Results for "Griffith M. A. R"

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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
XAssist: A System for the Automation of X-ray Astrophysics AnalysisMar 05 2003XAssist is a NASA AISR-funded project for the automation of X-ray astrophysics, with emphasis on galaxies. It is nearing completion of its initially funded effort, and is working well for Chandra and ROSAT HRI data. Initial support for XMM-Newton data ... More
Bosonic Dirac Materials on a honeycomb antiferromagnetic Ising modelApr 12 2019Motivated by the recent proposal of Bosonic Dirac materials (BDM), we revisited the Ising model on a honeycomb lattice in the presence of the longitudinal and transverse fields. We apply linear spin-wave theory to obtain the magnon dispersion and its ... More
ASCA Observations of the Starburst-Driven Superwind Galaxy NGC 2146: Broad Band (0.6 - 9 keV) Spectral PropertiesOct 26 1998We report ASCA GIS and SIS observations of the nearby (D = 11.6 Mpc), nearly edge-on, starburst galaxy NGC 2146. These X-ray spectral data complement ROSAT PSPC and HRI imaging discussed by Armus et al., 1995. The broad band (0.6-9 keV) X-ray spectrum ... More
Complex X-ray spectral variability in Mkn 421 observed with XMM-NewtonApr 10 2002The bright blazar Mkn 421 has been observed four times for uninterrupted durations of ~ 9 - 13 hr during the performance verification and calibration phases of the XMM-Newton mission. The source was strongly variable in all epochs, with variability amplitudes ... 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
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
Resolving the X-ray Spectral Paradox: XMM-Newton Spectra of Faint Sources in the Lockman HoleJun 01 2001Using 100ks of XMM-Newton data on the Lockman Hole, we show how the X-ray background 'spectral paradox' is being resolved. We find the summed spectra of the Type I AGN, Type II AGN, and the unidentified objects. We conclude that the hard slope of the ... 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
Metal-insulator transition at B=0 in an ultra-low density ($r_{s}=23$) two dimensional GaAs/AlGaAs hole gasOct 12 1997We have observed a metal-insulator transition in an ultra-low density two dimensional hole gas formed in a high quality GaAs-AlGaAs heterostructure at B=0. At the highest carrier density studied ($p_{s}=2.2x10^{10} cm^{-2}, r_{s}=16$) the hole gas is ... 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
HI Emission and Absorption in the Southern Galactic Plane SurveyDec 15 2000We present preliminary results from the Southern Galactic Plane Survey (SGPS) Test Region and Parkes data. As part of the pilot project for the Southern Galactic Plane Survey, observations of a Test Region (325.5 deg < l < 333.5 deg; -0.5 deg < b < 3.5 ... 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
The Morphologically Divided Redshift Distribution of Faint GalaxiesJan 29 1999We have constructed a morphologically divided redshift distribution of faint field galaxies using a statistically unbiased sample of 196 galaxies brighter than I = 21.5 for which detailed morphological information (from the Hubble Space Telescope) as ... More
Probing the terminator region atmosphere of the Hot-Jupiter XO-1b with transmission spectroscopyFeb 12 2010We report here the first infrared spectrum of the hot-Jupiter XO-1b. The observations were obtained with NICMOS instrument onboard the Hubble Space Telescope during a primary eclipse of the XO-1 system. Near photon-noise-limited spectroscopy between 1.2 ... More
Evidence for a high energy curvature in the XMM-Newton spectrum of the ULX NGC1313 X-1Nov 03 2005ASCA X-ray spectra of many ULXs were described in terms of optically thick emission from hot (kT ~1-2keV) accretion disks, while recent XMM-Newton and Chandra observations have revealed a cool (kT ~0.2keV), soft X-ray excess emission from a number of ... More
X-ray Variability as a Probe of Advection-Dominated Accretion in Low-Luminosity AGNApr 29 1998As a class, LINERs and Low-Luminosity AGN tend to show little or no significant short-term variability (i.e., with time-scales less than a day). This is a marked break for the trend of increased variability in Seyfert 1 galaxies with decreased luminosity. ... More
Magnetic field induced charge redistribution in disordered graphene double quantum dotsMay 07 2015We have studied the transport properties of a large graphene double quantum dot under the influence of background disorder potential and magnetic field. At low temperatures, the evolution of the charge-stability diagram as a function of B-field is investigated ... More
Supershells as Molecular Cloud Factories: Parsec Resolution Observations of HI and 12CO(J=1-0) in GSH 287+04-17 and GSH 277+00+36Dec 24 2010We present parsec-scale resolution observations of the atomic and molecular ISM in two Galactic supershells, GSH 287+04-17 and GSH 277+00+36. HI synthesis images from the Australia Telescope Compact Array are combined with 12CO(J=1-0) data from the NANTEN ... More
