Results for "Jason A. Dittmann"

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Trigonometric Parallaxes for 1,507 Nearby Mid-to-Late M-dwarfsDec 11 2013The MEarth survey is a search for small rocky planets around the smallest, nearest stars to the Sun as identified by high proper motion with red colors. We augmented our planetary search time series with lower cadence astrometric imaging and obtained ... More
A Tentative Detection of a Starspot During Consecutive Transits of an Extrasolar Planet from the Ground: No Evidence of a Double Transiting Planet System Around TrES-1Jun 23 2009There have been numerous reports of anomalies during transits of the planet TrES-1b. Recently, Rabus and coworkers' analysis of HST observations lead them to claim brightening anomalies during transit might be caused by either a second transiting planet ... More
Calibration of the MEarth Photometric System: Optical Magnitudes and Photometric Metallicity Estimates for 1802 Nearby M-dwarfsOct 22 2015The MEarth Project is a photometric survey systematically searching the smallest stars nearest to the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late M dwarfs. We ... More
Follow-up Observations of the Neptune Mass Transiting Extrasolar Planet HAT-P-11bMay 07 2009Jun 18 2009We have confirmed the existence of the transiting super Neptune extrasolar planet HAT-P-11b. On May 1, 2009 UT the transit of HAT-P-11b was detected at the University of Arizona's 1.55m Kuiper Telescope with 1.7 millimag rms accuracy. We find a central ... More
The Impact of Stellar Rotation on the Detectability of Habitable Planets Around M DwarfsApr 11 2016Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active for billions of years. We compile rotation periods for ... More
On the Apparent Orbital Inclination Change of the Extrasolar Transiting Planet TrES-2bJul 09 2009Mar 13 2010On June 15, 2009 UT the transit of TrES-2b was detected using the University of Arizona's 1.55 meter Kuiper Telescope with 2.0-2.5 millimag RMS accuracy in the I-band. We find a central transit time of $T_c = 2454997.76286 \pm0.00035$ HJD, an orbital ... More
A Search for Additional Bodies in the GJ 1132 Planetary System from 21 Ground-based Transits and a 100 Hour Spitzer CampaignNov 29 2016We present the results of a search for additional bodies in the GJ 1132 system through two methods: photometric transits and transit timing variations of the known planet. We collected 21 transit observations of GJ 1132b with the MEarth-South array since ... More
Connections and Metrics Respecting Standard PurificationJun 08 1998Standard purification interlaces Hermitian and Riemannian metrics on the space of density operators with metrics and connections on the purifying Hilbert-Schmidt space. We discuss connections and metrics which are well adopted to purification, and present ... More
The rotation and Galactic kinematics of mid M dwarfs in the Solar NeighborhoodNov 03 2015Feb 18 2016Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and are expected ... More
A Mid-life crisis? Sudden Changes in Radio and X-Ray Emission from Supernova 1970GMar 26 2014Mar 29 2014Supernovae provide a backdrop from which we can probe the end state of stellar evolution in the final years before the progenitor star explodes. As the shock from the supernova expands, the timespan of mass loss history we are able to probe also extends, ... More
An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M DwarfsSep 04 2015Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by H-alpha emission), rotation period, and stellar age. Previous ... More
Disentangling Time Series Spectra with Gaussian Processes: Applications to Radial Velocity AnalysisFeb 18 2017Measurements of radial velocity variations from the spectroscopic monitoring of stars and their companions are essential for a broad swath of astrophysics, providing access to the fundamental physical properties that dictate all phases of stellar evolution ... More
EVLA Observations Constrain the Environment and Progenitor System of Type Ia Supernova 2011feJan 04 2012Mar 13 2012We report unique EVLA observations of SN 2011fe representing the most sensitive radio study of a Type Ia supernova to date. Our data place direct constraints on the density of the surrounding medium at radii ~10^15-10^16 cm, implying an upper limit on ... More
Discovery and Precise Characterization by the MEarth Project of LP 661-13, an Eclipsing Binary Consisting of Two Fully Convective Low-mass StarsSep 12 2016We report the detection of stellar eclipses in the LP 661-13 system. We present the discovery and characterization of this system, including high resolution spectroscopic radial velocities and a photometric solution spanning two observing seasons. LP ... More
