Results for "Kate Y. L. Su"

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Signpost of Multiple Planets in Debris DisksJul 05 2013We review the nearby debris disk structures revealed by multi-wavelength images from Spitzer and Herschel, and complemented with detailed spectral energy distribution modeling. Similar to the definition of habitable zones around stars, debris disk structures ... More
Could the planets around HR 8799 be brown dwarfs?Aug 30 2010We consider the limiting case for orbital stability of the companions to HR 8799. This case is only consistent with ages for the system of ~100 Myr, not with the 1 Gyr age proposed from astroseismology. The discrepancy probably arises because the inclination ... More
The first 40 million years of circumstellar disk evolution: the signature of terrestrial planet formationJan 07 2017We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2 Myr up to ~ 40 Myr: NGC 1333, NGC 1960, NGC 2232, NGC 2244, NGC 2362, ... More
A Comprehensive Dust Model Applied to the Resolved Beta Pictoris Debris Disk from Optical to Radio WavelengthsMay 05 2016We investigate whether varying the dust composition (described by the optical constants) can solve a persistent problem in debris disk modeling--the inability to fit the thermal emission without over-predicting the scattered light. We model five images ... More
Debris Distribution in HD 95086 - A Young Analog of HR 8799Nov 29 2014HD 95086 is a young early-type star that hosts (1) a 5 MJ planet at the projected distance of 56 AU revealed by direct imaging, and (2) a prominent debris disk. Here we report the detection of 69 um crystalline olivine feature from the disk using the ... More
Herschel Observations and Updated Spectral Energy Distributions of Five Sunlike Stars with Debris DisksOct 04 2016Observations from the Herschel Space Observatory have more than doubled the number of wide debris disks orbiting Sunlike stars to include over 30 systems with R > 100 AU. Here we present new Herschel PACS and re-analyzed Spitzer MIPS photometry of five ... More
What Sets the Radial Locations of Warm Debris Disks?Aug 23 2017The architectures of debris disks encode the history of planet formation in these systems. Studies of debris disks via their spectral energy distributions (SEDs) have found infrared excesses arising from cold dust, warm dust, or a combination of the two. ... More
A Study of H2 Emission in Three Bipolar Proto-Planetary Nebulae: IRAS 16594-4656, Hen 3-401, and Rob 22Aug 18 2008We have carried out a spatial-kinematical study of three proto-planetary nebulae, IRAS 16594-4656, Hen 3-401, and Rob 22. High-resolution H2 images were obtained with NICMOS on the HST and high-resolution spectra were obtained with the Phoenix spectrograph ... More
High-Resolution Near-Infrared Imaging and Polarimetry of Four Proto-Planetary NebulaeApr 22 2003High-resolution near-infrared HST NICMOS (F160W, F222M) images and polarization (2 um) observations were made of four bipolar proto-planetary nebulae (PPNs): IRAS 17150-3224, IRAS 17441-2411, IRAS 17245-3951, and IRAS 16594-4656. The first three of these ... More
A Spitzer MIPS Study of 2.5-2.0 M\odot Stars in Scorpius-CentaurusJul 14 2012We have obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 {\mu}m and 70 {\mu}m observations of 215 nearby, Hipparcos B- and A-type common proper motion single and binary systems in the nearest OB association, Scorpius-Centaurus. ... More
A statistically significant lack of debris discs in medium separation binary systemsJul 10 2019Jul 11 2019We compile a sample of 341 binary and multiple star systems with the aim of searching for and characterising Kuiper belt-like debris discs. The sample is assembled by combining several smaller samples studied in previously published work with targets ... More
Searching for Saturn's Dust Swarm: Limits on the size distribution of Irregular Satellites from km to micron sizesJul 11 2011We describe a search for dust created in collisions between the Saturnian irregular satellites using archival \emph{Spitzer} MIPS observations. Although we detected a degree scale Saturn-centric excess that might be attributed to an irregular satellite ... More
An Infrared Imaging Study of the Bipolar Proto-Planetary Nebula IRAS 16594-4656Jul 20 2006High-resolution mid-infrared images have been obtained in N-band and Q-band for the proto-planetary nebula IRAS 16594-4656. A bright equatorial torus and a pair of bipolar lobes can clearly be seen in the infrared images. The torus appears thinner at ... More
