Roma Tre University

About: Roma Tre University is a education organization based out in Rome, Lazio, Italy. It is known for research contribution in the topics: Large Hadron Collider & Galaxy. The organization has 4434 authors who have published 15352 publications receiving 374888 citations. The organization is also known as: Universita degli Studi Roma Tre & RomaTre.

The Lack of BLR in Low Accretion Rate AGN as Evidence of their Origin in the Accretion Disk

Abstract: In this paper we present evidence suggesting that the absence or presence of Hidden Broad Line Regions (HBLRs) in Seyfert 2 galaxies is regulated by the rate at which matter accretes onto a central supermassive black hole, in units of Eddington rate. We use the intrinsic (i.e. unabsorbed) X-ray luminosities of these sources and their black hole masses (estimated by using the well known relationship between nuclear mass and bulge luminosity in galaxies) to derive the nuclear accretion rate in units of Eddington. We find that virtually all HBLR sources have accretion rate larger than a threshold value of $\dot{m}_{thres} \simeq 10^{-3}$ (in Eddington units), while non-HBLR sources lie at $\dot{m} \ls \dot{m}_{thres}$. These data nicely fit predictions from a model proposed by Nicastro (2000), in which the Broad Line Regions (BLRs) are formed by accretion disk instabilities occurring in proximity of the critical radius at which the disk changes from gas pressure dominated to radiation pressure dominated. This radius diminishes with decreasing accretion rates; for low enough accretion rates (and therefore luminosities), the critical radius becomes smaller than the innermost stable orbit, and BLRs cannot form.

Electron reconstruction and identification in the ATLAS experiment using the 2015 and 2016 LHC proton-proton collision data at s=13 TeV

Abstract: Algorithms used for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC) are presented in this paper; these algorithms a ...

Current drive at plasma densities required for thermonuclear reactors

Abstract: Future tokamak nuclear fusion reactors depend on efficient current drive methods, but it is hard to penetrate the high-density plasma in these devices. In this paper the authors show that radio frequency waves coupled to lower hybrid plasma waves, when the peripheral temperature of the plasma is high, can penetrate the plasma core.

Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at √s = 8 TeV with the ATLAS detector

Abstract: The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1 fb(-1) of proton-proton collision data at = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via or , where denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of . For a branching fraction of 100%, top squark masses in the range 270-645 GeV are excluded for masses below 30 GeV. For a branching fraction of 50% to either or , and assuming the mass to be twice the mass, top squark masses in the range 250-550 GeV are excluded for masses below 60 GeV.