Characterizing the shapes of galaxy clusters using moments of the gravitational lensing shear

Schulz, Alexia; White, Martin

doi:10.1016/j.astropartphys.2005.09.003

Cited by 7 publications

(6 citation statements)

References 22 publications

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“…In cosmological simulations, dark matter halos are generally found to be prolate with typical axis ratios of ∼ 2:1. This elongation is generally found to decrease as a function of radius (Barnes & Efstathiou 1987;Warren et al 1992;Jing & Suto 2002;Schulz et al 2005;Lemze et al 2011). This trend may be dampened by baryons which are more dominant at smaller radii and act to make halos more spherical due to their collisional nature (e.g., Kazantzidis et al 2004).…”

Section: Discussionmentioning

confidence: 93%

Clash: Precise New Constraints on the Mass Profile of the Galaxy Cluster A2261

Coe

Umetsu

Zitrin

et al. 2012

ApJ

134

119

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We precisely constrain the inner mass profile of Abell 2261 (z = 0.225) for the first time and determine this cluster is not "over-concentrated" as found previously, implying a formation time in agreement with ΛCDM expectations. These results are based on strong lensing analyses of new 16-band HST imaging obtained as part of the Cluster Lensing and Supernova survey with Hubble (CLASH). Combining this with revised weak lensing analyses of Subaru wide field imaging with 5band Subaru + KPNO photometry, we place tight new constraints on the halo virial mass M vir = 2.2 ± 0.2 × 10 15 M h −1 70 (within r vir ≈ 3 Mpc h −1 70 ) and concentration c vir = 6.2 ± 0.3 when assuming a spherical halo. This agrees broadly with average c(M, z) predictions from recent ΛCDM simulations which span 5 c 8. Our most significant systematic uncertainty is halo elongation along the line of sight. To estimate this, we also derive a mass profile based on archival Chandra X-ray observations and find it to be ∼ 35% lower than our lensing-derived profile at r 2500 ∼ 600 kpc. Agreement can be achieved by a halo elongated with a ∼ 2 : 1 axis ratio along our line of sight. For this elongated halo model, we find M vir = 1.7 ± 0.2 × 10 15 M h −1 70 and c vir = 4.6 ± 0.2, placing rough lower limits on these values. The need for halo elongation can be partially obviated by non-thermal pressure support and, perhaps entirely, by systematic errors in the X-ray mass measurements. We estimate the effect of background structures based on MMT/Hectospec spectroscopic redshifts and find these tend to lower M vir further by ∼ 7% and increase c vir by ∼ 5%.

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Section: Discussionmentioning

confidence: 93%

Clash: Precise New Constraints on the Mass Profile of the Galaxy Cluster A2261

Coe

Umetsu

Zitrin

et al. 2012

ApJ

134

119

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“…Triaxiality is also useful in predicting – and hence can be constrained by – a variety of gravitational lensing observations, including weak and strong lens statistics (Bartelmann 1995; Van Waerbeke et al 2000; Schulz, Hennawi & White 2005; Bradač et al 2006; Carbone, Baccigalupi & Matarrese 2006; Bernstein 2007; Riquelme & Spergel 2007; Broadhurst et al 2008; Limousin et al 2008; Mandelbaum et al 2008, 2009; Schneider & Er 2008; Bernstein & Nakajima 2009; Zitrin et al 2009; Jönsson et al 2010), and gravitational flexion (e.g. Hawken & Bridle 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Triaxiality is also useful in predicting -and hence can be constrained by -a variety of gravitational lensing observations, including weak and strong lens statistics (Bartelmann 1995;Van Waerbeke et al 2000;Schulz et al 2005;Bradač et al 2006;Carbone et al 2006;Bernstein 2007;Riquelme & Spergel 2007;Broadhurst et al 2008;Limousin et al 2008;Schneider & Er 2008;Mandelbaum et al 2008Mandelbaum et al , 2009Zitrin et al 2009;Bernstein & Nakajima 2009;Jönsson et al 2010), and gravitational flexion (e.g., Hawken & Bridle 2009). By measuring the shapes of dark matter halos, galaxy-galaxy lensing can provide constraints on galaxy formation models and the nature of dark matter (Hoekstra et al 2004;Mandelbaum et al 2006;Parker et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Modelling the shapes of the largest gravitationally bound objects

