scholarly journals Mass density slope of elliptical galaxies from strong lensing and resolved stellar kinematics

2018 ◽  
Vol 475 (2) ◽  
pp. 2403-2414 ◽  
Author(s):  
N Lyskova ◽  
E Churazov ◽  
T Naab
Keyword(s):  
Mass Density ◽  
Elliptical Galaxies ◽  
Stellar Kinematics ◽  
Strong Lensing

scholarly journals Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

2015 ◽  
Vol 11 (A29B) ◽  
pp. 793-794
Author(s):  
Keren Sharon ◽  
Michael D. Gladders ◽  
Jane R. Rigby ◽  
Matthew B. Bayliss ◽  
Eva Wuyts ◽  
...  
Keyword(s):  
Mass Density ◽  
High Redshift ◽  
High Mass ◽  
Quality Data ◽  
High Quality Data ◽  
Strong Lensing ◽  
Modeling Techniques ◽  
Lens Modeling ◽  
High Redshift Universe ◽  
Mass Reconstruction

AbstractDriven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to 0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most “famous” strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

scholarly journals The Dark Halo – Spheroid Conspiracy

2012 ◽  
Vol 8 (S295) ◽  
pp. 208-208
Author(s):  
Rhea-Silvia Remus ◽  
Andreas Burkert ◽  
Klaus Dolag ◽  
Peter H. Johansson ◽  
Thorsten Naab ◽  
...  
Keyword(s):  
Elliptical Galaxies ◽  
Total Density ◽  
Dark Halo ◽  
Coma Cluster ◽  
Density Profiles ◽  
Stellar Component ◽  
Strong Lensing ◽  
The Galaxy ◽  
Good Agreement

AbstractObservational results from strong lensing and dynamical modeling indicate that the total density profiles of early-type galaxies are close to isothermal, i.e. ρtot ∝ rγ with γ ≈ −2. To understand the origin of this universal slope we study a set of simulated spheroids formed in cosmological hydrodynamical zoom-in simulations (see Oser et al. 2010 for more details). We find that the total stellar plus dark matter density profiles of all our simulations on average can be described by a power law with a slope of γ ≈ −2.1, with a tendency towards steeper slopes for more compact, lower mass ellipticals, while the total intrinsic velocity dispersion is flat for all simulations, independent of the values of γ. Our results are in good agreement with observations of Coma cluster ellipticals (Thomas et al. 2007) and results from strong lensing (Sonnenfeld et al. 2012). We find that for z ≳ 2 the majority of the stellar build-up occurs through in-situ star formation, i.e. the gas falls to the center of the galaxy and forms stars, causing the galaxy to be more compact and thus the stellar component to be more dominant. As a result, the total density slopes at z ≈ 2 are generally steeper (around γ ≈ −3). Between z = 2 and z = 0 galaxies grow mostly through dry merging, with each merging event shifting the slope more towards γ ≈ −2. We conclude from our simulations that the steepness of the slope of present day galaxies is a signature of the importance of mostly dry mergers in the formation of an elliptical, and suggest that all elliptical galaxies will with time end up in a configuration with a density slope of γ ≈ −2. For a more detailed analysis with a larger sample of simulations see Remus et al. (2013).

scholarly journals The Radial Velocities of Planetary Nebulae in NGC 3379

1993 ◽  
Vol 155 ◽  
pp. 570-570
Author(s):  
Robin Ciardullo ◽  
George Jacoby
Keyword(s):  
Radial Velocity ◽  
Absorption Line ◽  
Planetary Nebula ◽  
Velocity Dispersion ◽  
Planetary Nebulae ◽  
Elliptical Galaxies ◽  
Emission Lines ◽  
Surface Photometry ◽  
Stellar Kinematics ◽  
Velocity Measurements

Several authors have analyzed the kinematics of elliptical galaxies using surface photometry in combination with absorption line velocity dispersion measurements. However, these analyses never explore the halos of galaxies, since the best absorption line measurements extend only ∼1 re. The only way to extend our knowledge of stellar kinematics to larger radii is to use the emission lines of planetary nebula for radial velocity measurements.

scholarly journals Enhanced cluster lensing models with measured galaxy kinematics

