The sources of intergalactic metals

Evan Scannapieco, C. Pichon, B. Aracil, P. Petitjean, R. J. Thacker, D. Pogosyan, J. Bergeron, H. M P Couchman

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

We study the clustering properties of metals in the intergalactic medium (IGM) as traced by 619 C IV and 81 Si IV absorption components with N ≥ 1012cm-2 and 316 Mg II and 82 Fe II absorption components with N ≥ 1011.5cm-2 in 19 high signal-to-noise ratio (60-100 pixel-1), high-resolution (R = 45 000) quasar spectra. C IV and Si IV trace each other closely and their line-of-sight correlation functions ξ(v) exhibit a steep decline at large separations and a flatter profile below %150 km s-1, with a large overall bias. These features do not depend on absorber column densities, although there are hints that the overall amplitude of ξ C IV (v) increases with time over the redshift range detected (1.5-3). Carrying out a detailed smoothed particle hydrodynamic simulation (2 × 3203, 57 Mpc3 comoving), we show that the C IV correlation function cannot be reproduced by models in which the IGM metallicity is constant or a local function of overdensity (Z α Delta;2/3). However, the properties of ξ C IV(v) are generally consistent with a model in which metals are confined within bubbles with a typical radius Rs about sources of mass ≥Ms. We derive best-fitting values of R s ≈ 2 comoving Mpc and Ms % 1012 M⊙ at z = 3. Our lower-redshift (0.5-2) measurements of the Mg II and Fe II correlation functions also uncover a steep decline at large separations and a flatter profile at small separations, but the clustering is even higher than in the z = 1.5-3 measurements, and the turnover is shifted to somewhat smaller distances, ≈75 km s-1. Again, these features do not change with column density, but there are hints that the amplitudes of ξMg II(v) and ξ Fe II(v) increase with time. We describe an analytic 'bubble' model for these species, which come from regions that are too compact to be accurately simulated numerically, deriving best-fitting values of Rs ≈ 2.4 Mpc and Ms & 1012 M⊙. Equally good analytic fits to all four species are found in a similarly biased high-redshift enrichment model in which metals are placed within 2.4 comoving Mpc of Ms ≈ 3 × 109 sources at z = 7.5.

Original languageEnglish (US)
Pages (from-to)615-637
Number of pages23
JournalMonthly Notices of the Royal Astronomical Society
Volume365
Issue number2
DOIs
StatePublished - Jan 2006
Externally publishedYes

Fingerprint

intergalactic media
metal
metals
bubble
bubbles
profiles
signal-to-noise ratio
quasars
line of sight
metallicity
absorbers
turnover
pixel
signal to noise ratios
hydrodynamics
pixels
radii
high resolution
simulation
particle

Keywords

  • Cosmology: observations
  • Galaxies: formation
  • Intergalactic medium
  • Quasars: absorption lines

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Scannapieco, E., Pichon, C., Aracil, B., Petitjean, P., Thacker, R. J., Pogosyan, D., ... Couchman, H. M. P. (2006). The sources of intergalactic metals. Monthly Notices of the Royal Astronomical Society, 365(2), 615-637. https://doi.org/10.1111/j.1365-2966.2005.09753.x

The sources of intergalactic metals. / Scannapieco, Evan; Pichon, C.; Aracil, B.; Petitjean, P.; Thacker, R. J.; Pogosyan, D.; Bergeron, J.; Couchman, H. M P.

In: Monthly Notices of the Royal Astronomical Society, Vol. 365, No. 2, 01.2006, p. 615-637.

Research output: Contribution to journalArticle

Scannapieco, E, Pichon, C, Aracil, B, Petitjean, P, Thacker, RJ, Pogosyan, D, Bergeron, J & Couchman, HMP 2006, 'The sources of intergalactic metals', Monthly Notices of the Royal Astronomical Society, vol. 365, no. 2, pp. 615-637. https://doi.org/10.1111/j.1365-2966.2005.09753.x
Scannapieco, Evan ; Pichon, C. ; Aracil, B. ; Petitjean, P. ; Thacker, R. J. ; Pogosyan, D. ; Bergeron, J. ; Couchman, H. M P. / The sources of intergalactic metals. In: Monthly Notices of the Royal Astronomical Society. 2006 ; Vol. 365, No. 2. pp. 615-637.
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AU - Aracil, B.

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AU - Thacker, R. J.

AU - Pogosyan, D.

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N2 - We study the clustering properties of metals in the intergalactic medium (IGM) as traced by 619 C IV and 81 Si IV absorption components with N ≥ 1012cm-2 and 316 Mg II and 82 Fe II absorption components with N ≥ 1011.5cm-2 in 19 high signal-to-noise ratio (60-100 pixel-1), high-resolution (R = 45 000) quasar spectra. C IV and Si IV trace each other closely and their line-of-sight correlation functions ξ(v) exhibit a steep decline at large separations and a flatter profile below %150 km s-1, with a large overall bias. These features do not depend on absorber column densities, although there are hints that the overall amplitude of ξ C IV (v) increases with time over the redshift range detected (1.5-3). Carrying out a detailed smoothed particle hydrodynamic simulation (2 × 3203, 57 Mpc3 comoving), we show that the C IV correlation function cannot be reproduced by models in which the IGM metallicity is constant or a local function of overdensity (Z α Delta;2/3). However, the properties of ξ C IV(v) are generally consistent with a model in which metals are confined within bubbles with a typical radius Rs about sources of mass ≥Ms. We derive best-fitting values of R s ≈ 2 comoving Mpc and Ms % 1012 M⊙ at z = 3. Our lower-redshift (0.5-2) measurements of the Mg II and Fe II correlation functions also uncover a steep decline at large separations and a flatter profile at small separations, but the clustering is even higher than in the z = 1.5-3 measurements, and the turnover is shifted to somewhat smaller distances, ≈75 km s-1. Again, these features do not change with column density, but there are hints that the amplitudes of ξMg II(v) and ξ Fe II(v) increase with time. We describe an analytic 'bubble' model for these species, which come from regions that are too compact to be accurately simulated numerically, deriving best-fitting values of Rs ≈ 2.4 Mpc and Ms & 1012 M⊙. Equally good analytic fits to all four species are found in a similarly biased high-redshift enrichment model in which metals are placed within 2.4 comoving Mpc of Ms ≈ 3 × 109 sources at z = 7.5.

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KW - Cosmology: observations

KW - Galaxies: formation

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