The Supershell-Molecular Cloud Connection in the Milky Way and BeyondSep 30 2012The role of large-scale stellar feedback in the formation of molecular clouds has been investigated observationally by examining the relationship between HI and 12CO(J=1-0) in supershells. Detailed parsec-resolution case studies of two Milky Way supershells ... 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
Quasi Periodic Oscillations and Strongly Comptonized X-ray emission from Holmberg IX X-1Feb 21 2006Feb 21 2006We report the discovery of a 200mHz quasi-periodic oscillation (QPO) in the X-ray emission from a bright ultra-luminous X-ray source (ULX) Holmberg IX X-1 using a long XMM-Newton observation. The QPO has a centroid at 202.5_{-3.8}^{+4.9}mHz, a coherence ... More
Linked evolution of gas and star formation in galaxies over cosmic historyJun 03 2008We compare the cosmic evolution of star formation rates in galaxies with that of their neutral hydrogen densities. We highlight the need for neutral hydrogen to be continually replenished from a reservoir of ionized gas to maintain the observed star formation ... More
Host galaxy morphologies of X-ray selected AGN: assessing the significance of different black hole fueling mechanisms to the accretion density of the Universe at z~1Apr 23 2009We use morphological information of X-ray selected AGN hosts to set limits on the fraction of the accretion density of the Universe at z~1 that is not likely to be associated with major mergers. Deep X-ray observations are combined with high resolution ... More
High velocity clouds in the Galactic All Sky Survey I. CatalogueSep 16 2013We present a catalogue of high-velocity clouds (HVCs) from the Galactic All Sky Survey (GASS) of southern-sky neutral hydrogen, which has 57 mK sensitivity and 1 km/s velocity resolution and was obtained with the Parkes Telescope. Our catalogue has been ... More
Early warning signals in plant disease outbreaksFeb 21 2018Dec 14 2018Summary 1. Infectious disease outbreaks in plants threaten ecosystems, agricultural crops and food trade. Currently, several fungal diseases are affecting forests worldwide, posing a major risk to tree species, habitats and consequently ecosystem decay. ... 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 Chandra COSMOS Legacy Survey: Compton Thick AGN at high redshiftMar 22 2018Sep 26 2018The existence of a large population of Compton thick (CT, $N_{H}>10^{24} cm^{-2}$) AGN is a key ingredient of most Cosmic X-ray background synthesis models. However, direct identification of these sources, especially at high redshift, is difficult due ... More
Antisymmetry in the Faraday Rotation Sky Caused by a Nearby Magnetized BubbleNov 01 2010Rotation measures of pulsars and extragalactic point sources have been known to reveal large-scale antisymmetries in the Faraday rotation sky with respect to the Galactic plane and halo that have been interpreted as signatures of the mean magnetic field ... More
Supershells in the Multi-Phase Milky Way: Insights from HI Synthesis Imaging and CO SurveysJun 15 2009We present new parsec-scale resolution data from a multi-phase study of the ISM in the walls of Galactic supershells. HI synthesis images and CO survey data reveal a wealth of substructure, including dense-tipped fingers and extended molecular clouds ... More
Weak Gravitational Lensing around Field Galaxies in HST Survey ImagesMay 17 1996Using data from the HST Medium Deep Survey, a long-term Key Project, together with generically similar archived data, we have discovered evidence for weak gravitational `shear' of background field galaxies (I = 22 -- 26) in the vicinity of isolated, foreground ... 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
Cosmic microwave background constraints on the epoch of reionizationDec 07 1998Jan 10 2001We use a compilation of cosmic microwave anisotropy data to constrain the epoch of reionization in the Universe, as a function of cosmological parameters. We consider spatially-flat cosmologies, varying the matter density $\Omega_0$ (the flatness being ... 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
Compact HI clouds at high forbidden velocities in the inner GalaxySep 23 2005The VLA Galactic Plane Survey (VGPS) of the first Galactic quadrant was searched for HI emission with velocities well above the maximum velocity allowed by Galactic rotation. A sample of 17 small fast-moving clouds was identified. The distribution of ... More
Rotation Measures of Extragalactic Sources Behind the Southern Galactic Plane: New Insights into the Large-Scale Magnetic Field of the Inner Milky WayApr 03 2007We present new Faraday rotation measures (RMs) for 148 extragalactic radio sources behind the southern Galactic plane (253o < l < 356o, |b| < 1.5o), and use these data in combination with published data to probe the large-scale structure of the Milky ... More
