Three-Dimensional Velocity and Density Reconstructions of the Local Universe With Cosmicflows-1

Courtois, H. M.; Hoffman, Yehuda; Tully, R. Brent; Gottlöber, Stefan

doi:10.1088/0004-637x/744/1/43

Cited by 95 publications

(88 citation statements)

References 36 publications

(44 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The Wiener Filter method was used to recover the full 3D peculiar velocity field from the observed map of radial velocities and to recover the underlying linear density field (Courtois et al 2012). The velocity field within a data zone of 3000 km s −1 was decomposed into a local component that is generated within the data zone and a tidal one that is generated by the mass distribution outside that zone.…”

Section: Current Resultsmentioning

confidence: 99%

Cosmic Flows surveys and CLUES simulations

Courtois

Tully

2012

Astron Nachr

View full text Add to dashboard Cite

'Cosmic Flows' is a program to determine galaxy distances for 30 000 galaxies with systematic errors below 2 %, almost ten times the number currently known and a five-fold improvement in systematics. The resultant velocity field will provide input for constrained local universe simulations: CLUES (www.clues-project.org). The observed and the simulated universe are then comparatively studied. This synergy of observations and theory distinguishes the program, and should lead to fundamental discoveries regarding the sources of deviations from the expansion of the universe. Specifically, the program should give a definitive answer to one of the most outstanding unsolved problem in cosmology: the cause of the motion of 630 km s −1 of our Galaxy manifested in the microwave background dipole. This paper presents current results with particular emphasis on the "great attractor" reconstruction.

show abstract

Section: Current Resultsmentioning

confidence: 99%

Cosmic Flows surveys and CLUES simulations

Courtois

Tully

2012

Astron Nachr

View full text Add to dashboard Cite

show abstract

“…The recipe is (1) calculate the velocity shear tensor, (2) evaluate the V-web and identify the attractors, (3) locate the bottom of a basin of attraction where the smallest eigenvalue of the shear tensor is maximal, then (4) identify the full domain of the basin of attraction by construction of the flow field in the frame of reference of the bottom of the basin of attraction. Operationally, the velocity field inferred from the Wiener Filter density reconstruction can be separated into local (divergent) and tidal components (Courtois et al 2012;Tully et al 2014). Local basins of attraction can be identified that metaphorically can be related to terrestrial watersheds.…”

Section: Discussionmentioning

confidence: 99%

The Arrowhead Mini-Supercluster of Galaxies

Pomarede

Tully

Hoffman

et al. 2015

ApJ

Self Cite

View full text Add to dashboard Cite

Superclusters of galaxies can be defined kinematically from local evaluations of the velocity shear tensor. The location where the smallest eigenvalue of the shear is positive and maximal defines the center of a basin of attraction. Velocity and density fields are reconstructed with Wiener Filter techniques. Local velocities due to the density field in a restricted region can be separated from external tidal flows, permitting the identification of boundaries separating inward flows toward a basin of attraction and outward flows. This methodology was used to define the Laniakea Supercluster that includes the Milky Way. Large adjacent structures include Perseus-Pisces, Coma, Hercules, and Shapley but current kinematic data are insufficient to capture their full domains. However, there is a small region trapped between Laniakea, Perseus-Pisces, and Coma that is close enough to be reliably characterized and that satisfies the kinematic definition of a supercluster. Because of its shape, it is given the name the Arrowhead Supercluster. This entity does not contain any major clusters. A characteristic dimension is ∼25 Mpc and the contained mass is only~ M 10 .15

show abstract

“…We use the Cosmicflows-2 (CF2, Tully et al 2013) catalog of distances as a starting point for our Wiener Filter reconstruction (Courtois et al 2012(Courtois et al , 2013. The ∼ 8000 galaxy distances in CF2 are gathered according to the cosmic distance ladder and are thus from an amalgum of six methodologies: Cepheid variables, Tip of the Red Giant Branch, Surface brightness fluctuations, Tully-Fisher relation, Fundamental plane and SuperNovae Ia.…”

Section: Cosmicflows-2 and The Wiener Filter Velocity Field Reconstrumentioning

confidence: 99%

The alignment of galaxy spin with the shear field in observations

Pahwa

Libeskind

Tempel

et al. 2016

Mon. Not. R. Astron. Soc.

Self Cite

View full text Add to dashboard Cite

Tidal torque theory suggests that galaxies gain angular momentum in the linear stage of structure formation. Such a theory predicts alignments between the spin of haloes and tidal shear field. However, non-linear evolution and angular momentum acquisition may alter this prediction significantly. In this paper, we use a reconstruction of the cosmic shear field from observed peculiar velocities combined with spin axes extracted from galaxies within 115 Mpc (∼ 8000 kms −1 ) from 2MRS catalog, to test whether or not galaxies appear aligned with principal axes of shear field. Although linear reconstructions of the tidal field have looked at similar issues, this is the first such study to examine galaxy alignments with velocity-shear field. Ellipticals in the 2MRS sample, show a statistically significant alignment with two of the principal axes of the shear field. In general, elliptical galaxies have their short axis aligned with the axis of greatest compression and perpendicular to the axis of slowest compression. Spiral galaxies show no signal. Such an alignment is significantly strengthened when considering only those galaxies that are used in velocity field reconstruction. When examining such a subsample, a weak alignment with the axis of greatest compression emerges for spiral galaxies as well. This result indicates that although velocity field reconstructions still rely on fairly noisy and sparse data, the underlying alignment with shear field is strong enough to be visible even when small numbers of galaxies are considered -especially if those galaxies are used as constraints in the reconstruction.

show abstract

Three-Dimensional Velocity and Density Reconstructions of the Local Universe With Cosmicflows-1

Cited by 95 publications

References 36 publications

Cosmic Flows surveys and CLUES simulations

Cosmic Flows surveys and CLUES simulations

The Arrowhead Mini-Supercluster of Galaxies

The alignment of galaxy spin with the shear field in observations

Contact Info

Product

Resources

About