The morphology of the X-ray and radio emitting features in central $\sim$ 50 kpc region around galaxy M87 strongly suggests that buoyant bubbles cosmic rays (inflated by an earlier nuclear active phase galaxy) rise through cooling gas at roughly half sound speed. In absence strong surface tension, initially spherical will transform into tori as they external medium. Such structures can be identified images halo M87. During their rise, uplift relatively cool from regions flow to larger...

An analytical model for extragalactic radio sources with pressure-confined jets is presented. We show that the properties of bow shock and gas surrounding these objects force to grow in a self-similar way provided density external atmosphere falls less steeply than 1/d2. Results from observations numerical simulations are used develop self-consistent large-scale structure FRII objects. The shown be stable against turbulence observed FRIIs divide between FRI jet power reproduced. overall...

(Abridged) The prevalence of radio-loud AGN activity in present-day massive halos is determined using a sample 625 nearby groups and clusters from the SDSS. Brightest group cluster galaxies (BCGs) are more likely to host than other same stellar mass (by less factor two at 5e11 M_sun, but over an order magnitude below 1e11 M_sun). distribution radio luminosities for BCGs does not depend on mass, however, similar that field mass. Neither fraction nor luminosity depends strongly velocity...

We present four Mpc-sized radio galaxies which consist of a pair double-lobed sources, aligned along the same axis, and with coinciding core. call these peculiar sources ‘double-double’ (DDRGs) propose general definition such sources: galaxy consists double common centre. Furthermore, two lobes inner source must have clearly extended, edge-brightened morphology. Adopting this definition, we find several other candidate DDRGs in literature. that all smaller (inner) is less luminous than...

This is the second in a series of papers presenting an analytical model for evolution FRII radio sources. In this paper we evaluate expected emission from source incorporating energy-loss processes relativistic electrons. By combining these results with our earlier dynamical calculate evolutionary tracks through power-linear size diagram. These are good agreement observed distribution sources The effects different forms magnetic field cocoon, redshift source, environment and defining...

A long-standing problem for models of galaxy formation has been the mismatch between predicted shape mass function dark matter halos and observed luminosity galaxies. The number massive is to decrease as a power law (N proportional M^-2) out very large masses, while cuts off exponentially at luminosities above L*. This implies that efficiency with which gas cools onto systems lower than expected. letter investigates role radio-loud active galactic nuclei (AGN) in continually re-heating...

The radio luminosity function (RLF) of galaxies and radio‐loud quasars is often modelled as a broken power law. break close to the dividing line between two Fanaroff–Riley (FR) morphological classes for large‐scale structure these objects. We use an analytical model size evolution FR type II (FR II) objects together with simple prescription I I) sources construct RLF. postulate that all start out morphology. Weaker jets subsequently disrupt within quasi‐constant density cores their host...

Human-generated textual data streams from services such as Twitter increasingly become geo-referenced. The spatial resolution of their coverage improves quickly, making them a promising instrument for sensing various aspects evolution and dynamics social systems. This work explores spacetime structures the topical content short messages in stream available Ireland. It uses streaming Latent Dirichlet Allocation topic model trained with an incremental variational Bayes method. posterior...

Radio galaxies are known to inflate lobes of hot relativistic plasmas into the intergalactic medium. Here we present hydrodynamical and magnetohydrodynamical simulations these plasma bubbles in FRII objects. We focus on later stages their evolution after jet has died down bow shock that surrounded at earlier vanished. investigate as they become subject Rayleigh-Taylor instabilities. From our calculate radio X-ray emissivities discuss appearance observations. Finally, influence large-scale...

We describe observational evidence for a new kind of interacting-binary-star outburst that involves both an accretion instability and increase in thermonuclear shell burning on the surface accreting white dwarf. refer to this type eruption as combination nova. In late 2000, prototypical symbiotic star Z Andromedae brightened by roughly two magnitudes optical. observed radio with VLA MERLIN, optical photometrically spectroscopically, far ultraviolet FUSE, X-rays Chandra XMM. The two-year-long...

