Results for "J. K. Teske"

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A subtle IR excess associated with a young White Dwarf in the Edinburgh-Cape Blue Object SurveyAug 15 2016We report the discovery of a subtle infrared excess associated with the young white dwarf EC\,05365--4749 at 3.35 and 4.6\,$\mu$m. Follow-up spectroscopic observations are consistent with a hydrogen atmosphere white dwarf of effective temperature 22\,800\,K ... More
The Curious Case of Elemental Abundance Differences in the Dual Hot Jupiter Hosts WASP-94ABJan 08 2016Binary stars provide an ideal laboratory for investigating the potential effects of planet formation on stellar composition. Assuming the stars formed in the same environment/from the same material, any compositional anomalies between binary components ... More
A 0.8-2.4 Micron Transmission Spectrum of the Hot Jupiter CoRoT-1bJan 14 2014Hot Jupiters with brightness temperatures > ~2000K can have TiO and VO molecules as gaseous species in their atmospheres. The TiO and VO molecules can potentially induce temperature inversions in hot Jupiter atmospheres and also have an observable signature ... More
Detailed Abundances of Stars with Small Planets Discovered by Kepler I: The First SampleNov 03 2015We present newly derived stellar parameters and the detailed abundances of 19 elements of seven stars with small planets discovered by NASA's Kepler Mission. Each star save one has at least one planet with a radius <= 1.6 R_Earth, suggesting a primarily ... More
Observations of Binary Stars with the Differential Speckle Survey Instrument. V. Toward an Empirical Metal-Poor Mass-Luminosity RelationMar 01 2015In an effort to better understand the details of the stellar structure and evolution of metal poor stars, the Gemini North telescope was used on two occasions to take speckle imaging data of a sample of known spectroscopic binary stars and other nearby ... More
The Effects of Stellar Companions on Exoplanet Radius DistributionsApr 26 2018Oct 29 2018Understanding the distribution and occurrence rate of small planets was a fundamental goal of the Kepler transiting exoplanet mission, and could be improved with K2 and TESS. Deriving accurate exoplanetary radii requires accurate measurements of the host ... More
Carbon and Oxygen Abundances in Cool Metal-rich Exoplanet Hosts: A Case Study of the C/O Ratio of 55 CancriSep 24 2013The super-Earth exoplanet 55 Cnc e, the smallest member of a five-planet system, has recently been observed to transit its host star. The radius estimates from transit observations, coupled with spectroscopic determinations of mass, provide constraints ... More
Optical Observations of the Transiting Exoplanet GJ 1214bFeb 14 2013Feb 22 2013We observed nine primary transits of the super-Earth exoplanet GJ 1214b in several optical photometric bands from March to August 2012, with the goal of constraining the short-wavelength slope of the spectrum of GJ 1214b. Our observations were conducted ... More
Measuring Organic Molecular Emission in Disks with Low Resolution Spitzer SpectroscopyApr 01 2011We explore the extent to which Spitzer IRS spectra taken at low spectral resolution can be used in quantitative studies of organic molecular emission from disks surrounding low mass young stars. We use Spitzer IRS spectra taken in both the high and low ... More
Reduced Activity And Large Particles From the Disintegrating Planet Candidate KIC 12557548bMay 24 2016The intriguing exoplanet candidate KIC 12557548b is believed to have a comet-like tail of dusty debris trailing a small rocky planet. The tail of debris scatters up to 1.3% of the stellar light in the Kepler observatory's bandpass (0.42 um to 0.9 um). ... More
Abundance Differences Between Exoplanet Binary Host Stars XO-2N and XO-2S -- Dependence on Stellar ParametersJan 09 2015Feb 02 2015The chemical composition of exoplanet host stars is an important factor in understanding the formation and characteristics of their orbiting planets. The best example of this to date is the planet-metallicity correlation. Other proposed correlations are ... More
