Results for "David J. Wilner"

total 218544took 0.18s
Ionized Gas Kinematics and Morphology in Sgr B2 Main on 1000 AU ScalesSep 20 2011We have imaged the Sgr B2 Main region with the Very Large Array in the BnA configuration ($\theta_{beam}$ = 0\farcs13) in both the H52$\alpha$ (45.453 GHz) radio recombination line (RRL) and 7 mm continuum emission. At a distance of 8500 pc, this spatial ... More
Imaging Carbon Monoxide Emission in the Starburst Galaxy NGC 6000Mar 29 2010We present measurements of carbon monoxide emission in the central region of the nearby starburst NGC 6000 taken with the Submillimeter Array. The J=2-1 transition of 12CO, 13CO, and C18O were imaged at a resolution of ~3''x2'' (450x300 pc). We accurately ... More
CCS Imaging of the Starless Core L1544: An Envelope with Infall and RotationApr 13 1999We have carried out observations of the starless core L1544 in the CCS (J_N=3_2-2_1) line at 9 millimeters wavelength using the BIMA array. The maps show an elongated condensation, 0.15 x 0.045 pc in size, with stronger emission at the edges. The appearance ... More
Millimeter Dust Emission in the GQ Lup SystemDec 12 2009We present Submillimeter Array observations of the GQ Lup system at 1.3 millimeters wavelength with $0\farcs4$ ($\sim$60 AU) resolution. Emission is detected from the position of the primary star, GQ Lup A, and is marginally resolved. No emission is detected ... More
Constraining a Model of Turbulent Coronal Heating for AU Microscopii with X-Ray, Radio, and Millimeter ObservationsJun 19 2013Many low-mass pre-main-sequence stars exhibit strong magnetic activity and coronal X-ray emission. Even after the primordial accretion disk has been cleared out, the star's high-energy radiation continues to affect the formation and evolution of dust, ... More
A Millimeter Continuum Size-Luminosity Relationship for Protoplanetary DisksJun 27 2017We present a sub-arcsecond resolution survey of the 340 GHz dust continuum emission from 50 nearby protoplanetary disks, based on new and archival observations with the Submillimeter Array. The observed visibility data were modeled with a simple prescription ... More
Millimeter Imaging of the beta Pictoris Debris Disk: Evidence for a Planetesimal BeltDec 10 2010We present observations at 1.3 millimeters wavelength of the beta Pictoris debris disk with beam size 4.3 x 2.6 arcsec (83 x 50 AU) from the Submillimeter Array. The emission shows two peaks separated by ~7 arsec along the disk plane, which we interpret ... More
The Masses of the Orion Proplyds from Submillimeter Dust EmissionJun 10 2005Jul 01 2005We have imaged the 880 micron continuum emission from the "proplyds" in the center of the Trapezium Cluster in Orion using the Submillimeter Array with a beam size 1.5'' FWHM and an rms of 2.7 mJy. Five sources are detected with fluxes in the range 18 ... More
Imaging Protoplanetary Disks with a Square Kilometer ArrayDec 14 2004The recent detections of extrasolar giant planets has revealed a surprising diversity of planetary system architectures, with many very unlike our Solar System. Understanding the origin of this diversity requires multi-wavelength studies of the structure ... More
Peculiar Near-Nucleus Outgassing of Comet 17P/Holmes During Its 2007 OutburstNov 17 2014We present high angular resolution Submillimeter Array observations ofthe outbursting Jupiter family comet 17P/Holmes on 2007 October 26-29, achieving a spatial resolution of 2.5", or ~3000 km at the comet distance. The observations resulted in detections ... More
An SMA Continuum Survey of Circumstellar Disks in the Serpens Star-Forming RegionNov 03 2017We present observations with the Submillimeter Array of the continuum emission at $\lambda = 1.3$ mm from 62 young stars surrounded by a protoplanetary disk in the Serpens star-forming region. The typical angular resolution for the survey in terms of ... More
Envelope Structure of Starless Core L694-2 Derived from a Near-Infrared Extinction MapAug 08 2003We present a near-infrared extinction study of the dark globule L694-2, a starless core that shows strong evidence for inward motions in molecular line profiles. The J,H, and K band data were taken using the European Southern Observatory New Technology ... More
