Abstract
Using N-body simulations of flat, dark energy-dominated cosmologies, we show that galaxies around simulated binary systems resembling the Local Group (LG) have low peculiar velocities, in good agreement with observational data. We have compared results for LG-like systems selected from large, high-resolution simulations of three cosmologies: a λCDM model, a λWDM model with a 2-keV warm dark matter candidate, and a quintessence (QCDM) model with an equation-of-state parameter w = -0.6. The Hubble flow is significantly colder around LGs selected in a flat, λ-dominated cosmology than around LGs in open or critical models, showing that a dark energy component manifests itself on the scales of nearby galaxies, cooling galaxy peculiar motions. Flows in the λWDM and QCDM models are marginally colder than in the λCDM one. The results of our simulations have been compared to existing data and to a new data set of 28 nearby galaxies with robust distance measures (Cepheids and surface brightness fluctuations). The measured line-of-sight velocity dispersion is given by σH = (88 ± 20 kms-1) × (R/7 Mpc). The best agreement with observations is found for LGs selected in the λCDM cosmology in environments with -0.1 < δρ/ρ < 0.6 on scales of 7 Mpc, in agreement with existing observational estimates on the local matter density. These results provide new, independent evidence for the presence of dark energy on scales of a few megaparsecs, corroborating the evidence gathered from observations of distant objects and the early Universe.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 941-948 |
| Number of pages | 8 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 359 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 21 2005 |
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Keywords
- Cosmology: theory
- Dark matter
- Galaxies: clusters: general
- Galaxies: haloes
- Large-scale structure of universe
- Methods: numerical
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
The signature of dark energy on the local Hubble flow. / Maccio, Andrea; Governato, Fabio; Horellou, Cathy.
In: Monthly Notices of the Royal Astronomical Society, Vol. 359, No. 3, 21.05.2005, p. 941-948.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The signature of dark energy on the local Hubble flow
AU - Maccio, Andrea
AU - Governato, Fabio
AU - Horellou, Cathy
PY - 2005/5/21
Y1 - 2005/5/21
N2 - Using N-body simulations of flat, dark energy-dominated cosmologies, we show that galaxies around simulated binary systems resembling the Local Group (LG) have low peculiar velocities, in good agreement with observational data. We have compared results for LG-like systems selected from large, high-resolution simulations of three cosmologies: a λCDM model, a λWDM model with a 2-keV warm dark matter candidate, and a quintessence (QCDM) model with an equation-of-state parameter w = -0.6. The Hubble flow is significantly colder around LGs selected in a flat, λ-dominated cosmology than around LGs in open or critical models, showing that a dark energy component manifests itself on the scales of nearby galaxies, cooling galaxy peculiar motions. Flows in the λWDM and QCDM models are marginally colder than in the λCDM one. The results of our simulations have been compared to existing data and to a new data set of 28 nearby galaxies with robust distance measures (Cepheids and surface brightness fluctuations). The measured line-of-sight velocity dispersion is given by σH = (88 ± 20 kms-1) × (R/7 Mpc). The best agreement with observations is found for LGs selected in the λCDM cosmology in environments with -0.1 < δρ/ρ < 0.6 on scales of 7 Mpc, in agreement with existing observational estimates on the local matter density. These results provide new, independent evidence for the presence of dark energy on scales of a few megaparsecs, corroborating the evidence gathered from observations of distant objects and the early Universe.
AB - Using N-body simulations of flat, dark energy-dominated cosmologies, we show that galaxies around simulated binary systems resembling the Local Group (LG) have low peculiar velocities, in good agreement with observational data. We have compared results for LG-like systems selected from large, high-resolution simulations of three cosmologies: a λCDM model, a λWDM model with a 2-keV warm dark matter candidate, and a quintessence (QCDM) model with an equation-of-state parameter w = -0.6. The Hubble flow is significantly colder around LGs selected in a flat, λ-dominated cosmology than around LGs in open or critical models, showing that a dark energy component manifests itself on the scales of nearby galaxies, cooling galaxy peculiar motions. Flows in the λWDM and QCDM models are marginally colder than in the λCDM one. The results of our simulations have been compared to existing data and to a new data set of 28 nearby galaxies with robust distance measures (Cepheids and surface brightness fluctuations). The measured line-of-sight velocity dispersion is given by σH = (88 ± 20 kms-1) × (R/7 Mpc). The best agreement with observations is found for LGs selected in the λCDM cosmology in environments with -0.1 < δρ/ρ < 0.6 on scales of 7 Mpc, in agreement with existing observational estimates on the local matter density. These results provide new, independent evidence for the presence of dark energy on scales of a few megaparsecs, corroborating the evidence gathered from observations of distant objects and the early Universe.
KW - Cosmology: theory
KW - Dark matter
KW - Galaxies: clusters: general
KW - Galaxies: haloes
KW - Large-scale structure of universe
KW - Methods: numerical
UR - http://www.scopus.com/inward/record.url?scp=19844382627&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=19844382627&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2005.08947.x
DO - 10.1111/j.1365-2966.2005.08947.x
M3 - Article
AN - SCOPUS:19844382627
VL - 359
SP - 941
EP - 948
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -