Detecting HeliumII reionization from a sudden injection of entropy in the intergalactic medium

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dc.creatorTheuns, Tom
dc.creatorZaroubi, Saleem
dc.creatorKim, Tae-Sun
dc.date2001-10-25
dc.date.accessioned2026-07-07T02:01:00Z
dc.date.available2026-07-07T02:01:00Z
dc.descriptionThe temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. A sudden injection of entropy from the reionization will increase the temperature of the gas, leading to a broadening of the hydrogen Lyman-alpha absorption lines produced in the IGM, and observed in the spectra of background quasars. We present a method based on wavelets to characterise objectively the line widths of such absorption lines. We use high resolution hydrodynamical simulations to demonstrate that the algorithm can detect changes in temperature of order of 50 per cent on scales > 5000 km/s. We apply the method to a UVES/VLT spectrum of quasar 0055--269 (emission redshift=3.7) and detect at the 99 per cent confidence level a sudden increase in temperature below redshift z=3.3, which we interpret as evidence for HeliumII reionization.
dc.description4 pages, proceedings XVIIth IAP colloqium, Gaseous matter in galaxies and intergalactic space
dc.identifierhttps://arxiv.org/abs/astro-ph/0110552
dc.identifierhttp://arxiv.org/abs/astro-ph/0110552
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/3602
dc.subjectAstrophysics
dc.titleDetecting HeliumII reionization from a sudden injection of entropy in the intergalactic medium
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