Detection of a Millimeter Flare From Proxima CentauriFeb 22 2018We present new analyses of ALMA 12-m and ACA observations at 233 GHz (1.3 mm) of the Proxima Centauri system with sensitivities of 9.5 and 47 $\mu$Jy beam$^{-1}$, respectively, taken from 2017 January 21 through 2017 April 25. These analyses reveal that ... More
The Structure of the Evolved Circumbinary Disk around V4046 SgrAug 20 2013We present sensitive, sub-arcsecond resolution Submillimeter Array observations of the protoplanetary disk around the nearby, pre-main sequence spectroscopic binary V4046 Sgr. We report for the first time a large inner hole (r=29 AU) spatially resolved ... More
A new twist to an old story: HE 0450-2958, and the ULIRG$\to $(optically bright QSO) transition hypothesisJan 09 2008May 21 2008We report on interferometric imaging of the CO J=1--0 and J=3--2 line emission from the controversial QSO/galaxy pair HE 0450--2958. {\it The detected CO J=1--0 line emission is found associated with the disturbed companion galaxy not the luminous QSO,} ... More
A Resolved Census of Millimeter Emission from Taurus Multiple Star SystemsMar 28 2012We present a high angular resolution millimeter-wave dust continuum imaging survey of circumstellar material associated with individual components of 23 multiple star systems in the Taurus-Auriga young cluster. Combined with previous measurements, these ... More
Submillimeter Interferometry of the Luminous Infrared Galaxy NGC 4418: A Hidden Hot Nucleus with an Inflow and an OutflowJan 09 2013We have observed the nucleus of the nearby luminous infrared galaxy NGC 4418 with subarcsec resolution at 860 and 450 micron for the first time to characterize its hidden power source. A ~20 pc (0.1") hot dusty core was found inside a 100 pc scale concentration ... More
Optical and Radio Observations of the T Tauri Binary KH 15D (V582 Mon): Stellar Properties, Disk Mass Limit and Discovery of a CO OutflowNov 30 2017Dec 02 2017We present VRIJHK photometry of the KH 15D T Tauri binary system for the 2015/16 and 2016/17 observing seasons. For the first time in the modern (CCD) era we are seeing Star B fully emerge from behind the trailing edge of the precessing circumbinary ring ... More
A Resolved Millimeter Emission Belt in the AU Mic Debris DiskMar 08 2012We present imaging observations at 1.3 millimeters of the debris disk surrounding the nearby M-type flare star AU Mic with beam size 3 arcsec (30 AU) from the Submillimeter Array. These data reveal a belt of thermal dust emission surrounding the star ... More
Science with an ngVLA: Resolved Substructures in Protoplanetary DisksOct 15 2018Terrestrial planets and the cores of giant planets are thought to be built by the collisional agglomeration of solids spanning over 20 orders of magnitude in size within a few million years. However, there is tension between this basic picture of planet ... 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
A High-Mass Protobinary System in the Hot Core W3(H2O)Nov 10 2005We have observed a high-mass protobinary system in the hot core W3(H2O) with the BIMA Array. Our continuum maps at wavelengths of 1.4mm and 2.8mm both achieve sub-arcsecond angular resolutions and show a double-peaked morphology. The angular separation ... More
Disk Properties and Density Structure of the Star-Forming Dense Core B335Jul 05 2003We present subarcsecond resolution dust continuum observations of the protostellar collapse candidate B335 made with the IRAM Plateau de Bure Interferometer at wavelengths of 1.2 and 3.0 mm. These observations probe to < 100 AU size scales and reveal ... More
Electronic Squeezing of Pumped Phonons: Negative U and Transient SuperconductivitySep 13 2016Advances in light sources and time resolved spectroscopy have made it possible to excite specific atomic vibrations in solids and to observe the resulting changes in electronic properties but the mechanism by which phonon excitation causes qualitative ... More
Infall, Outflow, Rotation, and Turbulent Motions of Dense Gas within NGC 1333 IRAS 4Aug 01 2001Millimeter wavelength observations are presented of NGC 1333 IRAS 4, a group of highly-embedded young stellar objects in Perseus, that reveal motions of infall, outflow, rotation, and turbulence in the dense gas around its two brightest continuum objects, ... More