A Spectroscopic Study of Type Ibc Supernova Host Galaxies from Untargeted SurveysJun 12 2012Sep 16 2012We present the largest spectroscopic study of the host environments of Type Ibc supernovae (SN Ibc) discovered exclusively by untargeted SN searches. Past studies of SN Ibc host environments have been biased towards high-mass, high-metallicity galaxies ... More
Effective Theories of ConfinementNov 21 2001We review some approaches to describe confinement in terms of effective (model) field theories. After a brief discussion of the dual Abelian Higgs model, we concentrate on a lattice analysis of the Faddeev-Niemi effective action conjectured to describe ... More
Four new eclipsing mid M-dwarf systems from the New Luyten Two Tenths catalogAug 09 2018Using data from the MEarth-North and MEarth-South transit surveys, we present the detection of eclipses in four mid M-dwarf systems: LP 107-25, LP 261-75, LP 796-24, and LP 991-15. Combining the MEarth photometry with spectroscopic follow-up observations, ... More
How to Constrain Your M dwarf II: the mass-luminosity-metallicity relation from 0.075 to 0.70$M_\odot$Nov 16 2018Jan 26 2019The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses. However, there is growing need for both a higher-precision relation and a better understanding of systematic effects (e.g., metallicity). Here ... More
The MEarth-North and MEarth-South transit surveys: searching for habitable super-Earth exoplanets around nearby M-dwarfsSep 02 2014Detection and characterization of potentially habitable Earth-size extrasolar planets is one of the major goals of contemporary astronomy. By applying the transit method to very low-mass M-dwarfs, it is possible to find these planets from the ground with ... More
Cone Beam Geometry Calibration for Micro Computed Tomography Systems using Arbitrary Fiducial Markers and the Relation Between Projection Matrices and Real Space GeometryAug 09 2018A method for the determination of the projection geometry within high resolution cone beam computed tomography systems (micro CT) based on few fiducial markers of unknown position within the field of view is described. By employing the projection matrix ... More
On the Curvature of Monotone Metrics and a Conjecture Concerning the Kubo-Mori MetricJun 02 1999It is the aim of this article to determine curvature quantities of an arbitrary Riemannian monotone metric on the space of positive matrices resp. nonsingular density matrices. Special interest is focused on the scalar curvature due to its expected quantum ... More
Note on Explicit Formulae for the Bures MetricAug 24 1998The aim of this paper is to derive explicit formulae for the Riemannian Bures metric on the manifold of (finite dimensional) nondegenerate density matrices. The computation of the Bures metric using the presented equations does not require any diagonalization ... More
Defining Subrings in Finitely Generated Fields of Characteristic Not TwoOct 22 2018We give a construction of a family of definable subrings of finitely generated fields $K$ of characteristic not two. We deduce that for any such $K$ there exists a first-order sentence $\varphi_K$ characterising $K$ in the class of finitely generated ... More
A rocky planet transiting a nearby low-mass starNov 11 2015M-dwarf stars -- hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun -- are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized ... More
Efficient ray tracing on 3D regular grids for fast generation of digitally reconstructed radiographs in iterative tomographic reconstruction techniquesSep 04 2016Cone beam projection is an essential and particularly time consuming part of any iterative tomographic reconstruction algorithm. On current graphics hardware especially the amount and pattern of memory accesses is a limiting factor when read-only textures ... More
Irreducibility of Polynomials over Global Fields is DiophantineJan 28 2016Oct 19 2017Given a global field $K$ and a positive integer $n$, we present a diophantine criterion for a polynomial in one variable of degree $n$ over $K$ not to have any root in $K$. This strengthens the known result that the set of non-$n$-th-powers in $K$ is ... More
Defining Subrings in Finitely Generated Fields of All CharacteristicsOct 22 2018Apr 09 2019We give a construction of a large first-order definable family of subrings of finitely generated fields $K$ of any characteristic. We deduce that for any such $K$ there exists a first-order sentence $\varphi_K$ characterising $K$ in the class of finitely ... More
A temperate rocky super-Earth transiting a nearby cool starApr 18 2017M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy [1]. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy ... More
Ultraproducts as a tool for first-order inexpressibility in the finite and infiniteOct 11 2013Ultraproducts are a well-known tool in the classical model theory of first-order logic. We explore their uses in the context of finite model theory.
