Results for "Michael Harris"

total 27286took 0.22s
Period relations and special values of Rankin-Selberg $L$-functionsAug 26 2016This is a survey of recent work on values of Rankin-Selberg $L$-functions of pairs of cohomological automorphic representations that are {\it critical} in Deligne's sense. The base field is assumed to be a CM field. Deligne's conjecture is stated in the ... More
Whittaker periods, motivic periods, and special values of tensor product L-functionsAug 23 2013Aug 28 2014Let $\mathcal K$ be an imaginary quadratic field. Let $\Pi$ and $\Pi'$ be irreducible generic cohomological automorphic representation of $GL(n)/{\mathcal K}$ and $GL(n-1)/{\mathcal K}$, respectively. Each of them can be given two natural rational structures ... More
Period relations and special values of Rankin-Selberg $L$-functionsAug 26 2016Dec 18 2016This is a survey of recent work on values of Rankin-Selberg $L$-functions of pairs of cohomological automorphic representations that are {\it critical} in Deligne's sense. The base field is assumed to be a CM field. Deligne's conjecture is stated in the ... More
Deligne's conjecture for automorphic motives over CM-fields, Part I: factorizationFeb 08 2018This is the first of two papers devoted to the relations between Deligne's conjecture on critical values of motivic $L$-functions and the multiplicative relations between periods of arithmetically normalized automorphic forms on unitary groups. The present ... More
interAdapt -- An Interactive Tool for Designing and Evaluating Randomized Trials with Adaptive Enrollment CriteriaApr 02 2014Jun 18 2014The interAdapt R package is designed to be used by statisticians and clinical investigators to plan randomized trials. It can be used to determine if certain adaptive designs offer tangible benefits compared to standard designs, in the context of investigators' ... More
Constraining CP-violating Higgs Sectors at the LHC using gluon fusionJun 12 2014We investigate the constraints that the LHC can set on a 126 GeV Higgs boson that is an admixture of CP eigenstates. Traditional analyses rely on Higgs couplings to massive vector bosons, which are suppressed for CP-odd couplings, so that these analyses ... More
The local Langlands conjecture for GL(n) over a p-adic field, n < pNov 29 1996Let F be a p-adic field and n a positive integer. The local Langlands conjecture asserts the existence of a bijection between irreducible admissible representations of GL(n,F) and n-dimensional admissible representations of the Weil-Deligne group of F. ... More
\widehat{G}-local systems on smooth projective curves are potentially automorphicSep 12 2016Let $X$ be a smooth, projective, geometrically connected curve over a finite field $\mathbb{F}_q$, and let $G$ be a split semisimple algebraic group over $\mathbb{F}_q$. Its dual group $\widehat{G}$ is a split reductive group over $\mathbb{Z}$. Conjecturally, ... More
Weight zero Eisenstein cohomology of Shimura varieties via Berkovich spacesAug 08 2012This brief article gives an alternative interpretation, based on a theorem of Berkovich, of the Eisenstein classes in the cohomology of Shimura varieties, used in forthcoming work of the author with K. W. Lan, R. Taylor, and J. Thorne.