A Trend Between Cold Debris Disk Temperature and Stellar Type: Implications for the Formation and Evolution of Wide-Orbit PlanetsAug 09 2013Cold debris disks trace the limits of planet formation or migration in the outer regions of planetary systems, and thus have the potential to answer many of the outstanding questions in wide-orbit planet formation and evolution. We characterized the infrared ... More
SPITZER/IRAC-MIPS Survey of NGC2244: Protostellar Disk Survival in the Vicinity of Hot StarsJan 25 2007We present the results from a survey of NGC 2244 from 3.6 to 24 micron with the Spitzer Space Telescope. The 24micron-8micron-3.6micron color composite image of the region shows that the central cavity surrounding the multiple O and B stars of NGC2244 ... More
A statistically significant lack of debris discs in medium separation binary systemsJul 10 2019We compile a sample of 341 binary and multiple star systems with the aim of searching for and characterising Kuiper belt-like debris discs. The sample is assembled by combining several smaller samples studied in previously published work with targets ... More
Variability of the Infrared Excess of Extreme Debris DisksMay 04 2012Debris disks with extremely large infrared excesses (fractional luminosities $> 10^{-2}$) are rare. Those with ages between 30 and 130 Myr are of interest because their evolution has progressed well beyond that of protoplanetary disks (which dissipate ... More
Locating the planetesimals belts in the multiple-planet systems HD 128311, HD 202206, HD 82943 and HR 8799May 17 2010Jun 21 2010In addition to the Sun, six other stars are known to harbor multiple planets and debris disks: HD 69830, HD 38529, HD 128311, HD 202206, HD 82943 and HR 8799. In this paper we set constraints on the location of the dust-producing planetesimals around ... More
Spatially Resolved Images of Dust Belt(s) Around the Planet-hosting Subgiant Kappa CrBFeb 27 2013Mar 08 2013We present Herschel spatially resolved images of the debris disc orbiting the subgiant Kappa CrB. Not only are these the first resolved images of a debris disc orbiting a subgiant, but Kappa CrB is a rare example of an intermediate mass star where a detailed ... More
A Debris Disk around the Central Star of the Helix Nebula?Feb 11 2007Excess emission from a point-like source coincident with the central star of the Helix Nebula is detected with Spitzer at 8, 24, and 70 um. At 24 um, the central source is superposed on an extended diffuse emission region. While the [OIV] 25.89 um line ... More
Large Impacts around a Solar Analog Star in the Era of Terrestrial Planet FormationMar 18 2015Mar 20 2015The final assembly of terrestrial planets occurs via massive collisions, which can launch copious clouds of dust that are warmed by the star and glow in the infrared. We report the real-time detection of a debris-producing impact in the terrestrial planet ... More
The Structure of the β Leonis Debris DiskSep 30 2010We combine nulling interferometry at 10 {\mu}m using the MMT and Keck Telescopes with spectroscopy, imaging, and photometry from 3 to 100 {\mu}m using Spitzer to study the debris disk around {\beta} Leo over a broad range of spatial scales, corresponding ... More
The Inner Debris Structure in the Fomalhaut Planetary SystemDec 11 2015Fomalhaut plays an important role in the study of debris disks and small bodies in other planetary systems. The proximity and luminosity of the star make key features of its debris, like the water ice-line, accessible. Here we present ALMA cycle 1, 870 ... More
Spitzer 24 um Survey for Dust Disks around Hot White DwarfsJan 26 2011Jun 30 2011Two types of dust disks around white dwarfs (WDs) have been reported: small dust disks around cool metal-rich WDs consisting of tidally disrupted asteroids, and a large dust disk around the hot central WD of the Helix planetary nebula (PN) possibly produced ... More
The Inner 25 AU Debris Distribution in the epsilon Eri SystemMar 30 2017Debris disk morphology is wavelength dependent due to the wide range of particle sizes and size-dependent dynamics influenced by various forces. Resolved images of nearby debris disks reveal complex disk structures that are difficult to distinguish from ... More
Deep ALMA Search for CO Gas in the HD 95086 Debris DiscNov 01 2018One of the defining properties of debris discs compared to protoplanetary discs used to be their lack of gas, yet small amounts of gas have been found around an increasing number of debris discs in recent years. These debris discs found to have gas tend ... More
