Results for "Ian A. Bond"

total 201151took 0.14s
Clues to the Metallicity Distribution in the Galactic Bulge: Abundances in MOA-2008-BLG310 and MOA-2008-BLG311Apr 13 2009May 08 2009We present abundance analyses based on high dispersion and high signal-to-noise ratio Magellan spectra of two highly microlensed Galactic bulge stars in the region of the main sequence turnoff with Teff ~ 5650 K. We find that MOA-2008-BLG310 has [Fe/H]= ... More
A Second Method to Photometrically Align Multi-Site Microlensing Light Curves: Source Color in Planetary Event MOA-2007-BLG-192Oct 12 2009At present, microlensing light curves from different telescopes and filters are photometrically aligned by fitting them to a common model. We present a second method based on photometry of common field stars. If two spectral responses are similar (or ... More
Identification of the OGLE-2003-BLG-235/MOA-2003-BLG-53 Planetary Host StarJun 02 2006Aug 03 2006We present the results of HST observations of the host star for the first definitive extrasolar planet detected by microlensing. The light curve model for this event predicts that the lens star should be separated from the source star by ~6mas at the ... More
The Demographics of Extrasolar Planets Beyond the Snow Line with Ground-based Microlensing SurveysMar 04 2009In the currently-favored paradigm of planet formation, the location of the snow line in the protoplanetary disk plays a crucial role. Determining the demographics of planets beyond the snow line of stars of various masses is thus essential for testing ... More
Parsimony, model adequacy and periodic correlation in forecasting time seriesNov 04 2016The merits of the modelling philosophy of Box \& Jenkins (1970) are illustrated with a summary of our recent work on seasonal river flow forecasting. Specifically, this work demonstrates that the principle of parsimony, which has been questioned by several ... More
Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas GiantsDec 31 2018We compare the planet-to-star mass-ratio distribution measured by gravitational microlensing to core accretion theory predictions from population synthesis models. The core accretion theory's runaway gas accretion process predicts a dearth of intermediate-mass ... More
Direct Extragalactic Distance Determination Using X-Ray ScatteringJul 20 2004We examine the feasibility of using dust-scattered X-rays for direct determination of distances to nearby galaxies with bright background AGNs, QSOs, or GRBs. We show how the Chandra X-Ray Observatory could be used to determine the distance to M31 to ... More
Competitive Accretion in Clusters and the IMFJan 26 2000Observations have revealed that most stars are born in clusters. As these clusters typically contain more mass in gas than in stars, accretion can play an important role in determining the final stellar masses. Numerical simulations of gas accretion in ... More
Spiral arm triggering of star formationNov 07 2006We present numerical simulations of the passage of clumpy gas through a galactic spiral shock, the subsequent formation of giant molecular clouds (GMCs) and the triggering of star formation. The spiral shock forms dense clouds while dissipating kinetic ... More
The Formation of Massive Binary StarsJan 13 2005The formation of massive stars in close binary systems is complicated due to their high radiation pressure, the crowded environment and the expected minimum separation for fragmentation being many times greater than the orbital separation. I discuss how ... More
Jordan manifolds and dispersionless KdV equationsOct 01 2000Multicomponent KdV-systems are defined in terms of a set of structure constants and, as shown by Svinolupov, if these define a Jordan algebra the corresponding equations may be said to be integrable, at least in the sense of having higher-order symmetries, ... More
Project Icarus: Preliminary Thoughts on the Selection of Probes and Instruments for an Icarus-style Interstellar MissionJun 04 2016In this paper we outline the range of probes and scientific instruments that will be required in order for Icarus to fulfill its scientific mission of exploring a nearby star, its attendant planetary system, and the intervening interstellar medium. Based ... More
Improved spread-location visualizationNov 04 2016The spread-location plot has often been used as a diagnostic plot suitable for many types of fitted statistical models. The spread-location plot which plots the absolute residual or square-root absolute residual versus fitted value along with a robust ... More
Necessary and Sufficient Condition for Nonsingular Fisher Information Matrix in ARMA ModelsNov 04 2016It is demonstrated that a necessary and sufficient condition that the Fisher information matrix of an ARMA model be nonsingular is that the model not be redundant, that is, the autoregressive and moving-average polynomials do not share common roots.
