In my talk I reviewed observations of the dark matter and total mass profiles in massive ETGs and clusters and their implications for ΛCDM. In this brief proceedings, I have extracted just a subset of material from my talk due to space limitations.

This is a brief introduction to the closing discussion of the IAU Symposium 295, ‘The Intriguing Life of Massive Galaxies’, that was held in Beijing from August 27 through 31, 2012. The discussion was focused on only four hot items, namely 1) the redshift evolution of the size of passively evolving galaxies, 2) the evolution with redshift of the specific star formation rate, 3) quenching of star formation in galaxies and dry merging, and 4) the IMF.

Elliptical galaxies comprise primarily old stars, which collectively generate a long-lasting feedback via stellar mass-loss and Type Ia SNe. This feedback can be traced by X-ray-emitting hot gas in and around such galaxies, in which little cool gas is typically present. However, the X-ray-inferred mass, energy, and metal abundance of the hot gas are often found to be far less than what are expected from the feedback, particularly in so-called low LX/LB ellipticals. This “missing” stellar feedback is presumably lost in galaxy-wide outflows, which can play an essential role in galaxy evolution (e.g., explaining the observed color bi-modality of galaxies). We are developing a model that can be used to properly interpret the X-ray data and to extract key information about the dynamics of the feedback and its interplay with galactic environment.

As found in Secco (2000, 2001), the presence of a (non-baryonic) dark halo in large-scale celestial objects, can induce a scale length on the luminous spheroid through the occurrence of an unexpected maximum in the virial potential energy (Clausius Virial, CV). The above mentioned investigations were grounded on two cored power law density profiles, but the same result is shown to hold for more refined and realistic models.

Distant planetary nebulae (PNe) are used to measure distances through the PN luminosity function, as kinematic tracers in determining the mass distribution in elliptical galaxies, and most recently, for measuring the kinematics of the diffuse stellar population in galaxy clusters. This article reviews the photometric and spectroscopic survey techniques that have been used to detect PNe beyond the Local Group, out to the Coma cluster at 100 Mpc distance. Contaminations by other emission sources and ways to overcome them will be discussed as well as some science highlights and future perspectives.

The structure of bulges and ellipticals, and their relation to galaxy halos are reviewed. Since many ellipticals contain faint disks, the qualitative distinction between bulges and ellipticals is more accurately described as a quantitative variation in Bulge/Disk ratio. The exception may be the brightest ellipticals, which are usually Bright (est) Cluster Members. The available evidence suggests that the spheroid properties are determined by more than halo properties alone. This is clearest for systems with low B/D ratio, where bulge velocity dispersions are similar to disk velocity dispersions. Constraints on the stellar formation scenarios are discussed.

Recent work have raised the intriguing possibility that the activity seen in most active galactic nuclei (AGN) is powered solely by young stars and supernova remnants in a burst of star formation at the time when the metal rich core of the spheroid of a normal, albeit young galaxy, was formed. The predicted emitted multifrequency spectrum, line width, variability and luminosity function of the young cores of ellipticals, are indistiguishable from those observed in Quasars. Only a small fraction (~5%) of the total mass of elliptical galaxies, the core mass, is needed to explain the observed luminosities and luminosity function of Quasars at z≥2.0.