Related papers: Disturbed Fossil Group Galaxy NGC 1132
We have detected extraplanar cold dust at distances out to > 10 kpc, situated in the halo of the interacting galaxy NGC 4631. The dust emission disk is much thinner than the warped HI disk and new structures emerge. In particular, a giant…
The inner disc of the local group galaxy M33 appears to be in settled rotational balance, and near IR images reveal a mild, large-scale, two-arm spiral pattern with no strong bar. We have constructed N-body models that match all the…
We analyze the linear stability of a dilute, hot plasma, taking into account the effects of stratification and anisotropic thermal conduction. The work is motivated by attempts to understand the dynamics of the intracluster medium in galaxy…
We use N-body/gasdynamical LambdaCDM cosmological simulations to examine the effect of the assembly of a central galaxy on the shape and mass profile of its dark halo. Two series of simulations are compared; one that follows only the…
Clumped dark matter arises naturally within the framwork of generic cosmological dark matter models. Invoking the existence of dark matter clumps can also solve may unexplained mysteries in astrophysics and geology or geophysics, eg. the…
We present a simulated cluster of galaxies, modeled with a pre-heated intracluster medium, that exhibits X-ray features similar to the `cold fronts' seen in Chandra observations. Mock observations at a particular epoch show factor two…
In this paper we test the idea that the low-metallicity hot gas in the centre of NGC 1291 is heated via a dynamical process. In this scenario, the gas from the outer gas-rich ring loses energy through bar-driven shocks and falls to the…
So how did the Galactic disk form and can the sequence of events ever be unravelled from the vast stellar inventory? This will require that some of the residual inhomogeneities from prehistory escaped the dissipative process at an early…
We present high-sensitivity radio continuum observations with the VLA and Ryle Telescope at 1.5, 4.9, 8.4 and 15.4 GHz of the dwarf irregular galaxy NGC 1569. The radio data show an extended, irregularly-shaped halo with filamentary…
The galaxy cluster Abell 1644 ($\bar{z}=0.047$) is known for its remarkable spiral-like X-ray emission. It was previously identified as a bimodal system, comprising the subclusters, A1644S and A1644N, each one centered on a giant elliptical…
Present-day galaxies are surrounded by cool and enriched halo gas extending to hundreds of kiloparsecs. This halo gas is thought to be the dominant reservoir of material available to fuel future star formation, but direct constraints on its…
NGC 4449 is an irregular galaxy with a moderately high star formation activity. The massive stars in NGC 4449 have given rise to many bright HII regions, superbubbles, supergiant shells, and "chimney-like" radial filaments. ROSAT X-ray…
We present Very Large Array 21-cm observations of the massive edge-on spiral galaxy NGC 5746. This galaxy has recently been reported to have a luminous X-ray halo, which has been taken as evidence of residual hot gas as predicted in galaxy…
Fossil turbulence processes are central to turbulence, turbulent mixing, and turbulent diffusion in the ocean and atmosphere, in astrophysics and cosmology, and in most other natural flows. George Gamov suggested in 1954 that galaxies might…
We analyzed deep $Chandra$ ACIS-I exposures of the cluster-scale X-ray halo surrounding the radio source 4C+37.11. This remarkable system hosts the closest resolved pair of super-massive black hole and an exceptionally luminous elliptical…
We present an analysis of Chandra X-ray observations of a compact group of galaxies, HCG 80 (z=0.03). The system is a spiral-only group composed of four late-type galaxies, and has a high-velocity dispersion of 309 km/s. With…
The starbusting, nearby (D = 32.9 Mpc) spiral (Sc) galaxy NGC2276 belongs to the sparse group dominated by the elliptical galaxy NGC2300. NGC2276 is a remarkable galaxy, as it displays a disturbed morphology at many wavelengths. This is…
We present analysis of Chandra and XMM-Newton observations of three early-type galaxies, NGC 57, NGC 7796 and IC 1531. All three are found in very low density environments, and appear to have no neighbours of comparable size. NGC 57 has a…
We present an analysis of a 50ks XMM observation of the merging galaxy cluster ClJ0152.7-1357 at z=0.83. In addition to the two main subclusters and an infalling group detected in an earlier Chandra observation of the system, XMM detects…
Recent observations have found extended multi-phase gas in a significant fraction of massive elliptical galaxies. We perform high-resolution three-dimensional hydrodynamical simulations of two idealized elliptical galaxies -- one…