Comparison Study on Sketching Behaviors with and without Interactive Pen Displays

Lee, Lai-Chung; Wei, Whei‐Jane

doi:10.1007/978-3-540-92719-8_51

Cited by 7 publications

(6 citation statements)

References 5 publications

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“…There is agreement within the theoretical community that the shapes of dark matter halos do exhibit alignment correlations, driven by the environment in which they form. This alignment is thought to be the theoretical analog of the alignment correlation seen for massive elliptical galaxies by [8,9,10,11,12] and the models found in [13] are in good agreement with these lat-ter measurements. These alignments seem to persist to very large scales (∼ 50 Mpc) which may indicate that the commonly adopted approximation of Gaussian tidal fields with negligible non-linear effects might not be fully justified [14,15].…”

Section: Introductionsupporting

confidence: 80%

Alignment of galaxy spins in the vicinity of voids

Slosar

White

2009

J. Cosmol. Astropart. Phys.

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We provide limits on the alignment of galaxy orientations with the direction to the void center for galaxies lying near the edges of voids. We locate spherical voids in volume limited samples of galaxies from the Sloan Digital Sky Survey using the HB inspired void finder and investigate the orientation of (color selected) spiral galaxies that are nearly edge-on or face-on. In contrast with previous literature, we find no statistical evidence for departure from random orientations. Expressed in terms of the parameter c, introduced by Lee & Pen to describe the strength of such an alignment, we find that c < 0.11(0.13) at 95% (99.7%) confidence limit within a context of a toy model that assumes a perfectly spherical voids with sharp boundaries.PACS numbers: 98.80.Jk, 98.80.Cq

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Section: Introductionsupporting

confidence: 80%

Alignment of galaxy spins in the vicinity of voids

Slosar

White

2009

J. Cosmol. Astropart. Phys.

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“…However, the scale at which this remains true at low redshifts is less clear as non-linear gravitational evolution generates a complex web of structures. We expect alignment of structures due to their position within the cosmic web (Lee et al 2008;Lee & Pen 2002;Aubert et al 2004;Codis et al 2015b;Patiri et al 2006;Codis et al 2014Codis et al , 2015aPaz et al 2008;Hahn et al 2007), and a bias in the clustering properties of galaxies. The dark matter field exhibits coherent structures even at very large scales (∼ 100h −1 Mpc), so the scale at which alignments cease to become significant remains an open question.…”

Section: Introductionmentioning

confidence: 96%

Minkowski Tensors in Two Dimensions: Probing the Morphology and Isotropy of the Matter and Galaxy Density Fields

Appleby¹,

Chingangbam²,

Park³

et al. 2018

ApJ

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We apply the Minkowski Tensor statistics to two dimensional slices of the three dimensional matter density field. The Minkowski Tensors are a set of functions that are sensitive to directionally dependent signals in the data, and furthermore can be used to quantify the mean shape of density fields. We begin by reviewing the definition of Minkowski Tensors and introducing a method of calculating them from a discretely sampled field. Focusing on the statistic W 1,1 2 -a 2 × 2 matrix -we calculate its value for both the entire excursion set and for individual connected regions and holes within the set. To study the morphology of structures within the excursion set, we calculate the eigenvalues λ 1 , λ 2 for the matrix W 1,1 2 of each distinct connected region and hole and measure their mean shape using the ratio β ≡ λ 2 /λ 1 . We compare both W 1,1 2 and β for a Gaussian field and a smoothed density field generated from the latest Horizon Run 4 cosmological simulation, to study the effect of gravitational collapse on these functions. The global statistic W 1,1 2 is essentially independent of gravitational collapse, as the process maintains statistical isotropy. However, β is modified significantly, with overdensities becoming relatively more circular compared to underdensities at low redshifts. When applying the statistics to a redshift-space distorted density field, the matrix W 1,1 2 is no longer proportional to the identity matrix and measurements of its diagonal elements can be used to probe the large-scale velocity field.

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“…The observational studies that try to measure angular momentum correlations use the galaxy shape as a proxy (Lee & Pen 2002;Lee & Erdogdu 2007;Jones et al 2010;Paz et al 2008). In this respect it is useful to have a theoretical baseline for the correlations of angular momentum and shape with the cosmic web.…”

Section: Introductionmentioning

confidence: 99%

Cosmic web alignments with the shape, angular momentum and peculiar velocities of dark matter haloes

Forero-Romero

Contreras

Padilla

2014

Monthly Notices of the Royal Astronomical Society

101

127

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We study the alignment of dark matter haloes with the cosmic web characterized by the tidal and velocity shear fields. We focus on the alignment of their shape, angular momentum and peculiar velocities. We use a cosmological N-body simulation that allows to study dark matter haloes spanning almost five orders of magnitude in mass (10 9 -10 14 ) h −1 M and spatial scales of (0.5-1.0)h −1 Mpc to define the cosmic web. The strongest alignment is measured for halo shape along the smallest tidal eigenvector, e.g. along filaments and walls, with a signal that gets stronger as the halo mass increases. In the case of the velocity shear field only massive haloes > 10 12 h −1 M tend to have their shapes aligned along the largest tidal eigenvector; that is, perpendicular to filaments and walls. For the angular momentum we find alignment signals only for haloes more massive than 10 12 h −1 M both in the tidal and velocity shear fields where the preferences is to be parallel to the middle eigenvector; perpendicular to filaments and parallel to walls. Finally, the peculiar velocities show a strong alignment along the smallest tidal eigenvector for all halo masses; haloes move along filaments and walls. The same alignment is present with the velocity shear, albeit weaker and only for haloes less massive than 10 12 h −1 M . Our results show that the two different algorithms used to define the cosmic web describe different physical aspects of nonlinear collapse and should be used in a complementary way to understand the cosmic web influence on galaxy evolution.

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Comparison Study on Sketching Behaviors with and without Interactive Pen Displays

Cited by 7 publications

References 5 publications

Alignment of galaxy spins in the vicinity of voids

Alignment of galaxy spins in the vicinity of voids

Minkowski Tensors in Two Dimensions: Probing the Morphology and Isotropy of the Matter and Galaxy Density Fields

Cosmic web alignments with the shape, angular momentum and peculiar velocities of dark matter haloes

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