Spitzer 24 Micron Observations of Open Cluster IC 2391 and Debris Disk Evolution of FGK StarsSep 06 2006We present 24 micron Spitzer/MIPS photometric observations of the ~50 Myr open cluster IC 2391. Thirty-four cluster members ranging in spectral type from B3-M5 were observed in the central square degree of the cluster. Excesses indicative of debris disks ... More
Resolved Submillimeter Observations of the HR 8799 and HD 107146 Debris DisksJul 15 2011We present 880 um Submillimeter Array observations of the debris disks around the young solar analogue HD 107146 and the multiple-planet host star HR 8799, at an angular resolution of 3" and 6", respectively. We spatially resolve the inner edge of the ... More
Searching for Planets in Holey Debris Disks with the Apodizing Phase PlateDec 16 2014We present our first results from a high-contrast imaging search for planetary mass companions around stars with gapped debris disks, as inferred from the stars' bright infrared excesses. For the six considered stars, we model the disks' unresolved infrared ... More
Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris DisksMar 18 2015Luminous debris disks of warm dust in the terrestrial planet zones around solar-like stars are recently found to vary, indicative of ongoing large-scale collisions of rocky objects. We use Spitzer 3.6 and 4.5 {\mu}m time-series observations in 2012 and ... More
Resolved Debris Discs Around A Stars in the Herschel DEBRIS SurveyOct 01 2012The majority of debris discs discovered so far have only been detected through infrared excess emission above stellar photospheres. While disc properties can be inferred from unresolved photometry alone under various assumptions for the physical properties ... More
Asteroid Belts in Debris Disk Twins: VEGA and FOMALHAUTJan 07 2013Vega and Fomalhaut, are similar in terms of mass, ages, and global debris disk properties; therefore, they are often referred as "debris disk twins". We present Spitzer 10-35 um spectroscopic data centered at both stars, and identify warm, unresolved ... More
HD 106906 b: A planetary-mass companion outside a massive debris diskDec 04 2013We report the discovery of a planetary-mass companion, HD 106906 b, with the new Magellan Adaptive Optics (MagAO) + Clio2 system. The companion is detected with Clio2 in three bands: $J$, $K_S$, and $L^\prime$, and lies at a projected separation of 7.1'' ... More
A deep search for planets in the inner 15 au around VegaSep 18 2018We present the results of a deep high-contrast imaging search for planets around Vega. Vega is an ideal target for high-contrast imaging because it is bright, nearby, and young with a face-on two-belt debris disk which may be shaped by unseen planets. ... More
ALMA 1.3 Millimeter Map of the HD 95086 SystemSep 28 2017Planets and minor bodies such as asteroids, Kuiper-belt objects and comets are integral components of a planetary system. Interactions among them leave clues about the formation process of a planetary system. The signature of such interactions is most ... More
Infrared Variability of Two Dusty White DwarfsAug 28 2018The most heavily polluted white dwarfs often show excess infrared radiation from circumstellar dust disks, which are modeled as a result of tidal disruption of extrasolar minor planets. Interaction of dust, gas, and disintegrating objects can all contribute ... More
Transfer reaction experiments with radioactive beams: from halos to the r-processMar 28 2013Transfer reactions are a powerful probe of the properties of atomic nuclei. When used in inverse kinematics with radioactive ion beams they can provide detailed information on the structure of exotic nuclei and can inform nucleosynthesis calculations. ... More
Lattice dynamical calculations of infinite layer iron oxides SrFeO2 and CaFeO2Jul 04 2008We report extensive lattice dynamical calculations of the newly discovered infinite-layer iron oxides SrFeO2 and CaFeO2. For SrFeO2, the parameters of the interatomic potential have been determined to reproduce the zone-centre phonon frequencies reported ... More
Calculations of ${\cal O}(p^6)$ Resonance Coupling Constants in the Scalar Sector of the ENJL ModelMay 28 2007We derive the scalar resonance coupling constants of resonance chiral theory from the Extended Nambu Jona-Lasinio model by using heat-kernel expansion.
