| Description |
We have detected strong overdensities of submillimeter galaxies (SMGs) around a sample of zvirgul2 QSOs using SCUBA 450 and 850 micron maps. In at least one case we have proved that most of those objects are indeed at the same redshift as the QSO, and hence related to it. If the other SMGs are also related to their entral QSOs they would represent high density peaks in the density of the early Universe, where present-day massive galaxies are thought to form. However, our understanding of the origin of such emission (expected to be due to thermal emission by dust heated by star formation) is very sketchy, since we only have one or, at best, two measurements of their far infra-red-submm Spectral Energy Distribution. Small scan maps with PACS and SPIRE on-board Herschel would provide crucial data around the expected peak of the emission for those SMGs, allowing an unambiguous determination of its spectral shape and strength, and hence proving its origin and providing accurate estimates of the physical properties of the emitting dust. This in turn can be used to quantify the star formation rates and dust masses, to understand the evolutionary status of these objects. Additionally, the high-sensitivity Herschel maps would probe the source counts around the QSOs in hitherto unexplored bands to unprecedented depth, providing vital clues to really understand the role of these objects in the formation of galaxies in these early peaks in the density of the Universe. |
