scholarly journals Probing the 2-D kinematic structure of early-type galaxies out to 3 effective radii

2009 ◽  
Vol 5 (H15) ◽  
pp. 67-67
Author(s):  
Robert N. Proctor ◽  
Duncan A. Forbes ◽  
Aaron J. Romanowsky ◽  
Jean P. Brodie ◽  
Jay Strader ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Rotation Velocity ◽  
New Technique ◽  
Kinematic Structure ◽  
Early Type ◽  
Spectroscopic Observations ◽  
Velocity Moments

We detail an innovative new technique for measuring the 2-D velocity moments (rotation velocity, velocity dispersion and Gauss-Hermite coefficients h3 and h4) using spectra from Keck DEIMOS multi-object spectroscopic observations. The data are used to reconstruct 2-D rotation velocity maps.

scholarly journals The SAMI Galaxy Survey: mass–kinematics scaling relations

2019 ◽  
Vol 487 (2) ◽  
pp. 2924-2936 ◽  
Author(s):  
Dilyar Barat ◽  
Francesco D’Eugenio ◽  
Matthew Colless ◽  
Sarah Brough ◽  
Barbara Catinella ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Rotation Velocity ◽  
Kinematic Parameter ◽  
Scaling Relations ◽  
Scaling Relation ◽  
Early Type ◽  
Dynamical Scaling ◽  
Integral Field Spectroscopy ◽  
Fisher Relation ◽  
Integral Field

ABSTRACT We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass M∗ and the general kinematic parameter $S_K = \sqrt{K V_{\rm rot}^2 + \sigma ^2}$ that combines rotation velocity Vrot and velocity dispersion σ. We show that the log M∗ – log SK relation: (1) is linear above limits set by properties of the samples and observations; (2) has slightly different slope when derived from stellar or gas kinematic measurements; (3) applies to both early-type and late-type galaxies and has smaller scatter than either the Tully–Fisher relation (log M∗ − log Vrot) for late types or the Faber–Jackson relation (log M∗ − log σ) for early types; and (4) has scatter that is only weakly sensitive to the value of K, with minimum scatter for K in the range 0.4 and 0.7. We compare SK to the aperture second moment (the ‘aperture velocity dispersion’) measured from the integrated spectrum within a 3-arcsecond radius aperture ($\sigma _{3^{\prime \prime }}$). We find that while SK and $\sigma _{3^{\prime \prime }}$ are in general tightly correlated, the log M∗ − log SK relation has less scatter than the $\log M_* - \log \sigma _{3^{\prime \prime }}$ relation.

scholarly journals Galaxy Formation: Some Comparisons between Theory and Observation

1983 ◽  
Vol 100 ◽  
pp. 391-399 ◽  
Author(s):  
S. Michael Fall
Keyword(s):  
Galaxy Formation ◽  
Total Mass ◽  
Virial Theorem ◽  
Velocity Dispersion ◽  
Rotation Velocity ◽  
Morphological Type ◽  
Fundamental Parameter ◽  
Mass Ratio ◽  
First Approximation ◽  
Type Form

Before theoretical ideas in this subject can be compared with observational data, it is necessary to consider the properties of galaxies that are likely to be relics of their formation. Most astronomers would agree that the list of important parameters should be headed by the total mass M, energy E and angular momentum J. Next on the list should probably be the relative contributions to these quantities from the disc and bulge components of galaxies and denoted D/B for the mass ratio. They can be estimated from the median (i.e. half-mass) radius R, velocity dispersion σ and rotation velocity v of each component, either through the virial theorem or through the luminosity L and an assumed value of M/L. As a first approximation, it is reasonable to suppose that galaxies of a given disc-to-bulge ratio or morphological type form a sequence with mass as the fundamental parameter. The comparison of theory with data is further simplified by considering the extreme cases of ellipticals, with D/B << 1, and late-type spirals, with D/B >> 1. The approach outlined below is to explore the consequences of relaxing in succession the constraints that E, J and M be conserved during the collapse of proto-galaxies. In this article I concentrate on theories that are based on some form of hierarchical clustering because the pancake and related theories are not yet refined enough for a detailed confrontation with observations.