C/O Ratios of Stars with Transiting Hot Jupiter ExoplanetsMar 26 2014The relative abundances of carbon and oxygen have long been recognized as fundamental diagnostics of stellar chemical evolution. Now, the growing number of exoplanet observations enable estimation of these elements in exoplanetary atmospheres. In hot ... More
Carbon and Oxygen Abundances in the Hot Jupiter Exoplanet Host Star XO-2N and its Binary CompanionApr 01 2013With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters ... More
Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010Sep 19 2017L dwarfs exhibit low-level, rotationally-modulated photometric variability generally associated with heterogeneous, cloud-covered atmospheres. The spectral character of these variations yields insight into the particle sizes and vertical structure of ... More
The Kepler Follow-Up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution ImagingDec 07 2016We present results from high-resolution, optical to near-IR imaging of host stars of Kepler Objects of Interest (KOIs), identified in the original Kepler field. Part of the data were obtained under the Kepler imaging follow-up observation program over ... More
The Kepler Follow-Up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution ImagingDec 07 2016Mar 10 2017We present results from high-resolution, optical to near-IR imaging of host stars of Kepler Objects of Interest (KOIs), identified in the original Kepler field. Part of the data were obtained under the Kepler imaging follow-up observation program over ... More
Time-Variable Accretion in the TW Hya Star/Disk SystemSep 08 2010We present two epochs of observations of TW Hya from the high-dispersion near-IR spectrograph ARIES at the MMT. We detect strong emission from the Brackett gamma transition of hydrogen, indicating an accretion rate substantially larger than previously ... More
Follow-up Imaging of Disk Candidates from the Disk Detective Citizen Science Project: New Discoveries and False-Positives in WISE Circumstellar Disk SurveysSep 25 2018The Disk Detective citizen science project aims to find new stars with excess 22-$\mu$m emission from circumstellar dust in the AllWISE data release from the Wide-field Infrared Survey Explorer (WISE). We evaluated 261 Disk Detective objects of interest ... More
Frequency of planets orbiting M dwarfs in the Solar neighbourhoodJun 11 2019The most abundant stars in the Galaxy, M dwarfs, are very commonly hosts to diverse systems of low-mass planets. Their abundancy implies that the general occurrence rate of planets is dominated by their occurrence rate around such M dwarfs. In this article, ... More
Stellar Chemical Clues As To The Rarity of Exoplanetary TectonicsJun 30 2017Jul 03 2017Earth's tectonic processes regulate the formation of continental crust, control its unique deep water and carbon cycles, and are vital to its surface habitability. A major driver of steady-state plate tectonics on Earth is the sinking of the cold subducting ... More
Observations of Binary Stars with the Differential Speckle Survey Instrument. VIII. Measures of Metal-Poor Stars and Triple Stars from 2015 to 2018Dec 12 2018We present 248 speckle observations of 43 binary and 19 trinary star systems chosen to make progress in two main areas of investigation: the fundamental properties of metal poor stars and star formation mechanisms. The observations were taken at the Gemini ... More
APOGEE Data Releases 13 and 14: Stellar Parameter and Abundance Comparisons With Independent AnalysesJul 25 2018Data from the SDSS-IV / Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) have been released as part of SDSS Data Releases 13 (DR13) and 14 (DR14). These include high resolution H-band spectra, radial velocities, and derived stellar parameters ... More
The Solar Twin Planet Search. I. Fundamental parameters of the stellar sampleAug 18 2014We are carrying out a search for planets around a sample of solar twin stars using the HARPS spectrograph. The goal of this project is to exploit the advantage offered by solar twins to obtain chemical abundances of unmatched precision. This survey will ... More
XO-2b: a hot Jupiter with a variable host star that potentially affects its measured transit depthMay 05 2015Aug 26 2015The transiting hot Jupiter XO-2b is an ideal target for multi-object photometry and spectroscopy as it has a relatively bright ($V$-mag = 11.25) K0V host star (XO-2N) and a large planet-to-star contrast ratio (R$_{p}$/R$_{s}\approx0.015$). It also has ... More
HATS-43b, HATS-44b, HATS-45b, and HATS-46b: Four Short Period Transiting Giant Planets in the Neptune-Jupiter Mass RangeJul 22 2017We report the discovery of four short period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses ... More
Magellan/PFS Radial Velocities of GJ 9827, a late K dwarf at 30 pc with Three Transiting Super-EarthsNov 03 2017Feb 28 2018The Kepler mission showed us that planets with sizes between that of Earth and Neptune appear to be the most common type in our Galaxy. These "super-Earths" continue to be of great interest for exoplanet formation, evolution, and composition studies. ... More
An ALMA and MagAO Study of the Substellar Companion GQ Lup BJan 26 2017Multi-wavelength observations provide a complementary view of the formation of young directly-imaged planet-mass companions. We report the ALMA 1.3 mm and Magellan adaptive optics (MagAO) H-alpha, i', z', and Ys observations of the GQ Lup system, a classical ... More
A Comparison of Spectroscopic versus Imaging Techniques for Detecting Close Companions to Kepler Objects of InterestAug 26 2015(Abbreviated) Kepler planet candidates require both spectroscopic and imaging follow-up observations to rule out false positives and detect blended stars. [...] In this paper, we examine a sample of 11 Kepler host stars with companions detected by two ... More
Stellar Companions to the Exoplanet Host Stars HD 2638 and HD 164509Aug 31 2016An important aspect of searching for exoplanets is understanding the binarity of the host stars. It is particularly important because nearly half of the solar-like stars within our own Milky Way are part of binary or multiple systems. Moreover, the presence ... More
Search for nearby Earth analogs I. 15 planet candidates found in PFS dataApr 18 2019The radial velocity method plays a major role in the discovery of nearby exoplanets. To efficiently find planet candidates from the data obtained in high precision radial velocity surveys, we apply a signal diagnostic framework to detect radial velocity ... More
The Magellan PFS Planet Search Program: Radial Velocity and Stellar Abundance Analyses of the 360 AU, Metal-Poor Binary "Twins" HD 133131A & BAug 22 2016Aug 29 2016We present a new precision radial velocity (RV) dataset that reveals multiple planets orbiting the stars in the $\sim$360 AU, G2$+$G2 "twin" binary HD 133131AB. Our 6 years of high-resolution echelle observations from MIKE and 5 years from PFS on the ... More
Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs II: Properties of 11 T-dwarfsDec 08 2016Brown dwarf spectra are rich in information revealing of the chemical and physical processes operating in their atmospheres. We apply a recently developed atmospheric retrieval tool to an ensemble of late T-dwarf (600-800K) near infrared spectra. With ... More
HATS-71b: A giant planet transiting an M3 dwarf star in TESS Sector 1Dec 21 2018We report the discovery of HATS-71b, a transiting gas giant planet on a P = 3.7955 day orbit around a G = 15.35 mag M3 dwarf star. HATS-71 is the coolest M dwarf star known to host a hot Jupiter. The loss of light during transits is 4.7%, more than any ... More
Constraining Stellar Photospheres as an Essential Step for Transmission Spectroscopy of Small ExoplanetsMar 14 2019Transmission spectra probe the atmospheres of transiting exoplanets, but these observations are also subject to signals introduced by magnetic active regions on host stars. Here we outline scientific opportunities in the next decade for providing useful ... More
TOI-150: A transiting hot Jupiter in the TESS southern CVZFeb 26 2019May 27 2019We report the detection of a hot Jupiter ($M_{p}=1.75_{-0.17}^{+0.14}\ M_{J}$, $R_{p}=1.38\pm0.04\ R_{J}$) orbiting a middle-aged star ($\log g=4.152^{+0.030}_{-0.043}$) in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone ... More
Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs II: Properties of 11 T-dwarfsDec 08 2016Jul 25 2017Brown dwarf spectra are rich in information revealing of the chemical and physical processes operating in their atmospheres. We apply a recently developed atmospheric retrieval tool to an ensemble of late T-dwarf (600-800K) near infrared spectra. With ... More
The LCES HIRES/Keck Precision Radial Velocity Exoplanet SurveyFeb 12 2017We describe a 20-year survey carried out by the Lick-Carnegie Exoplanet Survey Team (LCES), using precision radial velocities from HIRES on the Keck-I telescope to find and characterize extrasolar planetary systems orbiting nearby F, G, K, and M dwarf ... More
TOI-150: A transiting hot Jupiter in the TESS southern CVZFeb 26 2019We report the detection of a hot Jupiter ($M_{p}=1.72\pm0.09\ M_{J}$, $R_{p}=1.38\pm0.04\ R_{J}$) orbiting a middle-aged star ($\log g=4.152^{+0.030}_{-0.043}$) in the TESS southern continuous viewing zone ($\beta=-79.59^{\circ}$). We confirm the planetary ... More
K2-106, a system containing a metal-rich planet and a planet of lower densityMay 11 2017Sep 26 2017Planets in the mass range from 2 to 15 MEarth are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters ... More
The test case of HD26965: difficulties disentangling weak Doppler signals from stellar activityJan 11 2018We report the discovery of a radial velocity signal that can be interpreted as a planetary-mass candidate orbiting the K dwarf HD26965, with an orbital period of 42.364$\pm$0.015 days, or alternatively, as the presence of residual, uncorrected rotational ... More
A Six-Planet System Around the Star HD 34445Oct 19 2017We present a new precision radial velocity dataset that reveals a multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists of 333 precision radial velocity observations, 56 of which were previously published, and 277 which are new ... More
Doppler Monitoring of the WASP-47 Multiplanet SystemOct 13 2015Oct 28 2015We present precise Doppler observations of WASP-47, a transiting planetary system featuring a hot Jupiter with both inner and outer planetary companions. This system has an unusual architecture and also provides a rare opportunity to measure planet masses ... More
Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transitsMar 08 2016Transits of exoplanets observed in the near-UV have been used to study the scattering properties of their atmospheres and possible star-planet interactions. We observed the primary transits of 15 exoplanets (CoRoT-1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-16b, ... More
Investigating the physical properties of transiting hot Jupiters with the 1.5-m Kuiper TelescopeAug 26 2017We present new photometric data of 11 hot Jupiter transiting exoplanets (CoRoT-12b, HAT-P-5b, HAT-P-12b, HAT-P-33b, HAT-P-37b, WASP-2b, WASP-24b, WASP-60b, WASP-80b, WASP-103b, XO-3b) in order to update their planetary parameters and to constrain information ... More
A planetary system around the nearby M dwarf Gl 357 including a transiting hot Earth-sized planet optimal for atmospheric characterisationApr 29 2019May 01 2019We report the detection of a transiting Earth-size planet around Gl 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). Gl 357 b (TOI-562.01) is a transiting hot Earth-sized planet (Teq=531+-12 K) with a radius ... More
SDSS-V: Pioneering Panoptic SpectroscopyNov 09 2017SDSS-V will be an all-sky, multi-epoch spectroscopic survey of over six million objects. It is designed to decode the history of the Milky Way, trace the emergence of the chemical elements, reveal the inner workings of stars, and investigate the origin ... More
Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M Dwarf System at 6.9 ParsecsJun 24 2019We present the discovery from TESS data of LTT 1445Ab. At a distance of 6.9 parsecs, it is the second nearest transiting exoplanet system found to date, and the closest one known for which the primary is an M dwarf. The host stellar system consists of ... More