Extreme Debris Disk Variability -- Exploring the Diverse Outcomes of Large Asteroid Impacts During the Era of Terrestrial Planet FormationMar 25 2019Apr 19 2019The most dramatic phases of terrestrial planet formation are thought to be oligarchic and chaotic growth, on timescales of up to 100-200 Myr, when violent impacts occur between large planetesimals of sizes up to proto-planets. Such events are marked by ... More
Extreme Debris Disk Variability -- Exploring the Diverse Outcomes of Large Asteroid Impacts During the Era of Terrestrial Planet FormationMar 25 2019The most dramatic phases of terrestrial planet formation are thought to be oligarchic and chaotic growth, on timescales of up to 100-200 Myr, when violent impacts occur between large planetesimals of sizes up to proto-planets. Such events are marked by ... More
New debris disk candidates: 24 micron stellar excesses at 100 MyrJun 01 2004Sixty three members of the 100 Myr old open cluster M47 (NGC 2422) have been detected at 24 micron with Spitzer. The Be star V 378 Pup shows an excess both in the near-infrared and at 24 micron (K-[24] = 2.4 mag), probably due to free-free emission from ... More
Shallow Ultraviolet Transits of WD 1145+017Apr 24 2019WD 1145+017 is a unique white dwarf system that has a heavily polluted atmosphere, an infrared excess from a dust disk, numerous broad absorption lines from circumstellar gas, and changing transit features, likely from fragments of an actively disintegrating ... More
The debris disk around gamma Doradus resolved with HerschelDec 06 2012We present observations of the debris disk around gamma Doradus, an F1V star, from the Herschel Key Programme DEBRIS (Disc Emission via Bias-free Reconnaissance in the Infrared/Submillimetre). The disk is well-resolved at 70, 100 and 160 micron, resolved ... More
A Thermal Infrared Imaging Study of Very Low-Mass, Wide Separation Brown Dwarf Companions to Upper Scorpius Stars: Constraining Circumstellar EnvironmentsFeb 04 2013We present a 3-5um LBT/MMT adaptive optics imaging study of three Upper Scorpius stars with brown dwarf (BD) companions with very low-masses/mass ratios (M_BD < 25M_Jup; M_BD / M_star ~ 1-2%), and wide separations (300-700 AU): GSC 06214, 1RXS 1609, and ... More
The Incidence of Debris Disks at 24 μm and 670 MyrFeb 29 2012We use Spitzer Space Telescope 24 {\mu}m data to search for debris disks among 122 AFGKM stars from the \sim 670 Myr clusters Hyades, Coma Ber, and Praesepe, utilizing a number of advances in data reduction and determining the intrinsic colors of main ... More
On the scalar nonet in the extended Nambu Jona-Lasinio modelJun 13 2007We discuss the lightest scalar resonances, $f_0(600)$, $\kappa(800)$, $a_0(980)$ and $f_0(980)$ in the extended Nambu Jona-Lasinio model. We find that the model parameters can be tuned, but unnaturally, to accommodate for those scalars except the $f_0(980)$. ... More
Microscopic Hamiltonian for Zn or Ni substituted high temperature cuprate superconductorsMay 29 2002Jul 31 2002We have derived the effective low energy Hamiltonian for Zn or Ni substituted high-T_c cuprates from microscopic three-band models consisting of the most relevant Cu or impurity 3d and O 2p orbitals. We find that both scattering potential and hopping ... More
2-D Radiation Transfer Model of Non-Spherically Symmetric Dust Shell in P roto-Planetary NebulaeJan 05 2000We have fitted the HST images and the spectral energy distributions (SEDs) of three proto-planetary nebulae (PPN) with a 2-D radiation transfer model. The geometric and mass loss properties of these PPN are also derived.
