Results for "J. I. Brown"

total 221121took 0.12s
AGN-Galaxy Clustering with the Panoramic Deep FieldsJan 29 2002The AGN-galaxy cross-correlation function of radio-quiet AGN and radio galaxies has been measured with the Panoramic Deep Fields. Colour selection criteria and photometric redshifts have been used to significantly increase the signal-to-noise of the angular ... More
Optimal Graphs for Independence and $k$-Independence PolynomialsOct 09 2017The independence polynomial $I(G,x)$ of a finite graph $G$ is the generating function for the sequence of the number of independent sets of each cardinality. We investigate whether, given a fixed number of vertices and edges, there exists optimally-least ... More
Optimal Domination PolynomialsApr 12 2019Let $G$ be a graph on $n$ vertices and $m$ edges and $D(G,x)$ the domination polynomial of $G$. In this paper we completely characterize the values of $n$ and $m$ for which optimal graphs exist for domination polynomials. We also show that there does ... More
The Halo Occupation Distribution of HI from 21cm Intensity Mapping at Moderate RedshiftsDec 11 2009The spatial clustering properties of HI galaxies can be studied using the formalism of the halo occupation distribution (HOD). The resulting parameter constraints describe properties like gas richness verses environment. Unfortunately, clustering studies ... More
On the Reliability Roots of Simplicial Complexes and MatroidsSep 27 2018Assume that the vertices of a graph $G$ are always operational, but the edges of $G$ fail independently with probability $q \in[0,1]$. The \emph{all-terminal reliability} of $G$ is the probability that the resulting subgraph is connected. The all-terminal ... More
The Protostellar Jet Model of Chondrule FormationFeb 17 2006A chondrule formation theory is presented where the chondrule formation zone is located within 0.1 AU of the protosun. This hot, optically thick, inner zone of the solar accretion disk is coincident with the formation region of the protosolar jet. The ... More
Vacuum Arc Ion SourcesApr 02 2014The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include ... More
The Evolution of Radio Galaxies at Intermediate RedshiftFeb 09 2001We describe a new estimate of the radio galaxy 1.4 GHz luminosity function and its evolution at intermediate redshifts (z~0.4). Photometric redshifts and color selection have been used to select Bj<23.5 early-type galaxies from the Panoramic Deep Fields, ... More
The Clustering of AGN and Galaxies at Intermediate RedshiftMar 16 2001Galaxies in the environments of 69 0.2<z<0.7 UBR selected AGN have been imaged to Bj~23.5. By applying photometric redshifts and color selection criteria to the galaxy catalogue, the AGN-galaxy cross-correlation function has been measured as a function ... More
The Clustering of Colour Selected GalaxiesMay 16 2000We present measurements of the angular correlation function of galaxies selected from a B_J=23.5 multicolour survey of two 5 degree by 5 degree fields located at high galactic latitudes. The galaxy catalogue of approximately 400,000 galaxies is comparable ... More
The Rarity of Star Formation in Brightest Cluster Galaxies as Measured by WISEJul 21 2014We present the mid-infrared (IR) star formation rates of 245 X-ray selected, nearby (z<0.1) brightest cluster galaxies (BCGs). A homogeneous and volume limited sample of BCGs was created by X-ray selecting clusters with L_x > 1x10^44 erg/s. The Wide-Field ... More
O_e(G) is a free module over O(G)Jul 28 2000We show that the quantised function algebra O_e(G) of a simply-connected semisimple algebraic group G at a root of unity is a free module over the subring isomorphic to O(G).