Evidence for Multiple Pathways to Deuterium Enhancements in Protoplanetary DisksFeb 17 2012The distributions of deuterated molecules in protoplanetary disks are expected to depend on the molecular formation pathways. We use observations of spatially resolved DCN emission from the disk around TW Hya, acquired during ALMA Science verification ... More
Vibrationally Excited HCN in the Luminous Infrared Galaxy NGC 4418Nov 30 2010Infrared pumping and its effect on the excitation of HCN molecules can be important when using rotational lines of HCN to probe dense molecular gas in galaxy nuclei. We report the first extragalactic detection of (sub)millimeter rotational lines of vibrationally ... More
The Mass Dependence Between Protoplanetary Disks and their Stellar HostsMay 22 2013Jun 13 2013We present a substantial extension of the mm-wave continuum photometry catalog for Taurus circumstellar dust disks. Combining new Submillimeter Array data with measurements in the literature, we construct a mm-wave luminosity distribution for Class II ... More
Matryoshka Holes: Nested Emission Rings in the Transitional Disk Oph IRS 48Sep 07 2012The processes that form transition disks - disks with depleted inner regions - are not well understood; possible scenarios include planet formation, grain growth and photoevaporation. Disks with spatially resolved dust holes are rare, but, in general, ... More
On the Ubiquity and Stellar Luminosity Dependence of Exocometary CO Gas: Detection around M Dwarf TWA 7Jan 15 2019Millimeter observations of CO gas in planetesimal belts show a high detection rate around A stars, but few detections for later type stars. We present the first CO detection in a planetesimal belt around an M star, TWA 7. The optically thin CO (J=3-2) ... More
A High Resolution Study of the Slowly Contracting, Starless Core L1544Jan 06 1999We present interferometric observations of N2H+(1--0) in the starless, dense core L1544 in Taurus. Red-shifted self-absorption, indicative of inward motions, is found toward the center of an elongated core. The data are fit by a non-spherical model consisting ... More
IRAS 16293-2442B: A Compact, Possibly Isolated Protoplanetary Disk in a Class 0 ObjectJan 27 2005Theoretical arguments suggest that protoplanetary disks around young stars should start small and grow with the addition of high angular momentum material to reach the radii of several hundred AUs that characterize the disks around optically visible T ... More
Inner Structure of Starless Core L694--2 Derived from Millimeter-Wave InterferometryJul 05 2003We study the density structure of candidate contracting starless core L694-2 using 1.3 mm dust continuum observations from the IRAM Plateau de Bure Interferometer and the Berkeley-Illinois-Maryland Array, probing spatial scales from 10000-500 AU. The ... More
Transient superconductivity from electronic squeezing of optically pumped phononsSep 13 2016May 04 2017Advances in light sources and time resolved spectroscopy have made it possible to excite specific atomic vibrations in solids and to observe the resulting changes in electronic properties but the mechanism by which phonon excitation causes qualitative ... More
Millimeter Observations of the Transition Disk around HD135344B (SAO 206462)Aug 30 2011We present \sim1" resolution 1.3 millimeter dust continuum and spectral line (12CO and 13CO J=2-1) observations of the transitional disk system HD 135344B obtained with the Submillimeter Array. The disk shows a Keplerian rotation pattern with an inclination ... More
A Disk-based Dynamical Mass Estimate for the Young Binary V4046 SgrSep 20 2012We present sensitive, arcsecond-resolution Submillimeter Array observations of the 12CO J=2-1 line emission from the circumstellar disk orbiting the double-lined spectroscopic binary star V4046 Sgr. Based on a simple model of the disk structure, we use ... More
A Closer Look at the LkCa 15 Protoplanetary DiskOct 18 2011We present 870 micron observations of dust continuum emission from the LkCa 15 protoplanetary disk at high angular resolution (with a characteristic scale of 0.25" = 35 AU), obtained with the IRAM Plateau de Bure interferometer and supplemented by slightly ... More
