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Adaptive Optics Observations of Exoplanets, Brown Dwarfs, & Binary StarsDec 08 2011The current direct observations of brown dwarfs and exoplanets have been obtained using instruments not specifically designed for overcoming the large contrast ratio between the host star and any wide-separation faint companions. However, we are about ... More

A New Method for Characterizing Very-Low-Mass Companions with Low Resolution Near-Infrared SpectroscopyApr 20 2015Apr 22 2015We present a new and computationally efficient method for characterizing very low mass companions using low resolution ($R\sim$30) near-infrared ($YJH$) spectra from high contrast imaging campaigns with integral field spectrograph (IFS) units. We conduct ... More

High-Contrast Observations in Optical and Infrared AstronomyMar 25 2009High-contrast observations in optical and infrared astronomy are defined as any observation requiring a technique to reveal a celestial object of interest that is in such close angular proximity to another source brighter by a factor of at least 10^5 ... More

The Effect of Binarity on Circumstellar Disk EvolutionJun 12 2019We present new results on how the presence of stellar companions affects disk evolution based on a study of the 5-11 Myr old Upper Scorpius OB Association. Of the 50 G0-M3 Upper Sco members with disks in our sample, only seven host a stellar companion ... More

The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-Rich Stars in the Solar NeighborhoodMar 15 2019Young stars in the solar neighborhood serve as nearby probes of stellar evolution and represent promising targets to directly image self-luminous giant planets. We have carried out an all-sky search for late-type ($\approx$K7$-$M5) stars within 100 pc ... More

The Luminous Erupting Dwarf Nova CV1 in the Dense Globular Cluster M15Aug 27 2004Despite decades-old predictions of the expected presence of dozens of cataclysmic variables in the cores of globular clusters, the number of irrefutable, out-bursting candidates is still barely a handful. Using multi-wavelength, multi-epoch HST images ... More

Cataclysmic and Close Binaries in Star Clusters. V. Erupting Dwarf Novae, Faint Blue Stars, X-ray sources, and the Classical Nova in the Core of M80Aug 18 2005Large populations of cataclysmic variables (CVs) in globular clusters have long been predicted, but the number of absolutely certain cluster CVs known in globulars is still less than 10. HST and Chandra observers have recently found dozens of cataclysmic ... More

Speckle Suppression with the Project 1640 Integral Field SpectrographDec 17 2010Project 1640 is a high-contrast imaging instrument recently commissioned at Palomar observatory. A combination of a coronagraph with an integral field spectrograph (IFS), Project 1640 is designed to detect and characterize extrasolar planets, brown dwarfs, ... More

Application of a damped Locally Optimized Combination of Images method to the spectral characterization of faint companions using an Integral Field SpectrographNov 25 2011High-contrast imaging instruments are now being equipped with integral field spectrographs (IFS) to facilitate the detection and characterization of faint substellar companions. Algorithms currently envisioned to handle IFS data, such as the Locally Optimized ... More

Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 BJan 06 2016Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet ... More

The Solar-System-Scale Disk Around AB AurigaeMar 25 2008The young star AB Aurigae is surrounded by a complex combination of gas-rich and dust dominated structures. The inner disk which has not been studied previously at sufficient resolution and imaging dynamic range seems to contain very little gas inside ... More

Constraining mass ratio and extinction in the FU Orionis binary system with infrared integral field spectroscopyNov 28 2012We report low resolution near infrared spectroscopic observations of the eruptive star FU Orionis using the Integral Field Spectrograph Project 1640 installed at the Palomar Hale telescope. This work focuses on elucidating the nature of the faint source, ... More

Erupting Dwarf Novae in the Large Magellanic CloudSep 10 2003We report the first likely detections of erupting Dwarf Novae (DN) in an external galaxy: the Large Magellanic Cloud. Six candidates were isolated from approximately a million stars observed every second night over 11 nights with the CTIO 8K x 8K Mosaic2 ... More

