Groups of Galaxies in the Two Micron All Sky Redshift Survey

Crook, Aidan C.; Huchra, J. P.; Martimbeau, N.; Masters, Karen L.; Jarrett, T. H.; Macri, Lucas M.

doi:10.1086/510201

Cited by 253 publications

(340 citation statements)

References 53 publications

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“…To do this, we follow the work of Basilakos et al (2010) in which the present observational value for ∆ obs vir (zc = 0) with 1 − σ (2 − σ) error has been calculated as 348±73(±146) based on a sub sample of the 2MASS high density contrast group catalogue (Crook et al 2007). In Fig.…”

Section: Numerical Results and Comparison With Observationmentioning

confidence: 99%

Evolution of spherical overdensities in holographic dark energy models

Naderi¹,

Malekjani²,

Pace³

2015

Monthly Notices of the Royal Astronomical Society

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In this work we investigate the spherical collapse model in flat FRW dark energy universes. We consider the Holographic Dark Energy (HDE) model as a dynamical dark energy scenario with a slowly time-varying equation-of-state (EoS) parameter w de in order to evaluate the effects of the dark energy component on structure formation in the universe. We first calculate the evolution of density perturbations in the linear regime for both phantom and quintessence behavior of the HDE model and compare the results with standard Einstein-de Sitter (EdS) and ΛCDM models. We then calculate the evolution of two characterizing parameters in the spherical collapse model, i.e., the linear density threshold δ c and the virial overdensity parameter ∆ vir . We show that in HDE cosmologies the growth factor g(a) and the linear overdensity parameter δ c fall behind the values for a ΛCDM universe while the virial overdensity ∆ vir is larger in HDE models than in the ΛCDM model. We also show that the ratio between the radius of the spherical perturbations at the virialization and turn-around time is smaller in HDE cosmologies than that predicted in a ΛCDM universe. Hence the growth of structures starts earlier in HDE models than in ΛCDM cosmologies and more concentrated objects can form in this case. It has been shown that the non-vanishing surface pressure leads to smaller virial radius and larger virial overdensity ∆ vir . We compare the predicted number of halos in HDE cosmologies and find out that in general this value is smaller than for ΛCDM models at higher redshifts and we compare different mass function prescriptions. Finally, we compare the results of the HDE models with observations.

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Section: Numerical Results and Comparison With Observationmentioning

confidence: 99%

Evolution of spherical overdensities in holographic dark energy models

Naderi¹,

Malekjani²,

Pace³

2015

Monthly Notices of the Royal Astronomical Society

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“…(13) Is the source considered to be at the center of the group/cluster? (14) Logarithmic total mass of the large environment halo in solar masses (Crook et al 2007). (15) Logarithmic radio power at 1.4 GHz in units of W Hz −1 from the NVSS or FIRST ( †) catalog.…”

Section: Atlas 3d : a Representative Lower-mass Comparisonmentioning

confidence: 99%

“…. Stars represent the MASSIVE galaxies considered to be at the centers of their respective group halos (Crook et al 2007). Circles represent MASSIVE galaxies considered to be satellite galaxies within the group halo.…”

Section: The L Xgas -σ E Relationmentioning

confidence: 99%

The Massive Survey. Iv. The X-Ray Halos of the Most Massive Early-Type Galaxies in the Nearby Universe

Goulding

Greene

et al. 2016

ApJ

115

156

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Studies of the physical properties of local elliptical galaxies are shedding new light on galaxy formation. Here we present the hot-gas properties of 33 early-type systems within the MASSIVE galaxy survey that have archival Chandra X-ray observations, and we use these data to derive X-ray luminosities (L X,gas ) and plasma temperatures (T gas ) for the diffuse gas components. We combine this with the ATLAS 3D survey to investigate the X-ray-optical properties of a statistically significant sample of early-type galaxies across a wide range of environments. When X-ray measurements are performed consistently in apertures set by the galaxy stellar content, we deduce that all early types (independent of galaxy mass, environment, and rotational support) follow a universal scaling law such that µL T X,gas gas 4.5 . We further demonstrate that the scatter in L X,gas around both K-band luminosity (L K ) and the galaxy stellar velocity dispersion (s e ) is primarily driven by T gas , with no clear trends with halo mass, radio power, or angular momentum of the stars. It is not trivial to tie the gas origin directly to either stellar mass or galaxy potential. Indeed, our data require a steeper relation between L L , K X,gas , and s e than predicted by standard mass-loss models. Finally, we find that T gas is set by the galaxy potential inside the optical effective radius. We conclude that within the innermost 10-30 kpc region, early types maintain pressure-supported hot gas, with a minimum T gas set by the virial temperature, but the majority show evidence for additional heating.

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“…Eke et al 2004), the Two Micron All Sky Redshift Survey (2MRS; e.g. Crook et al 2007), and the Sloan Digital Sky Survey (SDSS; e.g. Goto 2005; Berlind et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Galaxy groups in the low-redshift Universe

Lim

et al. 2017

Monthly Notices of the Royal Astronomical Society

133

179

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We apply a halo-based group finder to four large redshift surveys, the 2MRS, 6dFGS, SDSS and 2dFGRS, to construct group catalogs in the low-redshift Universe. The group finder is based on that of Yang et al. but with an improved halo mass assignment so that it can be applied uniformly to various redshift surveys of galaxies. Halo masses are assigned to groups according to proxies based on the stellar mass/luminosity of member galaxies. The performances of the group finder in grouping galaxies according to common halos and in halo mass assignments are tested using realistic mock samples constructed from hydrodynamical simulations and empirical models of galaxy occupation in dark matter halos. Our group finder finds ∼ 94% of the correct true member galaxies for 90 − 95% of the groups in the mock samples; the halo masses assigned by the group finder are un-biased with respect to the true halo masses, and have a typical uncertainty of ∼ 0.2 dex. The properties of group catalogs constructed from the observational samples are described and compared with other similar catalogs in the literature.

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Groups of Galaxies in the Two Micron All Sky Redshift Survey

Cited by 253 publications

References 53 publications

Evolution of spherical overdensities in holographic dark energy models

Evolution of spherical overdensities in holographic dark energy models

The Massive Survey. Iv. The X-Ray Halos of the Most Massive Early-Type Galaxies in the Nearby Universe

Galaxy groups in the low-redshift Universe

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