The majority of the globular clusters associated with the Sagittarius dwarf galaxy are faint. In this respect it differs significantly from the globular cluster systems surrounding typical giant galaxies. The observation that most of globular clusters in the outer halo of the Galaxy are also sub-luminous may be understood by assuming that these clusters once also belonged to faint clusterrich d...

We discuss the link between the observations of distant quasars and those of massive dark objects in the cores of many local galaxies. We show how the formation of early black holes gives rise to the luminosity function of high z quasars, while it imprints into their dark local relics a related shape of the mass-dispersion correlation. We propose that in its lower section the correlation slope ...

This Letter presents the color distributions of the globular cluster (GC) systems of 12 Virgo elliptical galaxies, measured using data from the Hubble Space Telescope. Bright galaxies with large numbers of detected GC’s show two distinct cluster populations with mean V − I colors near 1.01 and 1.26. The GC population of M86 is a clear exception; its color distribution shows a single sharp peak ...

This Letter presents the color distributions of the globular cluster (GC) systems of 12 Virgo elliptical galaxies, measured using data from the Hubble Space Telescope. Bright galaxies with large numbers of detected GC’s show two distinct cluster populations with mean V − I colors near 1.01 and 1.26. The GC population of M86 is a clear exception; its color distribution shows a single sharp peak ...

Recent observations have demonstrated a significant growth in the integrated stellar mass of the red sequence since z = 1, dominated by a steadily increasing number of galaxies with stellar masses M∗ < 10M⊙. In this paper, we use the COMBO-17 photometric redshift survey in conjunction with deep Spitzer 24μm data to explore the relationship between star formation and the growth of stellar mass. ...

Of 90 extragalactic objects chosen from the I RAS catalog on the basis of brightness at 60 μm and "warm" infrared color [f.(25 μm)lfv(60 μm) > 0.2], 12 have luminosities characteristic of quasars. These 12 ultraluminous objects have Seyfert spectra, and nine of them show morphological evidence for recent collisions or mergers-they plausibly represent a transition stage between cooler ultralumin...

The effect of the global rotation of the universe on the formation of galaxies is investigated. It is found that the global rotation provides a natural origin for the rotation of galaxies, and the morphology of the objects formed from gravitational instability in a rotating and expanding universe depends on the amplitude of the density fluctuation, different values of the amplitude of the fluct...

The time dependent tidal interaction of the Local Group Dwarf Spheroidal (dS) Galaxies with the Milky Way (MW) can fundamentally affect their dynamical properties. The model developed here extends earlier numerical descriptions of dS-MW tidal interactions. We explore the dynamical evolution of dS systems in circular or elliptical MW orbits in the framework of a parametric oscillator. An analyti...

General relativistic models of star clusters with large redshifts are investigated to see whether such objects can be stable and long-lived based on evaporation and collision timescales and stability criteria. We find that physically reasonable models of massive clusters of stellar remnants can exist with masses ≥ 10 M⊙, which could simulate black holes at the center of galaxies with large M/L ...

The recent discovery of an X-ray jet in the z=4.3 quasar GB 1508+5714 by Yuan et al. (astro-ph/0309318) and Siemiginowska et al. (astro-ph/0310241) prompted a search for its radio counterpart. Here, we report the successful discovery of faint radio emission from the jet at 1.4 GHz using archival VLA data. Possible interpretations of the X-ray jet as synchrotron or inverse Compton emission off t...