Infrared spectra and photometry of complete samples of PG and 2MASS quasarsAug 25 2014As a step toward a comprehensive overview of the infrared diagnostics of the central engines and host galaxies of quasars at low redshift, we present Spitzer Space Telescope spectroscopic (5-40 {\mu}m) and photometric (24, 70 and 160 {\mu}m) measurements ... More
Formation and Evolution of Planetary Systems: Cold Outer Disks Associated with Sun-like starsJun 18 2005We present the discovery of debris systems around three solar mass stars based upon observations performed with the Spitzer Space Telescope as part of a Legacy Science Program, ``the Formation and Evolution of Planetary Systems'' (FEPS). We also confirm ... More
Spitzer Surveys of Infrared Excesses of White DwarfsDec 07 2010IR excesses of white dwarfs (WDs) can be used to diagnose the presence of low-mass companions, planets, and circumstellar dust. Using different combinations of wavelengths and WD temperatures, circumstellar dust at different radial distances can be surveyed. ... More
Spitzer Surveys of IR Excesses of White DwarfsDec 07 2010IR excesses of white dwarfs (WDs) can be used to diagnose the presence of low-mass companions, planets, and circumstellar dust. Using different combinations of wavelengths and WD temperatures, circumstellar dust at different radial distances can be surveyed. ... More
Hard X-ray and Infrared Emission from Apparently Single White DwarfsJan 01 2007The photospheric emission of a white dwarf (WD) is not expected to be detectable in hard X-rays or the mid-IR. Hard X-ray (~1 keV) emission associated with a WD is usually attributed to a binary companion; however, emission at 1 keV has been detected ... More
Extinction and the Dimming of KIC 8462852Aug 24 2017Sep 01 2017To test alternative hypotheses for the behavior of KIC 8462852, we obtained measurements of the star over a wide wavelength range from the UV to the mid-infrared from October 2015 through December 2016, using Swift, Spitzer and at AstroLAB IRIS. The star ... More
Dusty Cometary Globules in W5Sep 11 2008We report the discovery of four dusty cometary tails around low mass stars in two young clusters belonging to the W5 star forming region. Fits to the observed emission profiles from 24 micron observations with the Spitzer Space Telescope give tail lifetimes ... More
Electron Interaction Effects in Periodically Driven Kitaev Model: Topology Breaking and Enhancement of Quantum ChaosApr 22 2016May 10 2016The effect of electron-electron interaction on Floquet topological superconducting chains is investigated numerically through full diagonalization and time evolution. The preservation of topology in the weak interacting regime is represented by a many-body ... More
Far Infrared Prperties of M DwarfsJul 03 2007We report the mid- and far-infrared properties of nearby M dwarfs. Spitzer/MIPS measurements were obtained for a sample of 62 stars at 24 um, with subsamples of 41 and 20 stars observed at 70 um and 160 um respectively. We compare the results with current ... More
A novel route to phase formation of cobalt oxyhydrates using KMnO4 as an oxidizing agentMay 12 2004We have first succeefully synthesized the sodium cobalt oxyhydrate superconductors using KMnO4 as a de-intercalating and oxidizing agent. It is a novel route to form the superconductive phase of NaxCoO2.yH2O without resorting to the commonly used Br2/CH3CN ... More
Highly Accelerated Multishot EPI through Synergistic Machine Learning and Joint ReconstructionAug 08 2018Dec 10 2018Purpose: To introduce a combined machine learning (ML) and physics-based image reconstruction framework that enables navigator-free, highly accelerated multishot echo planar imaging (msEPI), and demonstrate its application in high-resolution structural ... More
Highly Accelerated Multishot EPI through Synergistic Machine Learning and Joint ReconstructionAug 08 2018Mar 24 2019Purpose: To introduce a combined machine learning (ML) and physics-based image reconstruction framework that enables navigator-free, highly accelerated multishot echo planar imaging (msEPI), and demonstrate its application in high-resolution structural ... More
Thermoelectric properties of Sr0.61Ba0.39Nb2O6-δ ceramics annealed in different oxygen-reduction conditionsApr 02 2014The thermoelectric properties of Sr0.61Ba0.39Nb2O6 ceramics, reduced in different conditions, were investigated in the temperature region from 323 K to 1073 K. The electrical transport behaviors of the samples are dominated by the thermal-activated polaron ... More