Recalibrating the Wide-field Infrared Survey Explorer (WISE) W4 FilterNov 20 2014We present a revised effective wavelength and photometric calibration for the Wide-field Infrared Survey Explorer (WISE) W4 band, including tests of empirically motivated modifications to its pre-launch laboratory-measured relative system response curve. ... More
The Slow Growth of Massive Galaxies in Rapidly Growing Dark Matter HalosJan 14 2010In cold dark matter cosmologies, the most massive dark matter halos are predicted to undergo rapid growth at z<1. While there is the expectation that massive galaxies will also rapidly grow via merging, recent observational studies conclude that the stellar ... More
Optical Spectroscopy of Embedded Young Stars in the Taurus-Auriga Molecular CloudApr 18 1998This paper describes the first optical spectroscopic survey of class I sources (also known as embedded sources and protostars) in the Taurus-Auriga dark cloud. We detect 10 of the 24 known class I sources in the cloud at 5500-9000 A. All detected class ... More
Slow Galaxy Growth within Rapidly Growing Dark Matter HalosSep 17 2009In cold dark matter cosmologies, the most massive dark matter halos undergo rapid growth between a redshift of z=1 and z=0, corresponding to the past 7 billion years of cosmic time. There is thus an expectation that the stellar masses of the most massive ... More
XMM-Newton X-ray study of early type stars in the Carina OB1 associationNov 22 2007X-ray properties of the stellar population in the Carina OB1 association are examined with special emphasis on early-type stars. Their spectral characteristics provide some clues to understanding the nature of X-ray formation mechanisms in the winds of ... More
Homotopies and automorphisms of crossed modules of groupoidsAug 16 2000Dec 10 2001We give a detailed description of the structure of the actor 2-crossed module related to the automorphisms of a crossed module of groupoids. This generalises work of Brown and Gilbert for the case of crossed modules of groups, and part of this is needed ... More
Microquasar Observations with MERLINDec 30 2004A series of observations of microquasar GRS1915+105 were made by the MERLIN telescope array in the spring of 2003 at 18 cm. The images show polarization in the jet components, with two epochs displaying Faraday rotation of about 2500 rad/m2. This effect ... More
Photometric redshifts for the next generation of deep radio continuum surveys - II. Gaussian processes and hybrid estimatesDec 12 2017Apr 12 2018Building on the first paper in this series (Duncan et al. 2018), we present a study investigating the performance of Gaussian process photometric redshift (photo-z) estimates for galaxies and active galactic nuclei detected in deep radio continuum surveys. ... More
Rays, modes, wavefield structure and wavefield stabilityDec 19 2003Mar 16 2004Sound propagation is considered in range-independent environments and environments consisting of a range-independent background on which a weak range-dependent perturbation is superimposed. Recent work on propagation of both types of environment, involving ... More
Meteoroid structure and ablation implications from multiple maxima meteor light curvesFeb 24 2014The Canadian Automated Meteor Observatory (CAMO) detects occasional meteors with two maxima in the image intensified CCD based light curves. We report early results from an analysis of 21 of these events. Most of these events show qualitatively similar ... More
On the Lagrangian Dynamics of Atmospheric Zonal Jets and the Permeability of the Stratospheric Polar VortexMay 18 2006The Lagrangian dynamics of zonal jets in the atmosphere are considered, with particular attention paid to explaining why, under commonly encountered conditions, zonal jets serve as barriers to meridional transport. The velocity field is assumed to be ... More
Zonal Jets as Transport Barriers in Planetary AtmospheresMar 19 2008The connection between transport barriers and potential vorticity (PV) barriers in PV-conserving flows is investigated with a focus on zonal jets in planetary atmospheres. A perturbed PV-staircase model is used to illustrate important concepts. This flow ... More
