### Abstract

We present a numerical study of the relation between the cosmic peculiar velocity field and the gravitational acceleration field. We show that on mildly non-linear scales (4-10 h^{-1} Mpc Gaussian smoothing), the distribution of the Cartesian coordinates of each of these fields is well approximated by a Gaussian. In particular, their kurtoses and negentropies are small compared to those of the velocity divergence and density fields. We find that at these scales the relation between the velocity and gravity field follows linear theory to good accuracy. Specifically, the systematic errors in velocity-velocity comparisons due to assuming the linear model do not exceed 6 per cent in β. To correct for them, we test various non-linear estimators of velocity from density. We show that a slight modification of the α-formula proposed by Kudlicki et al. yields an estimator which is essentially unbiased and has a small variance.

Original language | English (US) |
---|---|

Pages (from-to) | 641-651 |

Number of pages | 11 |

Journal | Monthly Notices of the Royal Astronomical Society |

Volume | 339 |

Issue number | 3 |

DOIs | |

State | Published - Mar 1 2003 |

Externally published | Yes |

### Fingerprint

### Keywords

- Cosmology: theory
- Dark matter
- Large-scale structure of universe
- Methods: numerical

### ASJC Scopus subject areas

- Space and Planetary Science

### Cite this

*Monthly Notices of the Royal Astronomical Society*,

*339*(3), 641-651. https://doi.org/10.1046/j.1365-8711.2003.06202.x

**Gaussianity of cosmic velocity fields and linearity of the velocity-gravity relation.** / Cieciela̧g, Pawel; Chodorowski, Michal J.; Kiraga, Marcin; Strauss, Michael A.; Kudlicki, Andrzej; Bouchet, François R.

Research output: Contribution to journal › Article

*Monthly Notices of the Royal Astronomical Society*, vol. 339, no. 3, pp. 641-651. https://doi.org/10.1046/j.1365-8711.2003.06202.x

}

TY - JOUR

T1 - Gaussianity of cosmic velocity fields and linearity of the velocity-gravity relation

AU - Cieciela̧g, Pawel

AU - Chodorowski, Michal J.

AU - Kiraga, Marcin

AU - Strauss, Michael A.

AU - Kudlicki, Andrzej

AU - Bouchet, François R.

PY - 2003/3/1

Y1 - 2003/3/1

N2 - We present a numerical study of the relation between the cosmic peculiar velocity field and the gravitational acceleration field. We show that on mildly non-linear scales (4-10 h-1 Mpc Gaussian smoothing), the distribution of the Cartesian coordinates of each of these fields is well approximated by a Gaussian. In particular, their kurtoses and negentropies are small compared to those of the velocity divergence and density fields. We find that at these scales the relation between the velocity and gravity field follows linear theory to good accuracy. Specifically, the systematic errors in velocity-velocity comparisons due to assuming the linear model do not exceed 6 per cent in β. To correct for them, we test various non-linear estimators of velocity from density. We show that a slight modification of the α-formula proposed by Kudlicki et al. yields an estimator which is essentially unbiased and has a small variance.

AB - We present a numerical study of the relation between the cosmic peculiar velocity field and the gravitational acceleration field. We show that on mildly non-linear scales (4-10 h-1 Mpc Gaussian smoothing), the distribution of the Cartesian coordinates of each of these fields is well approximated by a Gaussian. In particular, their kurtoses and negentropies are small compared to those of the velocity divergence and density fields. We find that at these scales the relation between the velocity and gravity field follows linear theory to good accuracy. Specifically, the systematic errors in velocity-velocity comparisons due to assuming the linear model do not exceed 6 per cent in β. To correct for them, we test various non-linear estimators of velocity from density. We show that a slight modification of the α-formula proposed by Kudlicki et al. yields an estimator which is essentially unbiased and has a small variance.

KW - Cosmology: theory

KW - Dark matter

KW - Large-scale structure of universe

KW - Methods: numerical

UR - http://www.scopus.com/inward/record.url?scp=0142041979&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0142041979&partnerID=8YFLogxK

U2 - 10.1046/j.1365-8711.2003.06202.x

DO - 10.1046/j.1365-8711.2003.06202.x

M3 - Article

AN - SCOPUS:0142041979

VL - 339

SP - 641

EP - 651

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -