Steps towards Lattice Virasoro Algebras: su(1,1)

An explicit construction is presented for the action of the su(1,1) subalgebra of the Virasoro algebra on path spaces for the c(2,q) minimal models. In the case of the Lee-Yang edge singularity, we show how this action already fixes the central charge of the full Virasoro algebra. For this case, we additionally construct a representation in terms of generators of the corresponding Temperley-Lieb algebra.Comment: 15 pages, plain TeX, 4 typos correcte

The energetics of giant radio galaxy lobes from inverse Compton scattering observations

Giant radio galaxy (GRG) lobes are excellent laboratories to study the evolution of the particle and B-field energetics. However, these results are based on assumptions of the shape and extension of the GRG lobe electron spectrum. We re-examine the energetics of GRG lobes as derived by inverse Compton scattering of CMB photons (ICS-CMB) by relativistic electrons in RG lobes to assess the physical conditions of RG lobes, their energetics and their radiation regime. We consider the GRG DA 240 recently observed by Suzaku as a reference case and we also discuss other RG lobes observed with Chandra and XMM. We model the spectral energy distribution of the DA 240 East lobe to get constraint on the shape and the extension of the electron spectrum in the lobe by using multi-frequency information from radio to gamma-rays. We use radio and X-ray data to constrain the shape and normalization of the electron spectrum and we then calculate the SZ effect expected in GRG lobes that is sensitive to the total electron energy density. We show that the electron energy density U_e derived form X-ray observations yields only a rough lower limit to its actual value and that most of the estimates of U_e based on X-ray measurements have to be increased even by a large factor by considering realistic estimates of the lower electron momentum p_1. This brings RG lobes away from the equipartition condition towards a particle-dominated and Compton power dominance regime. We use the distribution of RG lobes in the U_e/U_B vs. U_e/U_CMB plane as a further divide between different physical regimes of particle and field dominance, and radiation mechanism dominance in RG lobes. We conclude that the SZ effect produced by ICS-CMB mechanism observable in RG lobes provides reliable estimate of p_1 and U_e and is the best tool to determine the total energy density of RG lobes and to assess their physical regime.Comment: 9 pages, 6 figures, A&A in pres

Two types of shock in the hotspot of the giant quasar 4C74.26: a high-resolution comparison from Chandra, Gemini & MERLIN

New Chandra observations have resolved the structure of the X-ray luminous southern hotspot in the giant radio quasar 4C74.26 into two distinct features. The nearer one to the nucleus is an extremely luminous peak, extended some 5 kpc perpendicular to the orientation of the jet; 19 kpc projected further away from the central nucleus than this is a fainter X-ray arc having similar symmetry. This arc is co-spatial with near-IR and optical emission imaged with Gemini, and radio emission imaged with MERLIN. The angular separation of the double shock structure (itself ~19 kpc or 10 arcsec in size) from the active nucleus which fuels them of ~550 kpc is a reminder of the challenge of connecting "unidentified" hard X-ray or Fermi sources with their origins.Comment: In press at MNRA

Complementary network-based approaches for exploring genetic structure and functional connectivity in two vulnerable, endemic ground squirrels

The persistence of small populations is influenced by genetic structure and functional connectivity. We used two network-based approaches to understand the persistence of the northern Idaho ground squirrel (Urocitellus brunneus) and the southern Idaho ground squirrel (U. endemicus), two congeners of conservation concern. These graph theoretic approaches are conventionally applied to social or transportation networks, but here are used to study population persistence and connectivity. Population graph analyses revealed that local extinction rapidly reduced connectivity for the southern species, while connectivity for the northern species could be maintained following local extinction. Results from gravity models complemented those of population graph analyses, and indicated that potential vegetation productivity and topography drove connectivity in the northern species. For the southern species, development (roads) and small-scale topography reduced connectivity, while greater potential vegetation productivity increased connectivity. Taken together, the results of the two network-based methods (population graph analyses and gravity models) suggest the need for increased conservation action for the southern species, and that management efforts have been effective at maintaining habitat quality throughout the current range of the northern species. To prevent further declines, we encourage the continuation of management efforts for the northern species, whereas conservation of the southern species requires active management and additional measures to curtail habitat fragmentation. Our combination of population graph analyses and gravity models can inform conservation strategies of other species exhibiting patchy distributions

Isotopic Constraints on the Chemical Evolution of Geothermal Fluids, Long Valley, CA