Unitarity-controlled resonances after Higgs discoveryMar 25 2015Jul 16 2015If the recently discovered Higgs boson's couplings deviate from the Standard Model expectation, we may anticipate new resonant physics in the weak boson fusion channels resulting from high scale unitarity sum rules of longitudinal gauge boson scattering. ... More
On the local Langlands correspondenceApr 22 2003The local Langlands correspondence for GL(n) of a non-Archimedean local field $F$ parametrizes irreducible admissible representations of $GL(n,F)$ in terms of representations of the Weil-Deligne group $WD_F$ of $F$. The correspondence, whose existence ... More
Testing rationality of coherent cohomology of Shimura varietiesDec 09 2012Let $G' \subset G$ be an inclusion of reductive groups whose real points have a non-trivial discrete series. Combining ergodic methods of Burger-Sarnak and the author with a positivity argument due to Li and the classification of minimal $K$-types of ... More
Limits from CGRO/EGRET Data on the Use of Antimatter as a Power Source by Extraterrestrial CivilizationsDec 20 2001Jun 15 2002I argue that the existence of cold antimatter in bulk is not permitted by the Standard Model, so that if a gamma-ray signature from antiproton annihilation were to be detected, it must represent either new physics or the action of intelligence. Time variability ... More
p-adic measures and square roots of triple product L-functionsOct 23 1996Let p be a prime number, and let f, g, and h be three modular forms of weights $\kappa$, $\lambda$, and $\mu$ for $SL(2,\Bbb{Z})$. We suppose $\kappa \geq \lambda + \mu$. In joint work with Kudla, one of the authors obtained a formula for the normalized ... More
Thermal inertia of near-Earth asteroids and implications for the magnitude of the Yarkovsky effectApr 15 2007Thermal inertia determines the temperature distribution over the surface of an asteroid and therefore governs the magnitude the Yarkovsky effect. The latter causes gradual drifting of the orbits of km-sized asteroids and plays an important role in the ... More
Efficient, Compact and Low Loss Thermo-Optic Phase Shifter in SiliconOct 14 2014We design a resistive heater optimized for efficient and low-loss optical phase modulation in a silicon-on-insulator (SOI) waveguide and characterize the fabricated devices. Modulation is achieved by flowing current perpendicular to a new ridge waveguide ... More
NEOSurvey 1: Initial results from the Warm Spitzer Exploration Science Survey of Near Earth Object PropertiesAug 12 2016Near Earth Objects (NEOs) are small Solar System bodies whose orbits bring them close to the Earth's orbit. We are carrying out a Warm Spitzer Cycle 11 Exploration Science program entitled NEOSurvey --- a fast and efficient flux-limited survey of 597 ... More
Dark Matter Halos in Galaxies and Globular Cluster Populations. II: Metallicity and MorphologyApr 13 2015An increasing body of data reveals a one-to-one linear correlation between galaxy halo mass and the total mass in its globular cluster (GC) population, M_{GCS} ~ M_h^{1.03 \pm 0.03}, valid over 5 orders of magnitude. We explore the nature of this correlation ... More
Self-field and magnetic-flux quantum mechanicsApr 06 2005Self-field and quantized magnetic-flux are employed to generate the quantum numbers n, m, and l of atomic physics. Wave-particle duality is shown to be a natural outcome of having a particle and its self-field.
Upper semicontinuity of the lamination hullSep 30 2016Let $K \subseteq \mathbb{R}^{2 \times 2}$ be a compact set, let $K^{rc}$ be its rank-one convex hull, and let $L(K)$ be its lamination convex hull. It is shown that the mapping $K \to \overline{L(K)}$ is not upper semicontinuous on the diagonal matrices ... More
Monomial principalization in the singular settingOct 04 2013Apr 15 2014We generalize an algorithm by Goward for principalization of monomial ideals in nonsingular varieties to work on any scheme of finite type over a field. The normal crossings condition considered by Goward is weakened to the condition that components of ... More
Dimer Statistics on a Bethe LatticeAug 27 2004We discuss the exact solutions of various models of the statistics of dimer coverings of a Bethe lattice. We reproduce the well-known exact results for noninteracting hard-core dimers by both a very simple geometrical argument and a general algebraic ... More
On a conjecture of JacquetNov 21 2001In this note, we prove in full generality a conjecture of Jacquet concerning the nonvanishing of the triple product L-function at the central point. Let $\kay$ be a number field and let $\pi_i$, $i=1$, 2, 3 be cuspidal automorphic representations of $GL_2(\A)$ ... More
Central Mass Concentration and Bar Dissolution in Nearby Spiral GalaxiesAug 26 2002We use data from the BIMA Survey of Nearby Galaxies (SONG) to investigate the relationship between ellipticity and central mass concentration in barred spirals. Existing simulations predict that bar ellipticity decreases as inflowing mass driven by the ... More
Eclipsing Binary Trojan Asteroid Patroclus: Thermal Inertia from Spitzer ObservationsAug 27 2009We present mid-infrared (8-33 micron) observations of the binary L5-Trojan system (617) Patroclus-Menoetius before, during, and after two shadowing events, using the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope.F or the first time, ... More
Computing Segre classes in arbitrary projective varietiesNov 21 2015Nov 26 2015We give an algorithm for computing Segre classes of subschemes of arbitrary projective varieties by computing degrees of a sequence of linear projections. Based on the fact that Segre classes of projective varieties commute with intersections by general ... More
On a linearized p-Laplace equation with rapidly oscillating coefficientsJun 15 2015Nov 19 2015Related to a conjecture of Tom Wolff, we solve a singular Neumann problem for a linearized p-Laplace equation in the unit disk.