The ultraviolet-infrared color-magnitude relation of star-forming galaxiesNov 14 2018In this note we identify and characterize the ultraviolet-infrared color-magnitude relation of star-forming galaxies. The ultraviolet to mid-infrared flux ratios of star-forming galaxies span over two orders of magnitude and show a clear dependence on ... More
Multiple Mechanisms Quench Passive Spiral GalaxiesOct 30 2017We examine the properties of a sample of 35 nearby passive spiral galaxies in order to determine their dominant quenching mechanism(s). All five low mass ($\textrm{M}_{\star} < 1 \times 10^{10} \textrm{M}_{\odot}$) passive spiral galaxies are located ... More
The Clustering Of Galaxies Around Radio-Loud AGNsMay 13 2013We examine the hypothesis that mergers and close encounters between galaxies can fuel AGNs by increasing the rate at which gas accretes towards the central black hole. We compare the clustering of galaxies around radio-loud AGNs with the clustering around ... More
Magnetic moments of the 2${^+_1}$ states around $^{132}$SnNov 25 2004Development of neutron-rich radioactive beams at the HRIBF facility has stimulated experimental and theoretical activity in heavy Sn and Te isotopes. Recently, the g-factor of the first 2$^+$ state in $^{132}$Te has been measured. We report here new shell-model ... More
The Many Assembly Histories of Massive Void Galaxies as Revealed by Integral Field SpectroscopyMar 21 2016We present the first detailed integral field spectroscopy study of nine central void galaxies with M*>10^10 Msun using the Wide Field Spectrograph (WiFeS) to determine how a range of assembly histories manifest themselves in the current day Universe. ... More
The evolution and star formation of dwarf galaxies in the Fornax ClusterJun 21 2001We present the results of a spectroscopic survey of 675 bright (16.5<Bj<18) galaxies in a 6 degree field centred on the Fornax cluster with the FLAIR-II spectrograph on the UK Schmidt Telescope. We measured redshifts for 516 galaxies of which 108 were ... More
Coexistence of Superconductivity and Antiferromagnetism Probed by Simultaneous NMR and Electrical Transport in (TMTSF)2PF6Apr 08 2005We report simultaneous NMR and electrical transport experiments in the pressure range near the boundary of the antiferromagnetic spin density wave (SDW) insulator and the metal-lic/superconducting (SC) phase in (TMTSF)2PF6. Measurements indicate a tricritical ... More
The influence of Red Spiral Galaxies on the Shape of the Local K-Band Luminosity FunctionNov 22 2014We have determined K-band luminosity functions for 13,325 local Universe galaxies as a function of morphology and color (for K_tot <= 10.75). Our sample is drawn from the 2MASS Extended Source Catalog, with all sample galaxies having measured morphologies ... More
The Weak Clustering of Gas-Rich GalaxiesAug 30 2006We examine the clustering properties of HI-selected galaxies through an analysis of the HI Parkes All-Sky Survey Catalogue (HICAT) two-point correlation function. Various sub-samples are extracted from this catalogue to study the overall clustering of ... More
Relationships between HI Gas Mass, Stellar Mass and Star Formation Rate of HICAT+WISE (HI-WISE) GalaxiesJul 17 2018We have measured the relationships between HI mass, stellar mass and star formation rate using the HI Parkes All Sky-Survey Catalogue (HICAT) and the Wide-field Infrared Survey Explorer (WISE). Of the 3,513 HICAT sources, we find 3.4 micron counterparts ... More
The Spectral Energy Distributions of Active Galactic NucleiFeb 19 2019We present ongoing work on the spectral energy distributions (SEDs) of active galactic nuclei (AGNs), derived from X-ray, ultraviolet, optical, infrared and radio photometry and spectroscopy. Our work is motivated by new wide-field imaging surveys that ... More
The Ubiquitous Radio Continuum Emission from the Most Massive Early-Type GalaxiesMar 15 2011We have measured the radio continuum emission of 396 early-type galaxies brighter than K = 9, using 1.4 GHz imagery from the NRAO VLA Sky Survey, Green Bank 300-ft Telescope and 64-m Parkes Radio Telescope. For M_K < -24 early-type galaxies, the distribution ... More
The Halo Occupation Distribution of HI GalaxiesAug 20 2009We perform an analysis of the spatial clustering properties of HI selected galaxies from the HI Parkes All Sky Survey (HIPASS) using the formalism of the halo occupation distribution (HOD). The resulting parameter constraints show that the fraction of ... More