LSPM J1112+7626: detection of a 41-day M-dwarf eclipsing binary from the MEarth transit surveySep 09 2011We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (I_C = 12.14 +/- 0.05) very low-mass binary system with an orbital period of 41.03236 +/- 0.00002 days, and component masses M_1 = 0.395 +/- 0.002 Msol and ... More
A 2 Earth Radius Planet Orbiting the Bright Nearby K-Dwarf Wolf 503Jun 09 2018Since its launch in 2009, the Kepler telescope has found thousands of planets with radii between that of Earth and Neptune. Recent studies of the distribution of these planets have revealed a rift in the population near 1.5-2.0$R_{\bigoplus}$, informally ... More
Stellar Flares from the First Tess Data Release: Exploring a New Sample of M-dwarfsJan 02 2019We perform a study of stellar flares for the 24,809 stars observed with 2 minute cadence during the first two months of the TESS mission. Flares may erode exoplanets' atmospheres and impact their habitability, but might also trigger the genesis of life ... More
The period ratio distribution of Kepler's candidate multiplanet systemsSep 11 2014Jan 13 2015We calculate and analyze the distribution of period ratios observed in systems of Kepler exoplanet candidates including studies of both adjacent planet pairs and all planet pairs. These distributions account for both the geometrical bias against detecting ... More
Counting Spanning Trees on Fractal GraphsNov 30 2012Using the method of spectral decimation and a modified version of Kirchhoffs Matrix-Tree Theorem, a closed form solution to the number of spanning trees on approximating graphs to a fully symmetric self-similar structure on a finitely ramified fractal ... More
Asymptotic geometry of the mapping class group and Teichmueller spaceFeb 17 2005Mar 02 2009In this work, we study the asymptotic geometry of the mapping class group and Teichmueller space. We introduce tools for analyzing the geometry of `projection' maps from these spaces to curve complexes of subsurfaces; from this we obtain information concerning ... More
Line Emission in AGN: Effects of Local Delays Upon Line VariabilityJun 04 1996Previous works concerning active galactic nuclei (AGN) variability (e.g., Blandford \& McKee 1982) have assumed that the emission characteristics of illuminated clouds are purely a function of the instant continuum flux to which they are exposed. This ... More
Line Emission from Stellar Winds in Active Galactic NucleiDec 01 1999This dissertation presents synthetic spectra and response functions of the red giant stellar line emission model of active galactic nuclei. Our results agree with the fundamental line emission characteristics of active galactic nuclei within the model ... More
Mass Function Gradients and the Need for Dark MatterFeb 16 1998Mar 05 1998There is substantial evidence that the initial mass function (IMF) may be a function of the local star formation conditions. In particular, the IMF is predicted to flatten with increasing local luminosity density, with the formation of massive stars being ... More
Ionization by bulk heating of electrons in capacitive radio frequency atmospheric pressure microplasmasAug 31 2012May 31 2013Electron heating and ionization dynamics in capacitively coupled radio frequency (RF) atmospheric pressure microplasmas operated in helium are investigated by Particle in Cell simulations and semi-analytical modeling. A strong heating of electrons and ... More
A second terrestrial planet orbiting the nearby M dwarf LHS 1140Aug 01 2018Nov 22 2018LHS 1140 is a nearby mid-M dwarf known to host a temperate rocky super-Earth (LHS 1140 b) on a 24.737-day orbit. Based on photometric observations by MEarth and Spitzer as well as Doppler spectroscopy from HARPS, we report the discovery of an additional ... More
Radiotherapy planning for glioblastoma based on a tumor growth model: Improving target volume delineationNov 22 2013Dec 19 2013Glioblastoma are known to infiltrate the brain parenchyma instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated ... More
Finite-frequency noise of interacting single-electron emitters: spectroscopy with higher noise harmonicsMay 08 2018We derive the symmetrized current-noise spectrum of a quantum dot, which is weakly tunnel-coupled to an electron reservoir and driven by a slow time-dependent gate voltage. This setup can be operated as an on-demand emitter of single electrons into a ... More
TESS Spots a Compact System of Super-Earths around the Naked-Eye Star HR 858May 13 2019Transiting Exoplanet Survey Satellite (TESS) observations have revealed a compact multi-planet system around the sixth-magnitude star HR 858 (TIC 178155732), located 32 parsecs away. Three planets, each about twice the size of Earth, transit this slightly-evolved, ... More
TESS Spots a Compact System of Super-Earths around the Naked-Eye Star HR 858May 13 2019May 15 2019Transiting Exoplanet Survey Satellite (TESS) observations have revealed a compact multi-planet system around the sixth-magnitude star HR 858 (TIC 178155732), located 32 parsecs away. Three planets, each about twice the size of Earth, transit this slightly-evolved, ... More