Differential and Functional Identities for the Elliptic TrilogarithmMar 13 2009When written in terms of $\vartheta$-functions, the classical Frobenius-Stickelberger pseudo-addition formula takes a very simple form. Generalizations of this functional identity are studied, where the functions involved are derivatives (including derivatives ... More
The long-term scientific benefits of a space economyJul 17 2016Utilisation of the material and energy resources of the Solar System will be essential for the development of a sustainable space economy and associated infrastructure. Science will be a major beneficiary of a space economy, even if its major elements ... More
Hopping between Random Locations: Spectrum and InstantonJun 22 2000Euclidean random matrices appear in a broad class of physical problems involving disorder. The problem of determining their spectra can be mapped, using the replica method, into the study of a scalar field theory with an interaction of the type e^(psi^2). ... More
Hyperbolic decay time seriesNov 02 2016Hyperbolic decay time series such as, fractional Gaussian noise (FGN) or fractional autoregressive moving-average (FARMA) process, each exhibit two distinct types of behaviour: strong persistence or antipersistence. Beran (1994) characterized the family ... More
Nonleptonic Two-Body Decays of D Mesons in Broken SU(3)Feb 10 1995Decays of the D mesons to two pseudoscalars, to two vectors, and to pseudoscalar plus vector are discussed in the context of broken flavor SU(3). A few assumptions are used to reduce the number of parameters. Amplitudes are fit to the available data, ... More
Testing for Chaos in Deterministic Systems with NoiseOct 15 2004Recently, we introduced a new test for distinguishing regular from chaotic dynamics in deterministic dynamical systems and argued that the test had certain advantages over the traditional test for chaos using the maximal Lyapunov exponent. In this paper, ... More
A New Test for ChaosAug 26 2002Jan 17 2003We describe a new test for determining whether a given deterministic dynamical system is chaotic or nonchaotic. (This is an alternative to the usual approach of computing the largest Lyapunov exponent.) Our method is a 0-1 test for chaos (the output is ... More
Fitting MA(q) Models in the Closed Invertible RegionNov 15 2016The use of reparameterization in the maximization of the likelihood function of the MA(q) model is discussed. A general method for testing for the presence of a parameter estimate on the boundary of an MA(q) model is presented. This test is illustrated ... More
Primordial triples and collisions of massive starsJan 29 2013Massive stars are known to have a high multiplicity, with examples of higher order multiples among the nearest and best studied objects. In this paper we study hierarchical multiple systems (an inner binary as a component of a wider binary) of massive ... More
Limits on initial mass segregation in young clustersMar 23 2009Mar 24 2009Mass segregation is observed in many star clusters, including several that are less than a few Myr old. Timescale arguments are frequently used to argue that these clusters must be displaying primordial segregation, because they are too young to be dynamically ... More
High-energy amplitudes in N=4 SYM in the next-to-leading orderNov 27 2009The high-energy behavior of the N=4 SYM amplitudes in the Regge limit can be calculated order by order in perturbation theory using the high-energy operator expansion in Wilson lines. At large $N_c$, a typical four-point amplitude is determined by a single ... More
On the stability of plane Couette-Poiseuille flow with uniform cross-flowMar 11 2010We present a detailed study of the linear stability of plane Couette-Poiseuille flow in the presence of a cross-flow. The base flow is characterised by the cross flow Reynolds number, $R_{inj}$ and the dimensionless wall velocity, $k$. Squire's transformation ... More
The IR stability of de Sitter QFT: Physical initial conditionsApr 21 2011This work uses Lorentz-signature in-in perturbation theory to analyze the late-time behavior of correlators in time-dependent interacting massive scalar field theory in de Sitter space. We study a scenario recently considered by Krotov and Polyakov in ... More
On higher spin symmetries in de Sitter QFTsNov 20 2015Mar 03 2016We consider the consequences of global higher-spin symmetries in quantum field theories on a fixed de Sitter background of spacetime dimension $D \ge 3$. These symmetries enhance the symmetry group associated with the isometries of the de Sitter background ... More
On the detection of superdiffusive behaviour in time seriesJul 25 2016Nov 17 2016We present a new method for detecting superdiffusive behaviour and for determining rates of superdiffusion in time series data. Our method applies equally to stochastic and deterministic time series data (with no prior knowledge required of the nature ... More
