scholarly journals Testing the warm dark matter paradigm with large-scale structures

2011 ◽  
Vol 84 (6) ◽  
Author(s):  
Robert E. Smith ◽  
Katarina Markovic
1987 ◽  
Vol 124 ◽  
pp. 335-348
Author(s):  
Neta A. Bahcall

The evidence for the existence of very large scale structures, ∼ 100h−1Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. Detection of a ∼ 2000 kms−1 elongation in the redshift direction in the distribution of the clusters is also described. Possible causes of the effect are peculiar velocities of clusters on scales of 10–100h−1Mpc and geometrical elongation of superclusters. If the effect is entirely due to the peculiar velocities of clusters, then superclusters have masses of order 1016.5M⊙ and may contain a larger amount of dark matter than previously anticipated.


1988 ◽  
Vol 130 ◽  
pp. 427-428
Author(s):  
Masayuki Umemura

A universe dominated by both hot (HDM) and cold dark matter (CDM) is proposed. In this context, the new features for the formation of dwarf galaxies, Lyα clouds, galaxies, and large-scale structures are presented.


2020 ◽  
Vol 492 (2) ◽  
pp. 2369-2382 ◽  
Author(s):  
Absem W Jibrail ◽  
Pascal J Elahi ◽  
Geraint F Lewis

ABSTRACT The standard cosmological paradigm currently lacks a detailed account of physics in the dark sector, the dark matter and energy that dominate cosmic evolution. In this paper, we consider the distinguishing factors between three alternative models – warm dark matter, quintessence, and coupled dark matter–energy – and lambda cold dark matter (ΛCDM) through numerical simulations of cosmological structure formation. Key halo statistics – halo spin/velocity alignment between large-scale structure and neighbouring haloes, halo formation time, and migration – were compared across cosmologies within the redshift range 0 ≤ z ≤ 2.98. We found the alignment of halo motion and spin to large-scale structures and neighbouring haloes to be similar in all cosmologies for a range of redshifts. The search was extended to low-density regions, avoiding non-linear disturbances of halo spins, yet very similar alignment trends were found between cosmologies, which are difficult to characterize and use as a probe of cosmology. We found that haloes in quintessence cosmologies form earlier than their ΛCDM counterparts. Relating this to the fact that such haloes originate in high-density regions, such findings could hold clues to distinguishing factors for the quintessence cosmology from the standard model. However, in general, halo statistics are not an accurate probe of the dark sector physics.


2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Kamal Bora ◽  
R. F. L. Holanda ◽  
Shantanu Desai

AbstractWe propose a new method to explore a possible departure from the standard time evolution law for the dark matter density. We looked for a violation of this law by using a deformed evolution law, given by $$\rho _c(z) \propto (1+z)^{3+\epsilon }$$ ρ c ( z ) ∝ ( 1 + z ) 3 + ϵ , and then constrain $$\epsilon $$ ϵ . The dataset used for this purpose consists of Strong Gravitational Lensing data obtained from SLOAN Lens ACS, BOSS Emission-line Lens Survey, Strong Legacy Survey SL2S, and SLACS; along with galaxy cluster X-ray gas mass fraction measurements obtained using the Chandra Telescope. Our analyses show that $$\epsilon $$ ϵ is consistent with zero within 1 $$\sigma $$ σ c.l., but the current dataset cannot rule out with high confidence level interacting models of dark matter and dark energy.


1988 ◽  
Vol 130 ◽  
pp. 229-238
Author(s):  
Neta A. Bahcall

The evidence for the existence of very large scale structures, ∼ 100h−1 Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. A “shell model” of galaxy clustering is described in which clusters of galaxies are located at shell intersections; the model yields results consistent with cluster observations. Detection of a ∼ 2000 km s−1 elongation in the redshift direction in the distribution of the clusters is also described. Possible causes of the effect are peculiar velocities of clusters on scales of 10–100h−1 Mpc and geometrical elongation of superclusters. If the effect is entirely due to the peculiar velocities of clusters, then superclusters have masses of order 1016,5M⊙ and may contain a larger amount of dark matter than previously anticipated.


2013 ◽  
Vol 53 (A) ◽  
pp. 560-572 ◽  
Author(s):  
Sergio Colafrancesco

The Sunyaev–Zel’dovich effect (SZE) is a relevant probe for cosmology and particle astrophysics. The Planck Era marks a definite step forward in the use of this probe for astrophysics and cosmology. Astrophysical applications to galaxy clusters, galaxies, radiogalaxies and large-scale structures are discussed. Cosmological relevance for the Dark Energy equation of state, modified Gravity scenarios, Dark Matter search, cosmic magnetism and other cosmological applications is also reviewed. Future directions for the study of the SZE and its polarization are finally outlined.


1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.


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