The Ionization Fraction in the DM Tau Protoplanetary DiskSep 12 2011We present millimeter-wave observations of several molecular ions in the disk around the pre-main-sequence star DM Tau and use these to investigate the ionization fraction in different regions of the disk. New Submillimeter Array (SMA) observations of ... More
Empirical Constraints on Turbulence in Protoplanetary Accretion DisksNov 16 2010We present arcsecond-scale Submillimeter Array observations of the CO(3-2) line emission from the disks around the young stars HD 163296 and TW Hya at a spectral resolution of 44 m/s. These observations probe below the ~100 m/s turbulent linewidth inferred ... More
Non-equilibrium Optical Conductivity: General Theory and Application to Transient PhasesMar 21 2017Jul 31 2017A non-equilibrium theory of optical conductivity of dirty-limit superconductors and commensurate charge density wave is presented. We discuss the current response to different experimentally relevant light-field probe pulses and show that a single frequency ... More
The Magnetized Environment of the W3(H2O) ProtostarsApr 17 2012We present the first interferometric polarization map of the W3(OH) massive star-forming region observed with the Submillimeter Array (SMA) at 878 mum with an angular resolution of 1.5 (about 3 \times 10 AU). Polarization is detected in the W3(H2O) hot ... More
SMA Imaging of the Maser Emission from the H30$α$ Radio Recombination Line in MWC349AJan 04 2008We used the Submillimeter Array to map the angular distribution of the H30$\alpha$ recombination line (231.9 GHz) in the circumstellar region of the peculiar star MWC349A. The resolution was $1\farcs2$, but because of high signal-to-noise ratio we measured ... More
The Epsilon Eridani System Resolved by Millimeter InterferometryJul 06 2015We present observations of Epsilon Eridani from the Submillimeter Array (SMA) at 1.3 millimeters and from the Australia Telescope Compact Array (ATCA) at 7 millimeters that reach an angular resolution of ~4" (13 AU). These first millimeter interferometer ... More
Resolved Millimeter Emission from the HD 15115 Debris DiskJan 23 2015We have used the Submillimeter Array (SMA) to make 1.3 millimeter observations of the debris disk surrounding HD 15115, an F-type star with a putative membership in the beta Pictoris moving group. This nearly edge-on debris disk shows an extreme asymmetry ... More
A Spatially Resolved Vertical Temperature Gradient in the HD 163296 DiskJun 27 2013We analyze sensitive, sub-arcsecond resolution ALMA Science Verification observations of CO emission lines in the protoplanetary disk hosted by the young, isolated Ae star HD 163296. The observed spatial morphology of the 12CO J=3-2 emission line is asymmetric ... More
The Spectral Correlation Function -- A New Tool for Analyzing Spectral-Line MapsMar 30 1999Apr 20 1999The "spectral correlation function" analysis we introduce in this paper is a new tool for analyzing spectral-line data cubes. Our initial tests, carried out on a suite of observed and simulated data cubes, indicate that the spectral correlation function ... More
Scaling Relations Associated with Millimeter Continuum Sizes in Protoplanetary DisksAug 30 2018We present a combined, homogenized analysis of archival Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations of the spatially resolved 340 GHz (870 $\mu$m) continuum emission from 105 nearby protoplanetary disks. ... More
Steepening of the 820 micron continuum surface-brightness profile signals dust evolution in TW Hya's diskDec 17 2015Grain growth in planet-forming disks is the first step toward the formation of planets. The growth of grains and their inward drift leaves a distinct imprint on the dust surface-density distribution and the resulting surface-brightness profile of the ... More
Molecular Line Observations of Infrared Dark Clouds: Seeking the Precursors to Intermediate and Massive Star FormationJun 12 2006We have identified 41 infrared dark clouds from the 8 micron maps of the Midcourse Space Experiment (MSX), selected to be found within one square degree areas centered on known ultracompact HII regions. We have mapped these infrared dark clouds in N2H+(1-0), ... More
