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  • The Environment of Passive ...
    Goto, Tomotsugu; Okamura, Sadanori; Sekiguchi, Maki; Bernardi, Mariangela; Brinkmann, Jon; GÓmez, Percy L; Harvanek, Michael; Kleinman, Scot J; Krzesinski, Jurek; Long, Dan; Loveday, Jon; Miller, Christopher J; Neilsen, Eric H; Newman, Peter R; Nitta, Atsuko; Sheth, Ravi K; Snedden, Stephanie A; Yamauchi, Chisato

    Publications of the Astronomical Society of Japan, 08/2003, Letnik: 55, Številka: 4
    Journal Article

    In previous work on galaxy clusters, several authors reported the discovery of an unusual population of galaxies, which have spiral morphologies, but do not show any star-formation activity. These galaxies are called “passive spirals”, and have been interesting since it has been difficult to understand the existence of such galaxies. Using a volume-limited sample ( $0.05 < z < 0.1$ and $M_{r^{*}} <-20.5$ ; 25813 galaxies) of the Sloan Digital Sky Survey data, we found 73 ( $0.28 \pm 0.03\%$ ) passive spiral galaxies and studied their environments. It is found that passive spiral galaxies exist in a local galaxy density of $1 \hbox{--} 2 \,\textrm{Mpc}^{-2}$ and have a 1–10 cluster-centric virial radius. Thus, the origins of passive spiral galaxies are likely to be cluster-related. These characteristic environments coincide with a previously reported environment where the galaxy star-formation rate suddenly declines and the so-called morphology-density relation turns. It is likely that the same physical mechanism is responsible for all of these observational results. The existence of passive spiral galaxies suggests that a physical mechanism that works calmly is preferred to dynamical origins such as major merger/interaction since such a mechanism would destroy the spiral-arm structures. Compared with the observed cluster galaxy evolution such as the Butcher-Oemler effect and the morphological Butcher-Oemler effect, passive spiral galaxies are likely to be a key galaxy population in transition between red, elliptical/S0 galaxies in low-redshift clusters and blue, spiral galaxies more numerous in higher-redshift clusters.