Magnetic Field Structure of the Large Magellanic Cloud from Faraday Rotation Measures of Diffuse Polarized EmissionSep 05 2012We present a study of the magnetic field of the Large Magellanic Cloud (LMC), carried out using diffuse polarized synchrotron emission data at 1.4 GHz acquired at the Parkes Radio Telescope and the Australia Telescope Compact Array. The observed diffuse ... More
Surface spin-flop phases and bulk discommensurations in antiferromagnetsDec 09 1996Phase diagrams as a function of anisotropy D and magnetic field H are obtained for discommensurations and surface states for a model antiferromagnet in which $H$ is parallel to the easy axis. The surface spin-flop phase exists for all $D$. We show that ... More
Quantitative Morphology of Moderate Redshift Galaxies : How Many Peculiars are There ?Sep 10 1996The advent of the Hubble Space Telescope (HST) has provided images of galaxies at moderate and high redshifts and changed the scope of galaxy morphologies considerably. It is evident that the Hubble Sequence requires modifications in order to incorporate ... More
The Consequences of the Cosmic Star-Formation Rate: X-ray Number CountsAug 18 2001We discuss the observable consequences for the detection of galaxies in the X-ray bandpass resulting from a peak in the cosmic star-formation rate at a redshift > 1. Following White & Ghosh, we assume a large evolution in the X-ray/B luminosity ratio ... 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
Direct Imaging of Coherent Quantum Transport in Graphene HeterojunctionsAug 08 2014We fabricate a graphene p-n-p heterojunction and exploit the coherence of weakly-confined Dirac quasiparticles to resolve the underlying scattering potential using low temperature scanning gate microscopy. The tip-induced perturbation to the heterojunction ... More
Tracing dense and diffuse neutral hydrogen in the halo of the Milky WayNov 25 2016Nov 28 2016We have combined observations of Galactic high-velocity HI from two surveys: a very sensitive survey from the Green Bank 140ft Telescope with limited sky coverage, and the less sensitive but complete Galactic All Sky Survey from the 64m Parkes Radio Telescope. ... More
Compressibility measurements of quasi-one-dimensional quantum wiresAug 05 2011We report measurements of the compressibility of a one-dimensional (1D) quantum wire, defined in the upper well of a GaAs/AlGaAs double quantum well heterostructure. A wire defined simultaneously in the lower well probes the ability of the upper wire ... More
Tracing dense and diffuse neutral hydrogen in the halo of the Milky WayNov 25 2016We have combined observations of Galactic high-velocity HI from two surveys: a very sensitive survey from the Green Bank 140ft Telescope with limited sky coverage, and the less sensitive but complete Galactic All Sky Survey from the 64m Parkes Radio Telescope. ... 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
An Interaction of a Magellanic Leading Arm High Velocity Cloud with the Milky Way DiskDec 14 2007The Leading Arm of the Magellanic System is a tidally formed HI feature extending $\sim 60\arcdeg$ from the Magellanic Clouds ahead of their direction of motion. Using atomic hydrogen (HI) data from the Galactic All Sky-Survey (GASS), supplemented with ... More
Evidence for chimney breakout in the Galactic supershell GSH 242-03+37Oct 11 2005We present new high resolution neutral hydrogen (H I) images of the Galactic supershell GSH 242-03+37. These data were obtained with the Parkes Radiotelescope as part of the Galactic All-Sky Survey (GASS). GSH 242-03+37 is one of the largest and most ... More
Observed Asymptotic Differences in Energies of Stable and Minimal Point Configurations on $\mathbb{S}^2$ and the Role of DefectsJul 01 2013Oct 02 2013Observations suggest that configurations of points on a sphere that are stable with respect to a Riesz potential distribute points uniformly over the sphere. Further, these stable configurations have a local structure that is largely hexagonal. Minimal ... 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
Multiplexed Charge-locking Device for Large Arrays of Quantum DevicesAug 12 2014Aug 21 2014We present a method of forming and controlling large arrays of gate-defined quantum devices. The method uses a novel, on-chip, multiplexed charge-locking system and helps to overcome the restraints imposed by the number of wires available in cryostat ... More
Detailed Shape and Evolutionary Behavior of the X-ray Luminosity Function of Active Galactic NucleiFeb 28 2015Mar 09 2015We construct the rest-frame 2--10 keV intrinsic X-ray luminosity function of Active Galactic Nuclei (AGNs) from a combination of X-ray surveys from the all-sky Swift BAT survey to the Chandra Deep Field-South. We use ~3200 AGNs in our analysis, which ... More