On the Implementation of the 0-1 Test for ChaosJun 08 2009In this paper we address practical aspects of the implementation of the 0-1 test for chaos in deterministic systems. In addition, we present a new formulation of the test which significantly increases its sensitivity. The test can be viewed as a method ... More
Improved multivariate portmanteau testNov 02 2016A new portmanteau diagnostic test for vector autoregressive moving average (VARMA) models that is based on the determinant of the standardized multivariate residual autocorrelations is derived. The new test statistic may be considered an extension of ... More
Broadband nature of power spectra for intermittent Maps with summable and nonsummable decay of correlationsOct 31 2015Mar 30 2016We present results on the broadband nature of the power spectrum $S(\omega)$, $\omega\in(0,2\pi)$, for a large class of nonuniformly expanding maps with summable and nonsummable decay of correlations. In particular, we consider a class of intermittent ... More
A test for a conjecture on the nature of attractors for smooth dynamical systemsNov 23 2013Mar 29 2014Dynamics arising persistently in smooth dynamical systems ranges from regular dynamics (periodic, quasiperiodic) to strongly chaotic dynamics (Anosov, uniformly hyperbolic, nonuniformly hyperbolic modelled by Young towers). The latter include many classical ... More
Homogenization for Deterministic Maps and Multiplicative NoiseApr 23 2013Apr 29 2015A recent paper of Melbourne & Stuart, A note on diffusion limits of chaotic skew product flows, Nonlinearity 24 (2011) 1361-1367, gives a rigorous proof of convergence of a fast-slow deterministic system to a stochastic differential equation with additive ... More
On Elicitation Complexity and Conditional ElicitationJun 23 2015Elicitation is the study of statistics or properties which are computable via empirical risk minimization. While several recent papers have approached the general question of which properties are elicitable, we suggest that this is the wrong question---all ... More
Central limit theorems and suppression of anomalous diffusion for systems with symmetryApr 03 2014Feb 23 2015We give general conditions for the central limit theorem and weak convergence to Brownian motion (the weak invariance principle / functional central limit theorem) to hold for observables of compact group extensions of nonuniformly expanding maps. In ... More
Faster ARMA maximum likelihood estimationNov 03 2016A new likelihood based AR approximation is given for ARMA models. The usual algorithms for the computation of the likelihood of an ARMA model require $O(n)$ flops per function evaluation. Using our new approximation, an algorithm is developed which requires ... More
Partial autocorrelation parameterization for subset autoregressionNov 04 2016A new version of the partial autocorrelation plot and a new family of subset autoregressive models are introduced. A comprehensive approach to model identification, estimation and diagnostic checking is developed for these models. These models are better ... More
Differential Morphology Between Rest-frame Optical and UV Emission from 1.5 < z < 3 Star-forming GalaxiesOct 07 2010Jan 06 2011We present the results of a comparative study of the rest-frame optical and rest-frame ultraviolet morphological properties of 117 star-forming galaxies (SFGs), including BX, BzK, and Lyman break galaxies with B<24.5, and 15 passive galaxies in the region ... More
On modular mod $\ell$ Galois representations with exceptional imagesNov 06 2003We give a parametrization of the possible Serre invariants $(N,k,\nu)$ of modular mod $\ell$ Galois representations of the exceptional types $A_4$, $S_4$, $A_5$, in terms of local data attached to the fields cut out by the associated projective representations. ... More
Crawling the Cosmic Network: Identifying and Quantifying Filamentary StructureMar 16 2010Jul 06 2010We present the Smoothed Hessian Major Axis Filament Finder (SHMAFF), an algorithm that uses the eigenvectors of the Hessian matrix of the smoothed galaxy distribution to identify individual filamentary structures. Filaments are traced along the Hessian ... More
Numerical calculation of second order perturbationsJul 16 2009Sep 17 2009We numerically solve the Klein-Gordon equation at second order in cosmological perturbation theory in closed form for a single scalar field, describing the method employed in detail. We use the slow-roll version of the second order source term and argue ... More
On the Validity of the 0-1 Test for ChaosJun 08 2009In this paper, we present a theoretical justification of the 0-1 test for chaos. In particular, we show that with probability one, the test yields 0 for periodic and quasiperiodic dynamics, and 1 for sufficiently chaotic dynamics.