We present Hα and [O iii] (5007 Å) images of the nebula powered by jet black hole candidate microquasar Cygnus X–1, observed with 2.5-m Isaac Newton Telescope (INT). The ring-like structure is luminous in there exists a thin outer shell high iii]/Hα flux ratio. This probably originates collisionally excited atoms close to front bow shock. Its presence indicates that gas shock as opposed photoionized, supporting jet-powered scenario. velocity was previously constrained at 20 < vs 360 km s−1;...

The creation of data-driven services generates new value streams, leading to the emergence actors and ultimately market configurations. In automotive industry, data generated by vehicles during use paves way for types services. Based on interviews with eleven prominent experts Central European we identify key in establishing vehicle their sharing relationships. We illustrate both a conceptual multi-actor model evaluate it context six real-life cases. Our study adopts an ecosystem perspective...

We present three-dimensional hydrodynamical simulations of buoyant gas in a typical cluster environment. In these simulations, hot matter was injected continuously into small region offset from the centre. agreement with previous analytic estimates, we found that bubbles evolve very differently depending on rate energy injection. Using tracer particles computed efficiency to stir intracluster medium (ICM) and find recurrent low-power sources are more effective mixing inner than rarer large...

A double-double radio galaxy (DDRG) is defined as consisting of a pair double sources with common centre. In this paper we present an analytical model in which the peculiar structure DDRGs caused by interruption jet flow central AGN. The new jets emerging from restarted AGN give rise to inner source within region old, outer cocoon. Standard models evolution FRII predict gas densities old cocoon that are insufficient explain observed properties structure. Therefore additional material must...

In the following paper we present an internal shocks model, iShocks, for simulating a variety of relativistic jet scenarios; these scenarios can range from single ejection event to almost continuous jet, and are highly user configurable. Although primary focus in is black hole X-ray binary jets, model scale source independent could be used supermassive holes active galactic nuclei or other flows such as jets neutron stars. Discrete packets plasma (or `shells') simulate volume. A two-shell...

Incumbent firms use corporate venture capital (CVC) as an interorganizational learning mechanism to get access new technologies or study and enter foreign markets. When companies adapt their product portfolios expand business activities geographically, strategic change takes place. Nonetheless, research still lacks understanding of CVC's impact on both dimensions change. Building theory, we examine the CVC activity portfolio geographic using a sample 1,458 units 6,751 transactions. Our...

Incumbent firms use corporate venture capital (CVC) as an interorganizational learning mechanism to get access new technologies or study and enter foreign markets. When companies adapt their product portfolios expand business activities geographically, strategic change takes place. Nonetheless, research still lacks understanding of CVC's impact on both dimensions change. Building theory, we examine the CVC activity portfolio geographic using a sample 1,458 units 6,751 transactions. Our...

Flat radio spectra with large brightness temperatures at the core of active galactic nuclei and X-ray binaries are usually interpreted as partially self-absorbed bases jet flows emitting synchrotron radiation. Here we extend previous models jets propagating angles to our line sight self-consistently include effects energy losses relativistic electrons due process itself adiabatic expansion flow. We also take into account gains through self-absorption. Two model classes presented. The...

We determine the maximum lifetime t_max of 52 FRII radio sources found in 26 central group galaxies from cross correlation Berlind SDSS catalog with VLA FIRST survey. Mock catalogs were produced to match selection criteria and redshift distribution our parent sample, while an analytical model was used calculate source sizes luminosities. The then determined via a comparison observed projected length distributions. estimate average is 1.5x10^7 years duty cycle ~8x10^8 years. Degeneracies...

We present Very Large Array images of a 'double–double radio galaxy', class objects in which two pairs lobes are aligned either side the nucleus. In this object, B0 925+420, we discover third pair lobes, close to core and again alignment with other lobes. This first-known 'triple–double' object strongly increases likelihood that these represent multiple episodes jet activity, as opposed knots an underlying jet. model terms their dynamical evolution. find inner consistent outer having been...