The 1.4 GHz Cosmic Star Formation History at z < 1.3Jan 31 2019We measure the cosmic star formation history out to z = 1.3 using a sample of 918 radio-selected star forming galaxies within the 2 square degree COSMOS field. To increase our sample size, we combine 1.4 GHz flux densities from the VLA-COSMOS catalogue ... More
On the roots of the subtree polynomialOct 19 2018For a tree $T$, the subtree polynomial of $T$ is the generating polynomial for the number of subtrees of $T$. We show that the complex roots of the subtree polynomial are contained in the disk $\left\{z\in\mathbb{C}\colon\ |z|\leq 1+\sqrt[3]{3}\right\}$, ... More
The ramifications of the centres: quantised function algebras at roots of unityDec 06 1999Jul 28 2000Let H be a Hopf algebra which is a finite module over a central sub-Hopf algebra R. We continue the study of such algebras begun in RT/9911234, concentrating in this case on the example of $O_{\epsilon}[G]$, a quantised function algebra at root of unity. ... More
Maximum Modulus of Independence Roots of Graphs and TreesDec 23 2018The independence polynomial of a graph is the generating polynomial for the number of independent sets of each size and its roots are called independence roots. We bound the maximum modulus, $\mbox{maxmod}(n)$, of an independence root over all graphs ... More
The ramification of centres: Lie algebras in positive characteristic and quantised enveloping algebrasNov 29 1999Let H be a Hopf algebra which is a finite module over a central sub-Hopf algebra R. The ramification behaviour of the maximal ideals of Z(H) with respect to the subalgebra R is studied. In the case when H is U(g), the enveloping algebra of a semisimple ... More
The Domination Equivalence Classes of PathsOct 11 2017A dominating set $S$ of a graph $G$ of order $n$ is a subset of the vertices of $G$ such that every vertex is either in $S$ or adjacent to a vertex of $S$. %The domination number $G$, denoted $\gamma (G)$, is the cardinality of the smallest dominating ... More
A New Star-Formation Rate Calibration from Polycyclic Aromatic Hydrocarbon Emission Features and Application to High Redshift GalaxiesJan 07 2016We calibrate the integrated luminosity from the polycyclic aromatic hydrocarbon (PAH) features at 6.2\micron, 7.7\micron\ and 11.3\micron\ in galaxies as a measure of the star-formation rate (SFR). These features are strong (containing as much as 5-10\% ... More
HI galaxies with little star formation: an abundance of LIERsMar 05 2019We present a sample of 91 HI galaxies with little or no star formation and discuss the analysis of the integral field unit (IFU) spectra of 28 of these galaxies. We identified HI galaxies from the HI Parkes All-Sky Survey Catalog (HICAT) with Wide-field ... More
The $z < 1.2$ optical luminosity function from a sample of $\sim410 \, 000$ galaxies in bootesNov 05 2015Using a sample of ~410 000 galaxies to depth I_AB = 24 over 8.26 deg^2 in the Bootes field (~10 times larger than z~1 luminosity function studies in the prior literature), we have accurately measured the evolving B-band luminosity function of red galaxies ... More
Low-temperature triple-alpha rate in a full three-body modelDec 09 2011Aug 02 2012A new full three-body method is introduced to compute the rate of the triple-alpha capture reaction which is the primary source of $^{12}$C in stars. In this work, we combine the Faddeev hyperspherical harmonics and the R-matrix method to obtain a full ... More
A deep optical/near-infrared catalog of SerpensFeb 08 2010We present a deep optical/near-infrared imaging survey of the Serpens molecular cloud. This survey constitutes the complementary optical data to the Spitzer "Core To Disk" (c2d) Legacy survey in this cloud. The survey was conducted using the Wide Field ... More
NUV signatures of environment driven galaxy quenching in SDSS groupsSep 08 2016We have investigated the effect of group environment on residual star formation in galaxies, using Galex NUV galaxy photometry with the SDSS group catalogue of Yang et al. (2007). We compared the (NUV $- r$) colours of grouped and non-grouped galaxies, ... More
Evidence for merging or disruption of red galaxies from the evolution of their clusteringNov 29 2006Dec 20 2006The formation and evolution of massive red galaxies form a crucial test of theories of galaxy formation based on hierarchical assembly. In this letter we use observations of the clustering of luminous red galaxies from the Bootes field and N-body simulations ... More
