相关论文: The interaction between rising bubbles and cold fr…
The halo of the Milky Way provides a laboratory to study the properties of the shocked hot gas that is predicted by models of galaxy formation. There is observational evidence of energy injection into the halo from past activity in the…
The gas temperature in the cores of many clusters of galaxies drops inward by about a factor of three or more within the central 100kpc radius. The radiative cooling time drops over the same region from 5 or more Gyr down to about 10^8 yr.…
Unopposed radiative cooling in clusters of galaxies results in excessive mass deposition rates. However, the cool cores of galaxy clusters are continuously heated by thermal conduction and turbulent heat diffusion due to minor mergers or…
Galactic outflows from local starburst galaxies typically exhibit a layered geometry, with cool $10^4\,$K flow sheathing a hotter $10^7\,$K, cylindrically-collimated, X-ray emitting plasma. Here, we argue that winds driven by…
We investigate the effect of three important processes by which AGN-blown bubbles transport material: drift, wake transport and entrainment. The first of these, drift, occurs because a buoyant bubble pushes aside the adjacent material,…
We present the analysis of a Chandra observation of the galaxy cluster Abell 133, which has a cooling flow core, a central radio source, and a diffuse, filamentary radio source which has been classified as a radio relic. The X-ray image…
We discuss Chandra results related to 1) cluster mergers and cold fronts and 2) interactions between relativistic plasma and hot cluster atmospheres. We describe the properties of cold fronts using NGC1404 in the Fornax cluster and A3667 as…
The circumnuclear disc (CND) orbiting the Galaxy's central black hole is a reservoir of material that can ultimately provide energy through accretion, or form stars in the presence of the black hole, as evidenced by the stellar cluster that…
We use a very deep 900 ks Chandra X-ray observation of the core of the Perseus cluster to measure and confirm the hard X-ray emission detected from a previous analysis. By fitting a model made up of multiple temperature components plus a…
X-ray observations of clusters of galaxies reveal the presence of edges in surface brightness and temperature, known as "cold fronts". In relaxed clusters with cool cores, these commonly observed edges have been interpreted as evidence for…
We analyze our new 144 ks deep Chandra observation of the sloshing cold front cluster RXJ2014.8-2430. Previous observations of RXJ2014.8-2430 with XMM-Newton shows evidence of a large scale, sloshing cold front around 800 kpc away from the…
The core of a neutron star contains several species of particles, whose relative equilibrium concentrations are determined by the local density. As the star spins down, its centrifugal force decreases continuously, and the star contracts.…
Thermal gas in the center of galaxy clusters can show substantial motions that generate surface-brightness and temperature discontinuities known as cold fronts. The motions may be triggered by minor or off-axis mergers that preserve the…
Sub-arcsecond images, taken in B, R, and H-Alpha filters, and area spectroscopy obtained with the WIYN 3.5-m telescope provide the basis for an investigation of the unusual structures in the stellar body and ionized gas in and around the…
We briefly review the prominent thermal and nonthermal sources near the Galactic center. These sources include the young stellar clusters, the Sgr B complex as well as the large-scale nonthermal filaments and lobes. Some of the recent radio…
(Abridged) Existing models invoking AGN activty to resolve the cooling flow conundrum in galaxy clusters focus exclusively on the role of the central galaxy. Such models require fine-tuning of highly uncertain microscopic transport…
The "sloshing" of the cold gas in the cores of relaxed clusters of galaxies is a widespread phenomenon, evidenced by the presence of spiral-shaped "cold fronts" in X-ray observations of these systems. In simulations, these flows of cold gas…
There is growing evidence that the active galactic nuclei (AGN) associated with the central elliptical galaxy in clusters of galaxies are playing an important role in the evolution of the intracluster medium (ICM) and clusters themselves.…
A deep Chandra observation of NGC 1265 (3C 83.1B), the prototype for the narrow-angled-tailed (NAT) radio galaxy, reveals a small cool X-ray thermal corona (~ 0.6 keV) embedded in the hot ICM of the Perseus cluster (~ 6.7 keV). The corona…
The center of the Milkyway is a host to energetic phenomena across many electromagnetic wave-bands and now possibly of high-energy neutrinos. We show that 5 out of 21 IceCube shower-like events, including a PeV event, likely originated from…