20-February-2014 Cosmic web alignments with the shape, angular momentum and peculiar velocities of dark matter halos Sergio Contreras Hantke1 Jaime E. Forero-Romero2, Nelson Padilla1 1 Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Santiago, Chile 2 Departamento de Física, Universidad de los Andes, Bogota, Colombia
Introduction Dark matter haloes are not only defined by their mass, their nature also depends on their env. Dark matter haloes reside in a network of voids, walls, filaments and knots, known as the cosmic web Understanding the environment effects in dark matter haloes will help us to have a better comprehension of the galaxy evolution theory We study how the shape, angular momentum and peculiar velocity of the dark matter haloes is related to the cosmic web
Introduction Dark matter haloes are not only defined by their mass, their nature also depends on their env. Dark matter haloes reside in a network of voids, walls, filaments and knots, known as the cosmic web Understanding the environment effects in dark matter haloes will help us to have a better comprehension of the galaxy evolution theory We study how the shape, angular momentum and peculiar velocity of the dark matter haloes is related to the cosmic web
Introduction Dark matter haloes are not only defined by their mass, their nature also depends on their env. Dark matter haloes reside in a network of voids, walls, filaments and knots, known as the cosmic web Understanding the environment effects in dark matter haloes will help us to have a better comprehension of the galaxy evolution theory White & shape, Rees angular (1978)momentum and We study how the peculiar velocity of the dark matter haloes is related to the cosmic web
Introduction Dark matter haloes are not only defined by their mass, their nature also depends on their env. Dark matter haloes reside in a network of voids, walls, filaments and knots, known as the cosmic web Understanding the environment effects in dark matter haloes will help us to have a better comprehension of the galaxy evolution theory We study how the shape, angular momentum and peculiar velocity of the dark matter haloes is related to the cosmic web
The T- & V- Web Use two different symmetric tensors to define cosmic web Diagonalize: get three real eigenvalues λ1 > λ2 > λ3 and their corresponding eigenvectors e1, e2 and e3 T-web/shear tensor = hessian of grav. pot. V-Web/Velocity shear tensor
The Dark Matter Simulation The Bolshoi Simulation 3 L = 250 mpc/h Np = 2048 WMAP 5 Cosmology We use two grids resolution to compute the cosmic web: 2563 and 5123 cells
The Multidark Database http://www.multidark.org
What do we know so far? What is new in this work? Several works have been done studying the alignment between the halo Shape and the cosmic web. Even more work has been done with the angular momentum and the cosmic web. Halo shape provides a strong alignment signal along filaments and sheets, more so for massive haloes. Halo spin tends to be oriented perpendicular to filaments and parallel to sheets, but it is a weaker than shape alignment.
What do we know so far? What is new in this work? We measure this relation with the public database to see how strong are these relations. We also use the peculiar velocity of the haloes to compare their alignment with the cosmic web. Finally, we look for evidence of halo properties, other than mass, in driving the alignments. We pay special attention to cases where there is a pivot mass scale around which the alignments switch sign
Measurement methods: Preferential Alignment The idea is to find out along which axes are halos aligned: Shape { = a,b,c V- & T-Web } a > b > c λ1 > λ2 > λ3
Measurement methods: Preferential Alignment The idea is to find out along which axes are halos aligned: Angular Momentum & Peculiar Velocity {} = a a V- & T-Web λ1 > λ2 > λ3
Measurement methods: Preferential Alignment The halo is alignment with if: The halo is alignment with if: The halo is alignment with if: Fig 5 of Libeskind et al. 2012
Average Alignment Angle Study the angle distribution between the shape, angular momentum and peculiar velocity with and Fig 5 of Libeskind et al. 2012
Results: The Halo Shape Low Mass Haloes: e1 ( ) e2 ( ) e3 (+) High Mass Haloes e1 (+++) e2 (- -) e3 (- -) Low Mass Haloes: e1 (- -) e2 ( ) e3 (++) High Mass Haloes e1 (- - -) e2 ( ) e3 (+++)
Results: The Halo Shape
Results: The Angular Momentum Low Mass Haloes: e1 (-) e2 ( ) e3 (+) High Mass Haloes e1 (-) e2 (+ +) e3 (-) Low Mass Haloes: e1 (-) e2 ( ) e3 (+) High Mass Haloes e1 ( ) e2 (+) e3 (--)
Results: The Angular Momentum
Results: The Peculiar Velocity Low Mass Haloes: e1 (-) e2 ( ) e3 (+) High Mass Haloes e1 (-) e2 (+ +) e3 (-) Low Mass Haloes: e1 (--) e2 ( - ) e3 ( ++) High Mass Haloes e1 ( ) e2 ( ) e3 ( )
Results: The Peculiar Velocity
Results: Interweb Alignment
Dependence on other halo parameters
Summary We use a public database to measure the relation between dark matter haloes and the cosmic web Stronger relation with the halo is found for the TWeb Dark matter halo shape show a strong relation with the cosmic Web Angular momentum shows a weaker relation with cosmic Web Peculiar velocity show a weak but constant relation with the T-Web
Phrase of the Day Humans always try to classify things...
Phrase of the Day Humans always try to classify things When they were classifying the animals, the platypus appear...
Phrase of the Day Humans always try to classify things When they were classifying the animals, the platypus appear...
Phrase of the Day Humans always try to classify things When they were classifying the animals, the platypus appear... That only proof that god has a sense of humour
Appendix Definition of V- T- Web T-Web V-Web