The Clustering of Extragalactic Extremely Red ObjectsNov 16 2004We have measured the angular and spatial clustering of 671 K<18.40, R-K>5 Extremely Red Objects (EROs) from a 0.98 square degree sub-region of the NOAO Deep Wide-Field Survey (NDWFS). Our study covers nearly 5 times the area and has twice the sample size ... More
Reply to ``Remarks on the simulation of Cl electrosorption on Ag(100) reported in Electrochimica Acta 50 (2005) 5518"Jun 29 2006We reply to remarks by Lang and Horanyi on the meaning of the notion of "electrosorption valency" used in I. Abou Hamad et al., Electrochim. Acta 50 (2005) 5518. It is concluded that, contrary to the assertion of Lang and Horanyi, the magnitude of the ... More
On the effects of size factor on albedo versus wavelength for light scattered by small particles under Mie and Rayleigh regimesJul 18 2013Scattering by particles significantly smaller than the wavelength is an important physical process in the rocky bodies in our solar system and beyond. A number of observations of spectral bluing (referred to in those papers as "Rayleigh scattering") on ... More
On Variational Principles for Gravitating Perfect FluidsJul 11 1994Jul 12 1994The connection is established between two different action principles for perfect fluids in the context of general relativity. For one of these actions, $S$, the fluid four--velocity is expressed as a sum of products of scalar fields and their gradients ... More
On the Unimodality of Independence Polynomials of Very Well-Covered GraphsSep 24 2017The independence polynomial $i(G,x)$ of a graph $G$ is the generating function of the numbers of independent sets of each size. A graph of order $n$ is very well-covered if every maximal independent set has size $n/2$. Levit and Mandrescu conjectured ... More
Equivalence relations for Mueller matrix symmetries of laboratory, LIDAR and planetary scattering geometriesSep 19 2014Symmetry relationships for optical observations of matter generally fall into several common scattering geometries. The 'planetary' configuration is preferred among a group of observers of extraterrestrial planets, 'laboratory' observations are performed ... More
SOUSA's Swift Supernova SiblingsMay 06 2015Swift has observed over three hundred supernovae in its first ten years. Photometry from the Ultra-Violet Optical Telescope (UVOT) is being compiled in the Swift Optical/Ultraviolet Supernovae Archive (SOUSA). The diversity of supernovae leads to a wide ... More
H-H dipole interactions in fcc metalsMar 27 2007Apr 12 2007It is observed that interstitial hydrogen nucleii on a metallic lattice are strongly coupled to their near neighbours by the unscreened electromagnetic field mediating transitions between low-lying states. It is shown that the dominant interaction is ... More
High temperature periodic BEC in deuterated metalsOct 16 2005The standard Frohlich model of the interaction of band states with phonons is applied to the case of deuterons solved in metals. A simple variational solution of this model predicts at least one highly coherent state of the deuteron-phonon system having ... More
Phonon-bound nucleon pairs predicted by the Bohm-Staver relationJan 25 2005Attention is drawn to recent observation of a fluid phase of hydrogen nucleii in transition metal hydrides. It is suggested that phonon exchange processes might be responsible for the phase transition since bound pair states, analogous to Cooper pairs, ... More
Black Hole Pair Creation and the Entropy FactorDec 06 1994Feb 03 1995It is shown that in the instanton approximation the rate of creation of black holes is always enhanced by a factor of the exponential of the black hole entropy relative to the rate of creation of compact matter distributions (stars). This result holds ... More
Tidal interactions at the edge of the Local Group: New evidence for tidal features in the Antlia Dwarf GalaxySep 19 2012Using deep B band imaging down to mu_{B} = 26 mag arcsec^{-2}, we present evidence for tidal tails in the Antlia Dwarf galaxy, one of the most distant members of the Local Group. This elongation is in the direction of Antlia's nearest neighbor, the Magellanic-type ... More
