2012A&A...541A..84M

Query : 2012A&A...541A..84M

2012A&A...541A..84M - Astronomy and Astrophysics, volume 541A, 84-84 (2012/5-1)

A brief analysis of self-gravitating polytropic models with a non-zero cosmological constant.

MERAFINA M., BISNOVATYI-KOGAN G.S. and TARASOV S.O.

Abstract (from CDS):

We investigate the equilibrium and stability of polytropic spheres in the presence of a non-zero cosmological constant. We solve the Newtonian gravitational equilibrium equation for a system with a polytropic equation of state of the matter P=Kργ introducing a non-zero cosmological constant Λ. We consider the cases of n=1,1.5,3 and construct series of solutions with a fixed value of Λ. For each value of n, the non-dimensional equilibrium equation has a family of solutions, instead of the unique solution of the Lane-Emden equation at Λ=0. The equilibrium state exists only for central densities ρ0 higher than the critical value ρc. There are no static solutions at ρ0<ρc. We investigate the stability of equilibrium solutions in the presence of a non-zero Λ and show that dark energy reduces the dynamic stability of the configuration. We apply our results to the analysis of the properties of the equilibrium states of clusters of galaxies in the present universe with non-zero Λ.

Abstract Copyright: ∼

Journal keyword(s): dark matter - dark energy - galaxies: clusters: general

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 NAME Local Group GrG ~ ~           ~ 8387 0

Query : 2012A&A...541A..84M

Basic data :
NAME Local Group -- Group of Galaxies
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types: 		GrG ([FWB89])
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) : 		No Coord.

Hierarchy : number of linked objects
whatever the membership probability is (see description here ) :

: 1
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%This number is the number of distinct objets linked, by using this button, you will obtain all links (may be more than one) from that object to his children

: 103 		: 10 Display criteria :

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Identifiers (3) :
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NAME LG NAME Local Group [FWB89] GrG 282

References (8387 between 1850 and 2024) (Total 8387)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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