A Huygens principle for diffusion and anomalous diffusion in spatially extended systemsApr 12 2013May 09 2013We present a universal view on diffusive behaviour in chaotic spatially extended systems for anisotropic and isotropic media. For anisotropic systems, strong chaos leads to diffusive behaviour (Brownian motion with drift) and weak chaos leads to superdiffusive ... More
Computer Algebra Derivation of the Bias of Burg EstimatorsNov 04 2016A symbolic method is discussed which can be used to obtain the asymptotic bias and variance to order $O(1/n)$ for estimators in stationary time series. Using this method the bias to $O(1/n)$ of the Burg estimator in AR(1) and AR(2) models is shown to ... More
The Absorbers Toward CSO 118: Superclustering at {z~3}, or an Intrinsic Absorption Complex?May 04 2001We present two low resolution (R~1300) high signal-to-noise spectra (Wr,lim~50mA) of the quasar CSO 118 (zem=2.97) taken with the Hobby-Eberly Telescope Marcario Low Resolution Spectrograph. We detect eight absorbers selected by the CIV 1548,1550 absorption ... More
Towards an understanding of the Of?p star HD 191612: optical spectroscopyJul 04 2007We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. Metal lines and HeII absorptions ... More
A Period and a Prediction for the Of?p Spectrum Alternator HD 191612Sep 08 2004Nov 12 2004The observational picture of the enigmatic O-type spectrum variable HD191612 has been sharpened substantially. A symmetrical, low-amplitude light curve with a period near 540 d has recently been reported from Hipparcos photometry. This period satisfies ... More
MOA-2012-BLG-505Lb: A super-Earth mass planet probably in the Galactic bulgeMar 31 2017May 19 2017We report the discovery of a super-Earth mass planet in the microlensing event MOA-2012-BLG-505. This event has the second shortest event timescale of $t_{\rm E}=10 \pm 1$ days where the observed data show evidence of planetary companion. Our 15 minute ... More
Very Large Telescope deep echelle spectroscopy of Galactic planetary nebulae NGC 6153, M 1-42 and Hf 2-2Jun 09 2016We present deep spectroscopy of three Galactic planetary nebulae (PNe) with large abundance discrepancy factors (ADFs): NGC6153, M1-42 and Hf2-2. The spectra were obtained with VLT/UVES and cover the whole optical range (3040-11,000 A) with a spectral ... More
Improved Pena-Rodriguez Portmanteau TestNov 04 2016Several problems with the diagnostic check suggested by Pena and Rodriguez [2002. A powerful portmanteau test of lack of fit for time series. J. Amer. Statist. Assoc. 97, 601-610.] are noted and an improved Monte-Carlo version of this test is suggested. ... More
A Three-Decade Outburst of the LMC Luminous Blue Variable R127 Draws to a CloseJul 09 2008The paradigmatic Luminous Blue Variable R127 in the Large Magellanic Cloud has been found in the intermediate, peculiar early-B state, and substantially fainter in visual light, signaling the final decline from its major outburst that began between 1978 ... More
Logarithmic deformations of the rational superpotential/Landau-Ginzburg construction of solutions of the WDVV equationsMay 30 2006The superpotential in the Landau-Ginzburg construction of solutions to the Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations is modified to include logarithmic terms. This results in deformations - quadratic in the deformation parameters - of the ... More
Models for the Formation of Massive StarsDec 05 2007Dec 17 2007The formation of massive stars is currently an unsolved problems in astrophysics. Understanding the formation of massive stars is essential because they dominate the luminous, kinematic, and chemical output of stars. Furthermore, their feedback is likely ... More
Spectral function of a Luttinger liquid coupled to phonons and angle-resolved photoemission measurements in the cuprate superconductorsFeb 18 2004Jan 25 2005We compute the finite-temperature single-particle spectral function of a one-dimensional Luttinger liquid coupled to an optical phonon band. The calculation is performed exactly for the case in which electron-phonon coupling is purely forward scattering. ... More
Modular Frobenius manifolds and their invariant flowsJun 03 2010The space of Frobenius manifolds has a natural involutive symmetry on it: there exists a map $I$ which send a Frobenius manifold to another Frobenius manifold. Also, from a Frobenius manifold one may construct a so-called almost dual Frobenius manifold ... More
Symmetries of F-manifolds with eventual identities and special families of connectionsMar 10 2011Sep 24 2012We construct a duality for F-manifolds with eventual identities and special families of connections and we describe its interactions with several well-known constructions from the theory of Frobenius and F-manifolds.
Einstein metrics on tangent bundles of spheresFeb 28 2002We give an elementary treatment of the existence of complete Kahler-Einstein metrics with nonpositive Einstein constant and underlying manifold diffeomorphic to the tangent bundle of the (n+1)-sphere.
