It is inferred from the symmetrical and luminous X-ray emission of fossil groups that they are mature, relaxed galaxy systems. Cosmological simulations and observations focusing on their dark halo and inter-galactic medium properties confirm their early formation. Recent photometric observations suggest that, unlike the majority of non-fossil brightest group galaxies (BGGs), the central early-t...

it is inferred from the symmetrical and luminous x-ray emission of fossil groups that they are mature, relaxed galaxy systems. cosmological simulations and observations focusing on their dark halo and inter-galactic medium properties confirm their early formation. recent photometric observations suggest that, unlike the majority of non-fossil brightest group galaxies (bggs), the central early-t...

A visual search has been made of four fields using United Kingdom 1.2m Schmidt Objective Prism plates with a reciprocal dispersion of 1 180 A/mm at HP. Such plate material is ideally suited to searches for emission-line galaxies. We present a catalogue of 53 emission-line objects, which comprises 45 galaxies, where individual HI1 regions are resolved in 16 bright galaxies; 8 are emission li...

Although there are many more stellar population studies of elliptical and lenticular galaxies, studies of spiral galaxies are catching up, due to higher signal to noise data on one hand, and better analysis methods on the other. Here I start by discussing some modern methods of analyzing integrated spectra of spiral galaxies, and comparing them with traditional methods. I then discuss some rece...

We measure the build-up of the stellar mass of galaxies from z = 6 to z = 1. Using 15 band multicolor imaging data in the NICMOS Ultra Deep Field we derive photometric redshifts and masses for 796 galaxies down to HAB = 26.5. The derived evolution of the global stellar mass density of galaxies is consistent with previous star formation rate density measurements over the observed range of redshi...

The rotation curves of a sample of 46 low- and high-surface brightness galaxies are considered in the context of Milgrom's modi_ed dynamics (MOND) to test a new interpolating function proposed by Zhao et al. (2010) [1] and compare with the results of simple interpolating function. The predicted rotation curves are calculated from the total baryonic matter based on the B-band surface photometry,...

We present deep HST/ACS observations of the G1 clump, a distinct stellar overdensity lying at ∼ 30 kpc along the south-western major axis of M31 close to the G1 globular cluster (Ferguson et al. 2002). Our well-populated colour-magnitude diagram reaches ∼7 magnitudes below the red giant branch tip with 90% completeness, and allows the detection of various morphological features which can be use...

We have found the stellar populations of early-type galaxies are homogeneous with no significant difference in color or Mg2 index, despite the dichotomy between X-ray extended early-type galaxies and X-ray compact ones. Since the X-ray properties reflect the potential gravitational structure and hence the process of galaxy formation, the homogeneity of the stellar populations implies that the f...

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. ...

Surface brightness fluctuations have been proved to be a very powerful technique to determine the distance and characterize the stellar content in extragalactic systems. Nevertheless, before facing the problem of stellar content in distant galaxies, we need to calibrate the method onto nearby well-known systems. In this paper we analyze the properties at J and Ks bands of a sample of 19 star cl...