New debris disks in nearby young moving groups
  A significant fraction of nearby young moving group members harbor
circumstellar debris dust disks. Due to their proximity and youth, these disks
are attractive targets for studying the early evolution of debris dust and
planetesimal belts. Here we present 70 and 160$\mu$m observations of 31 systems
in the $\beta$ Pic moving group, and in the Tucana-Horologium, Columba, Carina
and Argus associations, using the Herschel Space Observatory. None of these
stars were observed at far-infrared wavelengths before. Our Herschel
measurements were complemented by photometry from the WISE satellite for the
whole sample, and by submillimeter/millimeter continuum data for one source, HD
48370. We identified six stars with infrared excess, four of them are new
discoveries. By combining our new findings with results from the literature, we
examined the incidence and general characteristics of debris disks around
Sun-like members of the selected groups. With their dust temperatures of <45 K
the newly identified disks around HD 38397, HD 48370, HD 160305, and BD-20 951
represent the coldest population within this sample. For HD 38397 and HD 48370,
the emission is resolved in the 70$\mu$m PACS images, the estimated radius of
these disks is ~90 au. Together with the well-known disk around HD 61005, these
three systems represent the highest mass end of the known debris disk
population around young G-type members of the selected groups. In terms of dust
content, they resemble the hypothesized debris disk of the ancient Solar
System.
