Shear and ellipticity in gravitational lenses
Reads0
Chats0
TLDR
In this paper, an independent shear axis can be produced by misalignments between the luminous galaxy and its dark matter halo, or by external shear perturbations due to galaxies and clusters correlated with the primary lens or along the line of sight.Abstract:
Galaxies modeled as singular isothermal ellipsoids with an axis ratio distribution similar to the observed axis ratio distribution of E and S0 galaxies are statistically consistent with both the observed numbers of two-image and four-image lenses and the inferred ellipticities of individual lenses. However, no four-image lens is well fitted by the model (typical χ2/Ndof ~ 20), the axis ratio of the model can be significantly different from that of the observed lens galaxy, and the major axes of the model and the galaxy may be slightly misaligned. We found that models with a second, independent, external shear axis could fit the data well (typical χ2/Ndof ~ 1), while adding the same number of extra parameters to the radial mass distribution does not produce such a dramatic improvement in the fit. An independent shear axis can be produced by misalignments between the luminous galaxy and its dark matter halo, or by external shear perturbations due to galaxies and clusters correlated with the primary lens or along the line of sight. We estimate that the external shear perturbations have no significant effect on the expected numbers of two-image and four-image lenses but that they can be important perturbations in individual lens models. However, the amplitudes of the external shears required to produce good fits are larger than our estimates for typical external shear perturbations (10%-15% shear instead of 1%-3%), suggesting that the origin of the extra angular structure must be intrinsic to the primary lens galaxy in most cases.read more
Citations
More filters
Journal ArticleDOI
The Sloan Lens ACS Survey. III. The Structure and Formation of Early-Type Galaxies and Their Evolution since z ≈ 1
Léon V. E. Koopmans,Tommaso Treu,Adam S. Bolton,Adam S. Bolton,Scott Burles,Leonidas A. Moustakas +5 more
TL;DR: In this article, a joint likelihood analysis of 15 massive field early-type galaxies selected from the Sloan Lens ACS (SLACS) Survey is presented, and the average position-angle difference between the light distribution and the total mass distribution is found to be = 0 degrees +/- 3 degrees (rms of 10 degrees).
Journal ArticleDOI
Probing the Coevolution of Supermassive Black Holes and Galaxies Using Gravitationally Lensed Quasar Hosts
Chien Y. Peng,Chien Y. Peng,Chris Impey,Hans-Walter Rix,Christopher S. Kochanek,Charles R. Keeton,Charles R. Keeton,Emilio E. Falco,Joseph Lehar,Brian McLeod +9 more
TL;DR: In the present-day universe, supermassive black hole masses (MBH) appear to be strongly correlated with their galaxy's bulge luminosity, among other properties.
Journal ArticleDOI
Evidence for substructure in lens galaxies
Shude Mao,Peter Schneider +1 more
TL;DR: In this paper, the authors argue that the discrepancy between observed and model-predicted flux ratios is due to substructure in the lens, and propose a strategy to model lens systems in which substructure is suspected.
Journal ArticleDOI
Gravitationally lensed quasars and supernovae in future wide-field optical imaging surveys
TL;DR: In this paper, the authors carried out a detailed calculation of the likely yields of several planned optical imaging surveys, using realistic distributions for the lens and source properties and taking magnification bias and image configuration detectability into account.
Journal ArticleDOI
Gravitational Lensing
TL;DR: Gravitational lensing has developed into one of the most powerful tools for the analysis of the dark universe as mentioned in this paper, and its main current applications and representative results achieved so far.
References
More filters
Journal ArticleDOI
The statistics of peaks of Gaussian random fields
TL;DR: In this paper, a set of new mathematical results on the theory of Gaussian random fields is presented, and the application of such calculations in cosmology to treat questions of structure formation from small-amplitude initial density fluctuations is addressed.
Journal ArticleDOI
An analytic expression for the luminosity function for galaxies
TL;DR: In this paper, a new analytic approximation for the luminosity function for galaxies is proposed, which shows good agreement with both a luminosity distribution for bright nearby galaxies and a composite luminosity distributions for cluster galaxies.
Journal ArticleDOI
Cluster evolution as a diagnostic for Ω
TL;DR: The population of rich galaxy clusters evolves much more rapidly in a universe with critical density than one with low density, thus offering the possibility of determining the cosmological density parameter, Omega_0 as discussed by the authors.
Journal ArticleDOI
0957 + 561 A, B: twin quasistellar objects or gravitational lens?
TL;DR: Difficulties arise in describing these two QSOs as two distinct objects and the possibility that they are two images of the same object formed by a gravitational lens is discussed.
Journal ArticleDOI
Non-linear evolution of cosmological power spectra
John A. Peacock,S. J. Dodds +1 more
TL;DR: In this paper, the power spectra of density fluctuations evolve into the non-linear regime of hierarchical clustering, and a spectrum-dependent fitting formula is proposed for low-density models with a cosmological constant.