On the NON-coevolution of SMBHs and massive relic galaxies
Anna Ferrè-Mateu



The existence in the local volume of a small number of massive compact galaxies without merging accretion since z~2, a.k.a. relics, is a natural prediction of the LCDM model. To date, only one galaxy, NGC1277, has been fully confirmed, but a handful of other relic candidates have been also reported. Interestingly, most of them seem to host ubermassive SMBHs, making them extreme outliers in the MBH-galaxy local scaling relations. These deviations challenge the assumed universal co-evolution between SMBHs and their host galaxy, and could be understood either as the SMBH being unusually large or the galaxy having lost part of its initial stellar mass. However, none of both assumptions have been successfully proven so far.

In this talk, I will first introduce the quest to find the elusive relic galaxies in the nearby Universe and then present a third explanation for the nature of such deviations, which is connected to the uncommon evolutionary path followed by these relic galaxies. Instead of following the two-phase growth channel expected for massive galaxies, they remain structurally untouched by skipping the second phase after z~2. I will show that if the outliers had followed the normal evolutionary path by growing in size via merger activity, the expected growth in mass would place them closer to the observed local relations.