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.

A New Mass Modelling Trick

2006 ◽  
Vol 2 (S235) ◽  
pp. 88-89
Author(s):  
Dalia Chakrabarty
Keyword(s):  
Distribution Function ◽  
Velocity Dispersion ◽  
Type Systems ◽  
Elliptical Galaxies ◽  
Space Distribution ◽  
Early Type ◽  
Phase Space Distribution ◽  
Mass Distributions ◽  
Kinematic Information ◽  
System Geometry

The estimation of the distribution of the total (luminous and dark) mass in early type systems is hard! Even for the lucky few systems for which kinematic information is available, its implementation is mired in problems, given uncertainties about the assumptions that enter the calculations; the most critical of such assumptions involve considerations of the system geometry and the shape of its velocity ellipsoid. This work offers an independent means of getting to the mass distributions of early type galaxies, without relying directly on the phase space distribution function. The methodology is based upon the well established idea that in elliptical galaxies, the largest variations in normalised velocity dispersion profiles occur typically at R < 0.5Re (Re≡ half-light radius) and at R ≥ 2Re.

scholarly journals Spectroscopic Observations of the Early-Type Contact Binary AW Lacertae

1989 ◽  
Vol 107 ◽  
pp. 354-354
Author(s):  
Y. Nakamura ◽  
A. Okazaki ◽  
J. Katahira
Keyword(s):  
Spectral Type ◽  
Variable Stars ◽  
Radial Velocities ◽  
Early Type ◽  
Mass Ratio ◽  
Photometric Analysis ◽  
Spectroscopic Observations ◽  
Type Contact ◽  
Contact Binary ◽  
Photometric Solution

Abstract.Spectroscopic observations were performed of the early-type contact binary AW Lac with an image-intensified coude spectrograph of 1.9−m telescope at the Okayama Astro-physical Observatory. A total of twenty-two spectra covering blue region with a dispersion of 16 Amm−1 have been secured on Kodak IIa-O baked plates. In every spectra sharp interstellar Call H,K lines are clearly seen. The spectral type of AW Lac has been estimated as early B, which substantially confirms the one adopted in the photometric analysis by Jiang et al. (1983) and is diffrent from A0 listed in General Catalogue of Variable Stars (Kholopov et al. 1985). Contrary to the suggestion by the photometric solution of Jiang et al., no definite secondary lines could be separated, though some indications of light contamination due to the secondary component are surely observed. This would imply that the light ratio of the components should be somewhat smaller than that derived by photometric analysis. No emission features appeared either. The measurement of radial velocities of the primary component for the orbital elements was made for twenty spectra by a conventional method. It was difficult to measure the radial velocities because the lines are quite broadened and deformed. Hence the measured values for the radial velocities should be regarded as rather preliminary. The derived spectroscopic elements, combined with the photometric data, give the absolute dimensions of the system for each assumed mass ratio q. For q = 1, being the adopted photometric solution by Jiang et al., we obtain too small value for the primary’s mass, comparing with its spectral type. For the mass ratio as small as q = 0.6, we can obtain a reasonable value for the mass of the primary. However, in order to get more definite conclusion the cross-correlation method would be more appropriate for the spectroscopic analysis of this system.

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 Study of central intensity ratio of early-type galaxies from low-density environment

2020 ◽  
Vol 500 (1) ◽  
pp. 1343-1349
Author(s):  
K Sruthi ◽  
C D Ravikumar
Keyword(s):  
Black Hole ◽  
Intensity Ratio ◽  
Velocity Dispersion ◽  
Host Galaxy ◽  
Low Density ◽  
Early Type ◽  
Central Intensity ◽  
Supermassive Black Hole

ABSTRACT We present correlations involving central intensity ratio (CIR) of 52 early-type galaxies, including 24 ellipticals and 28 lenticulars, selected from low-density environment in the nearby (&lt;30 Mpc) universe. CIR is found to be negatively and significantly correlated with the mass of the central supermassive black hole, central velocity dispersion, absolute B-band magnitude, stellar bulge mass, and central Mg2 index of the host galaxy. The study proposes the use of CIR as a simple, fast, and efficient photometric tool for exploring the co-evolution scenario existing in galaxies.

