UV background fluctuations traced by metal ions at z ≈ 3

L. Graziani, A. Maselli, U. Maio

Research output: Contribution to journalArticle

Abstract

Here we investigate how LyC-opaque systems present in the intergalactic medium at z ≈ 3 can distort the spectral shape of a uniform UV background (UVB) through radiative transfer (RT) effects. With this aim in mind, we perform a multifrequency RT simulation through a cosmic volume of 10 h-1 cMpc scale polluted by metals, and self-consistently derive the ions of all the species. The UVB spatial fluctuations are traced by the ratio of He II and H I column density, η, and the ratio of C IV and Si IV optical depths, ξ . We find that: (i) η spatially fluctuates through overdense systems (Δ) with statistically significant deviations δη > 25 per cent in 18 per cent of the volume; (ii) same fluctuations in ξ are also present in 34 per cent of the enriched domain (only 8 per cent of the total volume) and derive from a combination of RT induced effects and in-homogeneous metal enrichment, both effective in systems with Δ > 1.5.

Original languageEnglish
Pages (from-to)L112-L117
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume482
Issue number1
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

radiative transfer
metal ions
ion
metal
intergalactic media
metals
optical thickness
optical depth
deviation
simulation
ions
effect

Keywords

  • Cosmology: theory

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

UV background fluctuations traced by metal ions at z ≈ 3. / Graziani, L.; Maselli, A.; Maio, U.

In: Monthly Notices of the Royal Astronomical Society: Letters, Vol. 482, No. 1, 01.01.2019, p. L112-L117.

Research output: Contribution to journalArticle

Graziani, L. ; Maselli, A. ; Maio, U. / UV background fluctuations traced by metal ions at z ≈ 3. In: Monthly Notices of the Royal Astronomical Society: Letters. 2019 ; Vol. 482, No. 1. pp. L112-L117.
@article{739e8e6caa504727bbe17f8d439b5420,
title = "UV background fluctuations traced by metal ions at z ≈ 3",
abstract = "Here we investigate how LyC-opaque systems present in the intergalactic medium at z ≈ 3 can distort the spectral shape of a uniform UV background (UVB) through radiative transfer (RT) effects. With this aim in mind, we perform a multifrequency RT simulation through a cosmic volume of 10 h-1 cMpc scale polluted by metals, and self-consistently derive the ions of all the species. The UVB spatial fluctuations are traced by the ratio of He II and H I column density, η, and the ratio of C IV and Si IV optical depths, ξ . We find that: (i) η spatially fluctuates through overdense systems (Δ) with statistically significant deviations δη > 25 per cent in 18 per cent of the volume; (ii) same fluctuations in ξ are also present in 34 per cent of the enriched domain (only 8 per cent of the total volume) and derive from a combination of RT induced effects and in-homogeneous metal enrichment, both effective in systems with Δ > 1.5.",
keywords = "Cosmology: theory",
author = "L. Graziani and A. Maselli and U. Maio",
year = "2019",
month = "1",
day = "1",
doi = "10.1093/mnrasl/sly199",
language = "English",
volume = "482",
pages = "L112--L117",
journal = "Monthly Notices of the Royal Astronomical Society: Letters",
issn = "1745-3925",
publisher = "Oxford University Press",
number = "1",

}

TY - JOUR

T1 - UV background fluctuations traced by metal ions at z ≈ 3

AU - Graziani, L.

AU - Maselli, A.

AU - Maio, U.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Here we investigate how LyC-opaque systems present in the intergalactic medium at z ≈ 3 can distort the spectral shape of a uniform UV background (UVB) through radiative transfer (RT) effects. With this aim in mind, we perform a multifrequency RT simulation through a cosmic volume of 10 h-1 cMpc scale polluted by metals, and self-consistently derive the ions of all the species. The UVB spatial fluctuations are traced by the ratio of He II and H I column density, η, and the ratio of C IV and Si IV optical depths, ξ . We find that: (i) η spatially fluctuates through overdense systems (Δ) with statistically significant deviations δη > 25 per cent in 18 per cent of the volume; (ii) same fluctuations in ξ are also present in 34 per cent of the enriched domain (only 8 per cent of the total volume) and derive from a combination of RT induced effects and in-homogeneous metal enrichment, both effective in systems with Δ > 1.5.

AB - Here we investigate how LyC-opaque systems present in the intergalactic medium at z ≈ 3 can distort the spectral shape of a uniform UV background (UVB) through radiative transfer (RT) effects. With this aim in mind, we perform a multifrequency RT simulation through a cosmic volume of 10 h-1 cMpc scale polluted by metals, and self-consistently derive the ions of all the species. The UVB spatial fluctuations are traced by the ratio of He II and H I column density, η, and the ratio of C IV and Si IV optical depths, ξ . We find that: (i) η spatially fluctuates through overdense systems (Δ) with statistically significant deviations δη > 25 per cent in 18 per cent of the volume; (ii) same fluctuations in ξ are also present in 34 per cent of the enriched domain (only 8 per cent of the total volume) and derive from a combination of RT induced effects and in-homogeneous metal enrichment, both effective in systems with Δ > 1.5.

KW - Cosmology: theory

UR - http://www.scopus.com/inward/record.url?scp=85057173735&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85057173735&partnerID=8YFLogxK

U2 - 10.1093/mnrasl/sly199

DO - 10.1093/mnrasl/sly199

M3 - Article

AN - SCOPUS:85057173735

VL - 482

SP - L112-L117

JO - Monthly Notices of the Royal Astronomical Society: Letters

JF - Monthly Notices of the Royal Astronomical Society: Letters

SN - 1745-3925

IS - 1

ER -