# Light-cone observables and gauge-invariance in the geodesic light-cone formalism

## Abstract

The remarkable properties of the geodesic light-cone (GLC) coordinates allow analytic expressions for the light-cone observables, providing a new non-perturbative way for calculating the effects of inhomogeneities in our Universe. However, the gauge-invariance of these expressions in the GLC formalism has not been shown explicitly. Here we provide this missing part of the GLC formalism by proving the gauge-invariance of the GLC expressions for the light-cone observables, such as the observed redshift, the luminosity distance, and the physical area and volume of the observed sources. Our study provides a new insight on the properties of the GLC coordinates and it complements the previous work by the GLC collaboration, leading to a comprehensive description of light propagation in the GLC representation.

- Authors:

- Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich (Switzerland)

- Publication Date:

- OSTI Identifier:
- 22676179

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 06; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPUTERIZED SIMULATION; DISTANCE; GAUGE INVARIANCE; LIGHT CONE; LUMINOSITY; PERTURBATION THEORY; RED SHIFT; UNIVERSE

### Citation Formats

```
Scaccabarozzi, Fulvio, and Yoo, Jaiyul, E-mail: fulvio@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch.
```*Light-cone observables and gauge-invariance in the geodesic light-cone formalism*. United States: N. p., 2017.
Web. doi:10.1088/1475-7516/2017/06/007.

```
Scaccabarozzi, Fulvio, & Yoo, Jaiyul, E-mail: fulvio@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch.
```*Light-cone observables and gauge-invariance in the geodesic light-cone formalism*. United States. doi:10.1088/1475-7516/2017/06/007.

```
Scaccabarozzi, Fulvio, and Yoo, Jaiyul, E-mail: fulvio@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch. Thu .
"Light-cone observables and gauge-invariance in the geodesic light-cone formalism". United States.
doi:10.1088/1475-7516/2017/06/007.
```

```
@article{osti_22676179,
```

title = {Light-cone observables and gauge-invariance in the geodesic light-cone formalism},

author = {Scaccabarozzi, Fulvio and Yoo, Jaiyul, E-mail: fulvio@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch},

abstractNote = {The remarkable properties of the geodesic light-cone (GLC) coordinates allow analytic expressions for the light-cone observables, providing a new non-perturbative way for calculating the effects of inhomogeneities in our Universe. However, the gauge-invariance of these expressions in the GLC formalism has not been shown explicitly. Here we provide this missing part of the GLC formalism by proving the gauge-invariance of the GLC expressions for the light-cone observables, such as the observed redshift, the luminosity distance, and the physical area and volume of the observed sources. Our study provides a new insight on the properties of the GLC coordinates and it complements the previous work by the GLC collaboration, leading to a comprehensive description of light propagation in the GLC representation.},

doi = {10.1088/1475-7516/2017/06/007},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 06,

volume = 2017,

place = {United States},

year = {Thu Jun 01 00:00:00 EDT 2017},

month = {Thu Jun 01 00:00:00 EDT 2017}

}