A planetary system around the nearby M dwarf Gl 357 including a transiting hot Earth-sized planet optimal for atmospheric characterisationApr 29 2019We report the detection of a transiting Earth-size planet around Gl 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). Gl 357 b (TOI-562.01) is a transiting hot Earth-like planet (Teq=531+-12 K) with a radius ... More
Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE SpectraMay 29 2018Jun 14 2018The first detailed chemical abundance analysis of the M dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5--1.7 \micron) high-resolution ($R$$\sim$22,500) spectra from the SDSS-APOGEE survey. We determined precise ... More
K2 Discovers a Busy Bee: An Unusual Transiting Neptune Found in the Beehive ClusterAug 16 2016Open clusters have been the focus of several exoplanet surveys but only a few planets have so far been discovered. The \emph{Kepler} spacecraft revealed an abundance of small planets around small, cool stars, therefore, such cluster members are prime ... More
Chemical Abundances of Main-Sequence, Turn-off, Subgiant and red giant Stars from APOGEE spectra I: Signatures of Diffusion in the Open Cluster M67Mar 12 2018Detailed chemical abundance distributions for fourteen elements are derived for eight high-probability stellar members of the solar metallicity old open cluster M67 with an age of $\sim$4 Gyr. The eight stars consist of four pairs, with each pair occupying ... More
Detecting Earth-like Biosignatures on Rocky Exoplanets around Nearby Stars with Ground-based Extremely Large TelescopesMar 22 2019As we begin to discover rocky planets in the habitable zone of nearby stars with missions like TESS and CHEOPS, we will need quick advancements on instrumentation and observational techniques that will enable us to answer key science questions, such as ... More
Doppler Monitoring of five K2 Transiting Planetary SystemsApr 05 2016May 05 2016In an effort to measure the masses of planets discovered by the NASA {\it K2} mission, we have conducted precise Doppler observations of five stars with transiting planets. We present the results of a joint analysis of these new data and previously published ... More
Chemical Abundances of M-dwarfs from the APOGEE Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186Dec 06 2016We report the first detailed chemical abundance analysis of the exoplanet-hosting M-dwarf stars Kepler-138 and Kepler-186 from the analysis of high-resolution ($R$ $\sim$ 22,500) $H$-band spectra from the SDSS IV - APOGEE survey. Chemical abundances of ... More
Chemical Abundances of M-dwarfs from the APOGEE Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186Dec 06 2016Feb 06 2017We report the first detailed chemical abundance analysis of the exoplanet-hosting M-dwarf stars Kepler-138 and Kepler-186 from the analysis of high-resolution ($R$ $\sim$ 22,500) $H$-band spectra from the SDSS IV - APOGEE survey. Chemical abundances of ... More
MagAO Imaging of Long-period Objects (MILO). I. A Benchmark M Dwarf Companion Exciting a Massive Planet around the Sun-like Star HD 7449Dec 14 2015Feb 03 2016We present high-contrast Magellan adaptive optics (MagAO) images of HD 7449, a Sun-like star with one planet and a long-term radial velocity (RV) trend. We unambiguously detect the source of the long-term trend from 0.6-2.15 \microns ~at a separation ... More
GALEX and Optical Observations of GW Librae During the Long Decline from SuperoutburstJan 06 2011The prototype of accreting, pulsating white dwarfs (GW Lib) underwent a large amplitude dwarf nova outburst in 2007. We used ultraviolet data from GALEX and ground-based optical photometry and spectroscopy to follow GW Lib for three years following this ... More
Spontaneous Magnetization of Composite FermionsOct 19 1999It is argued that the composite fermion liquid is a promising candidate for an observation of the elusive, interaction driven magnetization first proposed by Bloch seven decades ago. In analogy to what is theoretically believed to be the case for the ... More
Two-Roton Bound State in the Fractional Quantum Hall EffectApr 27 2000The true nature of the lowest-energy, long-wavelength neutral excitation of the fractional quantum Hall effect has been a long outstanding problem. In this Letter, we establish that it is a two-roton bound state.