Constraints on a Putative Planet Sculpting the V4046 Sagittarii Circumbinary DiskApr 18 2019We analyze the highest-resolution millimeter continuum and near-infrared (NIR) scattered-light images presented to date of the circumbinary disk orbiting V4046 Sgr, a ~20 Myr old actively accreting, close binary T Tauri star system located a mere 72.4 ... More
H2CO and N2H+ in Protoplanetary Disks: Evidence for a CO-ice Regulated ChemistryJan 11 2013We present Submillimeter Array observations of H2CO and N2H+ emission in the disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296 at 2"-6" resolution and discuss the distribution of these species with respect to CO freeze-out. The H2CO ... More
Grain growth signatures in the protoplanetary discs of Chamaeleon and LupusJul 02 2012We present ATCA results of a 3 and 7 mm continuum survey of 20 T Tauri stars in the Chamaeleon and Lupus star forming regions. This survey aims to identify protoplanetary discs with signs of grain growth. We detected 90% of the sources at 3 and 7 mm, ... More
Structure of Protostellar Collapse Candidate B335 Derived from Near-Infrared Extinction MapsAug 29 2001We present a near-infrared extinction study of the dark globule B335, a protostellar collapse candidate, using data from HST/NICMOS and the W.M. Keck Observatory. These data allow a new quantitative test of the "inside-out" collapse model previously proposed ... More
ALMA observations of the dense and shocked gas in the nuclear region of NGC 4038 (Antennae galaxies)Oct 31 2016We present 1" (<100 pc) resolution maps of millimeter emission from five molecules-CN, HCN, HCO+, CH3OH, and HNCO-obtained towards NGC 4038, which is the northern galaxy of the mid-stage merger, Antennae galaxies, with the Atacama Large Millimeter/submillimeter ... More
Resolved Millimeter-Wavelength Observations of Debris Disks around Solar-Type StarsOct 29 2015The presence of debris disks around young main sequence stars hints at the existence and structure of planetary systems. Millimeter-wavelength observations probe large grains that trace the location of planetesimal belts. The FEPS (Formation and Evolution ... More
Science with an ngVLA: Stellar Emission as a Source of Flux Bias in Debris DisksOct 15 2018Our understanding of stellar atmospheres and our ability to infer architectures of extrasolar planetary systems rely on understanding the emission of stars at submillimeter to centimeter wavelengths. In this chapter we describe how unconstrained stellar ... More
MESAS: Measuring the Emission of Stellar Atmospheres at Submm/mm wavelengthsApr 26 2018In the early stages of planet formation, small dust grains grow to become mm sized particles in debris disks around stars. These disks can in principle be characterized by their emission at submillimeter and millimeter wavelengths. Determining both the ... More
Resolved Images of Large Cavities in Protoplanetary Transition DisksMar 01 2011Circumstellar disks are thought to experience a rapid "transition" phase in their evolution that can have a considerable impact on the formation and early development of planetary systems. We present new and archival high angular resolution (0.3" = 40-75 ... More
Very Large Array Observations of Ammonia in Infrared-Dark Clouds I: Column Density and Temperature StructureMay 20 2011Jul 20 2011We present Very Large Array observations of NH3 (1,1) and (2,2) in a sample of six infrared-dark clouds (IRDCs) with distances from 2 to 5 kpc. We find that ammonia serves as an excellent tracer of dense gas in IRDCs, showing no evidence of depletion, ... More
ALMA Observations of the Debris Disk of Solar Analogue Tau CetiJul 08 2016We present 1.3 mm observations of the Sun-like star $\tau$ Ceti with the Atacama Large Millimeter/submillimeter Array (ALMA) that probe angular scales of $\sim1$'' (4 AU). This first interferometric image of the $\tau$ Ceti system, which hosts both a ... More
The Coupled Physical Structure of Gas and Dust in the IM Lup Protoplanetary DiskOct 03 2016The spatial distribution of gas and solids in protoplanetary disks determines the composition and formation efficiency of planetary systems. A number of disks show starkly different distributions for the gas and small grains compared to millimeter-centimeter ... More
