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

Cited by in corpus (8)

• Constraints from Ly-$\alpha$ forests on non-thermal dark matter including resonantly-produced sterile neutrinos
• VoIgt profile Parameter Estimation Routine (VIPER): H I photoionization rate at z<0.5
• A new Measurement of the Intergalactic Temperature at $z\sim 2.55-2.95$
• Exploring the Thermal State of the Low-Density Intergalactic Medium at z=3 with an Ultra-High Signal-to-Noise QSO Spectrum
• The effect of stellar and AGN feedback on the low redshift Lyman-$\alpha$ forest in the Sherwood simulation suite
• Thermal state of the intergalactic medium at $z\sim 2-4$
• A Novel Statistical Method for Measuring the Temperature-Density Relation in the IGM Using the $b$-$N_{\text{HI}}$ Distribution of Absorbers in the Ly$\alpha$ Forest
• Jeans smoothing of the Ly$\alpha$ forest absorption lines