Constraints in the Δ0-Ω0 plane from gravitational lensing

2005 ◽  
Vol 201 ◽  
pp. 245-254
Author(s):  
Phillip. Helbig
Keyword(s):  
Gravitational Lensing ◽  
Cosmological Parameters ◽  
Gravitational Lenses ◽  
Extragalactic Surveys

I review simultaneous constraints on the cosmological parameters Δ0 and Ω0 from gravitational lensing. The emphasis is on systematic extragalactic surveys for strong gravitational lenses, mainly the largest and best-defined such survey, JVAS/CLASS.

scholarly journals Cosmological Applications of Gravitational Lensing

1996 ◽  
Vol 168 ◽  
pp. 209-217
Author(s):  
Peter Schneider
Keyword(s):  
Gravitational Lensing ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Gravitational Lens ◽  
Mass Determination ◽  
Gravitational Lenses ◽  
Distant Object ◽  
The Many ◽  
The Universe

It was recognized very early that the gravitational lens effect can be used as an efficient cosmological tool. Of the many researchers who foresaw the use of lensing, F. Zwicky and S. Refsdal should be explicitly mentioned. The perhaps most accurate predictions and foresights by these two authors are as follows: Zwicky estimated the probability that a distant object is multiply imaged to be about 1/400, and thus that the observation of this effect is “a certainty” [73] – his value, which was obtained by a very crude reasoning, is in fact very close to current estimates of the lensing probability of high-redshift QSOs. He predicted that the magnification caused by gravitational light deflection will allow a “deeper look” into the universe –in fact, the spectroscopy of very faint galaxies which are imaged into giant luminous arcs have yielded spectral information which would be very difficult to obtain without these ‘natural telescopes’. And third, Zwicky saw that gravitational lenses may be used to determine the mass of distant extragalactic objects[72] – in fact, the mass determination of clusters masses from giant luminous arcs is as least as accurate as other methods, but does not rely on special assumptions (like spherical symmetry, virial or thermal equilibrium) inherent in other methods, and the determination of the mass within the inner 0.9 arcseconds of the lensing galaxy in the quadruple QSO 2237+0305 to within 2% [52] is the most accurate extragalactic mass determination known. Refsdal predicted the use of gravitational lenses for determining cosmological parameters and for testing cosmological theories [48][49] – we shall return to these issues below.

scholarly journals Influence of Gravitational Lensing on Estimates of Ω in Neutral Hydrogen

1996 ◽  
Vol 173 ◽  
pp. 97-98
Author(s):  
Matthias Bartelmann ◽  
Abraham Loeb
Keyword(s):  
Observational Data ◽  
Gravitational Lensing ◽  
Column Density ◽  
Spiral Galaxies ◽  
Neutral Hydrogen ◽  
Absorption Lines ◽  
Gravitational Lenses ◽  
High Column

A wealth of observational data supports the commonly held view that damped Lyman-α (Lyα) absorption in QSO spectra is associated with neutral-hydrogen (HI) disks in spiral galaxies. Most of the HI probed by QSO absorption lines is traced by damped Lyα lines because of their high column densities, N > 1020 cm–2. The spiral galaxies hosting the HI disks can act as gravitational lenses on the QSOs. If the HI column density increases towards the center of the disks, as suggested by observations of local galaxies, the magnification bias preferentially selects for high column-density systems. The estimates of HI in damped Lyα systems can then systematically be distorted by gravitational lensing.

scholarly journals Density profile and line-of-sight mass contamination of SLACS gravitational lenses

2009 ◽  
Vol 5 (H15) ◽  
pp. 75-75
Author(s):  
C. C. Guimarães ◽  
Laerte Sodré
Keyword(s):  
Density Profile ◽  
Gravitational Lensing ◽  
Anisotropy Parameter ◽  
Stellar Dynamics ◽  
Joint Analysis ◽  
Gravitational Lenses ◽  
Confidence Levels ◽  
Effective Constant ◽  
Bayesian Evidence ◽  
The Galaxy

We use data from 58 strong lensing events surveyed by the Sloan Lens ACS Survey to estimate the projected galaxy mass inside their Einstein radii by two independent methods: stellar dynamics and strong gravitational lensing. We perform a joint analysis of both estimates examining the galaxy-lens density profile (that we approximate by a power law), the anisotropy of the velocity distribution (represented by an effective constant parameter), and a possible line-of-sigh (l.o.s.) mass contamination (which is suggested by various independent works in the literature). For each model, a likelihood analysis is performed to find the parameters that produce the best agreement between the dynamical and lensing masses, and the parameter confidence levels. The Bayesian evidence is calculated to allow a comparison among the models. We find a degeneracy among the slope of the density profile, the anisotropy parameter and the l.o.s. mass contamination. For a density profile close to isothermal, a l.o.s. mass contamination of the order of a few percent is possible, being less probable with larger anisotropy.