Spectral Curve Fitting for Automatic Hyperspectral Data AnalysisJan 22 2014Automatic discovery and curve fitting of absorption bands in hyperspectral data can enable the analyst to identify materials present in a scene by comparison with library spectra. This procedure is common in laboratory spectra, but is challenging for ... More
The Ultraviolet Brightest Type Ia Supernova 2011deAug 05 2014We present and discuss the UV/optical photometric light curves and absolute magnitudes of the Type Ia supernova (SN) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observed--more than a factor of ten brighter ... More
Probing the puncture for black hole simulationsAug 26 2009Oct 23 2009With the puncture method for black hole simulations, the second infinity of a wormhole geometry is compactified to a single "puncture point" on the computational grid. The region surrounding the puncture quickly evolves to a trumpet geometry. The computational ... More
Strongly Hyperbolic Extensions of the ADM HamiltonianMar 03 2008Jul 10 2008The ADM Hamiltonian formulation of general relativity with prescribed lapse and shift is a weakly hyperbolic system of partial differential equations. In general weakly hyperbolic systems are not mathematically well posed. For well posedness, the theory ... More
RDDI phase in hydrogenated metals - some clarificationsOct 15 2006We present further evidence for the coherent RDDI phase postulated in our earlier paper and clarify the reasons why the intersite tunnelling amplitude is increased by many orders of magnitude when a mesoscopic domain undergoes such a transition.
Superconducting protons in metalsApr 01 2005The hitherto neglected phonon-exchange interaction between interstitial protons in metal lattices is found to be large. It is shown that this effect may give rise to a phase of protonic superconductivity, characterized by the formation of Cooper-like ... More
Proton-Rich Nuclear Statistical EquilibriumAug 14 2008Proton-rich material in a state of nuclear statistical equilibrium (NSE) is one of the least studied regimes of nucleosynthesis. One reason for this is that after hydrogen burning, stellar evolution proceeds at conditions of equal number of neutrons and ... More
Cl electrosorption on Ag(100): Lateral interactions and electrosorption valency from comparison of Monte Carlo simulations with chronocoulometry experimentsFeb 16 2005Mar 24 2005We present Monte Carlo Simulations using an equilibrium lattice-gas model for the electrosorption of Cl on Ag(100) single-crystal surfaces. Fitting the simulated isotherms to chronocoulometry experiments, we extract parameters such as the electrosorption ... More
Generalized Harmonic Equations in 3+1 FormSep 08 2011Nov 29 2011The generalized harmonic equations of general relativity are written in 3+1 form. The result is a system of partial differential equations with first order time and second order space derivatives for the spatial metric, extrinsic curvature, lapse function ... More
Action Principle for the Generalized Harmonic Formulation of General RelativityAug 18 2010Sep 07 2011An action principle for the generalized harmonic formulation of general relativity is presented. The action is a functional of the spacetime metric and the gauge source vector. An action principle for the Z4 formulation of general relativity has been ... More
Collective dipole oscillations in hydrogenated metalsAug 12 2006It is observed that low-lying transitions of an interstitial hydrogen adatom on a metallic lattice correspond classically to dipoles oscillating at frequencies where band electrons typically have a low electromagnetic absorption. Such transitions hence ... More
Circular Polarization and Coherent BackscatteringJul 23 2017We extend the work of Mishchenko et al. (2000) regarding the exact results of the polarization effect, using the theory of Amic et al. (1997) to derive a model prediction for the polarization coherent opposition effect at small angles. Our extension is ... More
A fault-tolerant non-Clifford gate for the surface code in two dimensionsMar 27 2019Magic-state distillation, used to perform non-Clifford gates, consumes an overwhelming majority of the resources of a surface code architecture for universal quantum computing. Here we show how to perform a fault-tolerant non-Clifford gate with the surface ... More