Dark Matter Halos in Galaxies and Globular Cluster PopulationsApr 07 2014We combine a new, comprehensive database for globular cluster populations in all types of galaxies with a new calibration of galaxy halo masses based entirely on weak lensing. Correlating these two sets of data, we find that the mass ratio $\eta \equiv ... More
Variations in Star Formation History and the Red Giant Branch TipJan 20 2004We examine the reliability of the tip of the red giant branch (TRGB) as a distance indicator for stellar populations with different star formation histories (SFHs) when photometric errors and completeness corrections at the TRGB are small. In general, ... More
Substructure in the Most Massive GEEC Groups: Field-like Populations in Dynamically Active GroupsJan 18 2012The presence of substructure in galaxy groups and clusters is believed to be a sign of recent galaxy accretion and can be used not only to probe the assembly history of these structures, but also the evolution of their member galaxies. Using the Dressler-Shectman ... More
Whittaker rational structures and special values of the Asai $L$-functionAug 08 2014Nov 27 2014Let $F$ be a totally real number field and $E/F$ a totally imaginary quadratic extension of $F$. Let $\Pi$ be a cohomological, conjugate self-dual cuspidal automorphic representation of $GL_n(\mathbb A_E)$. Under a certain non-vanishing condition we relate ... More
Large deviation analysis of a simple information engineJun 26 2015Information thermodynamics provides a framework for studying the effect of feedback loops on entropy production. It has enabled the understanding of novel thermodynamic systems such as the information engine which can be seen as a modern version of `Maxwell's ... More
Discovery of an Unusually Red L-type Brown DwarfJul 17 2012We report the discovery of an unusually red brown dwarf found in a search for high proper motion objects using WISE and 2MASS data. WISEP J004701.06+680352.1 is moving at 0.44$ arcsec/yr and lies relatively close to the Galactic Plane (b=5.2 degrees). ... More
Astrophysical Effects of nu+gamma-->nu+gamma+gamma and Its Crossed ProcessesJul 09 1997Recently, Dicus and Repko computed nu gamma --> nu gamma gamma for energies below the threshold for e^{+}e^{-} pair production. They found across section on the order of 10^{-52} omega ^{gamma} with gamma =10, where omega is the CMS energy of one of the ... More
Bosonic transport simulations in a large-scale programmable nanophotonic processorJul 13 2015Jul 20 2015Environmental noise and disorder play a critical role in quantum particle and wave transport in complex media, including solid-state and biological systems. Recent work has predicted that coupling between noisy environments and disordered systems, in ... More
An integrated source of spectrally filtered correlated photons for large scale quantum photonic systemsSep 29 2014We demonstrate the generation of quantum-correlated photon-pairs combined with the spectral filtering of the pump field by more than 95dB using Bragg reflectors and electrically tunable ring resonators. Moreover, we perform demultiplexing and routing ... More
A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable DiskOct 26 2016Binary and multiple star systems are a frequent outcome of the star formation process, and as a result, almost half of all sun-like stars have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate ... More
Deep Learning with Coherent Nanophotonic CircuitsOct 07 2016Artificial Neural Networks are computational network models inspired by signal processing in the brain. These models have dramatically improved the performance of many learning tasks, including speech and object recognition. However, today's computing ... More
WISEP J004701.06+680352.1: An intermediate surface gravity, dusty brown dwarf in the AB Dor Moving GroupDec 04 2014We present spectroscopy, astrometry, and photometry of the brown dwarf WISEP J004701.06+680352.1 (W0047+68), an unusually red field L dwarf at a distance of $12.2 \pm 0.4$ parsecs. The three-dimensional space motion identifies it as a member of the AB ... More
A game-theoretic framework for classifier ensembles using weighted majority voting with local accuracy estimatesFeb 03 2013In this paper, a novel approach for the optimal combination of binary classifiers is proposed. The classifier combination problem is approached from a Game Theory perspective. The proposed framework of adapted weighted majority rules (WMR) is tested against ... More