Layered semiconductor EuTe 4 with charge density wave order in square tellurium sheetsJan 18 2019We report a novel quasi-two dimensional compound of EuTe4 hosting charge density waves (CDW) instability. The compound has a crystallographic structure in a orthorhombic space group Pmmn (No.59) with cell parameters a = 4.6347(2){\AA}, b = 4.5119(2){\AA}, ... More
Spitzer IRS Spectroscopy of the 10 Myr-old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial ZoneApr 07 2011We describe Spitzer IRS spectroscopic observations of the 10 Myr-old star, EF Cha. Compositional modeling of the spectra from 5 {\mu}m to 35 {\mu}m confirms that it is surrounded by a luminous debris disk with LD/L\star ~ 10-3, containing dust with temperatures ... More
Resolved Millimeter Observations of the HR 8799 Debris DiskFeb 20 2018We present 1.3 millimeter observations of the debris disk surrounding the HR 8799 multi-planet system from the Submillimeter Array to complement archival ALMA observations that spatially filtered away the bulk of the emission. The image morphology at ... More
The Decay of Debris Disks around Solar-Type StarsFeb 25 2014We present a Spitzer MIPS study of the decay of debris disk excesses at 24 and 70 $\mu$m for 255 stars of types F4 - K2. We have used multiple tests, including consistency between chromospheric and X-ray activity and placement on the HR diagram, to assign ... More
Impermeable Barrier Films and Protective Coatings Based on Reduced Graphene OxideMay 09 2014Barrier films preventing permeation of gases and moistures are important for many industries ranging from food to medical and from chemical to electronic. From this perspective, graphene has recently attracted particular interest because its defect free ... More
Numerical study of the density of states for the bag modelSep 07 2001The density of states for an extended MIT bag model is studied numerically by using a parameterized smooth representation which provides the best fit to the numerical data. It is found that the mass dependence of the surface term in the density of states ... More
Spitzer/MIPS 24 micron Detection of Photoevaporating Protoplanetary DisksAug 29 2006We present 24 micron images of three protoplanetary disks being photoevaporated around high mass O type stars. These objects have ``cometary'' structure where the dust pulled away from the disk by the photoevaporating flow is forced away from the O star ... More
Low-Altitude Reconnection Inflow-Outflow Observations during a 2010 November 3 Solar EruptionNov 08 2011Jun 26 2012For a solar flare occurring on 2010 November 3, we present observations using several SDO/AIA extreme-ultraviolet (EUV) passbands of an erupting flux rope followed by inflows sweeping into a current sheet region. The inflows are soon followed by outflows ... More
Strong-field terahertz-optical mixing in excitonsFeb 11 2002Driving a double-quantum-well excitonic intersubband resonance with a terahertz (THz) electric field of frequency \omega_{THz} generated terahertz optical sidebands \omega=\omega_{THz}+\omega_{NIR} on a weak NIR probe. At high THz intensities, the intersubband ... More
HST NICMOS Observation of Proto-Planetary NebulaeJan 06 2000We report NICMOS wide-band and polarimetric observations of four proto-planetary nebulae. Molecular hydrogen emission is detected near the ends of the bipolar lobes of IRAS 17150-3224, which is evidence for the interaction of a fast, collimated outflow ... More
Voltage-controlled wavelength conversion by terahertz electro-optic modulation in double quantum wellsJan 17 2002An undoped double quantum well (DQW) was driven with a terahertz (THz) electric field of frequency \omega_{THz} polarized in the growth direction, while simultaneously illuminated with a near-infrared (NIR) laser at frequency \omega_{NIR}. The intensity ... More
Spitzer Observations of V838 Monocerotis: Detection of a Rare Infrared Light EchoMay 05 2006We present Spitzer observations of the unusual variable V838 Monocerotis. Extended emission is detected around the object at 24, 70 and 160um. The extended infrared emission is strongly correlated spatially with the HST optical light echo images taken ... More
Analytical Results for a Hole in an AntiferromagnetJan 17 1996The Green's function for a hole moving in an antiferromagnet is derived analytically in the long-wavelength limit. We find that the infrared divergence is eliminated in two and higher dimensions so that the quasiparticle weight is finite. Our results ... More