A Missing-Link in the Supernova-GRB Connection: The Case of SN 2012apFeb 25 2014Apr 23 2015Gamma Ray Bursts (GRBs) are characterized by ultra-relativistic outflows, while supernovae are generally characterized by non-relativistic ejecta. GRB afterglows decelerate rapidly usually within days, because their low-mass ejecta rapidly sweep up a ... More
A TESS Dress Rehearsal: Planetary Candidates and Variables from K2 Campaign 17Jun 08 2018We produce light curves for all ~34,000 targets observed with K2 in Campaign 17 (C17), identifying 34 planet candidates, 184 eclipsing binaries, and 222 other periodic variables. The location of the C17 field means follow-up can begin immediately now ... More
A Wolf in Sheepskin: Extraordinary Supernova 2012au Veiled Behind Ordinary Radio EmissionSep 13 2013We present extensive radio and X-ray observations of SN\, 2012au, the energetic radio luminous supernova of type Ib that may be a link between subsets of hydrogen-poor superluminous and normal core-collapse supernovae. The observations closely follow ... More
Deuteron binding energies and form factors from light front field theoryDec 12 2001The objective of this paper is to investigate how the breaking of manifest rotational invariance in light-front dynamics affects the binding energy and the form factors of the deuteron. To do this, we derive new light-front nucleon-nucleon one- and two-meson-exchange ... More
Disc galaxy modelling with a particle-by-particle M2M methodOct 19 2012Jan 09 2013We have developed the initial version of a new particle-by-particle adaptation of the made-to-measure (M2M) method, aiming to model the Galactic disc from upcoming Galactic stellar survey data. In our new particle-by-particle M2M, the observables of the ... More
On the Kurosh problem for algebras over a general fieldFeb 02 2011Smoktunowicz, Lenagan, and the second-named author recently gave an example of a nil algebra of Gelfand-Kirillov dimension at most three. Their construction requires a countable base field, however. We show that for any field $k$ and any monotonically ... More
Dynamic Modeling of Nontargeted and Targeted Advertising Strategies in an OligopolyOct 27 2015With the growing collection of sales and marketing data and depth of detailed knowledge of consumer habits and trends, firms are gaining the capability to discern customers of other firms from the potential market of uncommitted consumers. Firms with ... More
A note on Fano manifolds whose second Chern character is positiveFeb 28 2006This note outlines some first steps in the classification of Fano manifolds for which $c_1^2-2c_2$ is positive or nef.
Video Object Segmentation using Supervoxel-Based GerrymanderingApr 18 2017Pixels operate locally. Superpixels have some potential to collect information across many pixels; supervoxels have more potential by implicitly operating across time. In this paper, we explore this well established notion thoroughly analyzing how supervoxels ... More
Chiral solitons in nuclei: Electromagnetic form factorsJul 26 2004Sep 08 2004We calculate the electromagnetic form factors of a bound proton. The Chiral Quark-Soliton model provides the quark and antiquark substructure of the proton, which is embedded in nuclear matter. This procedure yields significant modifications of the form ... More
Polarized quark distributions in nuclear matterMay 16 2005Jul 22 2005We compute the polarized quark distribution function of a bound nucleon. The Chiral Quark-Soliton model provides the quark and antiquark substructure of the nucleon embedded in nuclear matter. Nuclear effects cause significant modifications to the polarized ... More
Almost Global Existence for 4-Dimensional Quasilinear Wave Equations in Exterior DomainsFeb 20 2014This article focuses on almost global existence for quasilinear wave equations with small initial data in 4-dimensional exterior domains. The nonlinearity is allowed to depend on the solution at the quadratic level as well as its first and second derivatives. ... More
Quasi-isometric classification of graph manifold groupsApr 03 2006Feb 08 2007We show that the fundamental groups of any two closed irreducible non-geometric graph-manifolds are quasi-isometric. This answers a question of Kapovich and Leeb. We also classify the quasi-isometry types of fundamental groups of graph-manifolds with ... More
Imaging of Ultraluminous Infrared Galaxies in the Near-UVMay 08 2000We present the first ground-based U' (3410 angstroms) images of Ultraluminous Infrared Galaxies (ULIGs). Strong U' emission (median total M_U' = -20.8) is seen in all systems and in some cases the extended tidal features (both the smooth stellar distribution ... More
Calculations of Nonlinear Wave-Packet Interferometry Signals in the Pump-Probe Limit as Tests for Vibrational Control over Electronic Excitation TransferOct 12 2009The preceding paper describes a strategy for externally influencing the course of short-time electronic excitation transfer (EET) in molecular dimers and observing the process by nonlinear wave-packet interferometry (nl-WPI). Within a sample of isotropically ... More
Divisor classes and the virtual canonical bundle for genus 0 mapsFeb 28 2006Some divisor class relations are proved and used to compute the Cartier divisor class of the virtual canonical bundle for genus 0 maps to a smooth target.