An isoperimetric inequality on the $\ell_p$ ballsJul 17 2006May 23 2008The normalised volume measure on the $\ell_p^n$ unit ball ($1\leq p\leq 2$) satisfies the following isoperimetric inequality: the boundary measure of a set of measure $a$ is at least $cn^{1/p}\tilde{a}\log^{1-1/p}(1/\tilde{a})$, where $\tilde{a}=\min(a,1-a)$. ... More

Tail-sensitive Gaussian asymptotics for marginals of concentrated measures in high dimensionJan 22 2005Aug 12 2005If the Euclidean norm is strongly concentrated with respect to a measure, the average distribution of an average marginal of this measure has Gaussian asymptotics that captures tail behaviour. If the marginals of the measure have exponential moments, ... More

Fluctuations of interlacing sequencesOct 09 2016In a series of works published in the 1990-s, Kerov put forth various applications of the Markov correspondence to the limiting shape of random continual diagrams arising in representation theory and spectral theory. We demonstrate on several examples ... More

The spectral edge of some random band matricesJun 22 2009Jun 24 2010We study the asymptotic distribution of the eigenvalues of random Hermitian periodic band matrices, focusing on the spectral edges. The eigenvalues close to the edges converge in distribution to the Airy point process if (and only if) the band is sufficiently ... More

Random matrices, non-backtracking walks, and orthogonal polynomialsMar 13 2007Oct 28 2007Several well-known results from the random matrix theory, such as Wigner's law and the Marchenko--Pastur law, can be interpreted (and proved) in terms of non-backtracking walks on a certain graph. Orthogonal polynomials with respect to the limiting spectral ... More

Fluctuations of interlacing sequencesOct 09 2016Oct 31 2016In a series of works published in the 1990-s, Kerov put forth various applications of the circle of ideas centred at the Markov moment problem to the limiting shape of random continual diagrams arising in representation theory and spectral theory. We ... More

On the critical points of random matrix characteristic polynomials and of the Riemann $ξ$-functionNov 30 2016A one-parameter family of point processes describing the distribution of the critical points of the characteristic polynomial of large random Hermitian matrices on the scale of mean spacing is investigated. Conditionally on the Riemann hypothesis and ... More

The Tracy--Widom law for some sparse random matricesMar 25 2009Jan 18 2011Consider the random matrix obtained from the adjacency matrix of a random d-regular graph by multiplying every entry by a random sign. The largest eigenvalue converges, after proper scaling, to the Tracy--Widom distribution.

Several applications of the moment method in random matrix theoryJun 13 2014Several applications of the moment method in random matrix theory, especially, to local eigenvalue statistics at the spectral edges, are surveyed, with emphasis on a modification of the method involving orthogonal polynomials.

An estimate for the average spectral measure of random band matricesJan 23 2011Jun 04 2011For a class of random band matrices of band width $W$, we prove regularity of the average spectral measure at scales $\epsilon \geq W^{-0.99}$, and find its asymptotics at these scales.

Positive temperature versions of two theorems on first-passage percolationJan 29 2013Jan 06 2014The estimates on the fluctuations of first-passsage percolation due to Talagrand (a tail bound) and Benjamini--Kalai--Schramm (a sublinear variance bound) are transcribed into the positive-temperature setting of random Schroedinger operators.

On the number of zeros of functions in analytic quasianalytic classesFeb 13 2019A space of analytic functions in the unit disc with uniformly continuous derivatives is said to be quasianalytic if the boundary value of a non-zero function from the class can not have a zero of infinite multiplicity. Such classes were described in the ... More

A limit theorem at the spectral edge for corners of time-dependent Wigner matricesDec 04 2013Sep 30 2014For the eigenvalues of principal submatrices of stochastically evolving Wigner matrices, we construct and study the edge scaling limit: a random decreasing sequence of continuous functions of two variables, which at every point has the distribution of ... More

On a uniqueness theorem of E. B. VulMar 05 2019We recall a uniqueness theorem of E. B. Vul pertaining to a version of the cosine transform originating in spectral theory. Then we point out an application to the Bernstein approximation problem with non-symmetric weights: a theorem of Volberg is proved ... More

Optical-NIR Color Gradients in Early Type Galaxies at z \leq 1.0Sep 27 2001Recent studies based on line indices of nearby early-type galaxies suggest that stars in the galaxies' inner part may be younger and more metal rich than stars in the outer part. If confirmed, the finding has a profound implication for the formation and ... More

The CfAO's Astronomy Course in COSMOS: Curriculum Design, Rationale, and ApplicationNov 02 2010From 2001 to 2007, COSMOS provided a teaching and outreach venue for the Center for Adaptive Optics Professional Development Program (CfAO PDP). COSMOS is a four-week residential mathematics and science summer program for high-school students organized ... More

High Resolution Infrared Imaging & Spectroscopy of the Z Canis Majoris System During Quiescence & OutburstDec 11 2012We present adaptive optics photometry and spectra in the JHKL-bands along with high spectral resolution K-band spectroscopy for each component of the Z Canis Majoris system. Our high angular resolution photometry of this very young (<1 Myr) binary, comprised ... More

Detection of Ks-band Thermal Emission from WASP-3bFeb 15 2012We report the detection of thermal emission from the hot Jupiter WASP-3b in the KS band, using a newly developed guiding scheme for the WIRC instrument at the Palomar Hale 200in telescope. Our new guiding scheme has improved the telescope guiding precision ... More

The nearby, young, isolated, dusty star HD 166191Aug 02 2013Sep 06 2013We report an in-depth study of the F8-type star HD 166191, identified in an ongoing survey for stars exhibiting infrared emission above their expected photospheres in the Wide-field Infrared Survey Explorer all-sky catalog. The fractional IR luminosity ... More

A New High Contrast Imaging Program at Palomar ObservatoryNov 30 2010We describe a new instrument that forms the core of a long-term high contrast imaging program at the 200-inch Hale Telescope at Palomar Observatory. The primary scientific thrust is to obtain images and low-resolution spectroscopy of brown dwarfs and ... More

Discovery and Characterization of a Faint Stellar Companion to the A3V Star Zeta VirginisFeb 04 2010Through the combination of high-order Adaptive Optics and coronagraphy, we report the discovery of a faint stellar companion to the A3V star zeta Virginis. This companion is ~7 magnitudes fainter than its host star in the H-band, and infrared imaging ... More

Observational Constraints on Companions inside of 10 AU in the HR 8799 Planetary SystemFeb 18 2011We report the results of Keck L'-band non-redundant aperture masking of HR 8799, a system with four confirmed planetary mass companions at projected orbital separations of 14 to 68 AU. We use these observations to place constraints on the presence of ... More

Characterization of the Companion to $μ$ HerApr 21 2016$\mu$ Her is a nearby quadruple system with a G-subgiant primary and several low mass companions arranged in a 2+2 architecture. While the BC components have been well characterized, the Ab component has been detected astrometrically and with direct imaging ... More

Know the Star, Know the Planet. V. Characterization of the Stellar Companion to the Exoplanet Host HD 177830Jul 28 2015Jul 29 2015HD 177830 is an evolved K0IV star with two known exoplanets. In addition to the planetary companions it has a late-type stellar companion discovered with adaptive optics imagery. We observed the binary star system with the PHARO near-IR camera and the ... More

Electric Field Conjugation with the Project 1640 coronagraphSep 24 2013The Project 1640 instrument on the 200-inch Hale telescope at Palomar Observatory is a coronagraphic instrument with an integral field spectrograph at the back end, designed to find young, self-luminous planets around nearby stars. To reach the necessary ... More

Ground-based detections of thermal emission from CoRoT-1b and WASP-12bSep 23 2011We report a new detection of the H-band thermal emission of CoRoT-1b and two confirmation detections of the Ks-band thermal emission of WASP-12b at secondary eclipses. The H-band measurement of CoRoT-1b shows an eclipse depth of 0.145%\pm0.049% with a ... More

Establishing Alpha Oph as a Prototype Rotator: Improved Astrometric OrbitOct 19 2010The nearby star Alpha Oph (Ras Alhague) is a rapidly rotating A5IV star spinning at ~89% of its breakup velocity. This system has been imaged extensively by interferometric techniques, giving a precise geometric model of the star's oblateness and the ... More