Abstract A spatial survey of the chemical and isotopic composition of fluids from the Long Valley hydrothermal system was conducted. Starting at the presumed hydrothermal upwelling zone in the west moat of the caldera, samples were collected from the Casa Diablo geothermal field and a series of monitoring wells defining a nearly linear, ~14 km long, west-to-east trend along the proposed fluid flow path Introduction The efficiency of heat extraction from geothermal reservoir rocks is limited by chemical processes and the physical characteristics of the reservoir. Specifically, mineral dissolution and precipitation and the geometry of heat and mass exchange between fluids and the reservoir lithologies of fractured dominated systems define the long term efficiency of heat extraction but are difficult to quantify and therefore predict. Increased knowledge about the water-rock exchange in geothermal systems and the size and spacing of the major fluid transporting fractures would be valuable information that impact decisions guiding the management of natural and enhanced geothermal systems

Suzaku X-ray Imaging of the Extended Lobe in the Giant Radio Galaxy NGC6251 Associated with the Fermi-LAT Source 2FGLJ1629.4+8236

We report the results of a Suzaku X-ray imaging study of NGC6251, a nearby giant radio galaxy with intermediate FR I/II radio properties. Our pointing direction was centered on the gamma -ray emission peak recently discovered with Fermi-LAT around the position of the north-west radio lobe 15 arcmin offset from the nucleus. After subtracting two "off-source" pointings adjacent to the radio lobe, and removing possible contaminants in the XIS field of view, we found significant residual X-ray emission most likely diffuse in nature. The spectrum of the excess X-ray emission is well fit by a power law with photon index \Gamma = 1.90 +- 0.15 and a 0.5 - 8 keV flux of 4 x 10^{-13} erg cm^{-2} s^{-1}. We interpret this diffuse X-ray emission component as being due to inverse-Compton up-scattering of the cosmic microwave background photons by ultrarelativistic electrons within the lobe, with only a minor contribution from the beamed emission of the large-scale jet. Utilizing archival radio data for the source, we demonstrate by means of broad-band spectral modeling that the -ray flux of the Fermi-LAT source 2FGL J1629.4+8236 may well be accounted for by the high-energy tail of the inverse-Compton continuum of the lobe. Thus, this claimed association of gamma-rays from the north-west lobe of NGC6251, together with the recent Fermi-LAT imaging of the extended lobes of Centaurus A, indicates that particles may be efficiently (re-)accelerated up to ultrarelativistic energies within extended radio lobes of nearby radio galaxies in general.Comment: 19 pages, 4 figures, accepted for publication in the Ap

Suzaku observation of the giant radio galaxy 3C 326

A Suzaku observation of a giant radio galaxy, 3C 326, which has a physical size of about 2 Mpc, was conducted on 2008 January 19 -- 21. In addition to several X-ray sources, diffuse emission was significantly detected associated with its west lobe, but the east lobe was contaminated by an unidentified X-ray source WARP J1552.4+2007. After careful evaluation of the X-ray and Non X-ray background, the 0.4 -- 7 keV X-ray spectrum of the west lobe is described by a power-law model. The photon index and 1 keV flux density was derived as $1.82_{-0.24}^{+0.26}\pm0.04$ and $19.4_{-3.2}^{+3.3}\pm 3.0$ nJy, respectively, where the first and second errors represent the statistical and systematic ones. The diffuse X-rays were attributed to be inverse Compton radiation by the synchrotron radio electrons scattering off the cosmic microwave background photons. This radio galaxy is the largest among those with lobes detected through inverse Compton X-ray emission. A comparison of the radio to X-ray fluxes yields the energy densities of electron and magnetic field as $u_e = (2.3 \pm 0.3 \pm 0.3) \times 10^{-13}$ ergs/cm3 and $u_m = (1.2_{-0.1}^{+0.2}\pm 0.2) \times 10^{-14}$ ergs/cm3, respectively. The galaxy is suggested to host a low luminosity nucleus with an absorption-corrected 2 -- 10 keV luminosity of $<2 \times 10^{42}$ ergs/s, together with a relatively weak radio core. The energetics in the west lobe of 3C 326 were compared with those of moderate radio galaxies with a size of $\sim 100$ kpc. The west lobe of 3C 326 is confirmed to agree with the correlations for the moderate radio galaxies, $u_e \propto D^{-2.2\pm0.4}$ and $u_m \propto D^{-2.4\pm0.4}$, where $D$ is their total physical size. This implies that the lobes of 3C 326 are still being energized by the jet, despite the current weakness of the nucleus.Comment: 11 pages, 10 figures, 6 tables, Accepted for ApJ (v706 issue