2018A&A...611A..81M


Query : 2018A&A...611A..81M

2018A&A...611A..81M - Astronomy and Astrophysics, volume 611A, 81-81 (2018/3-1)

Bose-Einstein condensate haloes embedded in dark energy.

MEMBRADO M. and PACHECO A.F.

Abstract (from CDS):


Context. We have studied clusters of self-gravitating collisionless Newtonian bosons in their ground state and in the presence of the cosmological constant to model dark haloes of dwarf spheroidal (dSph) galaxies. Aim. We aim to analyse the influence of the cosmological constant on the structure of these systems. Observational data of Milky Way dSph galaxies allow us to estimate the boson mass.
Methods. We obtained the energy of the ground state of the cluster in the Hartree approximation by solving a variational problem in the particle density. We have also developed and applied the virial theorem. Dark halo models were tested in a sample of 19 galaxies. Galaxy radii, 3D deprojected half-light radii, mass enclosed within them, and luminosity-weighted averages of the square of line-of-sight velocity dispersions are used to estimate the particle mass.
Results. Cosmological constant repulsive effects are embedded in one parameter ξ. They are appreciable for ξ > 10–5. Bound structures appear for ξ≤ξc=1.65x10–4, what imposes a lower bound for cluster masses as a function of the particle mass. In principle, these systems present tunnelling through a potential barrier; however, after estimating their mean lifes, we realize that their existence is not affected by the age of the Universe. When Milky Way dSph galaxies are used to test the model, we obtain 3.5–1.0+1.3x10–22eV for the particle mass and a lower limit of 5.1–2.8+2.2x106M for bound haloes.
Conclusions. Our estimation for the boson mass is in agreement with other recent results which use different methods. From our particle mass estimation, the treated dSph galaxies would present dark halo masses ∼5-11x107M. With these values, they would not be affected by the cosmological constant (ξ<10–8). However, dark halo masses smaller than 107M (ξ>10–5) would already feel their effects. Our model that includes dark energy allows us to deal with these dark haloes. Assuming quantities averaged in the sample of galaxies, 10–5<ξ≤ξc dark haloes would contain stars up to ∼8-15kpc with luminosities ∼9-4x103L. Then, their observation would be complicated. The comparison of our lower bound for dark halo masses with other bounds based on different arguments, leads us to think that the cosmological constant is actually the responsible of limiting the halo mass.

Abstract Copyright: © ESO 2018

Journal keyword(s): dark matter - dark energy - galaxies: dwarf

Simbad objects: 24

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Number of rows : 24
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1263 4
2 NAME Tri II G 02 13 17.40 +36 10 42.4           ~ 103 0
3 NAME Fornax Dwarf Spheroidal G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1648 1
4 NAME Carina dSph G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1071 0
5 NAME UMa II Galaxy G 08 51 30.0 +63 07 48     13.3     ~ 345 0
6 NAME Leo T G 09 34 53.4 +17 03 05     15.1     ~ 357 0
7 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 414 1
8 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1143 1
9 NAME Dwarf Elliptical Galaxy in Sex G 10 13 02.9 -01 36 53   12 10.4     ~ 790 0
10 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 298 1
11 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 291 0
12 NAME UMa Region reg 11 00 +50.0           ~ 322 0
13 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 801 0
14 NAME Leo IV Dwarf Galaxy G 11 32 57.0 -00 32 00     15.1     ~ 358 1
15 NAME Coma Dwarf Galaxy G 12 26 59.0 +23 54 15     14.1     ~ 421 1
16 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 238 2
17 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 297 1
18 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 396 0
19 NAME UMi Galaxy G 15 09 11.34 +67 12 51.7   13.60 10.6     ~ 1286 0
20 NAME Draco II Gl? 15 52 47.6 +64 33 55           ~ 81 0
21 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 311 1
22 NAME Dra dSph G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1269 1
23 NAME MW Group GrG ~ ~           ~ 16 0
24 NAME Local Group GrG ~ ~           ~ 7831 0

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2022.11.28-07:09:34

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