Erupting Cataclysmic Variable Stars in the Nearest Globular Cluster, NGC 6397: Intermediate Polars?Jun 28 2005Jul 01 2005NGC 6397 is the closest globular cluster, and hence the ideal place to search for faint stellar populations such as cataclysmic variables (CVs). HST and Chandra observers have identified nine certain and likely CVs in this nearby cluster, including several ... More

A Data Cube Extraction Pipeline for a Coronagraphic Integral Field SpectrographApr 27 2011Project 1640 is a high contrast near-infrared instrument probing the vicinities of nearby stars through the unique combination of an integral field spectrograph with a Lyot coronagraph and a high-order adaptive optics system. The extraordinary data reduction ... More

A warm Jupiter-sized planet transiting the pre-main sequence star V1298 TauFeb 26 2019We report the detection of V1298 Tau b, a warm Jupiter-sized planet ($R_P = 0.90 \pm 0.05~ R_\mathrm{Jup}, P = 24.1$ days) transiting a young solar analog with an estimated age of 23 million years. While hot Jupiters have been previously reported around ... More

The Lyot Project Direct Imaging Survey of Substellar Companions: Statistical Analysis and Information from NondetectionsJun 17 2010The Lyot project used an optimized Lyot coronagraph with Extreme Adaptive Optics at the 3.63m Advanced Electro-Optical System telescope (AEOS) to observe 86 stars from 2004 to 2007. In this paper we give an overview of the survey results and a statistical ... More

An extension of a Bourgain--Lindenstrauss--Milman inequalityJun 18 2007Let || . || be a norm on R^n. Averaging || (\eps_1 x_1, ..., \eps_n x_n) || over all the 2^n choices of \eps = (\eps_1, ..., \eps_n) in {-1, +1}^n, we obtain an expression ||| . ||| which is an unconditional norm on R^n. Bourgain, Lindenstrauss and Milman ... More

The trimmed Anderson model at strong disorder: localisation and its breakupSep 29 2014Jan 10 2015We explore the properties of discrete random Schroedinger operators in which the random part of the potential is supported on a sub-lattice. In particular, we provide new conditions on the sub-lattice under which Anderson localisation happens at strong ... More

A Hyperelliptic View on Teichmuller Space. IIJul 09 2009Using the methods of the previous paper [ABG], we show that the Teichmuller space T of all closed Riemann surfaces is fibred twice over the Teichmuller space H of hyperelliptic ones. Both fibre bundles \pi_1,\pi_2:T->H are real algebraic (rational). They ... More

An isoperimetric inequality for uniformly log-concave measures and uniformly convex bodiesMar 28 2007Nov 21 2007We prove an isoperimetric inequality for the uniform measure on a uniformly convex body and for a class of uniformly log-concave measures (that we introduce). These inequalities imply (up to universal constants) the log-Sobolev inequalities proved by ... More

A note on superposition of two unknown states using Deutsch CTC modelMay 17 2016Sep 05 2016In a recent work, authors prove a yet another no-go theorem that forbids the existence of a universal probabilistic quantum protocol producing a superposition of two unknown quantum states. In this short note, we show that in the presence of closed time ... More

Almost Euclidean sections of the N-dimensional cross-polytope using O(N) random bitsJan 03 2007Oct 20 2008It is well known that R^N has subspaces of dimension proportional to N on which the \ell_1 norm is equivalent to the \ell_2 norm; however, no explicit constructions are known. Extending earlier work by Artstein--Avidan and Milman, we prove that such a ... More

Froehlich Polaron and Bipolaron: Recent DevelopmentsApr 23 2009Apr 27 2009It is remarkable how the Froehlich polaron, one of the simplest examples of a Quantum Field Theoretical problem, as it basically consists of a single fermion interacting with a scalar Bose field of ion displacements, has resisted full analytical or numerical ... More

Character varieties as a tensor productOct 09 2016In this short note we show that representation and character varieties of discrete groups can be viewed as tensor products of suitable functors over the PROP of cocommutative Hopf algebras. Such view point has several interesting applications. First, ... More

