Searching Arxiv, refresh for possibly better results.
Results for "Griffith M. A. R"
total 376179took 0.26s
Machine learning topological phases in real spaceJan 07 2019Feb 13 2019We develop a supervised machine learning algorithm that is able to learn topological phases for finite systems in real space. The algorithm employs diagonalization in real space together with any supervised learning algorithm to learn topological phases ... More Hard X-ray Variability in M82: Evidence for a Nascent AGN?Mar 24 1999We report on the detection of hard (2-10 keV) X-ray variability in the starburst galaxy M82 over the course of 9 ASCA observations. Long-term variability occurred on a time scale of days, with a change in flux by a factor of up to 4, corresponding to ... More Thermodynamic Limit for Dipolar MediaDec 15 2000We prove existence of a shape and boundary condition independent thermodynamic limit for fluids and solids of identical particles with electric or magnetic dipole moments. Our result applies to fluids of hard core particles, to dipolar soft spheres and ... More Thermodynamic Limit for Polydisperse FluidsDec 15 2000We examine the thermodynamic limit of fluids of hard core particles that are polydisperse in size and shape. In addition, particles may interact magnetically. Free energy of such systems is a random variable because it depends on the choice of particles. ... More The effect of reionization on the COBE normalizationJan 10 2001We point out that the effect of reionization on the microwave anisotropy power spectrum is not necessarily negligible on the scales probed by COBE. It can lead to an upward shift of the COBE normalization by more than the one-sigma error quoted ignoring ... More MHD Code Using Multi Graphical Processing Units: SMAUG+Oct 14 2017This paper introduces the Sheffield Magnetohydrodynamics Algorithm Using GPUs (SMAUG+), an advanced numerical code for solving magnetohydrodynamic (MHD) problems, using multi-GPU systems. Multi-GPU systems facilitate the development of accelerated codes ... More Ground-based NIR emission spectroscopy of HD189733bApr 04 2011Sep 28 2011We investigate the K and L band dayside emission of the hot-Jupiter HD 189733b with three nights of secondary eclipse data obtained with the SpeX instrument on the NASA IRTF. The observations for each of these three nights use equivalent instrument settings ... More Machine learning topological phases in real spaceJan 07 2019We develop a supervised machine learning algorithm that is able to learn topological phases for finite systems in real space. The algorithm employs diagonalization in real space together with any supervised learning algorithm to learn topological phases ... More GSH23.0-0.7+117, a neutral hydrogen shell in the inner GalaxyFeb 19 2004GSH23.0-0.7+117 is a well-defined neutral hydrogen shell discovered in the VLA Galactic Plane Survey (VGPS). Only the blueshifted side of the shell was detected. The expansion velocity and systemic velocity were determined through the systematic behavior ... More The Southern Galactic Plane Survey: The Test RegionDec 13 2000The Southern Galactic Plane Survey (SGPS) is a project to image the HI line emission and 1.4 GHz continuum in the fourth quadrant of the Milky Way at high resolution using the Australia Telescope Compact Array (ATCA) and the Parkes Radio Telescope. In ... More Two Large HI Shells in the Outer Galaxy near l=279 degreesMar 11 2000As part of a survey of HI 21-cm emission in the Southern Milky Way, we have detected two large shells in the interstellar neutral hydrogen near l=279 deg. The center velocities are +36 and +59 km/s, which puts the shells at kinematic distances of 7 and ... More Supergiant Shells and Molecular Cloud Formation in the LMCNov 29 2012We investigate the influence of large-scale stellar feedback on the formation of molecular clouds in the Large Magellanic Cloud (LMC). Examining the relationship between HI and 12CO(J=1-0) in supergiant shells (SGSs), we find that the molecular fraction ... More Kramers' doublet ground state in topological Kondo insulatorsSep 16 2018We consider the simplest variant of a Kondo insulator where a doublet of localized $f$-electrons hybridizes with spin-degenerate conduction electrons. We