Gravitational Lensing as Probe of Large Scale Structure of the Universe

2005 ◽  
Vol 201 ◽  
pp. 437-438
Author(s):  
V. B. Bhatia ◽  
D. Jain ◽  
S. Mahajan ◽  
N. Panchapakesan

We apply gravitational lensing statistics to: (1) place a limit on the cosmological constant (ΩΛ); (2) place a limit on the average red-shift (< z >) of gamma-ray bursters (GRBs); (3) investigate models of galaxy evolution to see how compatible these models are with lensing statistics. We also point out the sources of uncertainty in lensing statistics, leading to uncertainty in the results.

2013 ◽  
Vol 23 ◽  
pp. 386-390
Author(s):  
RENYI MA ◽  
DONGSU RYU ◽  
HYESUNG KANG

Based on the cosmological hydrodynamic simulation, we study the properties of shock waves formed during the formation of the large scale structure (LSS) of the universe, and investigate their contribution to the cosmic ray (CR) fraction in the intergalactic medium (IGM). It is found that while strong accretion shocks prevail at high redshift, weak internal shocks become dominant in the intracluster medium (ICM) as galaxy clusters form and virialize at low redshift, z < 1. The accumulated CR proton energy is likely to be less than 10 % of the thermal energy in the ICM, since weak shocks of M ≲ 3 are most abundant. This is consistent with the upper limit constrained by radio and gamma-ray observations of galaxy clusters. In the warm-hot medium (WHIM) inside filaments, CRs and gas could be almost in energy equipartition, since relatively stronger shocks of 5 ≲ M ≲ 10 are dominant there. We suggest that the non-thermal emissions from the CR electrons and protons accelerated by cosmological shock waves could provide a new way to detect the WHIM of the universe.


2015 ◽  
Vol 24 (05) ◽  
pp. 1530011 ◽  
Author(s):  
Toshifumi Futamase

Gravitational lensing is a unique and direct probe of mass in the universe. It depends only on the law of gravity and does not depend on the dynamical state nor the composition of matter. Thus, it is used to study the distribution of the dark matter in the lensing object. Combined with the traditional observations such as optical and X-ray, it gives us useful informations of the structure formation in the universe. The lensing observables depend also on the global geometry as well as large scale structure of the universe. Therefore it is possible to withdraw useful constraints on the cosmological parameters once the distribution of lensing mass is accurately known. Since the first discovery of the lensing event by a galaxy in 1979, various kinds of lensing phenomena caused by star, galaxy, cluster of galaxies and large scale structure have been observed and are used to study mass distribution in various scales and cosmology. Thus, the gravitational lensing is now regarded as an indispensable research field in the observational cosmology. In this paper, we give an instructive introduction to gravitational lensing and its applications to cosmology.


1990 ◽  
Vol 365 ◽  
pp. 22 ◽  
Author(s):  
Michal Jaroszynski ◽  
Changbom Park ◽  
Bohdan Paczynski ◽  
J. Richard, III Gott

2011 ◽  
Vol 54 (10) ◽  
pp. 983-1005 ◽  
Author(s):  
Vladimir N Lukash ◽  
Elena V Mikheeva ◽  
A M Malinovsky

Physics Today ◽  
1981 ◽  
Vol 34 (8) ◽  
pp. 62-63 ◽  
Author(s):  
P. J. E. Peebles ◽  
Simon D. M. White

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