Baryon-to-entropy ratio in very high energy nuclear collisionsOct 10 1996We compute as a function of rapidity $y$ the baryon number carried by quarks and antiquarks with $p_T > p_0 \approx$ 2 GeV produced in Pb+Pb collisions at TeV energies. The computation is carried out in lowest order QCD perturbation theory using structure ... More
Heavy ion collision multiplicities and gluon distribution functionsJun 28 2001Atomic number ($A$) and energy ($\roots$) scaling exponents of multiplicity and transverse energy in heavy ion collisions are analytically derived in the perturbative QCD + saturation model. The exponents depend on the small-$x$ behaviour of gluon distribution ... More
Production of transverse energy from minijets in next-to-leading order perturbative QCDFeb 01 2000Jun 13 2000We compute in next-to-leading order (NLO) perturbative QCD the transverse energy carried into the central rapidity unit of hadron or nuclear collisions by the partons freed in the few-GeV subcollisions. The formulation is based on a rapidity window and ... More
Lower limits for E_T and N_ch from pQCD & hydrodynamics at the central rapidity unit in central Au-Au collisions at RHICJun 21 1999Final state average transverse energy and charged particle multiplicity at the central rapidity unit of central Au-Au collisions at RHIC are studied within a framework of lowest order perturbative QCD and Bjorken's hydrodynamical picture. In particular, ... More
Mixed States of Composite Fermions Carrying Two and Four VorticesOct 09 2000There now exists preliminary experimental evidence for some fractions, such as $\nu$ = 4/11 and 5/13, that do not belong to any of the sequences $\nu=n/(2pn\pm 1)$, $p$ and $n$ being integers. We propose that these states are mixed states of composite ... More
Roton Instability of the Spin Wave Excitation in the Fully Polarized Quatum Hall State and the Phase Diagram at $ν= 2$Jan 04 2000We consider the effect of interactions on electrons confined to two dimensions at Landau level filling $\nu=2$, with the specific aim to determine the range of parameters where the fully polarized state is stable. We calculate the charge and the spin ... More
275 Candidates and 149 Validated Planets Orbiting Bright Stars in K2 Campaigns 0-10Feb 14 2018Mar 26 2018Since 2014, NASA's K2 mission has observed large portions of the ecliptic plane in search of transiting planets and has detected hundreds of planet candidates. With observations planned until at least early 2018, K2 will continue to identify more planet ... More
Density wave patterns for fermionic dipolar molecules on a square optical lattice: Mean-field-theory analysisFeb 03 2011We model a system of ultracold fermionic dipolar molecules on a two-dimensional square lattice. Assuming that the molecules are in their nondegenerate hyperfine ground state, and that the dipole moment is polarized perpendicular to the plane (as in the ... More
Transverse energy from minijets in ultrarelativistic nuclear collisions: a next-to-leading order analysisOct 27 2000We compute in next-to-leading order (NLO) perturbative QCD the amount of transverse energy produced into a rapidity region $\Delta Y$ of a nuclear collision from partons created in the few-GeV subcollisions. The NLO formulation assumes collinear factorization ... More
TBA for the Toda chainJun 15 2010We give a direct derivation of a proposal of Nekrasov-Shatashvili concerning the quantization conditions of the Toda chain. The quantization conditions are formulated in terms of solutions to a nonlinear integral equation similar to the ones coming from ... More
Centrality dependence of multiplicities in ultrarelativistic nuclear collisionsSep 21 2000We compute the centrality dependence of multiplicities of particles produced in ultrarelativistic nuclear collisions at various energies and atomic numbers. The computation is carried out in perturbative QCD with saturated densities of produced gluons ... More
Pairings on hyperelliptic curvesAug 26 2009Sep 23 2009We assemble and reorganize the recent work in the area of hyperelliptic pairings: We survey the research on constructing hyperelliptic curves suitable for pairing-based cryptography. We also showcase the hyperelliptic pairings proposed to date, and develop ... More
Real Space Multiple Scattering Calculations of Relativistic Electron Energy Loss SpectraAug 31 2007{\it Ab initio} calculations of relativistic electron energy loss spectra (REELS) are carried out using a generalization of the real-space Green's function code FEFF8 which is applicable to general aperiodic materials. Our approach incorporates relativistic ... More
