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Faber-Jackson and Tully-Fisher scaling relations for elliptical and spiral galaxy samples up to z=1 provide evidence for a differential behaviour of galaxy evolution with mass. In compliance with the downsizing scenario, the stellar populations of less massive galaxies display a stronger evolution than the more massive ones. For spirals, this may be attributed to a suppressed star formation efficiency in small dark matter halos. For ellipticals, star formation must have been negligible at least during the past ~4Gyr in all environments.
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In their evolution, star-forming galaxies are known to follow scaling relations between some fundamental physical quantities, such as the mass-metallicity and the main sequence relations. We aim at studying the evolution of galaxies that, at a given redshift, lie simultaneously on the mass-metallicity and main sequence relations (MZR, MSR). To this aim, we use the analytical, leaky-box chemical evolution model of Spitoni et al. (2017), in which galaxy evolution is described by an infall timescale $tau$ and a wind efficiency $lambda$. We provide a detailed analysis of the temporal evolution of galactic metallicity, stellar mass, mass-weighted age and gas fraction. The evolution of the galaxies lying on the MZR and MSR at $zsim0.1$ suggests that the average infall time-scale in two different bins of stellar masses ($M_{star}<10^{10} M_{odot}$ and $M_{star}>10^{10} M_{odot}$) decreases with decreasing redshift. This means that at each redshift, only the youngest galaxies can be assembled on the shortest timescales and still belong to the star-forming MSR. In the lowest mass bin, a decrease of the median $tau$ is accompanied by an increase of the median $lambda$ value. This implies that systems which have formed at more recent times will need to eject a larger amount of mass to keep their metallicity at low values. Another important result is that galactic downsizing, as traced by the age-mass relation, is naturally recovered by imposing that local galaxies lie on both the MZR and MSR. Finally, we study the evolution of the hosts of C$_{rm IV}$ -selected AGN, which at $zsim 2$ follow a flat MZR, as found by Mignoli et al. (2019). If we impose that these systems lie on the MSR, at lower redshifts we find an inverted MZR, meaning that some additional processes must be at play in their evolution.
In recent years the global seismic scaling relations for the frequency of maximum power and for the large frequency separation have caught the attention of various fields of astrophysics. With the exquisite photometry of textit{Kepler}, the uncertainties in the seismic observables are small enough to estimate masses and radii with a precision of only a few per cent. Even though this seems to work quite well for main-sequence stars, there is empirical evidence, mainly from studies of eclipsing binary systems, that the seismic scaling relations overestimate the mass and radius of red giants by about 15 and 5%, respectively. Model-based corrections of the $Delta u -$scaling reduce the problem but do not solve it. We re-examine the global oscillation parameters of the giants in the binary systems in order to determine their seismic fundamental parameters and find them to agree with the dynamic parameters from the literature if we adopt nonlinear scalings. We note that a curvature and glitch corrected $Delta u_mathrm{cor}$ should be preferred over a local or average values. We then compare the observed seismic parameters of the cluster giants to those scaled from independent measurements and find the same nonlinear behaviour as for the eclipsing binaries. Our final proposed scaling relations are based on both samples and cover a broad range of evolutionary stages from RGB to RC stars: $g/sqrt{T_mathrm{eff}} = ( u_mathrm{max}/ u_mathrm{max,odot})^{1.0075pm0.0021}$ and $sqrt{barrho} = (Delta u_mathrm{cor}/Delta u_mathrm{cor,odot})[eta - (0.0085pm0.0025) log^2 (Delta u_mathrm{cor}/Delta u_mathrm{cor,odot})]^{-1}$, where $g$, $T_mathrm{eff}$, and $barrho$ are in solar units, $ u_mathrm{max,odot}=3140pm5mu$Hz and $Delta u_mathrm{cor,odot}=135.08pm0.02mu$Hz , and $eta$ is equal to one in case of RGB stars and $1.04pm0.01$ for RC stars.