Real eigenvalues in the non-Hermitian Anderson modelJul 07 2017Jan 28 2018The eigenvalues of the Hatano--Nelson non-Hermitian Anderson matrices, in the spectral regions in which the Lyapunov exponent exceeds the non-Hermiticity parameter, are shown to be real and exponentially close to the Hermitian eigenvalues. This complements ... More

Bounds on the concentration function in terms of Diophantine approximationJun 18 2007Nov 20 2007We demonstrate a simple analytic argument that may be used to bound the Levy concentration function of a sum of independent random variables. The main application is a version of a recent inequality due to Rudelson and Vershynin, and its multidimensional ... More

The KPZ equation and moments of random matricesJan 08 2018Dec 13 2018The logarithm of the diagonal matrix element of a high power of a random matrix converges to the Cole-Hopf solution of the Kardar-Parisi-Zhang equation in the sense of one-point distributions.

Anomalous Behavior of the Upper Critical Field in Extreme Type-II Superconductors at Low TemperaturesOct 22 1998We present a detailed numerical calculation of the upper critical field $H_{c2}(T)$ for a bulk extreme type-II superconductor. Particular emphasis is placed on the high-field, low-temperature regime of the HT-phase diagram. In this regime it is necessary ... More

Semi-classical analysis of non self-adjoint transfer matrices in statistical mechanics. IJul 29 2014Jan 10 2015We propose a way to study one-dimensional statistical mechanics models with complex-valued action using transfer operators. The argument consists of two steps. First, the contour of integration is deformed so that the associated transfer operator is a ... More

Order-Invariant MSO is Stronger than Counting MSO in the FiniteJun 26 2007Mar 20 2008We compare the expressiveness of two extensions of monadic second-order logic (MSO) over the class of finite structures. The first, counting monadic second-order logic (CMSO), extends MSO with first-order modulo-counting quantifiers, allowing the expression ... More

On the Measure of the Absolutely Continuous Spectrum for Jacobi MatricesJul 28 2010Nov 30 2010We apply the methods of classical approximation theory (extreme properties of polynomials) to study the essential support $\Sigma_{ac}$ of the absolutely continuous spectrum of Jacobi matrices. First, we prove an upper bound on the measure of $\Sigma_{ac}$ ... More

Density of states of a type-II superconductor in a high magnetic field: Impurity effectsJun 28 1997We have calculated the density of states $N(\omega)$ of a dirty but homogeneous superconductor in a high magnetic field. We assume a dilute concentration of scalar impurities and find how $N(\omega)$ behaves as one crosses from the weak scattering to ... More

On `A characterization of R-Fuchsian groups acting on the complex hyperbolic plane'Jul 10 2011We indicate a C-Fuchsian counter-example to the result with the above title announced at http://www.maths.dur.ac.uk/events/Meetings/LMS/2011/GAL11/program.pdf and prove a stronger statement.

Reflections, bendings, and pentagonsJan 07 2012Jan 10 2012We study relations between reflections in (positive or negative) points in the complex hyperbolic plane. It is easy to see that the reflections in the points q_1,q_2 obtained from p_1,p_2 by moving p_1,p_2 along the geodesic generated by p_1,p_2 and keeping ... More

The Kappa Andromedae System: New Constraints on the Companion Mass, System Age & Further MultiplicitySep 13 2013Kappa Andromedae is a B9IVn star at 52 pc for which a faint substellar companion separated by 55 AU was recently announced. In this work, we present the first spectrum of the companion, "kappa And B," using the Project 1640 high-contrast imaging platform. ... More

Spectral Typing of Late Type Stellar Companions to Young Stars from Low Dispersion Near-Infrared Integral Field Unit DataMay 04 2012We used the Project 1640 near-infrared coronagraph and integral field spectrograph to observe 19 young solar type stars. Five of these stars are known binary stars and we detected the late-type secondaries and were able to measure their JH spectra with ... More

