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...

We show that it is not possible in the absence of dark matter to construct a four-dimensional metric that explains galactic observations. In particular, by working with an effective potential it is shown that a metric which is constructed to fit flat rotation curves in spiral galaxies leads to the wrong sign for the bending of light i.e. repulsion instead of attraction. Hence, without dark matt...

The molecular components of three giant H ii regions (NGC 5461, NGC 5462, NGC 5471) in the galaxy M101 are investigated with new observations from single dish telescopes (James Clerk Maxwell Telescope and the NRAO 12-meter) and from the Owens Valley millimeter array. Of the three H ii regions, only NGC 5461 had previously been detected in CO emission. We calculate preliminary values for the mol...

We present the CO(1-0) and CO(2-1) line maps obtained observing with the SEST a ∼ 1 × 1 region of the Vela Molecular Ridge, Cloud D. This cloud is part of an intermediate-mass star forming region that is relatively close to the Sun. Our observations reveal, over a wide range of spatial scales (from ∼ 0.1 to a few parsecs), a variety of dense structures such as arcs, filaments and clumps, that a...

We present new interferometric CO(1-0) and single-dish CO(3-2) observations of the central parts of D478, a large (> 200 pc) dark dust cloud located in a quiescent region of the inner disk of M31 where single-dish CO(1-0) and CO(2-1) observations were previously obtained. Only a small fraction (< 15%) of the CO(1-0) flux previously detected in this region with the single-dish telescope is recor...

Using the OVRO, Nobeyama, and IRAM mm-arrays, we searched for “disk”outflow systems in three high-mass (proto)star forming regions: G 16.59−0.05, G 23.01−0.41, and G28.87+0.07. These were selected from a sample of NH3 cores (Codella, Testi & Cesaroni) associated with OH and H2O maser emission (Foster & Caswell) and with no or very faint continuum emission. Our imaging of molecular line (includi...

Early type galaxies (ETGs) are known to possess a number of quite useful scaling relations among their photometric and/or kinematical quantities. We propose a unified picture reducing both the fundamental plane and the photometric plane to suitable projections of a single relation. Modelling the ETG as a two component system, made out of a luminous Sersic profile and a NFW dark halo, and applyi...

The tensor virial theorem for subsystems is formulated for threecomponent systems and further effort is devoted to a special case where the inner subsystems and the central region of the outer one are homogeneous, the last surrounded by an isothermal homeoid. The virial equations are explicitly written under the additional restrictions: (i) similar and similarly placed inner subsystems, and (ii...

In the present work, a modified correlation is presented for the second virial coefficients of both polar and nonpolar fluids based on the corresponding states principle. The second virial coefficients of gaseous polar and non-polar compounds were calculated and compared with experimental data and with other correlations. Comparisons with the existing correlations show that the present work is ...