We construct a large data set of global structural parameters for 1300 field and cluster spiral galaxies and explore the joint distribution of luminosity L, optical rotation velocity V, and disk size R at I- and 2MASS K-bands. The I- and K-band velocity-luminosity (VL) relations have log-slopes of 0.29 and 0.27, respectively with sigma_ln(VL)~0.13, and show a small dependence on color and morphological type in the sense that redder, early-type disk galaxies rotate faster than bluer, later-type disk galaxies for most luminosities. The VL relation at I- and K-bands is independent of surface brightness, size and light concentration. The log-slope of the I- and K-band RL relations is a strong function of morphology and varies from 0.25 to 0.5. The average dispersion sigma_ln(RL) decreases from 0.33 at I-band to 0.29 at K, likely due to the 2MASS selection bias against lower surface brightness galaxies. Measurement uncertainties are sigma_ln(V)~0.09, sigma_ln(L)~0.14 and somewhat larger and harder to estimate for ln(R). The color dependence of the VL relation is consistent with expectations from stellar population synthesis models. The VL and RL residuals are largely uncorrelated with each other; the RV-RL residuals show only a weak positive correlation. These correlations suggest that scatter in luminosity is not a significant source of the scatter in the VL and RL relations. The observed scaling relations can be understood in the context of a model of disk galaxies embedded in dark matter halos that invokes low mean spin parameters and dark halo expansion, as we describe in our companion paper (Dutton et al. 2007). We discuss in two appendices various pitfalls of standard analytical derivations of galaxy scaling relations, including the Tully-Fisher relation with different slopes. (Abridged).
X-ray observations of an entropy floor in nearby groups and clusters of galaxies offer evidence that important non-gravitational processes, such as radiative cooling and/or preheating, have strongly influenced the evolution of the intracluster medium (ICM). We examine how the presence of an entropy floor modifies the thermal Sunyaev-Zeldovich (SZ) effect. A detailed analysis of scaling relations between X-ray and SZ effect observables and also between the two primary SZ effect observables is presented. We find that relationships between the central Compton parameter and the temperature or mass of a cluster are extremely sensitive to the presence of an entropy floor. The same is true for correlations between the integrated Compton parameter and the X-ray luminosity or the central Compton parameter. In fact, if the entropy floor is as high as inferred in recent analyses of X-ray data, a comparison of these correlations with both current and future SZ effect observations should show a clear signature of this excess entropy. Moreover, because the SZ effect is redshift-independent, the relations can potentially be used to track the evolution of the cluster gas and possibly discriminate between the possible sources of the excess entropy. To facilitate comparisons with observations, we provide analytic fits to these scaling relations.
To study the dust evolution in the cosmological structure formation history, we perform a smoothed particle hydrodynamic simulation with a dust enrichment model in a cosmological volume. We adopt the dust evolution model that represents the grain size distribution by two sizes and takes into account stellar dust production and interstellar dust processing. We examine the dust mass function and the scaling properties of dust in terms of the characteristics of galaxies. The simulation broadly reproduces the observed dust mass functions at redshift $z = 0$, except that it overproduces the massive end at dust mass $M_mathrm{d} gtrsim 10^{8}$ ${rm M}_odot$. This overabundance is due to overproducing massive gas/metal-rich systems, but we also note that the relation between stellar mass and gas-phase metallicity is reproduced fairly well by our recipe. The relation between dust-to-gas ratio and metallicity shows a good agreement with the observed one at $z=0$, which indicates successful implementation of dust evolution in our cosmological simulation. Star formation consumes not only gas but also dust, causing a decreasing trend of the dust-to-stellar mass ratio at the high-mass end of galaxies. We also examine the redshift evolution up to $z sim~ 5$, and find that the galaxies have on average the highest dust mass at $z = 1-2$. For the grain size distribution, we find that galaxies with metallicity $sim 0.3~ Z_odot$ tend to have the highest small-to-large grain abundance ratio; consequently, the extinction curves in those galaxies have the steepest ultraviolet slopes.
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