Gemini Planet Imager Observational Calibrations V: Astrometry and DistortionJul 09 2014We present the results of both laboratory and on sky astrometric characterization of the Gemini Planet Imager (GPI). This characterization includes measurement of the pixel scale of the integral field spectrograph (IFS), the position of the detector with ... More

Three Wide Planetary-Mass Companions to FW Tau, ROXs 12, and ROXs 42BNov 29 2013Jan 02 2014We report the discovery of three planetary-mass companions (M = 6--20 $M_{Jup}$) in wide orbits ($\rho \sim$ 150--300 AU) around the young stars FW Tau (Taurus-Auriga), ROXs 12 (Ophiuchus), and ROXs 42B (Ophiuchus). All three wide planetary-mass companions ... More

The Palomar Kernel Phase Experiment: Testing Kernel Phase Interferometry for Ground-based Astronomical ObservationsOct 21 2015At present, the principal limitation on the resolution and contrast of astronomical imaging instruments comes from aberrations in the optical path, which may be imposed by the Earth's turbulent atmosphere or by variations in the alignment and shape of ... More

Discovery of a low-mass companion around HR3549Sep 18 2015We report the discovery of a low-mass companion to HR3549, an A0V star surrounded by a debris disk with a warm excess detected by WISE at 22 $\mu$m ($10\sigma$ significance). We imaged HR3549 B in the L-band with NAOS-CONICA, the adaptive optics infrared ... More

Friends of Hot Jupiters III: An Infrared Spectroscopic Search for Low-Mass Stellar CompanionsOct 27 2015Surveys of nearby field stars indicate that stellar binaries are common, yet little is known about the effects that these companions may have on planet formation and evolution. The Friends of Hot Jupiters project uses three complementary techniques to ... More

The Water Abundance of the Directly Imaged Substellar Companion κ And b Retrieved from a Near Infrared SpectrumApr 01 2015Mar 10 2016Spectral retrieval has proven to be a powerful tool for constraining the physical properties and atmospheric compositions of extrasolar planet atmospheres from observed spectra, primarily for transiting objects but also for directly imaged planets and ... More

A Survey for H$α$ Pulsar Bow ShocksFeb 22 2014We report on a survey for H$\alpha$ bow shock emission around nearby $\gamma$-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around {\it Fermi} ... More

A Limit Theorem for Stochastically Decaying Partitions at the EdgeApr 05 2016Oct 05 2016In this paper, we study the asymptotic behavior of the first, second, and so on rows of stochastically decaying partitions. We establish that, with appropriate scaling in time and length, the sequence of rows converges to the Airy$_2$ line ensemble. This ... More

FPGA Implementation of High Speed Reconfigurable Filter Bank for Multi-standard Wireless Communication ReceiversSep 15 2016In next generation wireless communication system, wireless transceivers should be able to handle wideband input signals compromising of multiple communication standards.Such multi-standard wireless communication receivers (MWCRs) need filter bank to extract ... More

One more proof of the Erdős--Turán inequality, and an error estimate in Wigner's lawJan 12 2009We prove the Erdos-Turan equidistribution inequality, using a construction due to Chebyshev, Markov, and Stieltjes. The method is applicable in a more general setting. As an example, we state another inequality that can be proved using this method. The ... More

A geometrothermodynamic approach to ideal quantum gases and Bose-Einstein condensatesDec 29 2015May 24 2016We analyze in the context of geometrothermodynamics the behavior of ideal quantum gases which satisfy either the Fermi statistics or the Bose statistics. Although the corresponding Hamiltonian does not contain a potential, indicating the lack of classical ... More

Complex Hyperbolic Structures on Disc Bundles over Surfaces. II. Example of a Trivial BundleDec 17 2005Feb 23 2007This article is based on the methods developed in [AGG]. We construct a complex hyperbolic structure on a trivial disc bundle over a closed orientable surface $\Sigma$ (of genus 2) thus solving a long standing problem in complex hyperbolic geometry (see ... More

A universality result for the smallest eigenvalues of certain sample covariance matricesDec 10 2008Jun 20 2009After proper rescaling and under some technical assumptions, the smallest eigenvalue of a sample covariance matrix with aspect ratio bounded away from 1 converges to the Tracy--Widom distribution. This complements the results on the largest eigenvalue, ... More