The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics ImagingMar 12 2012May 28 2012We present diffraction-limited \ks band and \lprime adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the disk is detected at ... More
A Young White Dwarf with an Infrared ExcessMay 11 2015Using observations of Spitzer/IRAC, we report the serendipitous discovery of excess infrared emission from a single white dwarf PG 0010+280. At a temperature of 27,220 K and a cooling age of 16 Myr, it is the hottest and youngest white dwarf to display ... More
Elementary Excitations in Trapped BEC and Zero Mode ProblemApr 04 2000We propose a natural expansion of the atomic field operator in studying elementary excitations in trapped Bose-Einstein Condensation (BEC) system near T=0K. Based on this expansion, a system of coupled equations for elementary excitations, which is equivalent ... More
The Origins Space TelescopeSep 19 2018The Origins Space Telescope, one of four large Mission Concept studies sponsored by NASA for review in the 2020 US Astrophysics Decadal Survey, will open unprecedented discovery space in the infrared, unveiling our cosmic origins. We briefly describe ... More
Dense molecular gas in quasar host galaxies: a search for HCN emission from BR B1202-0725 at z=4.695Dec 04 2003We report on the results of a search using the VLA for redshifted HCN(1-0) emission from the host galaxy of BR B1202-0725, an optically luminous quasar at z=4.695. The host galaxy emits strongly in the rest-frame far-infrared, and shows characteristics ... More
Hardy's paradox for multi-settings and high-dimensional systemsMay 12 2018Recently, Chen et al introduced an alternative form of Hardy's paradox for $2$-settings and high-dimensional systems [Phy. Rev. A 88, 062116 (2013)], in which there is a great progress in improving the maximum probability of the nonlocal event. Here, ... More
Revealing a Triangular Lattice Ising Antiferromagnet in a Single-Crystal CeCd$_3$As$_3$Dec 12 2016We report the single-crystal growth and the fundamental magnetic and thermodynamic properties of a rare-earth triangular lattice antiferromagnet CeCd$_3$As$_3$. In this rare-earth antiferromagnet, the Ce local moments form a perfect triangular lattice. ... More
Simulating defect textures on coalescing nematic shellsSep 18 2013Two nematic shells brought in contact coalesce in order to reduce their interfacial tension. This process proceeds through the creation of a liquid neck-like bridge through which the encapsulated fluid flows. Following this topological transition, We ... More
Phonon dynamics in SrFe2As2 and SrFeAsF parent pnictide compounds: How different/similar when compared to Ca- and Ba-compounds?Dec 09 2009Aug 06 2010We report detailed measurements of temperature dependence and ab initio lattice dynamical calculations of the phonon density-of-states of two Sr based iron pnictide parent compounds; SrFe2As2 and SrFeAsF. Although both compounds undergo a magnetic as ... More
Magnetic correlations in spin ice Ho2-xYxTi2O7 as revealed by neutron polarization analysisMar 24 2010Nov 10 2010We present single-crystal neutron-diffuse-scattering measurements with polarization analysis on the spin ice Ho2-xYxTi2O7 (x = 0, 0.3, and 1). At 2 K, the spin flip scattering patterns are typical of a nearest-neighbor spin ice and the effects of Y doping ... More
Atomic Imaging Using Secondary Electrons in a Scanning Transmission Electron Microscope : Experimental Observations and Possible MechanismsAug 30 2010We report our detailed investigation of high-resolution imaging using secondary electrons (SE) with a subnanometer probe in an aberration-corrected transmission electron microscope, Hitachi HD2700C. This instrument also allows us to acquire the corresponding ... More
Nodeless energy gaps of single-crystalline Ba0.68K0.32Fe2As2 as seen via 75As NMRFeb 22 2011Apr 20 2011We report $^{75}$As nuclear magnetic resonance studies on a very clean hole-doped single-crystal Ba$_{0.68}$K$_{0.32}$Fe$_{2}$As$_{2}$ ($T_{\rm {c}}=38.5$ K). The spin-lattice relaxation rate $1/T_{1}$ shows an exponential decrease below $T \simeq 0.45 ... More
Density-controlled quantum Hall ferromagnetic transition in a two-dimensional hole systemJun 07 2017Quantum Hall ferromagnetic transitions are typically achieved by increasing the Zeeman energy through in-situ sample rotation, while transitions in systems with pseudo-spin indices can be induced by gate control. We report here a gate-controlled quantum ... More
