FR0 Radio Galaxies and Their Place in the Radio Morphology Classification

So-called FR0 radio galaxies have recently emerged as a family of active galaxies with all the same properties as FRI radio galaxies except for their ratio of core to total emission, which is about 30 times higher than that of FRI sources. We show how their properties fit within the gap paradigm as low, prograde, spinning black holes whose progenitors are powerful FRII quasars that transitioned rapidly from the cold mode into advection-dominated accretion over a few million years. The prediction is that if sufficient fuel exists, FR0 radio galaxies will evolve into full-fledged FRI radio galaxies and the observational dearth of FRI radio galaxies compared to FR0s at low redshift tells us about the supply of gas in the low-redshift FR0s. Given the model prescription, this 5–1 FR0 to FRI ratio implies that at low redshift, the FRII quasar class of active galaxies struggles to fuel its black hole beyond 1.3 times its original mass. In addition to this, we illustrate model prescriptions for the black hole mass, black hole spin, redshift, and environment distribution for FR0 radio galaxies by fitting them within a paradigm that views them as a continuous class of active galaxies that are sandwiched between FRII quasars and FRI radio galaxies

The emergence of the X-ray luminosity/cluster richness relation for radio galaxies

The idea that mergers are more likely in dense groups or clusters coupled with the assumption that such events lead to cold gas flows onto black holes, suggests a direct relationship between the radiative efficiency of an active galactic nucleus and environmental richness. Observations, however, increasingly challenge this and other basic expectations. Mounting evidence, for example, shows an inverse trend between near-Eddington accreting objects and environmental richness. Broken down by radio galaxy subgroup, recent work has explored connections between low excitation radio galaxies with Fanaroff-Riley II jet morphology (FRII LERGs) and other radio galaxies. We make contact with that work by adding a discussion of the recently discovered FR0 radio galaxies and show how to fit them in a picture in which FRII LERGs are not initial nor final phases in the lifetime of a radio galaxy, but de facto transition states. We describe how to understand the observed X-ray luminosity/cluster richness relation as a fundamental correlation on the nature of the jet-disk connection

Scale Invariant Jet Suppression Across the Black Hole Mass Scale

We provide a schematic framework for understanding observations of jet suppression in soft state black hole X-ray binaries based on the Blandford-Payne process and the net magnetic flux threading the black hole. Due to the geometrical thinness of soft state disks, mass-loading of field lines is ineffective compared to both geometrically thick disks as well as thin disks with greater black hole threading flux, a simple physical picture that allows us to understand the weakness of jets in radiatively efficient thin disks accreting in the prograde direction around high-spinning black holes. Despite a simplicity that forbids insights into the complexity of turbulent-driven evolution or the physics of the observed short-term time variability, we show how the breadth of this framework is such that it can serve as a coarse-grained foundation for understanding black hole accretion and jet formation across the mass scale

The unusual active galaxy H1821+643 and the elusive nature of FRI quasars

The moderate spin estimate for the black hole at the center of the cool core cluster H1821+643 motivates the completion of a story about this object's origin and evolution that was in the making since the work by Blundell and Rawlings over two decades ago as the first example of a massive black hole accreting at near Eddington rates with an FRI jet. This elusive combination of properties was explained in our 2010 model where we showed it to be part of a small parameter space that includes X shaped radio galaxies. As an accreting black hole that never experienced a counterrotating phase, H1821+643 is constrained by theory to produce a jet for spin values between 0.1 and about 0.7 and an FRI jet for a slightly smaller range. The feedback from such a black hole is not subject to a tilted jet and is why star formation rates remain high in this cluster environment. The prediction is that H1821+643 is within millions of years of becoming jetless.Comment: in pres

Quantitative uniqueness for elliptic equations with singular lower order terms

We use a Carleman type inequality of Koch and Tataru to obtain quantitative estimates of unique continuation for solutions of second order elliptic equations with singular lower order terms. First we prove a three sphere inequality and then describe two methods of propagation of smallness from sets of positive measure.Comment: 23 pages, v2 small changes are done and some mistakes are correcte

Two minimal incision fasciotomy for chronic exertional compartment syndrome of the lower leg

Chronic exertional compartment syndrome (CECS) of the leg is a pathological condition often related to overuse in subject who engage repetitive physical activities. Fascial release is the mainstay of surgical management. The purpose of this study was to evaluate the results obtained with a double incision decompressive fasciotomy. Eighteen consecutive athletes with a diagnosis of anterior and/or lateral CECS of the leg were operated on with a minimal double incision fascial release after a mean period of 4months after onset of symptoms. In 11 cases (61%) CECS was bilateral. Surgery was performed without tourniquet and active mobilization was starting immediately. Sports activities were resumed gradually at a mean period of 25days. The athletes were followed until 2years. All resumed pre-injury level sports activity. Two patients (18%) of the 11 who underwent to bilateral fasciotomy referred a sensation of leg weakness for an average period of 3months. The surgical technique presented in this paper seems to be a good mean to treat anterior and lateral leg CECS. The use of tourniquet is deconselled to obtain an accurate intraoperative haemostasis so reducing the risk of post-operative haematom

Magnetic reconnection and Blandford-Znajek process around rotating black holes

We provide a semi-analytic comparison between the Blandford-Znajek (BZ) and the magnetic reconnection power for accreting black holes in the curved spacetime of a rotating black hole. Our main result is that for a realistic range of astrophysical pa- rameters, the reconnection power may compete with the BZ power. The field lines anchored close to or on the black hole usually evolve to open field lines in general rel- ativistic magnetohydrodynamic (GRMHD) simulations. The BZ power is dependent on the black hole spin while magnetic reconnection power is independent of it for the near force-free magnetic configuration with open field lines adopted in our theoretical study. This has obvious consequences for the time evolution of such systems particu- larly in the context of black hole X-ray binary state transitions. Our results provide analytical justification of the results obtained in GRMHD simulations

Minimal invasive surgery for coronoid fracture: technical note

Operative treatment of coronoid fracture often requires a large dissection of soft tissue, resulting in elbow stiffness and functional limitation. The authors present a minimal invasive, safe technique, useful in the case of isolated coronoid fracture associated with elbow dislocation. This technique does not require soft tissue dissection and allows an early unlimited resumption of sports activitie