Analytical studies of Spectrum Broadcast Structures in Quantum Brownian MotionMar 14 2016Spectrum Broadcast Structures are a new and fresh concept in the quantum-to-classical transition, introduced recently in the context of decoherence and the appearance of objective features in quantum mechanics. These are specific quantum state structures, ... More
Objectivisation In Simplified Quantum Brownian Motion ModelsJan 26 2015Feb 24 2015Birth of objective properties from subjective quantum world has been one of the key questions in the quantum-to-classical transition. Basing on recent results in the field, we study it in a quantum mechanical model of a boson-boson interaction-quantum ... More
Turning cool star X-ray spectra upside downOct 28 2004H1504+65 is a young white dwarf with an effective temperature of 200,000 K and is the hottest post-AGB star ever analysed with detailed model atmospheres. Chandra LETG+HRC-S spectra have revealed the richest X-ray absorption line spectrum recorded from ... More
Structure in the Lyman-Alpha ForestSep 10 1997The spatial distribution of Ly-alpha forest absorption systems toward a group of 8, closely spaced QSOs has been analysed and evidence for large scale structure has been found at <z> = 2.8. Our technique is based on the first and second moments of the ... More
Information transfer during the universal gravitational decoherenceDec 28 2016Nov 09 2017Recently Pikovski et al. have proposed in [ Pikovski I et al. 2015 Nature Phys. 11, 668] an intriguing universal decoherence mechanism, suggesting that gravitation may play a conceptually important role in the quantum-to-classical transition, albeit vanishingly ... More
Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs I: Characterizing Benchmarks, Gl570D and HD3651BApr 24 2015May 28 2015Interpreting the spectra of brown dwarfs is key to determining the fundamental physical and chemical processes occurring in their atmospheres. Powerful Bayesian atmospheric retrieval tools have recently been applied to both exoplanet and brown dwarf spectra ... More
Building an Inclusive AAS - The Critical Role of Diversity and Inclusion Training for AAS Council and Astronomy LeadershipOct 05 2016Diversity, equity and inclusion are the science leadership issues of our time. As our nation and the field of astronomy grow more diverse, we find ourselves in a position of enormous potential and opportunity: a multitude of studies show how groups of ... More
New binary parameters for the symbiotic recurrent nova T Coronae BorealisNov 13 1997Apr 19 1998The amplitude of the ellipsoidal variability, the mass function, and the evolutionary limits on the component masses have been used to constrain the binary system parameters. Contrary to all previous studies, our analysis shows that the mass ratio of ... More
Renormalization of composite operatorsNov 10 2000Feb 06 2001The blocked composite operators are defined in the one-component Euclidean scalar field theory, and shown to generate a linear transformation of the operators, the operator mixing. This transformation allows us to introduce the parallel transport of the ... More
Highly ionized Fe X-ray lines at energies 7.7-8.6 keVSep 09 2008Fe XXV lines at 1.85 A (6.70 keV) and nearby Fe XXIV satellites have been widely used for determining the temperature of the hottest parts of solar flare and tokamak plasmas, though the spectral region is crowded and the lines are blended during flare ... More
Exploiting non-adiabatic density shifts in neutrino interactionsMay 13 2005Sep 05 2006In this paper, we give an exact analytical solution to the case of neutrinos propagating through multiple non-adiabatic density profiles. The resulting oscillation probability needs to be modelled in 4-dimensional parameter space $\{n,L_0,d,\Delta L\}$, ... More
Quantitative spectroscopy of close binary starsAug 19 2011Aug 23 2011The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution, a vital aspect ... More
Lepton flavour violating Higgs Boson decays, tau --> mu gamma and B(s) --> mu+mu- in the constrained MSSM+NR with large tan betaOct 24 2005Jul 17 2006Realistic predictions are made for the rates of lepton flavour violating Higgs boson decays, tau --> mu gamma, mu --> e gamma, Bs --> mu+mu-, Bs --> tau mu and tau --> 3mu, via a top-down analysis of the Minimal Supersymmetric Standard Model(MSSM) constrained ... More
B/s0 anti-B/s0 mixing in the MSSM with large tan betaAug 17 2006Feb 25 2007The Bs-Bsbar mixing parameter Delta Ms is studied in the MSSM with large tan beta. The recent Tevatron measurement of Delta Ms is used to constrain the MSSM parameter space. From this analysis the often neglected contribution to Delta Ms from the operator ... More