Covariant formulations of BSSN and the standard gaugeFeb 20 2009May 22 2009The BSSN and standard gauge equations are written in covariant form with respect to spatial coordinate transformations. The BSSN variables are defined as tensors with no density weights. This allows us to evolve a given set of initial data using two different ... More
Enhanced low energy fusion rate in palladium (Pd) due to vibrational deuteron dipole-dipole interactions and associated resonant tunneling that over-cancels the Jastrow factor between deuteron pair wavefunctionsNov 12 2007We show that interstitial hydrogen nucleii on a metallic lattice are strongly coupled to their near neighbours by the unscreened electromagnetic field mediating transitions between low-lying states. We then show that in almost-stoichiometric PdD clusters, ... More
Puncture Evolution of Schwarzschild Black HolesMay 09 2007Jan 15 2008The moving puncture method is analyzed for a single, non-spinning black hole. It is shown that the puncture region is not resolved by current numerical codes. As a result, the geometry near the puncture appears to evolve to an infinitely long cylinder ... More
SDSS J163030.58+423305.8: A 40 minute Orbital Period Detached White Dwarf BinarySep 28 2011We report the discovery of a new detached, double white dwarf system with an orbital period of 39.8 min. We targeted SDSS J163030.58+423305.8 (hereafter J1630) as part of our radial velocity program to search for companions around low-mass white dwarfs ... More
Evidence from $^{77}$Se Knight shifts for triplet superconductivity in (TMTSF)$_2$PF$_6$Jan 23 2000The layered quasi-one-dimensional molecular superconductor (TMTSF)$_2$PF$_6$ is a very exotic material with a superconducting order parameter whose ground state symmetry has remained ill-defined. Here we present a pulsed NMR Knight shift (K) study of ... More
Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope WPFC2Nov 21 2002(abridged) We present the discovery of two T dwarf binaries, 2MASS 1225-2739AB and 2MASS 1534-2952AB, identified in a sample of ten T dwarfs imaged with the Hubble Space Telescope Wide Field Planetary Camera 2. The separations of the two binary systems ... More
Red Galaxy Clustering in the NOAO Deep Wide-Field SurveyJun 05 2003Jul 08 2003We have measured the clustering of z<0.9 red galaxies and constrained models of the evolution of large-scale structure using the initial 1.2 sq. degree data release of the NOAO Deep Wide-Field Survey (NDWFS). The area and BwRI passbands of the NDWFS allow ... More
Detection of H Alpha Emission in a Methane (T-Type) Brown DwarfMar 20 2000We report the detection of H{$\alpha$} emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux, log(L$_{H{\alpha}}$/L$_{bol}$) = $-$4.3, is roughly ... More
Calibrating Star Formation in WISE using Total Infrared LuminosityOct 10 2017May 28 2018We present accurate resolved $WISE$ photometry of galaxies in the combined SINGS and KINGFISH sample. The luminosities in the W3 12$\mu$m and W4 23$\mu$m bands are calibrated to star formation rates (SFRs) derived using the total infrared luminosity, ... More
The science case for a modern, multi-wavelength, polarization-sensitive LIDAR in orbit around MarsMay 30 2014We present the scientific case to build a multiple-wavelength, active, near-infrared (NIR) instrument to measure the reflected intensity and polarization characteristics of backscattered radiation from planetary surfaces and atmospheres. We focus on the ... More
Atoms in a radiofrequency-dressed optical latticeJan 02 2008We load cold atoms into an optical lattice dramatically reshaped by radiofrequency (rf) coupling of state-dependent lattice potentials. This rf dressing changes the unit cell of the lattice at a subwavelength scale, such that its curvature and topology ... More
A Photometrically and Spectroscopically Confirmed Population of Passive Spiral GalaxiesJun 12 2016We have identified a population of passive spiral galaxies from photometry and integral field spectroscopy. We selected z<0.035 spiral galaxies that have WISE colours consistent with little mid-infrared emission from warm dust. Matched aperture photometry ... More
Galaxy and Mass Assembly (GAMA): maximum likelihood determination of the luminosity function and its evolutionMay 05 2015We describe modifications to the joint stepwise maximum likelihood method of Cole (2011) in order to simultaneously fit the GAMA-II galaxy luminosity function (LF), corrected for radial density variations, and its evolution with redshift. The whole sample ... More