scholarly journals The mass–size plane of EAGLE galaxies

2019 ◽  
Vol 629 ◽  
pp. L3 ◽  
Author(s):  
M. S. Rosito ◽  
P. B. Tissera ◽  
S. E. Pedrosa ◽  
C. D. P. Lagos
Keyword(s):  
Velocity Dispersion ◽  
Bimodal Distribution ◽  
Early Type ◽  
Chemical Abundances ◽  
Radial Profiles ◽  
Mass Size ◽  
Hydrodynamical Simulations ◽  
Star Formation Histories ◽  
Disc Galaxies ◽  
Second Peak

Context. Current observational results show that both late- and early-type galaxies follow tight mass–size planes on which physical properties such as age, velocity dispersion, and metallicity correlate with the scatter on the plane. Aims. We study the mass–size plane of galaxies in cosmological hydrodynamical simulations, as a function of velocity dispersion, age, chemical abundances, ellipticity, and spin parameters with the aim of assessing to what extent the current cosmological paradigm can reproduce these observations and provide a physical interpretation of them. Methods. We selected a sample of well-resolved galaxies from the (100 Mpc)3 simulation of the EAGLE Project. This sample is composed of 508 spheroid-dominated galaxies and 1213 disc-dominated galaxies. The distributions of velocity dispersion, age, metallicity indicators and gradients, and spin parameters across the mass–size plane are analysed. Furthermore, we study the relation between shape and kinematic parameters. The results are compared with observations. Results. The mass-weighted ages of the EAGLE galaxies are found to vary along lines of constant velocity dispersion on the mass–size plane, except for galaxies with velocity dispersions higher than ∼150 km s−1. Negative age gradients tend to be found in extended disc galaxies in agreement with observations. However, the age distributions of early-type galaxies show a larger fraction with inverted radial profiles. The distribution of metallicity gradients does not show any clear dependence on this plane. Galaxies with similar spin parameters (λ) display larger sizes as their dynamical masses increase. Stellar-weighted ages are found to be good proxies for λ in galaxies with low ellipticity (ε). A bimodal distribution of λ is found so that the high-λ peak is dominated by discs with young stellar populations (SPs), while the second peak is mainly populated by slow rotators (λ <  0.2) with old stars. Our findings suggest that the physical processes that regulate the star formation histories in galaxies might also affect the angular moment budgets of gas and stars, and as a consequence their morphology.

scholarly journals The DN − σ and Fundamental Plane Relations as Distance Indicators of Early Type Galaxies in the Virgo and Fornax Clusters

1996 ◽  
Vol 171 ◽  
pp. 366-366
Author(s):  
M. D'Onofrio ◽  
S. Zaggia ◽  
M. Capaccioli ◽  
G. Longo ◽  
N. Caon
Keyword(s):  
Rotation Velocity ◽  
Geometrical Parameters ◽  
Early Type ◽  
Homogeneous Sample ◽  
Fundamental Plane ◽  
Total Luminosity ◽  
The Mean ◽  
Distance Indicators ◽  
Light Profiles

We investigate the properties of early-type galaxies as distance indicators by applying the Dn – σ, Fundamental Plane (FP), and log(m) – log re relations to a complete and fairly homogeneous sample of galaxies members of the Virgo and Fornax clusters. The relative mean distance of the two clusters can be derived with an accuracy up to ∼ 3% provided that the internal kinematics of the galaxies is taken into account and a correct statistical approach is used.The residuals of the Dn – σ and FP relationships do not correlate with many structural and geometrical parameters of the galaxies: the mean effective surface brightness, the total luminosity, the average ellipticity and the Fourier coefficient a4 of the isophotes, and, the exponent m of the r1/m law which parametrizes the shape of the light profiles. On the other hand, the kinematics of the galaxies affect both relations producing residuals that correlate with the maximum rotation velocity Vmax and the (V/σ) ratio.Once confirmed by future more accurate observations, this effect would introduce a sistematic bias in the distance determination of the clusters; a problem difficult to manage if the internal kinematics of the cluster members is unknown.

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