Polarization Gradient Study of Interstellar Medium Turbulence Using The Canadian Galactic Plane SurveyDec 13 2016We have investigated the magneto-ionic turbulence in the interstellar medium through spatial gradients of the complex radio polarization vector in the Canadian Galactic Plane Survey (CGPS). The CGPS data cover 1300 square-degrees, over the range ${53^{\circ}}\leq{\ell}\leq{192^{\circ}}$, ... More
A study of the optical and polarisation properties of InGaN/GaN multiple quantum wells grown on a-plane and m-plane GaN substratesNov 11 2016In this paper we report on a comparative study of the low temperature emission and polarisation properties of InGaN/GaN quantum wells (QWs) grown on nonpolar a-plane and m-plane free-standing bulk GaN substrates where the In content varied from 0.14 to ... More
Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanetsDec 14 2013Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H2O, CH4, CO, and CO2) in a few exoplanets. ... 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
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
Associated Spectral and Temporal State Transition of the bright ULX NGC1313 X-1May 23 2009(Abridged) Stellar mass black hole X-ray binaries exhibit X-ray spectral states which also have distinct and characteristic temporal properties. These states are believed to correspond to different accretion disk geometries. We present analysis of two ... More
The Chandra Deep Field North Survey. VI. The Nature of the Optically Faint X-ray Source PopulationJul 23 2001Sep 01 2001We provide constraints on the nature of the optically faint (I>=24) X-ray source population from a 1 Ms Chandra exposure of a 8.4x8.4 arcmin region containing the Hubble Deep Field North. We detect 47 (2,400 deg^-2) optically faint X-ray sources. The ... 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
Magnetic Fields and Ionized Gas in the inner Galaxy: An Outer Scale for Turbulence and the Possible Role of HII RegionsMar 29 2004We present an analysis of rotation measure (RM) fluctuations from the Test Region of the Southern Galactic Plane Survey (SGPS), along with emission measure (EM) fluctuations in the same field taken from the Southern H-Alpha Sky Survey Atlas. The structure ... 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
The Life Cycle of the Central Molecular Zone. I: Inflow, Star Formation, and WindsMay 03 2019We present a study of the gas cycle and star formation history in the central 500 pc of the Milky Way, known as Central Molecular Zone (CMZ). Through hydrodynamical simulations of the inner 4.5 kpc of our Galaxy, we follow the gas cycle in a completely ... More
New Constraints on the Galactic Halo Magnetic Field using Rotation Measures of Extragalactic Sources Towards the Outer GalaxyJun 14 2012We present a study of the Milky Way disk and halo magnetic field, determined from observations of Faraday rotation measure (RM) towards 641 polarized extragalactic radio sources in the Galactic longitude range 100-117 degs, within 30 degs of the Galactic ... More
An investigation of the origin of soft X-ray excess emission from Narrow-line Seyfert 1 galaxies Akn564 and Mrk1044Sep 12 2007We investigate the origin of the soft X-ray excess emission from narrow-line Seyfert 1 galaxies Akn564 and Mrk1044 using XMM-Newton observations. We find clear evidence for time delays between the soft and hard X-ray emission from Akn564 based on a 100ks ... More
X-ray emission from active galactic nuclei with intermediate mass black holesJan 23 2008We present a systematic X-ray study of eight AGNs with intermediate mass black holes (M_BH 8-95x10^4 Msun) based on 12 XMM-Newton observations. The sample includes the two prototype AGNs in this class - NGC4395 and POX52 and six other AGNs discovered ... More
The Southern Galactic Plane Survey: Polarized Radio Continuum Observations and AnalysisSep 01 2006The Southern Galactic Plane Survey (SGPS) is a radio survey in the 21 cm H I line and in 1.4 GHz full-polarization continuum, observed with the Australia Telescope Compact Array and the Parkes 64m single dish telescope. The survey spans a Galactic longitude ... 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
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
Variability monitoring of the hydroxyl maser emission in G12.889+0.489Jul 04 2012Through a series of observations with the Australia Telescope Compact Array we have monitored the variability of ground-state hydroxyl maser emission from G12.889+0.489 in all four Stokes polarisation products. These observations were motivated by the ... More
Faraday Tomography of the North Polar Spur: Constraints on the distance to the Spur and on the Magnetic Field of the GalaxyAug 17 2015We present radio continuum and polarization images of the North Polar Spur (NPS) from the Global Magneto-Ionic Medium Survey (GMIMS) conducted with the Dominion Radio Astrophysical Observatory 26-m Telescope. We fit polarization angle versus wavelength ... More
