assumptions. A common one is that radial flows can be neglected in the outer…

Astrophysics of Galaxies · Physics 2025-03-31 Francesco Sylos Labini , Giordano De Marzo , Matteo Straccamore

Observations of nearby galaxies reveal a strong correlation between the mass of the central dark object M and the velocity dispersion sigma of the host galaxy, of the form log(M/M_sun) = a + b*log(sigma/sigma_0); however, published…

We investigate the relation between the central velocity dispersion, sigma_0, and the circular velocity, V_c, in galaxies. In addition to previously available data, we consider an observationally homogeneus sample of 52 high surface…

Astrophysics · Physics 2007-05-23 A. Pizzella , E. Dalla Bonta' , E. M. Corsini , L. Coccato , F. Bertola

In order to recognize environmental effects on the evolution of dwarf galaxies in clusters of galaxies, it is first necessary to quantify the properties of objects which have evolved in relative isolation. With oxygen abundance as the gauge…

This chapter reviews how galactic inflows influence galaxy metallicity. The goal is to discuss predictions from theoretical models, but particular emphasis is placed on the insights that result from using models to interpret observations.…

Astrophysics of Galaxies · Physics 2017-05-31 Kristian Finlator

We investigate the radial metallicity gradients and azimuthal metallicity distributions on the Galactocentric $X$--$Y$ plane using mono-temperature stellar populations selected from LAMOST MRS young stellar sample. The estimated radial…

Astrophysics of Galaxies · Physics 2023-06-14 Chun Wang , Haibo Yuan , Maosheng Xiang , Yuan-Sen Ting , Yang Huang , Xiaowei Liu

The link between nuclear activity and the host galaxy remains elusive. It seems now clear that the galactic environment is not the key, and that there is no significant apparent difference in terms of the presence of bars/spirals between…

Astrophysics · Physics 2007-05-23 Eric Emsellem

The correlation between the Mg absorption index and the velocity dispersion (sigma) of local elliptical galaxies is very tight. Because the Mg absorption depends on both metallicity and age of the underlying stellar population the observed…

Astrophysics · Physics 2007-05-23 Bodo L. Ziegler , Ralf Bender

Within the disk model framework used to approximately describe flattened galaxies, we develop an iterative method of determining column mass density from rotation curve supplemented with isotropic velocity dispersion profile. This…

Astrophysics of Galaxies · Physics 2015-12-08 Szymon Sikora , Łukasz Bratek , Joanna Jałocha , Marek Kutschera

Both observations and recent numerical simulations of the circumgalactic medium (CGM) support the hypothesis that a self-regulating feedback loop suspends the gas density of the ambient CGM close to the galaxy in a state with a ratio of…

Astrophysics of Galaxies · Physics 2021-02-24 G. M. Voit

The observed oxygen abundances in a number of irregular galaxies have been compared with predictions of the closed-box model of chemical and photometric evolution of galaxies. Oxygen is found to be deficient with respect to the predicted…

Astrophysics · Physics 2009-10-31 L. S. Pilyugin , F. Ferrini

Metals are found in all baryonic phases and environments, and our knowledge of their distribution `in and around galaxies' has significantly improved over the past few years. Theoretical work has shown that the fraction of metals in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Gabriella De Lucia

The stellar velocity dispersion, $\sigma$, is a quantity of crucial importance for spiral galaxies, where it enters fundamental dynamical processes such as gravitational instability and disc heating. Here we analyse a sample of 34 nearby…

Astrophysics of Galaxies · Physics 2019-09-25 Keoikantse Moses Mogotsi , Alessandro B. Romeo

We examine the Mg-sigma relation for early-type galaxies in the EFAR sample and its dependence on cluster properties. A maximum likelihood fit gives global Mg-sigma relations of Mgb'=0.131log(sigma)-0.131 and Mg2=0.257log(sigma)-0.305, with…

Dark matter halos with self-interacting dark matter (SIDM) experience a unique evolutionary phenomenon, in that their central regions eventually collapse to high density through the runaway gravothermal process after initially forming a…

Astrophysics of Galaxies · Physics 2025-09-30 Zhichao Carton Zeng , Annika H. G. Peter , Xiaolong Du , Andrew Benson , Jiaxuan Li , Charlie Mace , Shengqi Yang

Velocity dispersion ($\sigma$) is a key driver for galaxy structure and evolution. We here present a comprehensive semi-empirical approach to compute $\sigma$ via detailed Jeans modelling assuming both a constant and scale-dependent…

Astrophysics of Galaxies · Physics 2022-01-05 Christopher Marsden , Francesco Shankar , Mariangela Bernardi , Ravi Sheth , Hao Fu , Andrea Lapi

We present maps of the mean metallicity distributions on the Galactocentric $R$--$Z$ plane at different azimuthal angles using red clump stars selected from the LAMOST and APOGEE surveys. In the inner disk ($R < $ 11\,kpc), the metallicity…

Astrophysics of Galaxies · Physics 2025-08-01 Chun Wang , Yang Huang , Timothy C. Beers , Payel Das , Haibo Yuan , Lizhi Xie , Shi Shao