2019 ◽  
Vol 631 ◽  
pp. A130 ◽  
Author(s):  
P. Bergamini ◽  
P. Rosati ◽  
A. Mercurio ◽  
C. Grillo ◽  
G. B. Caminha ◽  
...  
Keyword(s):  
Mass Distribution ◽  
Velocity Dispersion ◽  
Stellar Kinematics ◽  
Multiple Images ◽  
Effective Velocity ◽  
Strong Lensing ◽  
The Galaxy ◽  
Galaxy Kinematics ◽  
Halo Masses

We present an improved determination of the total mass distribution of three massive clusters from the Cluster Lensing and Supernova Survey with Hubble and Hubble Frontier Fields, MACS J1206.2−0847 (z = 0.44), MACS J0416.1−2403 (z = 0.40), Abell S1063 (z = 0.35). We specifically reconstructed the sub-halo mass component with robust stellar kinematics information of cluster galaxies, in combination with precise strong lensing models based on large samples of spectroscopically identified multiple images. We used integral-field spectroscopy in the cluster cores, from the Multi Unit Spectroscopic Explorer on the Very Large Telescope, to measure the stellar velocity dispersion, σ, of 40−60 member galaxies per cluster, covering four to five magnitudes to mF160W ≃ 21.5. We verified the robustness and quantified the accuracy of the velocity dispersion measurements with extensive spectral simulations. With these data, we determined the normalization and slope of the galaxy L–σ Faber–Jackson relation in each cluster and used these parameters as a prior for the scaling relations of the sub-halo population in the mass distribution modeling. When compared to our previous lens models, the inclusion of member galaxies’ kinematics provides a similar precision in reproducing the positions of the multiple images. However, the inherent degeneracy between the central effective velocity dispersion, σ0, and truncation radius, rcut, of sub-halos is strongly reduced, thus significantly alleviating possible systematics in the measurements of sub-halo masses. The three independent determinations of the σ0 − rcut scaling relation in each cluster are found to be fully consistent, enabling a statistical determination of sub-halo sizes as a function of σ0, or halo masses. Finally, we derived the galaxy central velocity dispersion functions of the three clusters projected within 16% of their virial radius, finding that they are well in agreement with each other. We argue that such a methodology, when applied to high-quality kinematics and strong lensing data, allows the sub-halo mass functions to be determined and compared with those obtained from cosmological simulations.

scholarly journals Testing the cosmic curvature at high redshifts: the combination of LSST strong lensing systems and quasars as new standard candles

2020 ◽  
Vol 496 (1) ◽  
pp. 708-717 ◽  
Author(s):  
Tonghua Liu ◽  
Shuo Cao ◽  
Jia Zhang ◽  
Marek Biesiada ◽  
Yuting Liu ◽  
...  
Keyword(s):  
Power Law ◽  
Density Profile ◽  
Mass Density ◽  
Model Parameters ◽  
Fundamental Parameter ◽  
Lens Model ◽  
Sis Model ◽  
Stringent Constraint ◽  
Strong Lensing ◽  
Mass Density Profile

ABSTRACT The cosmic curvature, a fundamental parameter for cosmology could hold deep clues to inflation and cosmic origins. We propose an improved model-independent method to constrain the cosmic curvature by combining the constructed Hubble diagram of high-redshift quasars with galactic-scale strong lensing systems expected to be seen by the forthcoming Large Synoptic Survey Telescope survey. More specifically, the most recent quasar data are used as a new type of standard candles in the range 0.036 < z < 5.100, whose luminosity distances can be directly derived from the non-linear relation between X-ray and UV luminosities. Compared with other methods, the proposed one involving the quasar data achieves constraints with higher precision (ΔΩk ∼ 10−2) at high redshifts (z ∼ 5.0). We also investigate the influence of lens mass distribution in the framework of three types of lens models extensively used in strong lensing studies (SIS model, power-law spherical model, and extended power-law lens model), finding the strong correlation between the cosmic curvature and the lens model parameters. When the power-law mass density profile is assumed, the most stringent constraint on the cosmic curvature Ωk can be obtained. Therefore, the issue of mass density profile in the early-type galaxies is still a critical one that needs to be investigated further.

scholarly journals Self-consistent Oblate-Spheroid Models

1987 ◽  
Vol 127 ◽  
pp. 489-490 ◽  
Author(s):  
J.L. Bishop
Keyword(s):  
Mass Density ◽  
Rotational Velocity ◽  
Oblate Spheroid ◽  
Computer Time ◽  
Elliptical Galaxies ◽  
Distribution Functions ◽  
Mass Model ◽  
Wide Range ◽  
Self Consistent ◽  
Associated Mass