analyse the symmetries of $f$-orbitals involved in the hybridization and point out that the effective ... More XMM - Newton observations of Markarian 421Nov 09 2000The BL Lac object Mrk 421 was observed on May 25, 2000 during the XMM - Newton CAL/PV phase. The high throughput of the X-ray telescopes and the spectral capabilities of the instruments allow an uninterrupted temporal and spectral study of the source ... More The VLA Galactic Plane SurveyMay 17 2006The VLA Galactic Plane Survey (VGPS) is a survey of HI and 21-cm continuum emission in the Galactic plane between longitude 18 degrees 67 degr. with latitude coverage from |b| < 1.3 degr. to |b| < 2.3 degr. The survey area was observed with the Very Large ... More Galaxy Morphology Without Classification: Self Organising MapsApr 01 1997We examine a general framework for visualizing datasets of high (> 2) dimensionality, and demonstrate it using the morphology of galaxies at moderate redshifts. The distributions of various populations of such galaxies are examined in a space spanned ... More Dynamic Evolution of Microscopic Wet Cracking NoisesNov 14 2015Sep 06 2016Characterizing the interaction between water and microscopic defects is one of the long-standing challenges in understanding a broad range of cracking processes. Different physical aspects of microscopic events, driven or influenced by water, have been ... More Wi-Fi Sensing: Applications and ChallengesJan 02 2019Wi-Fi technology has strong potentials in indoor and outdoor sensing applications, it has several important features which makes it an appealing option compared to other sensing technologies. This paper presents a survey on different applications of Wi-Fi ... More Finite Size Effects in Topological Quantum Phase TransitionsMar 02 2019The interest in the topological properties of materials brings into question the problem of topological phase transitions. As a control parameter is varied, one may drive a system through phases with different topological properties. What is the nature ... More Excited-state hydroxyl maser polarimetry: Who ate all the πs?Apr 27 2015We present polarimetric maser observations with the Australia Telescope Compact Array (ATCA) of excited-state hydroxyl (OH) masers. We observed 30 fields of OH masers in full Stokes polarization with the Compact Array Broadband Backend (CABB) at both ... More The Outer Disk of the Milky Way Seen in 21-cm AbsorptionJan 08 2009Three recent surveys of 21-cm line emission in the Galactic plane, combining single dish and interferometer observations to achieve resolution of 1 arcmin to 2 arcmin, 1 km/s, and good brightness sensitivity, have provided some 650 absorption spectra ... More The Exceptionally Luminous Type II-L SN 2008esAug 18 2008Sep 03 2008We report on our early photometric and spectroscopic observations of the extremely luminous Type II supernova (SN) 2008es. With an observed peak optical magnitude of m_V = 17.8 and at a redshift z = 0.213, SN 2008es had a peak absolute magnitude of M_V ... More The type IIb SN 2008ax: spectral and light curve evolutionMay 13 2008Jun 19 2008We present spectroscopy and photometry of the He-rich supernova (SN) 2008ax. The early-time spectra show prominent P-Cygni H lines, which decrease with time and disappear completely about two months after the explosion. In the same period He I lines become ... More Radio Polarimetry in the Southern Galactic Plane SurveyOct 05 2003We present radio polarimetric observations of a test region for the Southern Galactic Plane Survey (SGPS), a radio survey in the Galactic plane in HI and polarized continuum at 1.4 GHz with the Australia Telescope Compact Array (ATCA) and the Parkes 64m ... More The Extended X-ray Halo of the Crab-like SNR G21.5-0.9Nov 13 2000Recent XMM-Newton observations reveal an extended (150") low-surface brightness X-ray halo in the supernova remnant G21.5-0.9. The near circular symmetry, the lack of any limb brightening and the non-thermal spectral form, all favour an interpretation ... More GMIMS: The Global Magneto-Ionic Medium SurveyDec 12 2008The Global Magneto-Ionic Medium Survey (GMIMS) is a project to map the diffuse polarized emission over the entire sky, Northern and Southern hemispheres, from 300 MHz to 1.8 