Initial conditions for star formation in clusters: physical and kinematical structure of the starless core Oph A-N6Nov 18 2011We present high spatial (<300 AU) and spectral (0.07 km/s) resolution Submillimeter Array observations of the dense starless cluster core Oph A-N6, in the 1 mm dust continuum and the 3-2 line of N2H+ and N2D+. The dust continuum observations reveal a ... More
Resolving the CO Snow Line in the Disk around HD 163296Jul 25 2011We report Submillimeter Array (SMA) observations of CO (J=2--1, 3--2 and 6--5) and its isotopologues (13CO J=2--1, C18O J=2--1 and C17O J=3--2) in the disk around the Herbig Ae star HD 163296 at ~2" (250 AU) resolution, and interpret these data in the ... More
A Disk-based Dynamical Mass Estimate for the Young Binary AK ScoMay 07 2015We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust in the disk orbiting the pre-main sequence binary AK Sco. By forward-modeling the disk velocity field traced by CO J=2-1 line ... More
The cometary composition of a protoplanetary disk as revealed by complex cyanidesMay 23 2015Observations of comets and asteroids show that the Solar Nebula that spawned our planetary system was rich in water and organic molecules. Bombardment brought these organics to the young Earth's surface, seeding its early chemistry. Unlike asteroids, ... More
Kuiper Belt-Like Hot and Cold Populations of Planetesimal Inclinations in the $β$ Pictoris Belt Revealed by ALMAFeb 11 2019The inclination distribution of the Kuiper belt provides unique constraints on its origin and dynamical evolution, motivating vertically resolved observations of extrasolar planetesimal belts. We present ALMA observations of millimeter emission in the ... More
Turbulence in the TW Hya DiskMar 10 2018Turbulence is a fundamental parameter in models of grain growth during the early stages of planet formation. As such, observational constraints on its magnitude are crucial. Here we self-consistently analyze ALMA CO(2-1), SMA CO(3-2), and SMA CO(6-5) ... More
Stringent Limits on the Polarized Submillimeter Emission from Protoplanetary DisksSep 07 2009We present arcsecond-resolution Submillimeter Array (SMA) polarimetric observations of the 880 um continuum emission from the protoplanetary disks around two nearby stars, HD 163296 and TW Hydrae. Although previous observations and theoretical work have ... More
[CII] line emission in BRI1335-0417 at z=4.4Aug 09 2010Using the 12m APEX telescope, we have detected redshifted emission from the 157.74micron [CII] line in the z=4.4074 quasar BRI1335-0417. The linewidth and redshift are in good agreement with previous observations of high-J CO line emission. We measure ... More
Constraining Gas-Phase Carbon, Oxygen, and Nitrogen in the IM Lup Protoplanetary DiskAug 31 2018We present new constraints on gas-phase C, N, and O abundances in the molecular layer of the IM Lup protoplanetary disk. Building on previous physical and chemical modeling of this disk, we use new ALMA observations of C$_2$H to constrain the C/O ratio ... More
Variable H$^{13}$CO$^+$ Emission in the IM Lup Disk: X-ray Driven Time-Dependent Chemistry?Jun 02 2017We report the first detection of a substantial brightening event in an isotopologue of a key molecular ion, HCO$^+$, within a protoplanetary disk of a T Tauri star. The H$^{13}$CO$^+$ $J=3-2$ rotational transition was observed three times toward IM Lup ... More
A Large Scale Survey of NGC1333Oct 19 2006We observed the clustered star forming complex NGC1333 with the BIMA and FCRAO telescopes in the transitions HCO+(1-0) and N2H+(1-0) over an 11'x11' area with resolution ~10" (0.015pc). The N2H+ emission follows very closely the submillimeter dust continuum ... More
Resolving The Moth at Millimeter WavelengthsJul 12 2013HD 61005, also known as "The Moth," is one of only a handful of debris disks that exhibit swept-back "wings" thought to be caused by interaction with the ambient interstellar medium (ISM). We present 1.3 mm Submillimeter Array (SMA) observations of the ... More
Imaging the Molecular Disk Orbiting the Twin Young Suns of V4046 SgrJul 22 2010We have imaged the disk surrounding the nearby (D~73 pc), ~12 Myr, classical T Tauri binary system V4046 Sgr with the Submillimeter Array (SMA) at an angular resolution of ~2". We detect a rotating disk in 12CO(2-1) and 13CO(2-1) emission, and resolve ... More