A method for the construction of models of axisymmetric galaxies is presented. in this formulation we determine the distribution function corresponding to a given gravitational potential and the associated mass density distribution. Although the realization of the model is numerical, the underlying theory is analytic and exact. This method allows us to construct a wide range of models without having to use linear programming and a large amount of computer time. Here we present the results from the application of this method to the “perfect” oblate-spheroid mass model. A large class of valid self-consistent distribution functions which depend on three isolating integrals of the motion is found. the kinematics of many models are consistent with those observed for elliptical galaxies. in particular, models generated by this formulation are in agreement with the observed values of the ratio of the maximum projected rotational velocity to the velocity dispersion along the line of sight versus ellipticity.

scholarly journals Dust and the observed dark matter content of galaxies

2004 ◽  
Vol 220 ◽  
pp. 343-344 ◽  
Author(s):  
Maarten Baes ◽  
Herwig Dejonghe ◽  
Jonathan I. Davies
Keyword(s):  
Dark Matter ◽  
Interstellar Dust ◽  
Optical Rotation ◽  
Elliptical Galaxies ◽  
Matter Content ◽  
Dark Matter Halo ◽  
Stellar Kinematics ◽  
The Galaxy ◽  
Dust Attenuation ◽  
Radiative Transfer Modeling

Using detailed Monte Carlo radiative transfer modeling, we examine the effects of absorption and scattering by interstellar dust on the observed kinematics of galaxies. Our modeling results have a direct impact on the derivation of the properties of dark matter haloes around both elliptical and spiral galaxies. We find that interstellar dust has a very significant effect on the observed stellar kinematics of elliptical galaxies, in the way that it mimics the presence of a dark matter halo. Taking dust into account in kinematical modeling procedures can reduce or even eliminate the need for dark matter at a few effective radii. Dust profoundly affects the optical rotation curve and stellar kinematics of edge-on disc galaxies. This effect, however, is significantly reduced when the galaxy is more than a few degrees from strictly edge-on. These results demonstrate that dust attenuation cannot be invoked as a possible mechanism to reconcile the discrepancies between the observed shallow slopes of LSB galaxy rotation curves and the dark matter cusps found in CDM cosmological simulations.

scholarly journals Stellar Kinematics of Elliptical Galaxies in Pairs

1990 ◽  
Vol 124 ◽  
pp. 33-36
Author(s):  
Rainer Madejsky ◽  
Ralf Bender
Keyword(s):  
Radial Velocity ◽  
Elliptical Galaxy ◽  
Orbital Plane ◽  
Elliptical Galaxies ◽  
Line Of Sight ◽  
Stellar Kinematics ◽  
Velocity Difference ◽  
The Moment ◽  
Inner Parts ◽  
Very High

Observations of elliptical galaxy pairs allow the study of different states of tidal interaction between galaxies. The comparison with normal elliptical galaxies directly reveals the disturbed morphological and kinematical properties. Numerical simulations have shown that with the known initial luminosity profile, the time elapsed since closest approach between two galaxies can be estimated from the radial position of the disturbances (Aguilar and White, 1986).The two galaxy pairs Arp 166 (NGC 750/1) and 3C 278 (NGC 4782/3) considered here exhibit distorted and nonconcentric isophotes (cf. Madejsky, 1989). In Arp 166 the major relative shift of the centers of the isophotes occurs in the outer parts while in 3C 278 the nonconcentric isophotes are more pronounced in the inner parts of the galaxies, suggesting that more time ha&elapsed since the moment of closest approach in Arp 166 than in 3C 278. Furthermore, in Arp 166, both galaxies have the same radial velocity, implying that their orbital plane is perpendicular to the line of sight. In turn, the galaxies NGC 4782 and NGC 4783 are moving with a very high radial velocity difference of 680kms-1. Taking into account the location of both galaxies, which are the dominant members of a small group of about 25 galaxies (De Souza and Quintana, 1990), the true velocity difference probably is not much higher than the observed radial velocity difference. Therefore it is very likely that we are viewing at high inclination onto (i.e. nearly parallel to) the orbital plane of the galaxies NGC 4782 and 4783.

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