Lopsidependency in the Moser-Tardos framework: Beyond the Lopsided Lovasz Local LemmaOct 07 2016The Lopsided Lov\'{a}sz Local Lemma (LLLL) is a powerful probabilistic principle which has been used in a variety of combinatorial constructions. While originally a general statement about probability spaces, it has recently been transformed into a variety ... More
On-off Threshold Models of Social ContagionSep 10 2012We study binary state contagion dynamics on a social network where nodes act in response to the average state of their neighborhood. We model the competing tendencies of imitation and non-conformity by incorporating an off-threshold into standard threshold ... More
Universality of the Future Chronological BoundaryApr 04 1997Sep 26 1997The purpose of this note is to establish, in a categorical manner, the universality of the Geroch-Kronheimer-Penrose causal boundary when considering the types of causal structures that may profitably be put on any sort of boundary for a spacetime. Actually, ... More
Nonlocal Modulation of Entangled PhotonsAug 06 2008We consider ramifications of the use of high speed light modulators to questions of correlation and measurement of time-energy entangled photons. Using phase modulators, we find that temporal modulation of one photon of an entangled pair, as measured ... More
Topology of the Future Chronological Boundary: Universality for Spacelike BoundariesJul 19 1999Nov 10 1999A method is presented for imputing a topology for any chronological set, i.e., a set with a chronology relation, such as a spacetime or a spacetime with some sort of boundary. This topology is shown to have several good properties, such as replicating ... More
Electromagnetically Induced Transparency and Quantum Heat EnginesNov 03 2016We describe how electromagnetically induced transparency may be used to construct a non-traditional near-ideal quantum heat engine as constrained by the Second Law. The engine is pumped by a thermal reservoir that may be either hotter or colder than that ... More
Improved parallel algorithms for hypergraph maximal independent setSep 20 2016Finding a maximal independent set in hypergraphs has been a long-standing algorithmic challenge. The best parallel algorithm for hypergraphs of rank $r$ was developed by Beame \& Luby (1990) and Kelsen (1992), running in time roughly $(\log n)^{r!}$. ... More
New bounds for the Moser-Tardos distribution: Beyond the Lovasz Local LemmaOct 30 2016Nov 01 2016The Lovasz Local Lemma (LLL) is a probabilistic principle which has been used in a variety of combinatorial constructions to show the existence of structures that have good "local" properties. Using the "LLL-distribution", one can show that the resulting ... More
Powers of Ideals and Fibers of MorphismsJul 26 2008Let X\subset PP^n be a projective scheme over a field, and let phi:X --> Y be a finite morphism. Our main result is a formula in terms of global data for the maximum of the Castelnuovo-Mumford regularity of the fibers of \phi, considered as subschemes ... More
The Binary White Dwarf LHS 3236Sep 04 2013The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 +/- 0.25 pc and a tangential velocity of 98 km/s, ... More
Deterministic parallel algorithms for fooling polylogarithmic juntas and the Lovasz Local LemmaOct 11 2016Many randomized algorithms can be derandomized efficiently using either the method of conditional expectations or probability spaces with low (almost-) independence. A series of papers, beginning with work by Luby (1988) and continuing with Berger & Rompel ... More
Near field imaging of small isotropic and extended anisotropic scatterersJan 12 2016Sep 11 2016In this paper, we consider two time-harmonic inverse scattering problems of reconstructing penetrable inhomogeneous obstacles from near field measurements. First we appeal to the Born approximation for reconstructing small isotropic scatterers via the ... More
Rational curves on hypersurfaces of low degree, IIJul 27 2002This is a continuation of "Rational curves on hypersurfaces of low degree", math.AG/0203088. We prove that if d^2+d+1 < n and d > 2, then for a general hypersurface X_d in P^n of degree d, for each degree e the space of rational curves of degree e on ... More
Lopsidependency in the Moser-Tardos framework: Beyond the Lopsided Lovasz Local LemmaOct 07 2016Dec 01 2016The Lopsided Lov\'{a}sz Local Lemma (LLLL) is a powerful probabilistic principle which has been used in a variety of combinatorial constructions. While originally a general statement about probability spaces, it has recently been transformed into a variety ... More
A remark on the Schottky locus in genus 4Jan 02 2003We determine the class of the (closure of the) Schottky locus in genus 4 in the Igusa- and the Voronoi compactification of A_4 and comment on the weight 8 modular form which vanishes on it.