Strong Electron Correlation in Nitrogenase Cofactor, FeMocoMay 22 2018FeMoco, MoFe$_7$S$_9$C, has been shown to be the active catalytic site for the reduction of nitrogen to ammonia in the nitrogenase protein. An understanding of its electronic structure including strong electron correlation is key to designing mimic catalysts ... More
Higher Fano manifolds and rational surfacesFeb 28 2006For a Fano manifold of pseudo-index at least 3 and $c_1^2-2c_2$ nef, we show irreducibility of certain spaces of curves on the Fano manifold implies the manifold is a union of rational surfaces.
Very twisting families of pointed lines on GrassmanniansFeb 28 2006There exist very twisting families of lines on Grassmannians and isotropic Grassmannians. This is a key step in proving existence of a rational section of a family of isotropic Grassmannians over a surface with vanishing Brauer obstruction.
Dimension and rank for mapping class groupsDec 15 2005Jan 12 2007We study the large scale geometry of the mapping class group, MCG. Our main result is that for any asymptotic cone of MCG, the maximal dimension of locally compact subsets coincides with the maximal rank of free abelian subgroups of MCG. An application ... More
Pion-only, chiral light-front model of the deuteronDec 27 2001We investigate the symptoms of broken rotational invariance, caused by the use of light front dynamics, for deuterons obtained using one- and two-pion-exchange potentials. A large mass splitting between states with m=0 and m=1 is found for the deuteron ... More
Don't be jelly: Exploring effective jellyfish locomotionApr 19 2019Jellyfish have been called one of the most energy-efficient animals in the world due to the ease in which they move through their fluid environment, by product of their morphological, muscular, and material properties. We investigated jellyfish locomotion ... More
Some Properties of 3x3 Octonionic Hermitian Matrices with Non-Real EigenvaluesOct 26 2000We discuss our preliminary attempts to extend previous work on 2x2 Hermitian octonionic matrices with non-real eigenvalues to the 3x3 case.
Octonionic Hermitian Matrices with Non-Real EigenvaluesJun 08 2000Oct 26 2000We extend previous work on the eigenvalue problem for Hermitian octonionic matrices by discussing the case where the eigenvalues are not real, giving a complete treatment of the 2x2 case, and summarizing some prelimenary results for the 3x3 case.
Lyapunov Exponent of Rank One Matrices: Ergodic Formula and Inapproximability of the Optimal DistributionMay 18 2019The Lyapunov exponent corresponding to a set of square matrices $\mathcal{A} = \{A_1, \dots, A_n \}$ and a probability distribution $p$ over $\{1, \dots, n\}$ is $\lambda(\mathcal{A},p) := \lim_{k \to \infty} \frac{1}{k} \,\mathbb{E} \log \|A_{\sigma_k} ... More
Spontaneous Emergence of Spatio-Temporal Order in Class 4 AutomataApr 30 2005We report surprisingly regular behaviors observed for a class 4 cellular automaton, the totalistic rule 20: starting from disordered initial configurations the automaton produces patterns which are periodic not only in time but also in space. This is ... More
A PRIMAL view of the Milky Way, made possible by Gaia and M2M modellingMar 05 2015We have developed our original made-to-measure (M2M) algorithm, PRIMAL, with the aim of modelling the Galactic disc from upcoming Gaia data. From a Milky Way like N-body disc galaxy simulation, we have created mock Gaia data using M0III stars as tracers, ... More
Ground states of the Wick-Cutkosky model using light-front dynamicsFeb 05 2000Mar 17 2000We consider the ground state in a model with scalar nucleons and a meson using the formalism of light-front dynamics. Light-front potentials for two-nucleon bound states are calculated using two approaches. First, light-front time-ordered perturbation ... More
BubbleNets: Learning to Select the Guidance Frame in Video Object Segmentation by Deep Sorting FramesMar 28 2019Semi-supervised video object segmentation has made significant progress on real and challenging videos in recent years. The current paradigm for segmentation methods and benchmark datasets is to segment objects in video provided a single annotation in ... More
Tukey-Inspired Video Object SegmentationNov 19 2018Nov 30 2018We investigate the problem of strictly unsupervised video object segmentation, i.e., the separation of a primary object from background in video without a user-provided object mask or any training on an annotated dataset. We find foreground objects in ... More