The Use of Extraterrestrial Resources to Facilitate Space Science and ExplorationMay 25 2016May 26 2016To-date, all human economic activity has depended on the resources of a single planet, and it has long been recognized that developments in space exploration could in principle open our closed planetary economy to external resources of energy and raw ... More
Fixed and Market Pricing for Cloud ServicesJan 26 2012This paper considers two simple pricing schemes for selling cloud instances and studies the trade-off between them. We characterize the equilibrium for the hybrid system where arriving jobs can choose between fixed or the market based pricing. We provide ... More
The brown dwarf desert as a consequence of orbital migrationNov 30 2001We show that the dearth of brown dwarfs in short-period orbits around Solar-mass stars - the brown dwarf desert - can be understood as a consequence of inward migration within an evolving protoplanetary disc. Brown dwarf secondaries forming at the same ... More
Reasoning about effects: from lists to cyber-physical agentsJan 24 2018Theories for reasoning about programs with effects initially focused on basic manipulation of lists and other mutable data. The next challenge was to consider higher-order programming, adding functions as first class objects to mutable data. Reasoning ... More
Frobenius manifolds and Frobenius algebra-valued integrable systemsFeb 28 2014Aug 31 2015The notion of integrability will often extend from systems with scalar-valued fields to systems with algebra-valued fields. In such extensions the properties of, and structures on, the algebra play a central role in ensuring integrability is preserved. ... More
What's in the Loop? The Anatomy of Double Higgs ProductionApr 21 2015Jul 16 2015Determination of Higgs self-interactions through the double Higgs production from gluon fusion is a major goal of current and future collider experiments. We point out this channel could help disentangle and resolve the nature of ultraviolet contributions ... More
Asymptotic Normality of the Maximum Pseudolikelihood Estimator for Fully Visible Boltzmann MachinesSep 29 2014Boltzmann machines (BMs) are a class of binary neural networks for which there have been numerous proposed methods of estimation. Recently, it has been shown that in the fully visible case of the BM, the method of maximum pseudolikelihood estimation (MPLE) ... More
Super-star clusters versus OB associationsSep 08 2010Super Star Clusters (Mecl > 10^5 Msol) are the largest stellar nurseries in our local Universe, containing hundreds of thousands to millions of young stars within a few light years. Many of these systems are found in external galaxies, especially in pairs ... More
Escaping stars from young low-N clustersAug 26 2010With the use of N-body calculations the amount and properties of escaping stars from low-N (N = 100 and 1000) young embedded star clusters prior to gas expulsion are studied over the first 5 Myr of their existence. Besides the number of stars also different ... More
Conformally flat pencils of metrics, Frobenius structures and a modified Saito constructionFeb 07 2005Mar 02 2005The structure of a Frobenius manifold encodes the geometry associated with a flat pencil of metrics. However, as shown in the authors' earlier work, much of the structure comes from the compatibility properties of the pencil rather than from the flatness ... More
Moment-Based Relaxation of the Optimal Power Flow ProblemDec 06 2013Jan 31 2014The optimal power flow (OPF) problem minimizes power system operating cost subject to both engineering and network constraints. With the potential to find global solutions, significant research interest has focused on convex relaxations of the non-convex ... More
Convex Relaxations of Optimal Power Flow Problems: An Illustrative ExampleOct 14 2015Recently, there has been significant interest in convex relaxations of the optimal power flow (OPF) problem. A semidefinite programming (SDP) relaxation globally solves many OPF problems. However, there exist practical problems for which the SDP relaxation ... More
General Truthfulness Characterizations Via Convex AnalysisNov 13 2012Jun 19 2014We present a model of truthful elicitation which generalizes and extends mechanisms, scoring rules, and a number of related settings that do not quite qualify as one or the other. Our main result is a characterization theorem, yielding characterizations ... More
Encoding fairness in a synchronous concurrent program algebra: extended version with proofsMay 04 2018Concurrent program refinement algebra provides a suitable basis for supporting mechanised reasoning about shared-memory concurrent programs in a compositional manner, for example, it supports the rely/guarantee approach of Jones. The algebra makes use ... More