Tighter inapproximability for set coverDec 06 2016Set Cover is a classic NP-hard problem; as shown by Slav\'{i}k (1997) the greedy algorithm gives an approximation ratio of $\ln n - \ln \ln n + \Theta(1)$. A series of works by Lund \& Yannakakis (1994), Feige (1998), Moshkovitz (2015) have shown that, ... More
Static- and Stationary-complete Spacetimes: Algebraic and Causal StructuresDec 24 2014Jun 05 2015This is intended as an analysis of the global properties of static and stationary spacetimes with complete (timelike) Killing field, with particular attention to quotients by group actions. This is presented in terms of algebraic structures which are ... More
Chern classes of automorphic vector bundles, IIJan 24 2018We prove that the $\ell$-adic Chern classes of canonical extensions of automorphic vector bundles, over toroidal compactifications of Shimura varieties of Hodge type over $\bar{ \mathbb{Q}}_p$, descend to classes in the $\ell$-adic cohomology of the minimal ... More
Can Multiband Observations Constrain Explanations for Knotty Jets?Feb 02 2010One can imagine a number of mechanisms that could be the cause of brighter/fainter segments of jets. In a sense, jets might be easier to understand if they were featureless. However we observe a wide variety of structures which we call "knots". By considering ... More
What can we learn about extragalactic radio jets from X-ray data?Feb 05 2003Feb 13 2003We review the current status of resolved X-ray emission associated with extragalactic radio jets and hotspots. The primary question for any particular jet is to decide if the X-rays come from the synchrotron process or from inverse Compton scattering. ... More
The Accessible Lasso ModelsJan 12 2015Jun 09 2016A new line of research on the lasso exploits the beautiful geometric fact that the lasso fit is the residual from projecting the response vector $y$ onto a certain convex polytope. This geometric picture also allows an exact geometric description of the ... More
On the $p$-version of FEM in one dimension: The known and unknown featuresJan 07 2014The paper analyses the convergence of the $p$-version of the FEM when the solution is piecewise analytic function. It focuses on pointwise convergence of the gradient. It shows that at boundary the rate is different than inside the element and there is ... More
Branching Brownian motion: Almost sure growth along scaled pathsJun 01 2009Apr 21 2010We give a proof of a result on the growth of the number of particles along chosen paths in a branching Brownian motion. The work follows the approach of classical large deviations results, in which paths in $C[0,1]$ are rescaled onto $C[0,T]$ for large ... More
Juggler's exclusion processApr 18 2011Jun 29 2012Juggler's exclusion process describes a system of particles on the positive integers where particles drift down to zero at unit speed. After a particle hits zero, it jumps into a randomly chosen unoccupied site. We model the system as a set-valued Markov ... More
Upper semicontinuity of the lamination hullSep 30 2016Oct 17 2016Let $K \subseteq \mathbb{R}^{2 \times 2}$ be a compact set, let $K^{rc}$ be its rank-one convex hull, and let $L(K)$ be its lamination convex hull. It is shown that the mapping $K \to \overline{L(K)}$ is not upper semicontinuous on the diagonal matrices ... More
Complete Affine Connection in the Causal Boundary: Static, Spherically Symmetric SpacetimesNov 10 2016The boundary at $\Cal I^+$, future null infinity, for a standard static, spherically symmetric spactime is examined for possible linear connections. Two independent methods are employed, one for treating $\Cal I^+$ as the future causal boundary, and one ... More
A new characterization of the exceptional Lie algebrasMar 13 2014For a simple Lie algebra, over $\mathbb{C}$, we consider the weight which is the sum of all simple roots and denote it $\tilde{\alpha}$. We formally use Kostant's weight multiplicity formula to compute the "dimension" of the zero-weight space. In type ... More
Simultaneous Modelling of the Stellar Halo and Globular Cluster System of NGC 5128Nov 27 2002An important test for models of galaxy formation lies in the metallicity distribution functions (MDFs) of spheroid stars and their globular clusters (GCs).We have compared the MDFs obtained from spectroscopy of the GCs and the star-by-star photometry ... More
SUSY Production Cross SectionsMar 03 1999We summarize the status of next-to-leading order perturbative quantum chromodynamics (pQCD) calculations of the cross sections for the production of squarks, gluinos, neutralinos, charginos, and sleptons as a function of the produced sparticle masses ... More
Computational Solutions for Today's NavyJan 10 2008Apr 08 2008New methods are being employed to meet the Navy's changing software-development environment.