Astrophysical $S_{E2}$ factor of the ${}^{12}\mathrm{C}(α,γ){}^{16}\mathrm{O}$ reaction through the ${}^{12}\mathrm{C}({}^{11}\mathrm{B},{}^{7}\mathrm{Li}){}^{16}\mathrm{O}$ transfer reactionNov 15 2018The ${}^{12}\mathrm{C}(\alpha,\gamma){}^{16}\mathrm{O}$ reaction plays a key role in the evolution of stars with masses of $M >$ 0.55 $M_\odot$. The cross-section of the ${}^{12}\mathrm{C}(\alpha,\gamma){}^{16}\mathrm{O}$ reaction within the Gamow window ... More
New Debris Disks Around Young, Low Mass Stars Discovered With The Spitzer Space TelescopeApr 05 2009(abridged) We present 24 and 70 micron MIPS observations of 70 A through M-type dwarfs with estimated ages from 8 Myr to 1.1 Gyr, as part of a Spitzer guaranteed time program. Our sample is selected from stars with common youth indicators such as lithium ... More
Substrate-induced structures of bismuth adsorption on graphene: a first principle studyJul 28 2015Feb 23 2016The geometric and electronic properties of Bi-adsorbed monolayer graphene, enriched by the strong effect of substrate, are investigated by first-principles calculations. The six-layered substrate, corrugated buffer layer, and slightly deformed monolayer ... More
Period Increase and Amplitude Distribution of Kink Oscillation of Coronal LoopMar 19 2018Coronal loops exist ubiquitously in the solar atmosphere. These loops puzzle astronomers over half a century. Solar magneto-seismology (SMS) provides a unique way to constrain the physical parameters of coronal loops. Here, we study the evolution of oscillations ... More
Spitzer observations of V4332 Sagittarii: Detection of Alumina DustJul 20 2007We present broad-band 24, 70 and 160 micron photometry, 5-35 micron and 55-90 micron spectra of the eruptive variable V4332 Sgr from Spitzer observations. The distinguishing feature of the 5-35 micron spectrum is an unusually broad absorption feature ... More
Debris Disks around Solar-Type Stars: Observations of the Pleiades with Spitzer Space TelescopeMar 01 2010Mar 15 2010We present Spitzer MIPS observations at 24 um of 37 solar-type stars in the Pleiades and combine them with previous observations to obtain a sample of 71 stars. We report that 23 stars, or 32 +/- 6.8%, have excesses at 24 um at least 10% above their photospheric ... More
Photoevaporation of Protoplanetary DisksJul 23 2008We present HST/NICMOS Paschen alpha images and low and high resolution IRS spectra of photoevaporating disk-tail systems originally detected at 24 micron near O stars. We find no Paschen alpha emission in any of the systems. The resulting upper limits ... More
Spin-Lattice Coupling in K0.8Fe1.6Se2 and KFe2Se2: Inelastic Neutron Scattering and ab-initio Phonon CalculationsJan 23 2013We report measurements of the temperature dependence of phonon densities of states in K0.8Fe1.6Se2 using inelastic neutron scattering technique. While cooling down to 150 K, a phonon peak splitting around 25 meV is observed and a new peak appears at 31 ... More
Modeling the Infrared Bow Shock at delta Velorum: Implications for Studies of Debris Disks and lambda Bootis StarsSep 26 2007We have discovered a bow shock shaped mid-infrared excess region in front of delta Velorum using 24 micron observations obtained with the Multiband Imaging Photometer for Spitzer (MIPS). The excess has been classified as a debris disk from previous infrared ... More
Steady-state evolution of debris disks around A starsMar 23 2007In this paper a simple analytical model for the steady-state evolution of debris disks due to collisions is confronted with Spitzer observations of main sequence A stars. All stars are assumed to have planetesimal belts with a distribution of initial ... More
The low level of debris disk activity at the time of the Late Heavy Bombardment: a Spitzer study of PraesepeMar 24 2009We present 24 micron photometry of the intermediate-age open cluster Praesepe. We assemble a catalog of 193 probable cluster members that are detected in optical databases, the Two Micron All Sky Survey (2MASS), and at 24 micron, within an area of ~ 2.47 ... More
Phonon dynamics in Sr0.6K0.4Fe2As2 and Ca0.6Na0.4Fe2As2Oct 24 2008We report inelastic neutron scattering measurements of the phonon density-of-states in superconducting Sr0.6K0.4Fe2As2 (Tc=30 K) and Ca0.6Na0.4Fe2As2 (Tc=18 K). Compared with the parent compound BaFe2As2 doping affects mainly the lower and intermediate ... More