Variations on the Berry-Esseen theoremFeb 21 2010We analyze the quality of the gaussian approximation to linear combinations of n independent, identically-distributed random variables with finite fourth moments. It turns out that there exist universal, simple linear combinations that perform better ... More

Any component of moduli of polarized hyperkaehler manifolds is dense in its deformation spaceAug 14 2010Oct 08 2012Let M be a compact hyperkaehler manifold, and W the coarse moduli of complex deformations of M. Every positive integer class v in $H^2(M)$ defines a divisor $D_v$ in W consisting of all algebraic manifolds polarized by v. We prove that every connected ... More

Friends of Hot Jupiters II: No Correspondence Between Hot-Jupiter Spin-Orbit Misalignment and the Incidence of Directly Imaged Stellar CompanionsDec 30 2014Jan 13 2015Multi-star systems are common, yet little is known about a stellar companion's influence on the formation and evolution of planetary systems. For instance, stellar companions may have facilitated the inward migration of hot Jupiters towards to their present ... More

Early Results from VLT-SPHERE: Long-Slit Spectroscopy of 2MASS 0122-2439B, a Young Companion Near the Deuterium Burning LimitApr 27 2015May 11 2015We present 0.95-1.80 $\mu$m spectroscopy of the $\sim$12-27 $M_{\rm Jup}$ companion orbiting the faint ($R$$\sim$13.6), young ($\sim$120 Myr) M-dwarf 2MASS J01225093--2439505 ("2M0122--2439 B") at 1.5 arcsecond separation (50 AU). Our coronagraphic long-slit ... More

Planets Around Low-Mass Stars (PALMS). VI. Discovery of a Remarkably Red Planetary-Mass Companion to the AB Dor Moving Group Candidate 2MASS J22362452+4751425Nov 01 2016We report the discovery of an extremely red planetary-mass companion to 2MASS J22362452+4751425, a $\approx$0.6 $M_{\odot}$ late-K dwarf likely belonging to the $\sim$120 Myr AB Doradus moving group. 2M2236+4751 b was identified in multi-epoch NIRC2 adaptive ... More

Discovery of Seven Companions to Intermediate Mass Stars with Extreme Mass Ratios in the Scorpius-Centaurus AssociationMay 14 2015We report the detection of seven low mass companions to intermediate-mass stars (SpT B/A/F; $M$$\approx$1.5-4.5 solar masses) in the Scorpius-Centaurus Association using nonredundant aperture masking interferometry. Our newly detected objects have contrasts ... More

Towards high-resolution astronomical imagingMay 15 2019This paper is a report from a recent meeting on "the Future of high-resolution imaging in the visible and infrared", reviewing the astronomical drivers for development and the technological advances that might boost performance. Each of the authors listed ... More

The First Scattered Light Image of the Debris Disk around the Sco-Cen target HD 129590Jun 14 2017We present the first scattered light image of the debris disk around HD 129590, a ~1.3 M$_\odot$ G1V member of the Scorpius Centaurus association with age ~10-16 Myr. The debris disk is imaged with the high contrast imaging instrument SPHERE at the Very ... More

Constraining the presence of giant planets in two-belt debris disk systems with VLT/SPHERE direct imaging and dynamical argumentsJul 03 2018Jul 11 2018Giant, wide-separation planets often lie in the gap between multiple, distinct rings of circumstellar debris: this is the case for the HR\,8799 and HD\,95086 systems, and even the solar system where the Asteroid and Kuiper belts enclose the four gas and ... More

No difference in orbital parameters of RV-detected giant planets between 0.1 and 5 au in single vs multi-stellar systemsApr 07 2017May 04 2017Our Keck/NIRC2 imaging survey searches for stellar companions around 144 systems with radial velocity (RV) detected giant planets to determine whether stellar binaries influence the planets' orbital parameters. This survey, the largest of its kind to ... More