Rossi

Sheth

Tormen

2011

Monthly Notices of the Royal Astronomical Society

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We combine the physics of the ellipsoidal collapse model with the excursion set theory to study the shapes of dark matter haloes. In particular, we develop an analytic approximation to the non-linear evolution that is more accurate than the Zeldovich approximation; we introduce a planar representation of halo axial ratios, which allows a concise and intuitive description of the dynamics of collapsing regions and allows one to relate the final shape of a halo to its initial shape; we provide simple physical explanations for some empirical fitting formulae obtained from numerical studies. Comparison with simulations is challenging, as there is no agreement about how to define a non-spherical gravitationally bound object. Nevertheless, we find that our model matches the conditional minor-to-intermediate axial ratio distribution rather well, although it disagrees with the numerical results in reproducing the minor-to-major axial ratio distribution. In particular, the mass dependence of the minor-to-major axis distribution appears to be the opposite to what is found in many previous numerical studies, where low-mass haloes are preferentially more spherical than high-mass haloes. In our model, the high-mass haloes are predicted to be more spherical, consistent with results based on a more recent and elaborate halo finding algorithm, and with observations of the mass dependence of the shapes of early-type galaxies. We suggest that some of the disagreement with some previous numerical studies may be alleviated if we consider only isolated haloes

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“…The development of e-commerce activities has changed the development model of enterprises [6]. Specifically, IEC has elevated the international marketing capabilities of international trade enterprises, solidified their relationship with their partners [7], changed their business models from production design to after-sales service departments [8], and granted them a competitive advantage. IEC also helps international trade enterprises build a new business management model that integrates logistics, capital flow, and information flow [9].…”

Section: Literature Reviewmentioning

confidence: 99%

The Impact of International Electronic Commerce on Export Trade: Evidence from China

Wang

Liu

Wen

et al. 2021

JTAER

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The impact of international electronic commerce (IEC) on export trade increases along with its expanding scale. Based on relevant data and the gravity model of China’s IEC export trade, this paper develops a theoretical model that can be used in IEC scenarios, applies regression equations, a Hausman test, and other empirical methods to verify relevant data, and performs a robustness test. The purpose of this paper is to explore the mechanism of IEC impact on China’s trade, and hopefully to study the temporal structural changes of the impact of IEC activities on China’s export trade based on the financial crisis and European debt crisis variables. The innovation of this paper is mainly reflected in the large sample of China’s trade selected in this paper. It can also determine the changes in the distance effect of international trade in the era of IEC, and reveal the mechanism by which IEC applications help foreign trade enterprises overcome economic crises. Four key conclusions are obtained as follows. First, the development of IEC has significantly promoted the expansion of China’s export trade scale. Second, in the context of the global financial crisis and European debt crisis, the positive promotion effect of IEC on exports is not significant. Third, the promotion effects of IEC on China’s exports to both developing and industrialized countries are significant, with the impact on developed country exports being slightly greater. Fourth, although the geographical distance for measuring transportation costs has a negative effect on China’s exports, such effect has been greatly weakened.

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Characterizing the shapes of galaxy clusters using moments of the gravitational lensing shear

Cited by 7 publications

References 22 publications

Clash: Precise New Constraints on the Mass Profile of the Galaxy Cluster A2261

Clash: Precise New Constraints on the Mass Profile of the Galaxy Cluster A2261

Modelling the shapes of the largest gravitationally bound objects

The Impact of International Electronic Commerce on Export Trade: Evidence from China

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