scholarly journals Gravitational Lensing

1992 ◽  
Vol 9 ◽  
pp. 3-32 ◽  
Author(s):  
Sjur Refsdal ◽  
Jean Surdej
Keyword(s):  
Gravitational Lensing ◽  
Gravitational Lens ◽  
Medium Size ◽  
Gravitational Lenses ◽  
Optical Lens ◽  
Basic Principles ◽  
History Of ◽  
Photometric Monitoring ◽  
A Site ◽  
Near Future

AbstractAtmospheric lensing effects deform our view of distant objects; similarly, without any doubt, gravitational lensing perturbs our view of the distant Universe and affects our physical understanding of various classes of extragalactic objects. We summarize here part of the theoretical and observational evidences supporting these claims.After briefly reviewing the history of gravitational lenses, we recall the basic principles underlying the formation of gravitationally lensed images of distant cosmic sources. We describe a simple optical lens experiment, which was actually shown during the oral discourse, and which accounts for all types of presently known gravitational lens systems.The various optical and radio searches for new gravitational lens systems that are being carried out at major observatories are reviewed. State-of-the-art observations of selected gravitational lens systems, obtained with highly performing ground-based telescopes, are then presented. These include several examples of multiply imaged QSO images, radio rings and giant luminous arcs.Through the modeling of these enigmatic objects, we show how it is possible to weigh the mass of distant lensing galaxies as well as to probe the distribution of luminous and dark matter in the Universe. Among the astrophysical and cosmological interests of observing and studying gravitational lenses, we also discuss the possibility of deriving the value of the Hubble parameter Ho from the measurement of a time delay, and how to determine the size and structure of distant quasars via the observational study of micro-lensing effects.At the end of this paper, we conclude on how to possibly achieve major astro-physical and cosmological goals in the near future by dedicating, on a site with good atmospheric seeing conditions, a medium size (2-3 m) telescope to the photometric monitoring of the multiple images of known and suspected gravitational lens systems.

scholarly journals Assessing the effect of lens mass model in cosmological application with updated galaxy-scale strong gravitational lensing sample

2019 ◽  
Vol 488 (3) ◽  
pp. 3745-3758 ◽  
Author(s):  
Yun Chen ◽  
Ran Li ◽  
Yiping Shu ◽  
Xiaoyue Cao
Keyword(s):  
Density Profile ◽  
Gravitational Lensing ◽  
Mass Density ◽  
Cosmological Parameters ◽  
Mass Model ◽  
Surface Mass ◽  
Cosmological Application ◽  
Surface Mass Density ◽  
Resolution Imaging ◽  
Lens Galaxies

ABSTRACT By comparing the dynamical and lensing masses of early-type lens galaxies, one can constrain both the cosmological parameters and the density profiles of galaxies. We explore the constraining power on cosmological parameters and the effect of the lens mass model in this method with 161 galaxy-scale strong lensing systems, which is currently the largest sample with both high-resolution imaging and stellar dynamical data. We assume a power-law mass model for the lenses, and consider three different parametrizations for γ (i.e. the slope of the total mass density profile) to include the effect of the dependence of γ on redshift and surface mass density. When treating δ (i.e. the slope of the luminosity density profile) as a universal parameter for all lens galaxies, we find the limits on the cosmological parameter Ωm are quite weak and biased, and also heavily dependent on the lens mass model in the scenarios of parametrizing γ with three different forms. When treating δ as an observable for each lens, the unbiased estimate of Ωm can be obtained only in the scenario of including the dependence of γ on both the redshift and the surface mass density, that is $\Omega _\mathrm{ m} = 0.381^{+0.185}_{-0.154}$ at 68 per cent confidence level in the framework of a flat ΛCDM model. We conclude that the significant dependencies of γ on both the redshift and the surface mass density, as well as the intrinsic scatter of δ among the lenses, need to be properly taken into account in this method.

scholarly journals Cross-correlation of the thermal Sunyaev–Zel’dovich effect and weak gravitational lensing: Planck and Subaru Hyper Suprime-Cam first-year data