Searching for Scatterers: High-Contrast Imaging of Young Stars Hosting Wide-Separation Planetary-Mass CompanionsJun 21 2016We have conducted an angular differential imaging survey with NIRC2 at Keck in search of close-in substellar companions to a sample of seven systems with confirmed planetary-mass companions (PMCs) on wide orbits (>50 AU). These wide-separation PMCs pose ... More

Towards high-resolution astronomical imagingMay 15 2019May 16 2019This paper is a report from a recent meeting on "the Future of high-resolution imaging in the visible and infrared", reviewing the astronomical drivers for development and the technological advances that might boost performance. Each of the authors listed ... More

Speckle Suppression Through Dual Imaging Polarimetry, and a Ground-Based Image of the HR 4796A Circumstellar DiskJun 16 2009Jun 25 2009We demonstrate the versatility of a dual imaging polarimeter working in tandem with a Lyot coronagraph and Adaptive Optics to suppress the highly static speckle noise pattern--the greatest hindrance to ground-based direct imaging of planets and disks ... More

Temporal Evolution of Coronagraphic Dynamic Range, and Constraints on Companions to VegaSep 12 2006The major obstacle to the direct detection of companions to nearby stars is the overwhelming brightness of the host star. Current instruments employing the combination of adaptive optics (AO) and coronagraphy can typically detect objects within 2'' of ... More

First Scattered-Light Image of the Debris Disk around HD 131835 with the Gemini Planet ImagerNov 20 2015We present the first scattered-light image of the debris disk around HD 131835 in $H$ band using the Gemini Planet Imager. HD 131835 is a $\sim$15 Myr old A2IV star at a distance of $\sim$120 pc in the Sco-Cen OB association. We detect the disk only in ... More

Satisfiability and Model Checking of CTL* with Graded Path ModalitiesOct 28 2014Graded path modalities count the number of paths satisfying a property, and generalize the existential (E) and universal (A) path modalities of CTL*. The resulting logic is called GCTL*. We settle the complexity of satisfiability of GCTL*, i.e., 2ExpTime-Complete, ... More

Complementarity in Genuine Nonlocality: A device independent outlookMar 30 2016May 10 2016The notion of complementarity or mutually exclusiveness of physical phenomenon has always been of keen interest to the physicists. In this work we show that there exists a complementary relationship in terms of the genuine non-locality of a multipartite ... More

Localisation for non-monotone Schroedinger operatorsJan 11 2012Oct 15 2012We study localisation effects of strong disorder on the spectral and dynamical properties of (matrix and scalar) Schroedinger operators with non-monotone random potentials, on the d-dimensional lattice. Our results include dynamical localisation, i.e. ... More

Resnet in Resnet: Generalizing Residual ArchitecturesMar 25 2016Residual networks (ResNets) have recently achieved state-of-the-art on challenging computer vision tasks. We introduce Resnet in Resnet (RiR): a deep dual-stream architecture that generalizes ResNets and standard CNNs and is easily implemented with no ... More

Machine Learning, Deepest Learning: Statistical Data Assimilation ProblemsJul 05 2017We formulate a strong equivalence between machine learning, artificial intelligence methods and the formulation of statistical data assimilation as used widely in physical and biological sciences. The correspondence is that layer number in the artificial ... More

A Hyperelliptic View on Teichmuller Space. ISep 11 2007Jul 09 2009We explicitly describe the Teichmuller space TH_n of hyperelliptic surfaces in terms of natural and effective coordinates as the space of certain (2n-6)-tuples of distinct points on the ideal boundary of the Poincare disc. We essentially use the concept ... More

Poisson asymptotics for random projections of points on a high-dimensional sphereFeb 28 2009May 25 2009Project a collection of points on the high-dimensional sphere onto a random direction. If most of the points are sufficiently far from one another in an appropriate sense, the projection is locally close in distribution to the Poisson point process.

Basic coordinate-free non-Euclidean geometryJul 02 2011These lecture notes are based on [arXiv: math/0702714, 0907.4469, 0907.4470]. We introduce and study basic aspects of non-Euclidean geometries from a coordinate-free viewpoint.