Closing up on Dark Sectors at Colliders: from 14 to 100 TeVSep 09 2015We investigate the reach of the LHC Run 2 and that of a future circular hadron collider with up to 100 TeV centre of mass energy for the exploration of potential Dark Matter sectors. These dark sectors are conveniently and broadly described by simplified ... More
p-adic L-functions for unitary groupsFeb 04 2016Aug 25 2016This paper completes the construction of $p$-adic $L$-functions for unitary groups. More precisely, in 2006, the last three named authors proposed an approach to constructing such $p$-adic $L$-functions (Part I). Building on more recent results, including ... More
On the Rigid Cohomology of Certain Shimura VarietiesNov 25 2014We construct the compatible system of $l$-adic representations associated to a regular algebraic cuspidal automorphic representation of $GL_n$ over a CM (or totally real) field and check local-global compatibility for the $l$-adic representation away ... More
Hubble Space Telescope Observations of White Dwarfs in the Globular Cluster M4Jul 26 1995With the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope, we have discovered in M4 (NGC 6121, C 1620-264) the first extensive sequence of cooling white dwarfs seen in a globular cluster. Adopting a distance modulus of (m-M)_V = 12.65 ... More
White Dwarfs in Globular Clusters: HST Observations of M4Feb 19 1997Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258 white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial distances from the cluster center were observed and sizeable WD populations were found in all three. ... More
Constraining Dark Sectors at Colliders: Beyond the Effective Theory ApproachNov 03 2014Feb 05 2015We outline and investigate a set of benchmark simplified models with the aim of providing a minimal simple framework for an interpretation of the existing and forthcoming searches of dark matter particles at the LHC. The simplified models we consider ... More
Ages for Globular Clusters in the Outer Galactic Halo: The Second Parameter Clusters Palomar~3, Palomar~4 and EridanusSep 14 1998We have used the WFPC2 camera on the Hubble Space Telescope to obtain photometry of the outer-halo globular clusters Palomar 3, Palomar 4, and Eridanus. These three are classic examples of the "second parameter" anomaly because of their red horizontal-branch ... More
A 25 Gb/s Silicon Photonics PlatformMar 04 2012Silicon has attracted attention as an inexpensive and scalable material system for photonic-electronic, system-on-chip development. For this, a platform with both photodetectors and modulators working at high speeds, with excellent cross-wafer uniformity, ... More
Identifying Breaks and Curvature in the Fermi Spectra of Bright Flat Spectrum Radio QuasarsOct 22 2012Nov 13 2012Knowing the site of gamma-ray emission in AGN jets will do much for our understanding of the physics of the source. In particular, if the emission region is close to the black hole then absorption of gamma-rays with photons from the broad-line region ... More
Peer assessment enhances student learningOct 14 2014Feedback has a powerful influence on learning, but it is also expensive to provide. In large classes, it may even be impossible for instructors to provide individualized feedback. Peer assessment has received attention lately as a way of providing personalized ... More
A Color-Magnitude Diagram for a Globular Cluster In the Giant Elliptical Galaxy NGC 5128Jun 30 1998The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for a large sample of stars in the outer halo of the giant elliptical NGC 5128 (d = 4 Mpc). The globular cluster N5128-C44, at the center of the Planetary Camera field, is well ... More
An Investigation into the Spectral Properties of Bright Fermi BlazarsMay 12 2014We investigate the spectral properties of blazars detected with the Fermi-Large Area Telescope (LAT) in the high energy regime 100 MeV - 100 GeV. We find that over long timescales a log-parabola provides an adequate description of the spectrum in almost ... More
Identifying Breaks and Curvature in the Fermi Spectra of Bright FSRQs and Constraining the Emission RegionOct 02 2012Deviation of the gamma-ray energy spectra of Flat Spectrum Radio Quasars (FSRQs) from a simple power law has been previously observed but the cause of this remains unidentified. If the gamma-ray emission region is close to the central black hole then ... More
Spatial and Temporal Variability of the Gamma Radiation from Earth's Atmosphere during a Solar CycleAug 21 2003The Solar Maximum Mission satellite's Gamma Ray Spectrometer observed Earth's atmosphere for most of the period 1980-1989. Its 28deg orbit ensured that a range of geomagnetic latitudes (geomagnetic cutoff rigidities) was sampled. We measured the variation ... More
