Matches in SemOpenAlex for { <https://semopenalex.org/work/W3100822768> ?p ?o ?g. }
- W3100822768 endingPage "133" @default.
- W3100822768 startingPage "133" @default.
- W3100822768 abstract "The lifetime of quasars is fundamental for understanding the growth of supermassive black holes, and is an important ingredient in models of the reionization of the intergalactic medium (IGM). However, despite various attempts to determine quasar lifetimes, current estimates from a variety of methods are uncertain by orders of magnitude. This work combines cosmological hydrodynamical simulations and 1D radiative transfer to investigate the structure and evolution of the He ii Lyα proximity zones around quasars at z ≃ 3–4. We show that the time evolution in the proximity zone can be described by a simple analytical model for the approach of the He ii fraction to ionization equilibrium, and use this picture to illustrate how the transmission profile depends on the quasar lifetime, quasar UV luminosity, and the ionization state of Helium in the ambient IGM (i.e., the average He ii fraction, or equivalently the metagalactic He ii ionizing background). A significant degeneracy exists between the lifetime and the average He ii fraction, however the latter can be determined from measurements of the He ii Lyα optical depth far from quasars, allowing the lifetime to be measured. We advocate stacking existing He ii quasar spectra at z ∼ 3, and show that the shape of this average proximity zone profile is sensitive to lifetimes as long as ∼30 Myr. At higher redshift z ∼ 4 where the He ii fraction is poorly constrained, degeneracies will make it challenging to determine these parameters independently. Our analytical model for He ii proximity zones should also provide a useful description of the properties of H i proximity zones around quasars at z ≃ 6–7." @default.
- W3100822768 created "2020-11-23" @default.
- W3100822768 creator A5018266021 @default.
- W3100822768 creator A5068565883 @default.
- W3100822768 creator A5075316431 @default.
- W3100822768 creator A5087123834 @default.
- W3100822768 date "2016-06-21" @default.
- W3100822768 modified "2023-09-24" @default.
- W3100822768 title "THE HE II PROXIMITY EFFECT AND THE LIFETIME OF QUASARS" @default.
- W3100822768 cites W1560669094 @default.
- W3100822768 cites W1606877724 @default.
- W3100822768 cites W1674032221 @default.
- W3100822768 cites W1709724524 @default.
- W3100822768 cites W1809537051 @default.
- W3100822768 cites W1884897161 @default.
- W3100822768 cites W1902574424 @default.
- W3100822768 cites W1926369493 @default.
- W3100822768 cites W1970156042 @default.
- W3100822768 cites W1970893391 @default.
- W3100822768 cites W1972992203 @default.
- W3100822768 cites W1973811431 @default.
- W3100822768 cites W1984797436 @default.
- W3100822768 cites W1985328401 @default.
- W3100822768 cites W1985645736 @default.
- W3100822768 cites W1986644900 @default.
- W3100822768 cites W1988226223 @default.
- W3100822768 cites W1989645959 @default.
- W3100822768 cites W1995083099 @default.
- W3100822768 cites W1996350922 @default.
- W3100822768 cites W1997535447 @default.
- W3100822768 cites W2003473618 @default.
- W3100822768 cites W2003559617 @default.
- W3100822768 cites W2005269826 @default.
- W3100822768 cites W2005411300 @default.
- W3100822768 cites W2006553744 @default.
- W3100822768 cites W2007083551 @default.
- W3100822768 cites W2008441954 @default.
- W3100822768 cites W2020756454 @default.
- W3100822768 cites W2023021327 @default.
- W3100822768 cites W2024319723 @default.
- W3100822768 cites W2027643543 @default.
- W3100822768 cites W2032469582 @default.
- W3100822768 cites W2035877537 @default.
- W3100822768 cites W2043253271 @default.
- W3100822768 cites W2055114673 @default.
- W3100822768 cites W2059537240 @default.
- W3100822768 cites W2061616354 @default.
- W3100822768 cites W2084345763 @default.
- W3100822768 cites W2085387831 @default.
- W3100822768 cites W2085745687 @default.
- W3100822768 cites W2089946882 @default.
- W3100822768 cites W2098564368 @default.
- W3100822768 cites W2106758945 @default.
- W3100822768 cites W2114662246 @default.
- W3100822768 cites W2124832126 @default.
- W3100822768 cites W2126048403 @default.
- W3100822768 cites W2127984363 @default.
- W3100822768 cites W2128089313 @default.
- W3100822768 cites W2129867880 @default.
- W3100822768 cites W2132899834 @default.
- W3100822768 cites W2134189776 @default.
- W3100822768 cites W2142146600 @default.
- W3100822768 cites W2145024951 @default.
- W3100822768 cites W2148567160 @default.
- W3100822768 cites W2154118553 @default.
- W3100822768 cites W2154955582 @default.
- W3100822768 cites W2157747035 @default.
- W3100822768 cites W2170302033 @default.
- W3100822768 cites W2593465249 @default.
- W3100822768 cites W2962694877 @default.
- W3100822768 cites W3098182046 @default.
- W3100822768 cites W3098221464 @default.
- W3100822768 cites W3098922903 @default.
- W3100822768 cites W3099593783 @default.
- W3100822768 cites W3100038651 @default.
- W3100822768 cites W3100778281 @default.
- W3100822768 cites W3101011831 @default.
- W3100822768 cites W3101176483 @default.
- W3100822768 cites W3101667439 @default.
- W3100822768 cites W3102202695 @default.
- W3100822768 cites W3102623566 @default.
- W3100822768 cites W3102860079 @default.
- W3100822768 cites W3102867206 @default.
- W3100822768 cites W3103020289 @default.
- W3100822768 cites W3103121943 @default.
- W3100822768 cites W3103642966 @default.
- W3100822768 cites W3103672896 @default.
- W3100822768 cites W3104305918 @default.
- W3100822768 cites W3104330986 @default.
- W3100822768 cites W3104567701 @default.
- W3100822768 cites W3104965217 @default.
- W3100822768 cites W3105395217 @default.
- W3100822768 cites W3105617911 @default.
- W3100822768 cites W3122554206 @default.
- W3100822768 cites W3123166212 @default.
- W3100822768 cites W3124582053 @default.
- W3100822768 doi "https://doi.org/10.3847/0004-637x/824/2/133" @default.
- W3100822768 hasPublicationYear "2016" @default.