A Complete Atlas of HI Absorption toward HII Regions in the Southern Galactic Plane Survey (SGPS1)Feb 05 2014We present a complete catalog of H I emission and absorption spectrum pairs, toward H II regions, detectable within the boundaries of the Southern Galactic Plane Survey (SGPS I), a total of 252 regions. The catalog is presented in graphical, numerical ... More
Vortex detection and quantum transport in mesoscopic graphene Josephson junction arraysApr 03 2014Jun 21 2015We investigate mesoscopic Josephson junction arrays created by patterning superconducting disks on monolayer graphene, concentrating on the high-$T/T_c$ regime of these devices and the phenomena which contribute to the superconducting glass state in diffusive ... 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
First Results from the XMM-Newton Observation in the Groth-Westphal Survey Strip RegionJun 01 2001We present the first results of the XMM-Newton observation on the Groth-Westphal Strip Field. The scheduled exposure time was 70 [ks]. We first analyzed about 50 [ks] of calibrated and cleaned EPIC-PN data, which were the only ones we could successfully ... More
Characterization of protonated and deuterated Tetra-Phenyl Butadiene Film in a Polystyrene MatrixFeb 13 2013We study the effect of deuteration and annealing on the fluorescence spectrum shape and VUV to visible conversion efficiency of TPB films in a polystyrene matrix with input light from 120 to 220 nm. We observed no discernible difference in the fluorescence ... 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
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
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
Time lags in Narrow-line Seyfert 1 galaxies and the origin of their soft excess emissionSep 12 2007The origin of soft X-ray excess emission from type 1 active galactic nuclei has remained a major problem for the last two decades. It has not been possible to distinguish alternative models for the soft excess emission despite the excellent data quality ... More
The Chandra COSMOS Legacy Survey: Clustering of X-ray selected AGN at 2.9<z<5.5 using photometric redshift Probability Distribution FunctionsSep 08 2016Sep 16 2016We present the measurement of the projected and redshift space 2-point correlation function (2pcf) of the new catalog of Chandra COSMOS-Legacy AGN at 2.9$\leq$z$\leq$5.5 ($\langle L_{bol} \rangle \sim$10$^{46}$ erg/s) using the generalized clustering ... 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
Calibrating the HISA temperature: Measuring the temperature of the Riegel-Crutcher cloudMay 24 2018HI self absorption (HISA) clouds are clumps of cold neutral hydrogen (HI) visible in front of warm background gas, which makes them ideal places to study the properties of the cold atomic component of the interstellar medium (ISM). The Riegel-Crutcher ... More
Applying experimental constraints to a one-dimensional model for BiS2 superconductivityAug 19 2015Recent ARPES measurements [Phys. Rev. B 92, 041113 (2015)] have confirmed the one-dimensional character of the electronic structure of CeO0.5F0.5BiS2, a representative of BiS2-based superconductors. In addition, several members of this family present ... More
Radio Synchrotron Fluctuation Statistics as a Probe of Magnetized Interstellar TurbulenceMar 09 2016We investigate how observations of synchrotron intensity fluctuations can be used to probe the sonic and Alfv\'enic Mach numbers of interstellar turbulence, based on mock observations performed on simulations of magnetohydrodynamic turbulence. We find ... More
Detection of a Coherent Magnetic Field in the Magellanic Bridge through Faraday RotationJan 21 2017We present an investigation into the magnetism of the Magellanic Bridge, carried out through the observation of Faraday rotation towards 167 polarized extragalactic radio sources spanning the continuous frequency range of 1.3 - 3.1 GHz with the Australia ... 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
Molecular Clouds in Supershells: A Case Study of Three Objects in the Walls of GSH 287+04-17 and GSH 277+00+36Aug 19 2011We present an in-depth case study of three molecular clouds associated with the walls of the Galactic supershells GSH 287+04-17 and GSH 277+00+36. These clouds have been identified in previous work as examples in which molecular gas is either being formed ... More
Cryogenic magnetic coil and superconducting magnetic shield for neutron electric dipole moment searchesJan 11 2017Jun 21 2017A magnetic coil operated at cryogenic temperatures is used to produce spatial, relative field gradients below 6 ppm/cm, stable for several hours. The apparatus is a prototype of the magnetic components for a neutron electric dipole moment (nEDM) search, ... More