The size and mass evolution of the massive galaxies over cosmic time

摘要

Once understood as the paradigm of passively evolving objects, the discoverythat massive galaxies experienced an enormous structural evolution in the lastten billion years has opened an active line of research. The most significantpending question in this field is the following: which mechanism has madegalaxies to grow largely in size without altering their stellar populationsproperties dramatically? The most viable explanation is that massive galaxieshave undergone a significant number of minor mergers which have deposited mostof their material in the outer regions of the massive galaxies. This scenario,although appealing, is still far from be observationally proved since thenumber of satellite galaxies surrounding the massive objects appearsinsufficient at all redshifts. The presence also of a population of nearbymassive compact galaxies with mixture stellar properties is another piece ofthe puzzle that still does not nicely fit within a comprehensive scheme. I willreview these and other intriguing properties of the massive galaxies in thiscontribution.