Scalar condensate decay in a fermionic heat bath in the early universeMay 31 2004Aug 25 2005We consider one-loop thermal effects on the decay of a scalar field zero mode initially dominating the energy density of the universe. We assume fermionic decay channels and take into account the effects due to both particle and hole excitations, and ... More
The Computational Complexity of the Lorentz Lattice GasJul 14 1996The Lorentz lattice gas is studied from the perspective of computational complexity theory. It is shown that using massive parallelism, particle trajectories can be simulated in a time that scales logarithmically in the length of the trajectory. This ... More
Cluster Populations in Abell 2125 and 2218Jun 08 2005We combine new narrow band photometry with archival WFPC2 data for A2218 ($z$=0.18) and A2125 ($z$=0.25), two clusters with intermediate redshifts but very different cluster properties, in order to examine the evolution of galaxy populations. A2218 is ... More
Narrow Band Continuum Colors of Distant Cluster PopulationsMar 11 2003In this poster, we present new results on narrow band photometry for A2218 ($z$=0.18) and A2125 ($z$=0.25), two clusters with similar redshifts, but very different cluster properties. A2218 is a dense, elliptical-rich cluster (Bautz-Morgan type II) similar ... More
Gauge Invariant three Boson Vertices and their Ward Identities in the Standard ModelMar 19 1995In the context of the Standard Model we extend the S--matrix pinch technique for non--conserved currents to the case of three boson vertices. We outline in detail how effective gauge invariant three boson vertices can be constructed, with all three incoming ... More
Superconducting elliptical cavitiesJan 12 2012We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along ... More
Conserving approximations for the attractive Holstein and Hubbard modelsFeb 06 1994Conserving approximations are applied to the attractive Holstein and Hubbard models (on an infinite-dimensional hypercubic lattice). All effects of nonconstant density of states and vertex corrections are taken into account in the weak-coupling regime. ... More
High Energy Nuclear CollisionsNov 15 1999Highlights of the results from ultrarelativistic heavy ion collisions at CERN-SPS are reviewed. In particular, I discuss how the experimental results indicate that a collective strongly interacting system has been produced, and what are the implications ... More
Centrality Dependence of Strangeness Enhancement in Ultrarelativistic Heavy Ion Collisions - a Core-Corona EffectOct 24 2008May 19 2009In ultrarelativistic heavy ion collisions, the multiplicity of multi-strange baryons per participating nucleon increases with centrality in a different fashion for different systems and energies. At RHIC, for copper+copper (CuCu) collisions the increase ... More
The Glassy Wormlike ChainMay 03 2007Jul 30 2007We introduce a new model for the dynamics of a wormlike chain in an environment that gives rise to a rough free energy landscape, which we baptise the glassy wormlike chain. It is obtained from the common wormlike chain by an exponential stretching of ... More
Existence Theorems for $\fracπ{n}$ Vortex ScatteringMar 02 1995The analysis of $90^{\circ}$ vortex-vortex scattering is extended to $\frac{\pi}{n}$ scattering in all head-on collisions of $n$ vortices in the Abelian Higgs model. A Cauchy problem with initial data that describe the scattering of $n$ vortices is formulated. ... More
Optical colour maps of Seyfert galaxies. II. More Seyfert 2sMay 22 1998We present optical broad band B-I colour maps of a further sample of 10 Seyfert 2 galaxies. In these bands, the contribution from emission lines to the total flux is small, and hence the images predominantly trace the continuum distribution. As in our ... More
On the Role of Irradiation and Evaporation in Strongly Irradiated Accretion Disks in the Black Hole X-ray Binaries: Toward an Understanding of FREDs and Secondary MaximaApr 12 2000We examine a new paradigm to account for the exponential decay seen in the light curves of some of the bright X-ray novae. These systems show an exponential decay in soft X-rays with an e-folding time constant of ~30 d. We investigate a scenario in which ... More
The Auxiliary Mass Method beyond the Local Potential ApproximationSep 09 1999Sep 14 1999We show that the evolution equation of the effective potential in the auxiliary mass method corresponds to a leading approximation of a certain series. This series is derived from an evolution equation of an effective action using a derivative expansion. ... More