Discovery probability of next-generation neutrinoless double-$β$ decay experimentsMay 08 2017Jul 21 2017The Bayesian discovery probability of future experiments searching for neutrinoless double-$\beta$ decay is evaluated under the popular assumption that neutrinos are their own antiparticles. A Bayesian global fit is performed to construct a probability ... More
Reduced fusion systems over $p$-groups with abelian subgroup of index $p$: IIJun 16 2016Jul 21 2017Let $p$ be an odd prime, and let $S$ be a $p$-group with a unique elementary abelian subgroup $A$ of index $p$. We classify the simple fusion systems over all such groups $S$ in which $A$ is essential. The resulting list, which depends on the classification ... More
M2M modelling of the Galactic disc via PRIMAL: Fitting to Gaia Error Added DataDec 17 2013Jul 01 2014We have adapted our made-to-measure (M2M) algorithm PRIMAL to use mock Milky Way like data constructed from an N-body barred galaxy with a boxy bulge in a known dark matter potential. We use M0 giant stars as tracers, with the expected error of the ESA ... More
ARREST: A RSSI Based Approach for Mobile Sensing and Tracking of a Moving ObjectJul 18 2017Oct 24 2017We present Autonomous Rssi based RElative poSitioning and Tracking (ARREST), a new robotic sensing system for tracking and following a moving, RF-emitting object, which we refer to as the Leader, solely based on signal strength information. This kind ... More
Switching between Limit Cycles in a Model of Running Using Exponentially Stabilizing Discrete Control Lyapunov FunctionJul 07 2018This paper considers the problem of switching between two periodic motions, also known as limit cycles, to create agile running motions. For each limit cycle, we use a control Lyapunov function to estimate the region of attraction at the apex of the flight ... More
Dynamics and Collisional Evolution of Closely Packed Planetary SystemsJun 06 2017High-multiplicity Kepler systems (referred to as Kepler multis) are often tightly packed and may be on the verge of instability. Many systems of this type could have experienced past instabilities, where the compact orbits and often low densities make ... More
Ruprecht 147: The oldest nearby open cluster as a new benchmark for stellar astrophysicsJun 27 2012Jan 05 2013Ruprecht 147 is a hitherto unappreciated open cluster that holds great promise as a standard in fundamental stellar astrophysics. We have conducted a radial velocity survey of astrometric candidates with Lick, Palomar, and MMT observatories and have identified ... More
Transit Observations of the WASP-10 SystemMar 09 2010We present here observations of the transit of WASP-10b on 14 October 2009 UT taken from the University of Arizona's 1.55 meter Kuiper telescope on Mt. Bigelow. Conditions were photometric and accuracies of 2.0 mmag RMS were obtained throughout the transit. ... More
Amplitude Variability in gamma Dor and delta Scuti stars observed by the Kepler SpacecraftMay 14 2016The NASA Kepler spacecraft data revealed a large number of multimode nonradially pulsating gamma Dor and delta Sct variable star candidates. The high precision long time-series photometry makes it possible to study amplitude variations of the frequencies. ... More
A Super-Earth and two sub-Neptunes transiting the bright, nearby, and quiet M-dwarf TOI-270Mar 14 2019We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three small planets transiting one of the brightest (K-mag 8.3) and nearest (22.5 parsec) M-dwarf hosts to date, TOI-270 (TIC 259377017). The system is observationally favourable, ... More
Custom Chipset and Compact Module Design for a 75-110 GHz Laboratory Signal SourceJul 19 2016We report on the development and characterization of a compact, full-waveguide bandwidth (WR-10) signal source for general-purpose testing of mm-wave components. The MMIC-based multichip module is designed for compactness and ease-of-use, especially in ... More
Optimization based evaluation of grating interferometric phase stepping series and analysis of mechanical setup instabilitiesApr 29 2018The diffraction contrast modalities accessible by X-ray grating interferometers are not imaged directly but have to be inferred from sine like signal variations occurring in a series of images acquired at varying relative positions of the interferometer's ... More
Approximation theorems for spaces of localitiesJan 09 2019The classical Artin--Whaples approximation theorem allows to simultaneously approximate finitely many different elements of a field with respect to finitely many pairwise inequivalent absolute values. Several variants and generalizations exist, for example ... More
