The broadening of Lyman-alpha forest absorption lines

Abstract

We provide an analytical description of the line broadening of HI absorbers in the Lyman-alpha forest resulting from Doppler broadening and Jeans smoothing. We demonstrate that our relation captures the dependence of the line-width on column density for narrow lines in z~3 mock spectra remarkably well. Broad lines at a given column density arise when the underlying density structure is more complex, and such clustering is not captured by our model. Our understanding of the line broadening opens the way to a new method to characterise the thermal state of the intergalactic medium and to determine the sizes of the absorbing structures.

12 pages, 15 figures, accepted for publication in MNRAS

References in corpus (8)

• A luminous quasar at a redshift of z = 7.085
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• Massloss of galaxies due to a UV-background
• HeII Reionization and its Effect on the IGM
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• Through Thick and Thin - HI Absorption in Cosmological Simulations
• The enrichment history of cosmic metals

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• Limits on non-canonical heating and turbulence in the intergalactic medium from the low redshift Lyman-alpha forest
• Thermal state of the intergalactic medium at $z\sim 2-4$
• The detectability of strong 21 centimetre forest absorbers from the diffuse intergalactic medium in late reionisation models
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• Hunting Primordial Black Hole Dark Matter in Lyman-$\alpha$ Forest
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• Constraining the Temperature-Density Relation of the Inter-Galactic Medium from Analytically Modeling Lyman-alpha Forest Absorbers
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