GHz. With an angular resolution of 30 - 60 arcmin and a frequency resolution ... More The broad-band X-ray spectrum of Mrk 3Apr 23 1998We have used non-simultaneous Ginga, ASCA and ROSAT observations to investigate the complex X-ray spectrum of the Seyfert 2 galaxy Mrk 3. We find that the composite spectrum can be well described in terms of a heavily cut-off hard X-ray continuum, iron ... More Iron Features in the XMM-Newton spectrum of NGC 4151Feb 05 2002We present a detailed analysis of the hard X-ray (>2.5 keV) EPIC spectra from the first observations of NGC 4151 made by XMM-Newton. We fit the spectra with a model consisting of a power-law continuum modified by line-of-sight absorption (arising in both ... More Observation of a Fifth of the Electron ChargeJan 17 1999We report the observation of quasi-particles with a charge q=e/5 detected by shot noise measurements in the 2/5 conducting channel (filling factor 2/5). This is in agreement with previous measurements that showed that the current in the lower, 1/3, channel ... More The complex soft X-ray spectrum of NGC 4151Jan 26 2004We present a detailed analysis of the complex soft X-ray spectrum of NGC 4151 measured by the RGS instruments aboard XMM-Newton. The XMM-Newton RGS spectra demonstrate that the soft X-ray emission is extremely rich in X-ray emission lines and radiative ... More RXTE monitoring observations of Markarian 3Mar 05 1999We present Rossi X-ray Timing Explorer, monitoring observations of the Seyfert 2 galaxy Markarian 3 spanning a 200 day period during which time the source flux varied by a factor $\sim 2$ in the 4-20 keV bandpass. In broad agreement with earlier Ginga ... More High resolution polarimetry of the inner GalaxyNov 06 2001We present our results from the Southern Galactic Plane Survey, an effort to map the fourth quadrant of the Milky Way in linear polarization at a frequency of 1.4 GHz and at a resolution of 1-2 arcmin. These data are a powerful probe of both the turbulence ... More HI Shells Behind the CoalsackAug 04 2001We report the discovery of two new large HI shells in the direction of the Coalsack nebula. Both shells were observed with the Parkes Radio Telescope as part of the Southern Galactic Plane Survey. The largest shell, GSH 304-00-12, is at a distance of ... More A Neutral Hydrogen Self-Absorption Cloud in the SGPSAug 26 2003Using data from the Southern Galactic Plane Survey (SGPS) we analyze an HI self-absorption cloud centered on l = 318.0 deg, b = -0.5 deg, and velocity, v = -1.1 km/s. The cloud was observed with the Australia Telescope Compact Array (ATCA) and the Parkes ... More Fitting Together the HI Absorption and Emission in the SGPSNov 13 2002In this paper we study 21-cm absorption spectra and the corresponding emission spectra toward bright continuum sources in the test region (326deg< l < 333 deg) of the Southern Galactic Plane Survey. This survey combines the high resolution of the Australia ... More "Missing Link" Clouds in the Southern Galactic Plane SurveyMar 24 2005We present an automated routine to search for HI self-absorption features within the Southern Galactic Plane Survey (SGPS). The data were taken with the Australia Telescope Compact Array (ATCA) and the Parkes Radio Telescope and encompass 3 deg by 105 ... More The Galactic Distribution of Large HI ShellsJun 20 2002We report the discovery of nineteen new HI shells in the Southern Galactic Plane Survey (SGPS). These shells, which range in radius from 40 pc to 1 kpc, were found in the low resolution Parkes portion of the SGPS dataset, covering Galactic longitudes ... More X-ray Fluctuation Power Spectral Densities of Seyfert 1 GalaxiesMar 12 2003Mar 18 2003By combining complementary monitoring observations spanning long, medium and short time scales, we have constructed power spectral densities (PSDs) of six Seyfert~1 galaxies. These PSDs span $\gtrsim$4 orders of magnitude in temporal frequency, sampling ... More Ferromagnetic Properties of ZrZn$_2$Oct 14 2005The low Curie temperature (T_C approx 28K) and small ordered moment (M_0 approx 0.17 mu_B f.u.^-1) of ZrZn2 make it one of the few examples of a weak itinerant ferromagnet. We report results of susceptibility, magnetization, resistivity and specific heat ... More