### Abstract

We present a method for defining higher order moments of a spin-2 field on the sky using the transformation properties of these statistics under rotation and parity. For the three-point function of the cosmic shear, we show that the eight logically possible combinations of the shear in three points can be divided into two classes; four combinations are even under parity transformations, and four are odd. We compute the expected value of the even-parity ones in the nonlinear regime using the halo model and conclude that on small scales, of the four combinations there is one that is expected to carry most of the signal for triangles close to isosceles. On the other hand, for collapsed triangles, all four combinations are expected to have roughly the same level of signal, although some of the combinations are negative and others positive. We estimate that a survey of a few square degrees area is enough to detect this signal above the noise at arcminute scales.

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

Pages (from-to) | 559-565 |

Number of pages | 7 |

Journal | Astrophysical Journal |

Volume | 584 |

Issue number | 2 I |

DOIs | |

State | Published - Feb 20 2003 |

### Fingerprint

### Keywords

- Cosmic microwave background
- Cosmology: theory
- Gravitational lensing
- Large-scale structure of universe

### ASJC Scopus subject areas

- Space and Planetary Science

### Cite this

*Astrophysical Journal*,

*584*(2 I), 559-565. https://doi.org/10.1086/345789

**Higher order moments of the cosmic shear and other spin-2 fields.** / Zaldarriaga, Matias; Scoccimarro, Román.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 584, no. 2 I, pp. 559-565. https://doi.org/10.1086/345789

}

TY - JOUR

T1 - Higher order moments of the cosmic shear and other spin-2 fields

AU - Zaldarriaga, Matias

AU - Scoccimarro, Román

PY - 2003/2/20

Y1 - 2003/2/20

N2 - We present a method for defining higher order moments of a spin-2 field on the sky using the transformation properties of these statistics under rotation and parity. For the three-point function of the cosmic shear, we show that the eight logically possible combinations of the shear in three points can be divided into two classes; four combinations are even under parity transformations, and four are odd. We compute the expected value of the even-parity ones in the nonlinear regime using the halo model and conclude that on small scales, of the four combinations there is one that is expected to carry most of the signal for triangles close to isosceles. On the other hand, for collapsed triangles, all four combinations are expected to have roughly the same level of signal, although some of the combinations are negative and others positive. We estimate that a survey of a few square degrees area is enough to detect this signal above the noise at arcminute scales.

AB - We present a method for defining higher order moments of a spin-2 field on the sky using the transformation properties of these statistics under rotation and parity. For the three-point function of the cosmic shear, we show that the eight logically possible combinations of the shear in three points can be divided into two classes; four combinations are even under parity transformations, and four are odd. We compute the expected value of the even-parity ones in the nonlinear regime using the halo model and conclude that on small scales, of the four combinations there is one that is expected to carry most of the signal for triangles close to isosceles. On the other hand, for collapsed triangles, all four combinations are expected to have roughly the same level of signal, although some of the combinations are negative and others positive. We estimate that a survey of a few square degrees area is enough to detect this signal above the noise at arcminute scales.

KW - Cosmic microwave background

KW - Cosmology: theory

KW - Gravitational lensing

KW - Large-scale structure of universe

UR - http://www.scopus.com/inward/record.url?scp=0042732206&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0042732206&partnerID=8YFLogxK

U2 - 10.1086/345789

DO - 10.1086/345789

M3 - Article

AN - SCOPUS:0042732206

VL - 584

SP - 559

EP - 565

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2 I

ER -