scholarly journals The cosmic evolution of the stellar mass–velocity dispersion relation of early-type galaxies

2020 ◽  
Vol 498 (1) ◽  
pp. 1101-1120
Author(s):  
Carlo Cannarozzo ◽  
Alessandro Sonnenfeld ◽  
Carlo Nipoti
Keyword(s):  
Mass Velocity ◽  
Selection Criteria ◽  
Velocity Dispersion ◽  
State Of The Art ◽  
Stellar Mass ◽  
Early Type ◽  
Bayesian Hierarchical ◽  
Cosmic Evolution ◽  
Stellar Velocity ◽  
Intrinsic Scatter

ABSTRACT We study the evolution of the observed correlation between central stellar velocity dispersion σe and stellar mass M* of massive ($M_*\gtrsim 3\times 10^{10}\, \mathrm{M_\odot}$) early-type galaxies (ETGs) out to redshift z ≈ 2.5, taking advantage of a Bayesian hierarchical inference formalism. Collecting ETGs from state-of-the-art literature samples, we build a fiducial sample (0 ≲ z ≲ 1), which is obtained with homogeneous selection criteria, but also a less homogeneous extended sample (0 ≲ z ≲ 2.5). Based on the fiducial sample, we find that at z ≲ 1 the M*–σe relation is well represented by $\sigma _{\mathrm{e}}\propto M_*^{\beta }(1+z)^{\zeta}$, with β ≃ 0.18 independent of redshift and ζ ≃ 0.4 (at a given M*, σe decreases for decreasing z, for instance by a factor of ≈1.3 from z = 1 to z = 0). When the slope β is allowed to evolve, we find it increasing with redshift: β(z) ≃ 0.16 + 0.26log (1 + z) describes the data as well as constant β ≃ 0.18. The intrinsic scatter of the M*–σe relation is ≃0.08 dex in σe at given M*, independent of redshift. Our results suggest that, on average, the velocity dispersion of individual massive (M* ≳ 3 × 1011M⊙) ETGs decreases with time while they evolve from z ≈ 1 to z ≈ 0. The analysis of the extended sample, over the wider redshift range 0 ≲ z ≲ 2.5, leads to results similar to that of the fiducial sample, with slightly stronger redshift dependence of the normalization (ζ ≃ 0.5) and weaker redshift dependence of the slope (dβ/dlog (1 + z) ≃ 0.18) when β varies with time. At z = 2 ETGs with $M_*\approx 10^{11}\, \mathrm{M_\odot}$ have, on average, ≈1.7 higher σe than ETGs of similar stellar mass at z = 0.

scholarly journals The merger-driven evolution of massive early-type galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 62-66
Author(s):  
Carlo Cannarozzo ◽  
Carlo Nipoti ◽  
Alessandro Sonnenfeld ◽  
Alexie Leauthaud ◽  
Song Huang ◽  
...  
Keyword(s):  
Mass Velocity ◽  
Selection Criteria ◽  
Velocity Dispersion ◽  
Ex Situ ◽  
Scaling Relations ◽  
Early Type ◽  
History Of ◽  
Kinematic Properties ◽  
Shed Light

AbstractThe evolution of the structural and kinematic properties of early-type galaxies (ETGs), their scaling relations, as well as their stellar metallicity and age contain precious information on the assembly history of these systems. We present results on the evolution of the stellar mass-velocity dispersion relation of ETGs, focusing in particular on the effects of some selection criteria used to define ETGs. We also try to shed light on the role that in-situ and ex-situ stellar populations have in massive ETGs, providing a possible explanation of the observed metallicity distributions.

scholarly journals The stellar mass Fundamental Plane: the virial relation and a very thin plane for slow rotators

2020 ◽  
Vol 494 (4) ◽  
pp. 5148-5160 ◽  
Author(s):  
M Bernardi ◽  
H Domínguez Sánchez ◽  
B Margalef-Bentabol ◽  
F Nikakhtar ◽  
R K Sheth
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Virial Theorem ◽  
Velocity Dispersion ◽  
Stellar Mass ◽  
Early Type ◽  
Fundamental Plane ◽  
Intrinsic Scatter ◽  
Virial Relation ◽  
Fast Rotating

ABSTRACT Early-type galaxies – slow and fast rotating ellipticals (E-SRs and E-FRs) and S0s/lenticulars – define a Fundamental Plane (FP) in the space of half-light radius Re, enclosed surface brightness Ie, and velocity dispersion σe. Since Ie and σe are distance-independent measurements, the thickness of the FP is often expressed in terms of the accuracy with which Ie and σe can be used to estimate sizes Re. We show that: (1) The thickness of the FP depends strongly on morphology. If the sample only includes E-SRs, then the observed scatter in Re is $\sim 16{{\ \rm per\ cent}}$, of which only $\sim 9{{\ \rm per\ cent}}$ is intrinsic. Removing galaxies with M* < 1011 M⊙ further reduces the observed scatter to $\sim 13{{\ \rm per\ cent}}$ ($\sim 4{{\ \rm per\ cent}}$ intrinsic). The observed scatter increases to $\sim 25{{\ \rm per\ cent}}$ usually quoted in the literature if E-FRs and S0s are added. If the FP is defined using the eigenvectors of the covariance matrix of the observables, then the E-SRs again define an exceptionally thin FP, with intrinsic scatter of only 5 per cent orthogonal to the plane. (2) The structure within the FP is most easily understood as arising from the fact that Ie and σe are nearly independent, whereas the Re−Ie and Re−σe correlations are nearly equal and opposite. (3) If the coefficients of the FP differ from those associated with the virial theorem the plane is said to be ‘tilted’. If we multiply Ie by the global stellar mass-to-light ratio M*/L and we account for non-homology across the population by using Sérsic photometry, then the resulting stellar mass FP is less tilted. Accounting self-consistently for M*/L gradients will change the tilt. The tilt we currently see suggests that the efficiency of turning baryons into stars increases and/or the dark matter fraction decreases as stellar surface brightness increases.

scholarly journals Compact Groups of Galaxies

1999 ◽  
Vol 186 ◽  
pp. 367-373
Author(s):  
P. Hickson
Keyword(s):  
Galaxy Evolution ◽  
Mass Velocity ◽  
Velocity Dispersion ◽  
Continuous Process ◽  
Physical Nature ◽  
Compact Groups ◽  
Early Type ◽  
Natural Explanation ◽  
Groups Of Galaxies ◽  
Formation And Evolution

This paper reviews some of the outstanding questions concerning compact groups of galaxies. These relate to the physical nature and dynamical status of the groups, their formation and evolution, and their role in galaxy evolution. The picture that emerges is that compact groups are generally physically dense systems, although often contaminated by optical projections. Their evolution is likely a continuous process of infall, interaction and merging. As new galaxies are added, and previous ones merge, the membership of the group evolves. I suggest that while the size of the group changes little, other physical properties such as total mass, gas mass, velocity dispersion, fraction of early-type galaxies increase with time. This picture is at least qualitatively consistent with observations and provides a natural explanation for the strongest correlations found in compact group samples.

scholarly journals The stellar velocity dispersion in nearby spirals: radial profiles and correlations

2019 ◽  
Author(s):  
Keoikantse Moses Mogotsi ◽  
Alessandro B Romeo
Keyword(s):  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Gravitational Instability ◽  
Stellar Mass ◽  
Radial Profiles ◽  
Stellar Velocity ◽  
The One ◽  
Radial Average ◽  
Field Area ◽  
Integral Field

Abstract The stellar velocity dispersion, σ, 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 spirals from the Calar Alto Legacy Integral Field Area (CALIFA) spectroscopic survey, deproject the line-of-sight σ to σR and present reliable radial profiles of σR as well as accurate measurements of ⟨σR⟩, the radial average of σR over one effective (half-light) radius. We show that there is a trend for σR to increase with decreasing R, that ⟨σR⟩ correlates with stellar mass (M⋆) and tested correlations with other galaxy properties. The most significant and strongest correlation is the one with M⋆: $\langle \sigma _{R}\rangle \propto M_{\star }^{0.5}$. This tight scaling relation is applicable to spiral galaxies of type Sa–Sd and stellar mass M⋆ ≈ 109.5–1011.5 M⊙. Simple models that relate σR to the stellar surface density and disc scale length roughly reproduce that scaling, but overestimate ⟨σR⟩ significantly.

scholarly journals ENVIRONMENTAL DEPENDENCE OF AGE, STELLAR MASS, STAR FORMATION RATE AND STELLAR VELOCITY DISPERSION OF ACTIVE GALACTIC NUCLEUS HOST GALAXIES

2021 ◽  
Vol 57 (1) ◽  
pp. 157-166
Author(s):  
Xin-Fa Deng ◽  
Xiao-Qing Wen
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Velocity Dispersion ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Apparent Magnitude ◽  
Host Galaxies ◽  
Stellar Velocity ◽  
Environmental Dependence

Using the apparent-magnitude limited active galactic nucleus (AGN) host galaxy sample of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12), we investigate the environmental dependence of age, stellar mass, the star formation rate (SFR) and stellar velocity dispersion of AGN host galaxies. We divide the whole apparent-magnitude limited AGN sample into many subsamples with a redshift binning size of Δz = 0.01, and analyse the environmental dependence of these galaxy properties of subsamples in each redshift bin. It turns out that these parameters of AGN host galaxies seemingly only have a weak environmental dependence.

scholarly journals The Effect of Stellar Mass on Kinematical Age Determination

1977 ◽  
Vol 45 ◽  
pp. 283-287
Author(s):  
Wilhelmina Iwanowska
Keyword(s):  
Force Field ◽  
Velocity Dispersion ◽  
Age Determination ◽  
Stellar Mass ◽  
Classical Formula ◽  
Stellar Ages ◽  
Stellar Velocity

It is believed that kinematical characteristics of a group of stars, as the velocity dispersion or the lag in rotation, change systematically with time. This kinematical evolution is widely used for the determination of stellar ages. In particular, velocity dispersion should increase with time owing to irregular galactic force field. A classical formula for the increase of stellar velocity v with the age τ

scholarly journals The extended Planetary Nebula Spectrograph (ePN.S) early-type galaxy survey: The kinematic diversity of stellar halos and the relation between halo transition scale and stellar mass

2018 ◽  
Vol 618 ◽  
pp. A94 ◽  
Author(s):  
C. Pulsoni ◽  
O. Gerhard ◽  
M. Arnaboldi ◽  
L. Coccato ◽  
A. Longobardi ◽  
...  
Keyword(s):  
Absorption Line ◽  
Phase Formation ◽  
Velocity Dispersion ◽  
Stellar Mass ◽  
Early Type ◽  
Two Phase ◽  
Low Surface Brightness ◽  
Central Regions ◽  
Adaptive Kernel ◽  
Kinematic Properties

Context. In the hierarchical two-phase formation scenario, the halos of early type galaxies (ETGs) are expected to have different physical properties from the galaxies’ central regions. Aims. The ePN.S survey characterizes the kinematic properties of ETG halos using planetary nebulae (PNe) as tracers, overcoming the limitations of absorption line spectroscopy at low surface brightness. Methods. We present two-dimensional velocity and velocity dispersion fields for 33 ETGs, including fast (FRs) and slow rotators (SRs). The velocity fields were reconstructed from the measured PN velocities using an adaptive kernel procedure validated with simulations, and extend to a median of 5.6 effective radii (Re). We complemented the PN kinematics with absorption line data from the literature, for a complete description of the kinematics from the center to the outskirts. Results. ETGs typically show a kinematic transition between inner regions and halo. Estimated transition radii in units of Re anti-correlate with stellar mass. SRs have increased but still modest rotational support at large radii. Most of the FRs show a decrease in rotation, due to the fading of the inner disk in the outer, more slowly rotating spheroid. 30% of the FRs are dominated by rotation also at large radii. Most ETGs have flat or slightly falling halo velocity dispersion profiles, but 15% of the sample have steeply falling profiles. All of the SRs and 40% of the FRs show signatures of triaxial halos such as kinematic twists or misalignments. We show with illustrative photometric models that this is consistent with the distribution of isophote twists from extended photometry. Conclusions. ETGs have more diverse kinematic properties in their halos than in the central regions. FRs do contain inner disk components but these frequently fade in outer spheroids which are often triaxial. The observed kinematic transition to the halo and its dependence on stellar mass is consistent with ΛCDM simulations and supports a two-phase formation scenario.

scholarly journals New axes for the stellar mass fundamental plane

2015 ◽  
Vol 11 (S317) ◽  
pp. 35-38
Author(s):  
Paul L. Schechter
Keyword(s):  
Velocity Dispersion ◽  
Scale Parameter ◽  
Elliptical Galaxy ◽  
Stellar Mass ◽  
Effective Radius ◽  
Dark Matter Halos ◽  
Fundamental Plane ◽  
Single Scale ◽  
Stellar Velocity ◽  
Good Proxy

AbstractWe argue that the stellar velocity dispersion observed in an elliptical galaxy is a good proxy for the halo velocity dispersion. As dark matter halos are almost completely characterized by a single scale parameter, the stellar velocity dispersion tells us the virial radius of the halo and the mass contained within. This permits non-dimensionalizing of the stellar mass and effective radius axes of the stellar mass fundamental plane by the virial radius and halo mass, respectively.

scholarly journals Scaling relations in early-type galaxies from integral-field stellar kinematics

2009 ◽  
Vol 5 (H15) ◽  
pp. 81-81
Author(s):  
M. Cappellari ◽  
N. Scott ◽  
K. Alatalo ◽  
L. Blitz ◽  
M. Bois ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Velocity Dispersion ◽  
Scaling Relations ◽  
Early Type ◽  
Stellar Kinematics ◽  
Fundamental Plane ◽  
The Past ◽  
Stellar Velocity ◽  
Integral Field ◽  
Significant Effort

Early-type galaxies (ETGs) satisfy a now classic scaling relation Re ∝ σ1.2eI−0.8e, the Fundamental Plane (FP; Djorgovski & Davis 1987; Dressler et al. 1987), between their size, stellar velocity dispersion and mean surface brightness. A significant effort has been devoted in the past twenty years to try to understand why the coefficients of the relation are not the ones predicted by the virial theorem Re ∝ σ2eI−1e.

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