A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar DisksMar 17 2015We present a CARMA 1.3 mm continuum survey toward 9 Class 0 protostars in the Perseus molecular cloud at $\sim$0.3$^{\prime\prime}$ (70 AU) resolution. This study approximately doubles the number of Class 0 protostars observed with spatial resolutions ... More
ALMA Measurements of Circumstellar Material in the GQ Lup SystemNov 18 2016We present ALMA observations of the GQ Lup system, a young Sun-like star with a substellar mass companion in a wide-separation orbit. These observations of 870 $\mu$m continuum and CO J=3-2 line emission with beam size $\sim0.3''$ ($\sim45$ AU) resolve ... More
Disk Imaging Survey of Chemistry with SMA: II. Southern Sky Protoplanetary Disk Data and Full Sample StatisticsApr 07 2011This is the second in a series of papers based on data from DISCS, a Submillimeter Array observing program aimed at spatially and spectrally resolving the chemical composition of 12 protoplanetary disks. We present data on six Southern sky sources - IM ... More
Disk Imaging Survey of Chemistry with SMA (DISCS): I. Taurus Protoplanetary Disk DataJul 08 2010Chemistry plays an important role in the structure and evolution of protoplanetary disks, with implications for the composition of comets and planets. This is the first of a series of papers based on data from DISCS, a Submillimeter Array survey of the ... More
Modeling the Resolved Disk Around the Class 0 Protostar L1527May 15 2013We present high-resolution sub/millimeter interferometric imaging of the Class 0 protostar L1527 IRS (IRAS 04368+2557) at 870 micron and 3.4 mm from the Submillimeter Array (SMA) and Combined Array for Research in Millimeter Astronomy (CARMA). We detect ... More
A 0.2 solar mass protostar with a Keplerian disk in the very young L1527 IRS systemDec 04 2012In their earliest stages, protostars accrete mass from their surrounding envelopes through circumstellar disks. Until now, the smallest observed protostar/envelope mass ratio was ~2.1. The protostar L1527 IRS is thought to be in the earliest stages of ... More
Velocity-resolved hot water emission detected toward HL Tau with the Submillimeter ArrayMar 31 2016Using the Submillimeter Array (SMA) on Mauna Kea, the H2-16O 10_2,9-9_3,6 transition (E_up=1863K) at 321.2 GHz has been detected toward the embedded low-mass protostar HL Tau. The line centroid is blue-shifted by 15 km/s with respect to the source velocity, ... More
First detection of c-C3H2 in a circumstellar diskFeb 01 2013We report the first detection of c-C3H2 in a circumstellar disk. The c-C3H2 J=6-5 line (217.882 GHz) is detected and imaged through Atacama Large Millimeter Array (ALMA) Science Verification observations toward the disk around the Herbig Ae star HD 163296 ... More
A break in the gas and dust surface density of the disc around the T Tauri star IM LupApr 07 2009We study the distribution and physical properties of molecular gas in the disc around the T Tauri star IM Lup on scales close to 200 AU. We investigate how well the gas and dust distributions compare and work towards a unified disc model that can explain ... More
Very Large Array Observations of Ammonia in Infrared-Dark Clouds II: Internal KinematicsJan 06 2012Infrared-dark clouds (IRDCs) are believed to be the birthplaces of rich clusters and thus contain the earliest phases of high-mass star formation. We use the Green Bank Telescope (GBT) and Very Large Array (VLA) maps of ammonia (NH3) in six IRDCs to measure ... More
PROSAC: A Submillimeter Array survey of low-mass protostars. II. The mass evolution of envelopes, disks, and stars from the Class 0 through I stagesSep 18 2009The key question about early protostellar evolution is how matter is accreted from the large-scale molecular cloud, through the circumstellar disk onto the central star. A sample of 20 Class 0 and I protostars has been observed in continuum at (sub)millimeter ... More
The Degree of Alignment Between Circumbinary Disks and Their Binary HostsJun 07 2019All four circumbinary (CB) protoplanetary disks orbiting short-period ($P < 20$ day) double-lined spectroscopic binaries (SB2s)---a group that includes UZ Tau E, for which we present new ALMA data---exhibit sky-plane inclinations $i_{\rm disk}$ which ... 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
