Broad Line Radio Galaxies: Jet Contribution to the nuclear X-Ray Continuum

It is shown that, for Broad Line Radio Galaxies the strength of the non-thermal beamed radiation, when present, is always smaller than the accretion flow by a factor < 0.7 in the 2-10 keV band. The result has been obtained using the procedure adopted for disentangling the Flat Spectrum Radio Quasar 3C 273 (Grandi & Palumbo 2004). Although this implies a significantly smaller non-thermal flux in Radio Galaxies when compared to Blazars, the jet component, if present, could be important at very high energies and thus easily detectable with GLAST.Comment: 12 pages including 2 figures (4 files), ApJ accepte

BeppoSAX Observations of Bright Radio Galaxies

BeppoSAX observations of Broad Line Radio Galaxies (BLRGs) have shown that they have a considerable variety of spectral properties and important differences with respect to their radio-quiet counter-part Seyfert 1s. In radio galaxies the soft photons are often absorbed by cold material. In contrast, in Seyfert 1s the soft photons are generally absorbed by warm gas. The iron lines, always detected in Seyfert 1s, are not always present in BLRGs and generally are weak. In addition, small iron line equivalent widths seem to correspond to weak reflection components in radio galaxies. The emerging picture of BLRGs is complex. Probably several X-ray components, jet, accretion flow and molecular torus, mixed in different way in different objects, contribute to the production of their X-ray spectrum and determine the observed variety. The weakness of the reprocessed features can be explained either by a dilution of the Seyfert-like continuum from non-thermal (jet) radiation or by an accretion gas that is hot and geometrically thick close to the black hole and cold geometrically thin (i.e. able to reprocess the primary X-ray radiation) at larger radii.Comment: 10 pages,invited talk at the meeting "X-ray Astronomy 1999: Stellar Endpoints, AGN and the Diffuse Background", held in Bologna, Italy, September 1999, Letters and Communications, in pres

Discovery of a FR0 radio galaxy emitting at γ\gamma-ray energies

We present supporting evidence for the first association of a Fermi source, 3FGLJ1330.0-3818, with the FR0 radio galaxy Tol1326-379. FR0s represent the majority of the local radio loud AGN population but their nature is still unclear. They share the same properties of FRIs from the point of view of the nuclear and host properties, but they show a large deficit of extended radio emission. Here we show that FR0s can emit photons at very high energies. Tol1326-379 has a GeV luminosity of $L_{>1~{\rm GeV}} \sim 2\times10^{42}$ erg s$^{-1}$, typical of FRIs, but with a steeper $\gamma$-ray spectrum ($\Gamma=2.78\pm 0.14$). This could be related to the intrinsic jet properties but also to a different viewing angle.Comment: 7 pages, 5 figures , accepted for publication on MNRA

X-ray study of a sample of FR0 radio galaxies: unveiling the nature of the central engine

FR0s are compact radio sources that represent the bulk of the Radio-Loud (RL) AGN population, but they are still poorly understood. Pilot studies on these sources have been already performed at radio and optical wavelengths: here we present the first X-ray study of a sample of 19 FR0 radio galaxies selected from the SDSS/NVSS/FIRST sample of Best & Heckman (2012), with redshift $\leq$ 0.15, radio size $\leq$ 10 kpc and optically classified as low-excitation galaxies (LEG). The X-ray spectra are modeled with a power-law component absorbed by Galactic column density with, in some cases, a contribution from thermal extended gas. The X-ray photons are likely produced by the jet as attested by the observed correlation between X-ray (2-10 keV) and radio (5 GHz) luminosities, similar to FRIs. The estimated Eddington-scaled luminosities indicate a low accretion rate. Overall, we find that the X-ray properties of FR0s are indistinguishable from those of FRIs, thus adding another similarity between AGN associated with compact and extended radio sources. A comparison between FR0s and low luminosity BL Lacs, rules out important beaming effects in the X-ray emission of the compact radio galaxies. FR0s have different X-ray properties with respect to young radio sources (e.g. GPS/CSS sources), generally characterized by higher X-ray luminosities and more complex spectra. In conclusion, the paucity of extended radio emission in FR0s is probably related to the intrinsic properties of their jets that prevent the formation of extended structures, and/or to intermittent activity of their engines.Comment: Accepted for publication in MNRAS (18 pages, 4 figures

The gamma-ray emission region in the FRII Radio Galaxy 3C 111

The Broad Line Radio Galaxy 3C 111, characterized by a Fanaroff-Riley II (FRII) radio morphology, is one of the sources of the Misaligned Active Galactic Nuclei sample, consisting of Radio Galaxies and Steep Spectrum Radio Quasars, recently detected by the Fermi-Large Area Telescope. Our analysis of the 24-month gamma-ray light curve shows that 3C 111 was only occasionally detected at high energies. It was bright at the end of 2008 and faint, below the Fermi-Large Area Telescope sensitivity threshold, for the rest of the time. A multifrequency campaign of 3C~111, ongoing in the same period, revealed an increase of the mm, optical and X-ray fluxes in 2008 September-November, interpreted by Chatterjee et al. (2011) as due to the passage of a superluminal knot through the jet core. The temporal coincidence of the mm-optical-X-ray outburst with the GeV activity suggests a co-spatiality of the events, allowing, for the first time, the localization of the gamma-ray dissipative zone in a FRII jet. We argue that the GeV photons of 3C 111 are produced in a compact region confined within 0.1 pc and at a distance of about 0.3 pc from the black hole.Comment: 8 pages, 4 figures. ApJL in pres

Sustainability in Peripheral and Ultra-Peripheral Rural Areas through a Multi-Attribute Analysis: The Case of the Italian Insular Region

Italy has adopted the strategy of inner areas, mainly based on physical distance from public services. The strategy promotes a multi-level and multi-fund governance approach and the local partnership of mayors. Our paper focuses on rural areas, identified by the national strategy of inner areas, as peripheral and ultra-peripheral, in the Italian insular region (Sicily and Sardinia). It analyzes, at the municipality level, socio-demographic, economic, and environmental sustainability using appropriate indicators. Aiming at discovering the underlying relationship portrayed by multi-attribute data in an information system, we applied rough set theory. The inductive decision rules obtained through this data mining methodology reveal the simultaneous presence or absence of important characteristics aiming at reaching different levels of sustainability. Without the requirement of statistical assumptions regarding data distribution or structures for collecting data, such as functions or equations, this method ensures the description of patterns exhibited by data. Of particular interest is the assessment of conditional attributes (i.e., the selected indicators), and the information connecting them to sustainability, as a decision attribute. The most important result is rule generation, specifically, decision rules that are able to suggest tools for policy makers at different levels