Are Passive Spiral Galaxies truly 'passive' and 'spiral'?: a   Near-Infrared perspective
  Passive spiral galaxies - unusual galaxies with spiral morphologies but without any sign of on-going star formation - have recently been shown to exist preferentially in cluster infalling regions. This discovery directly connects passive spiral galaxies to cluster galaxy evolution studies, such as the Butcher-Oemler effect or the morphology-density relation. Thus, detailed study of passive spiral galaxies could potentially yield new insight on the underlying physical mechanisms governing cluster galaxy evolution.   However, in previous work, passive spiral galaxies were selected from low-resolution optical images with $\sim$1.5 arcsec seeing. Passive spirals could therefore be mis-identified as S0 galaxies, or as dusty-starburst galaxies which are not passive at all. To address this issue we performed deep, high-resolution, near-infrared imaging of 32 passive spiral galaxies with UKIRT. 
Chisato Yamauchi and Tomotsugu Goto