Double DCO+ rings reveal CO ice desorption in the outer disk around IM LupAug 28 2015In a protoplanetary disk, a combination of thermal and non-thermal desorption processes regulate where volatiles are liberated from icy grain mantles into the gas phase. Non-thermal desorption should result in volatile-enriched gas in disk-regions where ... More
Weak Turbulence in the HD 163296 Protoplanetary Disk Revealed by ALMA CO ObservationsOct 05 2015Turbulence can transport angular momentum in protoplanetary disks and influence the growth and evolution of planets. With spatially and spectrally resolved molecular emission line measurements provided by (sub)millimeter interferometric observations, ... 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
A Spatially Resolved Inner Hole in the Disk around GM AurigaeMar 25 2009We present 0.3 arcsec resolution observations of the disk around GM Aurigae with the Submillimeter Array (SMA) at a wavelength of 860 um and with the Plateau de Bure Interferometer at a wavelength of 1.3 mm. These observations probe the distribution of ... More
654 GHz Continuum and C18O (6-5) Observations of G240.31+0.07 with the Submillimeter ArrayNov 12 2006We report a dual-band observation at 223 and 654 GHz (460 micron) toward an ultracompact (UC) HII region, G240.31+0.07, with the Submillimeter Array. With a beam size of 1"5 X 0"8, the dust continuum emission is resolved into two clumps, with clump A ... More
Discovery of a Low Mass Bipolar Molecular Outflow from L1014-IRS with the Submillimeter ArraySep 29 2005Using the Submillimeter Array we report the discovery of a compact low mass bipolar molecular outflow from L1014-IRS and confirm its association with the L1014 dense core at 200 pc. Consequently, L1014-IRS is the lowest luminosity (L \~0.09 Lsun) and ... More
Observational Constraints on Submillimeter Dust OpacityDec 15 2010Infrared extinction maps and submillimeter dust continuum maps are powerful probes of the density structure in the envelope of star-forming cores. We make a direct comparison between infrared and submillimeter dust continuum observations of the low-mass ... More
New Radio Sources and the Composite Structure of Component B in the Very Young Protostellar System IRAS 16293-2422Aug 17 2007In this article, we report high-resolution (~ 0.1" -- 0.3"), high-sensitivity (~ 50 -100 uJy beam-1) Very Large Array 0.7 and 1.3 cm observations of the young stellar system IRAS 16293-2422 in rho-Ophiuchus. In the 0.7 cm image, component A to the south-east ... More
Constraints on Planetesimal Collision Models in Debris DisksMar 17 2016Observations of debris disks offer a window into the physical and dynamical properties of planetesimals in extrasolar systems through the size distribution of dust grains. In particular, the millimeter spectral index of thermal dust emission encodes information ... More
Molecular Superbubbles in the Starburst Galaxy NGC 253Sep 15 2005The central 2x1 kpc of the starburst galaxy NGC 253 has been imaged using the Submillimeter Array at a 60 pc resolution in the J=2-1 transitions of 12CO, 13CO, and C18O as well as in the 1.3 mm continuum. Molecular gas and dust are mainly in the circumnuclear ... More
Chemical Imaging of the CO Snow Line in the HD 163296 DiskOct 04 2015The condensation fronts (snow lines) of H2O, CO and other abundant volatiles in the midplane of a protoplanetary disk affect several aspects of planet formation. Locating the CO snow line, where the CO gas column density is expected to drop substantially, ... More
Keck/NIRC2 Imaging of the Warped, Asymmetric Debris Disk around HD 32297Jun 20 2012Jul 17 2012We present Keck/NIRC2 $K_{s}$ band high-contrast coronagraphic imaging of the luminous debris disk around the nearby, young A star HD 32297 resolved at a projected separation of $r$ = 0.3-2.5\arcsec{} ($\approx$ 35-280 AU). The disk is highly warped to ... More
An ALMA survey of DCN/H$^{13}$CN and DCO$^+$/H$^{13}$CO$^+$ in protoplanetary disksJan 06 2017Feb 10 2017The deuterium enrichment of molecules is sensitive to their formation environment. Constraining patterns of deuterium chemistry in protoplanetary disks is therefore useful for probing how material is inherited or reprocessed throughout the stages of star ... More