Power Computations for Intervention AnalysisNov 05 2016In many intervention analysis applications time series data may be expensive or otherwise difficult to collect. In this case the power function is helpful since it can be used to determine the probability that a proposed intervention analysis application ... More
High Resolution Spectroscopy and High Contrast Imaging with the ELT : looking for O$_2$ in Proxima bJan 30 2019We research the requirements of High Contrast Imaging when combined with the cross correlation (CC) of high resolution spectra with known spectroscopic templates for detecting and characterising exoplanets in reflected light. We simulate applying the ... More
EKR sets for large $n$ and $r$Oct 28 2012Let $\A\subset\binom{[n]}{r}$ be a compressed, intersecting family and let $X\subset[n]$. Let $\A(X)={A\in\A:A\cap X\ne\emptyset}$ and $\S_{n,r}=\binom{[n]}{r}({1})$. Motivated by the Erd\H{o}s-Ko-Rado theorem, Borg asked for which $X\subset[2,n]$ do ... More
Pwning Level Bosses in MATLAB: Student Reactions to a Game-Inspired Computational Physics CourseOct 11 2014We investigated student reactions to two computational physics courses incorporating several videogame-like aspects. These included use of gaming terminology such as "levels," "weapons," and "bosses"; a game-style point system linked to course grades; ... More
Sparsity-Exploiting Moment-Based Relaxations of the Optimal Power Flow ProblemApr 20 2014Nov 17 2014Convex relaxations of non-convex optimal power flow (OPF) problems have recently attracted significant interest. While existing relaxations globally solve many OPF problems, there are practical problems for which existing relaxations fail to yield physically ... More
Mutual information between thermo-field doubles and disconnected holographic boundariesNov 13 2012Jun 10 2013We use mutual information as a measure of the entanglement between 'physical' and thermo-field double degrees of freedom in field theories at finite temperature. We compute this "thermo-mutual information" in simple toy models: a quantum mechanics two-site ... More
Orbital migration and the brown dwarf desertOct 08 2002The orbital elements of extreme mass ratio binaries will be modified by interactions with surrounding circumstellar disks. For brown dwarf companions to Solar-type stars the resulting orbital migration is sufficient to drive short period systems to merger, ... More
A Redux on "When is the Top Quark a Parton?"May 23 2014Jun 11 2014If a new heavy particle phi is produced in association with the top quark in a hadron collider, the production cross section exhibits a collinear singularity of the form log(m_phi/m_t), which can be resummed by introducing a top quark parton distribution ... More
Free floating planets in stellar clusters?Jan 05 2001We have simulated encounters between planetary systems and single stars in various clustered environments. This allows us to estimate the fraction of systems liberated, the velocity distribution of the liberated planets, and the separation and eccentricity ... More
Generalized Legendre transformations and symmetries of the WDVV equationsOct 18 2016The Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations, as one would expect from an integrable system, has many symmetries, both continuous and discrete. One class - the so-called Legendre transformations - were introduced by Dubrovin. They are a ... More
Precision metrology using weak measurementsOct 20 2013May 31 2015Weak values and measurements have been proposed as means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly ... More
Portmanteau Tests for ARMA Models with Infinite VarianceNov 04 2016Autoregressive and moving-average (ARMA) models with stable Paretian errors is one of the most studied models for time series with infinite variance. Estimation methods for these models have been studied by many researchers but the problem of diagnostic ... More
Measurements of Transit Timing Variations for WASP-5bSep 29 2010Nov 29 2010We have observed 7 new transits of the `hot Jupiter' WASP-5b using a 61 cm telescope located in New Zealand, in order to search for transit timing variations (TTVs) which can be induced by additional bodies existing in the system. When combined with other ... More
Heavy-ion double charge exchange reactions: a tool towards 0v\b{eta}\b{eta} nuclear matrix elementsNov 12 2015The knowledge of the nuclear matrix elements for the neutrinoless double beta decay is fundamental for neutrino physics. In this paper, an innovative technique to extract information on the nuclear matrix elements by measuring the cross section of a double ... More