Revolutionizing our View of Protostellar Multiplicity and Disks: The VLA Nascent Disk and Multiplicity (VANDAM) Survey of the Perseus Molecular CloudJul 05 2016There is substantial evidence for disk formation taking place during the early stages of star formation and for most stars being born in multiple systems; however, protostellar multiplicity and disk searches have been hampered by low resolution, sample ... More
The MINOS Light Injection Calibration SystemApr 17 2002A description is given of the light-injection calibration system that has been developed for the MINOS long-baseline neutrino oscillation experiment. The system is based upon pulsed blue LEDs monitored by PIN photodiodes. It is designed to measure non-linearities ... More
Spine proofs for Lp-convergence of branching-diffusion martingalesNov 02 2006Using the foundations laid down in Hardy and Harris (2006) ["A new formulation of the spine approach in branching diffusions", arXiv:math.PR/0611054], we present new spine proofs of the L^p-convergence p>=1) of some key `additive' martingales for three ... More
Globular clusters and supermassive black holes in galaxies: further analysis and a larger sampleDec 18 2013We explore several correlations between various large-scale galaxy properties, particularly total globular cluster population (N_GCS), the central black hole mass (M_BH), velocity dispersion (nominally sigma_e), and bulge mass (M_dyn). Our data sample ... More
The Metallicity Distribution in the Halo Stars of NGC 5128: Implications for Galaxy FormationOct 08 1998The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for a sample of 10,000 red giant stars in the outer halo of the giant elliptical NGC 5128. Comparison with the fiducial RGBs of Milky Way globular clusters and model isochrones ... More
M87, Globular Clusters, and Galactic Winds: Issues in Giant Galaxy FormationJan 22 1998New VRI photometry is presented for the globular clusters in the innermost 140'' of the M87 halo. The results are used to discuss several issues concerning the formation and evolution of globular cluster systems in supergiant ellipticals like M87. (1) ... More
The almost-sure population growth rate in branching Brownian motion with a quadratic breeding potentialDec 07 2009Feb 10 2010In this note we consider a branching Brownian motion (BBM) on $\mathbb{R}$ in which a particle at spatial position $y$ splits into two at rate $\beta y^2$, where $\beta>0$ is a constant. This is a critical breeding rate for BBM in the sense that the expected ... More
Internal energy density of the critical three-state Potts model on the kagome latticeJan 08 2014It has been conjectured that the internal energy density of the Potts model on a semi-infinite strip with a width $L$ does not have any finite-size corrections at the critical point $K=K_c$. By factorizing the transfer matrix for the kagome lattice with ... More
X-ray Emission Processes in Radio JetsSep 27 2001The emission processes responsible for the observed X-rays from radio jets are commonly believed to be non-thermal, but in any particular case, it is unclear if synchrotron emission or one or more varieties of inverse Compton emission predominates. We ... More
Non-perturbative improvement of the vector current in Wilson lattice QCDJun 17 2015Many observables of interest in lattice QCD are extracted from correlation functions involving the vector current. If Wilson fermions are used, it is therefore of practical importance that, besides the action, the current be O($a$) improved in order to ... More
A constructive algorithm for the LLL on permutationsDec 08 2016While there has been significant progress on algorithmic aspects of the Lov\'{a}sz Local Lemma (LLL) in recent years, a noteworthy exception is when the LLL is used in the context of random permutations. The breakthrough algorithm of Moser & Tardos only ... More
The p-Laplacian with respect to measuresOct 12 2011Nov 05 2012We introduce a definition for the $p$-Laplace operator on positive and finite Borel measures that satisfy an Adams-type embedding condition.
Chemodynamics of Compact Stellar Systems in NGC 5128: How similar are Globular Clusters, Ultra-Compact Dwarfs, and Dwarf Galaxies?Feb 09 2010Velocity dispersion measurements are presented for luminous GCs in NGC 5128 derived from high-res. UVES spectra. The measurements are made with the pPXF code that parametrically recovers line-of-sight velocity dispersions. Combining the measured velocity ... More
A 2dF spectroscopic study of globular clusters in NGC 5128: Probing the formation history of the nearest giant EllipticalMar 07 2008We have performed a spectroscopic study of globular clusters (GCs) in the giant elliptical NGC 5128 using the 2dF facility at the Anglo-Australian telescope. We obtained integrated optical spectra for a total of 254 GCs, 79 of which are newly confirmed ... More
Jet photoproduction and the structure of the photonDec 08 1997Jan 19 1998Various jet observables in photoproduction are studied and compared to data from HERA. The feasibility of using a dijet sample for constraining the parton distributions in the photon is then studied. For the current data the experimental and theoretical ... More