Galaxy Cluster Correlation Function to z ~ 1.5 in the IRAC Shallow Cluster SurveyNov 12 2007We present the galaxy cluster autocorrelation function of 277 galaxy cluster candidates with 0.25 \le z \le 1.5 in a 7 deg^2 area of the IRAC Shallow Cluster Survey. We find strong clustering throughout our galaxy cluster sample, as expected for these ... More
Experimental investigation of planar ion trapsNov 02 2005Feb 09 2006Chiaverini et al. [Quant. Inf. Comput. 5, 419 (2005)] recently suggested a linear Paul trap geometry for ion trap quantum computation that places all of the electrodes in a plane. Such planar ion traps are compatible with modern semiconductor fabrication ... More
Calibrating the James Webb Space Telescope filters as star formation rate indicatorsDec 03 2018We have calibrated the 6.5 m James Webb Space Telescope (JWST) mid-infrared filters as star formation rate indicators, using JWST photometry synthesized from $Spitzer$ spectra of 49 low redshift galaxies, which cover a wider luminosity range than most ... More
Effects of flake size on mode-locking behavior for flake-graphene saturable absorber mirrorsApr 14 2016After advent of graphene as a saturable absorber many experiments have been conducted to produce short pulse duration pulses. Here, we have measured the properties of flake-graphene saturable absorber mirrors of various flake sizes dependent on fabrication ... More
The Shortest Period Detached Binary White Dwarf SystemMar 11 2011We identify SDSS J010657.39-100003.3 (hereafter J0106-1000) as the shortest period detached binary white dwarf (WD) system currently known. We targeted J0106-1000 as part of our radial velocity program to search for companions around known extremely low-mass ... More
Cubical abelian groups with connections are equivalent to chain complexesDec 11 2002The theorem of the title is deduced from the equivalence between crossed complexes and cubical $\omega$-groupoids with connections proved by the authors in 1981. In fact we prove the equivalence of five categories defined internally to an additive category ... More
Universal fault-tolerant measurement-based quantum computationNov 28 2018Certain physical systems that one might consider for fault-tolerant quantum computing where qubits do not readily interact, for instance photons, are better suited for measurement-based quantum-computational protocols. We develop a framework to map fault-tolerant ... More
Modelling autophagy selectivity by receptor clustering on peroxisomesOct 03 2016When subcellular organelles are degraded by autophagy, typically some, but not all, of each targeted organelle type are degraded. Autophagy selectivity must not only select the correct type of organelle, but must discriminate between individual organelles ... More
Accelerating the Universe with Gravitational WavesSep 10 2009Feb 10 2010Inflation generically produces primordial gravitational waves with a red spectral tilt. In this paper we calculate the backreaction produced by these gravitational waves on the expansion of the universe. We find that in radiation domination the backreaction ... More
A storage-based model of heterocyst commitment and patterning in cyanobacteriaDec 02 2013When deprived of fixed nitrogen (fN), certain filamentous cyanobacteria differentiate nitrogen-fixing heterocysts. There is a large and dynamic fraction of stored fN in cyanobacterial cells, but its role in directing heterocyst commitment has not been ... More
Heterocyst placement strategies to maximize growth of cyanobacterial filamentsMay 25 2012Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria develop a regular pattern of heterocyst cells that fix nitrogen for the remaining vegetative cells. We examine three different heterocyst placement strategies by quantitatively ... More
Effective dissipation: breaking time-reversal symmetry in driven microscopic energy transmissionJul 20 2016Oct 03 2016At molecular scales, fluctuations play a significant role and prevent biomolecular processes from always proceeding in a preferred direction, raising the question of how limited amounts of free energy can be dissipated to obtain directed progress. We ... More