2020 ◽  
Vol 492 (4) ◽  
pp. 4780-4804 ◽  
Author(s):  
Ken Osato ◽  
Masato Shirasaki ◽  
Hironao Miyatake ◽  
Daisuke Nagai ◽  
Naoki Yoshida ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Cross Correlation ◽  
High Redshift ◽  
Cosmological Parameters ◽  
First Year ◽  
Weak Gravitational Lensing ◽  
Mass Bias ◽  
Cross Correlation Analysis ◽  
Sunyaev Zel'dovich Effect ◽  
Calibration Techniques

ABSTRACT Cross-correlation analysis of the thermal Sunyaev–Zel’dovich (tSZ) effect and weak gravitational lensing (WL) provides a powerful probe of cosmology and astrophysics of the intracluster medium. We present the measurement of the cross-correlation of tSZ and WL from Planck and Subaru Hyper-Suprime Cam. The combination enables us to study cluster astrophysics at high redshift. We use the tSZ-WL cross-correlation and the tSZ autopower spectrum measurements to place a tight constraint on the hydrostatic mass bias, which is a measure of the degree of non-thermal pressure support in galaxy clusters. With the prior on cosmological parameters derived from the analysis of the cosmic microwave background anisotropies by Planck and taking into account foreground contributions both in the tSZ autopower spectrum and the tSZ-WL cross-correlation, the hydrostatic mass bias is estimated to be $26.9^{+8.9}_{-4.4} {{\ \rm per\ cent}}$ ($68{{\ \rm per\ cent}}$ CL), which is consistent with recent measurements by mass calibration techniques.

scholarly journals Gravitational lenses as probes of the distribution of dark matter in the universe

1986 ◽  
Vol 119 ◽  
pp. 545-546
Author(s):  
R. Cowsik ◽  
P. Ghosh
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Gravitational Lenses ◽  
The Universe ◽  
Individual Galaxies

Studies of the characteristic properties of gravitational lensing by clusters of galaxies suggest that the dark matter in them is probably smoothly distributed on the scale of the cluster itself, rather than being clumped into halos around individual galaxies.

scholarly journals GRAVITATIONAL LENSING BOUND ON THE AVERAGE REDSHIFT OF GAMMA RAY BURSTS IN MODELS WITH EVOLVING LENSES

1999 ◽  
Vol 08 (04) ◽  
pp. 507-517 ◽  
Author(s):  
DEEPAK JAIN ◽  
N. PANCHAPAKESAN ◽  
S. MAHAJAN ◽  
V. B. BHATIA
Keyword(s):  
Gravitational Lensing ◽  
Gamma Ray ◽  
Cosmological Parameters ◽  
Evolutionary Model ◽  
Gamma Ray Bursts ◽  
The Other ◽  
Upper Limit ◽  
Evolving Model ◽  
Evolving Models ◽  
The Universe

Identification of gravitationally lensed Gamma Ray Bursts (GRBs) in the BATSE 4B catalog can be used to constrain the average redshift <z> of the GRBs. In this paper we investigate the effect of evolving lenses on the <z> of GRBs in different cosmological models of the universe. The cosmological parameters Ω and Λ have an effect on the <z> of GRBs. The other factor which can change the <z> is the evolution of galaxies. We consider three evolutionary model of galaxies. In particular, we find that the upper limit on <z> of GRBs is higher in evolving model of galaxies as compared to non-evolving models of galaxies.

GRAVITATIONAL LENS AMPLIFICATION OF GRAVITATIONAL RADIATION

2002 ◽  
Vol 11 (07) ◽  
pp. 1067-1074 ◽  
Author(s):  
ALEXANDER F. ZAKHAROV ◽  
YURI V. BARYSHEV
Keyword(s):  
Gravitational Wave ◽  
Gravitational Lensing ◽  
Gravitational Radiation ◽  
Gravitational Lens ◽  
Wave Form ◽  
Gravitational Lenses ◽  
Approximation Model ◽  
Radiation Sources ◽  
Wave Space ◽  
Stellar Masses

In a recent paper by Wang, Turner and Stebbins (1996) an influence of gravitational lensing on increasing an estimated rate of gravitational radiation sources was considered. We show that the authors used the geometrical optics approximation model for gravitational lensing and thus they gave overestimated rate of possible events for possible sources of gravitational radiation for the advanced LIGO detector. We show also that if we would use a more correct model of gravitational lensing, one could conclude that more strong influence on increasing rate of estimated events of gravitational radiation for advanced LIGO detector could give gravitational lenses of galactic masses but not gravitational lenses of stellar masses as Wang et al. concluced. Moreover, binary gravitational lenses could give essential distortion of gravitational wave form template, especially gravitational wave template of periodic sources and the effect could be significant for templates of quasi-periodic sources which could be detected by a future gravitational wave space detector like LISA.

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