A Revised Orbital Ephemeris for HAT-P-9bJun 17 2010We present here three transit observations of HAT-P-9b taken on 14 February 2010, 18 February 2010, and 05 April 2010 UT from the University of Arizona's 1.55 meter Kuiper telescope on Mt. Bigelow. Our transit light curves were obtained in the I filter ... More
TESS Discovery of a Transiting Super-Earth in the $π$ Mensae SystemSep 16 2018Nov 08 2018We report the detection of a transiting planet around $\pi$ Mensae (HD 39091), using data from the Transiting Exoplanet Survey Satellite (TESS). The solar-type host star is unusually bright (V=5.7) and was already known to host a Jovian planet on a highly ... More
The Science Case for an Extended Spitzer MissionOct 11 2017Although the final observations of the Spitzer Warm Mission are currently scheduled for March 2019, it can continue operations through the end of the decade with no loss of photometric precision. As we will show, there is a strong science case for extending ... More
Mathematical Morphology: Star/Galaxy Differentiation & Galaxy Morphology ClassificationNov 02 2006We present an application of Mathematical Morphology (MM) for the classification of astronomical objects, both for star/galaxy differentiation and galaxy morphology classification. We demonstrate that, for CCD images, 99.3 +/- 3.8 % of galaxies can be ... More
The Moduli and Gravitino (non)-Problems in Models with Strongly Stabilized ModuliOct 31 2013In gravity mediated models and in particular in models with strongly stabilized moduli, there is a natural hierarchy between gaugino masses, the gravitino mass and moduli masses: $m_{1/2} \ll m_{3/2} \ll m_{\phi}$. Given this hierarchy, we show that 1) ... More
Identifying Exoplanets with Deep Learning III: Automated Triage and Vetting of TESS CandidatesApr 04 2019May 14 2019NASA's Transiting Exoplanet Survey Satellite (TESS) presents us with an unprecedented volume of space-based photometric observations that must be analyzed in an efficient and unbiased manner. With at least $\sim1,000,000$ new light curves generated every ... More
TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844Sep 19 2018Data from the newly-commissioned \textit{Transiting Exoplanet Survey Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf located 15 pc away. The planet has a radius of $1.32\pm 0.02$ $R_\oplus$ and orbits the star every 11 hours. ... More
Clocked single-spin source based on a spin-split superconductorFeb 29 2016Sep 23 2016We propose an accurate clocked single-spin source for ac-spintronic applications. Our device consists of a superconducting island covered by a ferromagnetic insulator layer through which it is coupled to superconducting leads. Single-particle transfer ... More
Effective lattice theories for Polyakov loopsJun 25 2003Oct 17 2003We derive effective actions for SU(2) Polyakov loops using inverse Monte Carlo techniques. In a first approach, we determine the effective couplings by requiring that the effective ensemble reproduces the single-site distribution of the Polyakov loops. ... More
Effective sigma models and lattice Ward identitiesOct 14 2002We perform a lattice analysis of the Faddeev-Niemi effective action conjectured to describe the low-energy sector of SU(2) Yang-Mills theory. To this end we generate an ensemble of unit vector fields ("color spins") n from the Wilson action. The ensemble ... More
Automorphic products of singular weight for simple latticesFeb 09 2015We classify the simple even lattices of square free level and signature (2,n) for n > 3. A lattice is called simple if the space of cusp forms of weight 1+n/2 for the dual Weil representation of the lattice is trivial. For a simple lattice every formal ... More
Equilibrium finite-frequency noise of an interacting mesoscopic capacitor studied in time-dependent density functional theoryFeb 27 2018We calculate the frequency-dependent equilibrium noise of a mesoscopic capacitor in time-dependent density functional theory (TDDFT). The capacitor is modeled as a single-level quantum dot with on-site Coulomb interaction and tunnel coupling to a nearby ... More
An Efficient Algorithm for Clustering of Large-Scale Mass Spectrometry DataJan 04 2013High-throughput spectrometers are capable of producing data sets containing thousands of spectra for a single biological sample. These data sets contain a substantial amount of redundancy from peptides that may get selected multiple times in a LC-MS/MS ... More