Nonlinear TeraHertz Coherent Excitation of Vibrational Modes of LiquidsDec 09 2015Dec 15 2015We report the first coherent excitation of intramolecular vibrational modes via the nonlinear interaction of a TeraHertz (THz) light field with molecular liquids. A terahertz-terahertz-Raman pulse sequence prepares the coherences with a broadband, high-energy, ... More
Swift/UVOT Photometry of the Planetary Nebula WeBo 1: Unmasking A Faint Hot Companion StarJun 14 2012We present an analysis of over 150 ks of data on the planetary nebula WeBo 1 (PN G135.6+01.0) obtained with the Swift Ultraviolet Optical Telescope (UVOT). The central object of this nebula has previously been described as a late-type K giant barium star ... More
HD148937: a multiwavelength study of the third Galactic member of the Of?p classMar 05 2008Three Galactic O-type stars belong to the rare class of Of?p objects: HD108, HD191612, and HD148937. The first two stars show a wealth of phenomena, including magnetic fields and strong X-ray emission, light variability, and dramatic periodic spectral ... More
Resolving Sirius-like binaries with the Hubble Space TelescopeOct 31 2000We present initial results from a Hubble Space Telescope ultraviolet imaging survey of stars known to have hot white-dwarf companions which are unresolved from the ground. The hot companions, discovered through their EUV or UV emission, are hidden by ... More
A Quadruple-Phase Strong Mg II Absorber at z~0.9902 Toward PG 1634+706Feb 14 2003The z=0.9902 system along the quasar PG 1634+706 line of sight is a strong MgII absorber (W(2796)>0.3A) with only weak CIV absorption (it is ``CIV-deficient''). To study this system, we used high-resolution spectra from both HST/STIS (R=30,000) and Keck/HIRES ... More
Characterizing the Chemistry of the Milky Way Stellar Halo: Detailed Chemical Analysis of a Metal-Poor Stellar StreamJan 11 2010Jan 18 2010We present the results of a detailed abundance analysis of one of the confirmed building blocks of the Milky Way stellar halo, a kinematically-coherent metal-poor stellar stream. We have obtained high resolution and high S/N spectra of 12 probable stream ... More
Detecting Extra-Solar Planets via Microlensing at High MagnificationSep 09 2002Extra-solar planets can be efficiently detected in gravitational microlensing events of high magnification. High accuracy photometry is required over a short, well-defined time interval only, of order 10-30 hours. Most planets orbiting the lens star are ... More
Planetary Microlensing at High MagnificationApr 29 2002May 20 2002Simulations of planetary microlensing at high magnification that were carried out on a cluster computer are presented. It was found that the perturbations due to two-thirds of all planets occur in the time interval [-0.5t_FWHM, 0.5t_ FWHM] with respect ... More
The Milky Way Tomography with SDSS: III. Stellar KinematicsAug 31 2009Jan 15 2010We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r<20 and proper-motion measurements derived from SDSS and POSS astrometry, including ~170,000 stars with radial-velocity measurements from the SDSS spectroscopic survey. ... More
Present-Day Descendants of z=3 Ly-α Emitting Galaxies in the Millennium-II Halo Merger TreesApr 05 2012Using the Millennium-II Simulation dark matter sub-halo merger histories, we created mock catalogs of Lyman Alpha Emitting (LAE) galaxies at z=3.1 to study the properties of their descendants. Several models were created by selecting the sub-halos to ... More
Sizes of Lyman-Alpha-Emitting Galaxies and Their Rest-Frame Ultraviolet Components at z=3.1Jul 13 2009Sep 21 2009We present a rest-frame ultraviolet analysis of ~120 z~3.1 Lyman Alpha Emitters (LAEs) in the Extended Chandra Deep Field South (ECDF-S). Using Hubble Space Telescope (HST) images taken as part of the Galaxy Evolution From Morphology and SEDS (GEMS) survey, ... More
Hubble Space Telescope Imaging and Spectroscopy of the Sirius-Like Triple Star System HD 217411Jul 16 2014We present Hubble Space Telescope imaging and spectroscopy of HD 217411, a G3 V star associated with the extreme ultraviolet excess source (EUV 2RE J2300-07.0). This star is revealed to be a triple system with a G 3V primary (HD 217411 A) separated by ... More
Cyclical period changes in the dwarf novae V2051 Oph and V4140 SgrJul 29 2003We report the identification of cyclical changes in the orbital period of the eclipsing dwarf novae V2051 Ophiuchi and V4140 Sagitarii. We used sets of white dwarf mid-eclipse timings to construct observed-minus-calculated diagrams covering, respectively, ... More
On the Origin of Intrinsic Narrow Absorption Lines in z<1 QSOsOct 10 2000We present a statistical analysis of the associated, high ionization narrow absorption line (NAL) systems in a sample of 59 QSOs defined from the HST QSO Absorption Line Key Project. We have compiled the QSO luminosities at 2500 A, 5 GHz, and 2 keV, spectral ... More