Results for "A. Ginsburg"

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Astro2020 Science White Paper: What is the lifecycle of gas and stars in galaxy centers?Mar 11 2019The closest galaxy center, our own Central Molecular Zone (CMZ; the central 500 pc of the Milky Way), is a powerful laboratory for studying the secular processes that shape galaxies across cosmic time, from large-scale gas flows and star formation to ... More
Hypervelocity Planets and Transits Around Hypervelocity StarsJan 06 2012Mar 14 2012The disruption of a binary star system by the massive black hole at the Galactic Centre, SgrA*, can lead to the capture of one star around SgrA* and the ejection of its companion as a hypervelocity star (HVS). We consider the possibility that these stars ... More
Star Formation Rates of Massive Molecular Clouds in the Central Molecular ZoneJan 23 2019Feb 21 2019We investigate star formation at very early evolutionary phases in five massive clouds in the inner 500 pc of the Galaxy, the Central Molecular Zone. Using interferometer observations of H$_2$O masers and ultra-compact H II regions, we find evidence of ... More
Hot ammonia around young O-type stars. III. High-mass star formation and hot core activity in W51~MainJan 21 2016This paper is the third in a series of ammonia multilevel imaging studies in well-known high-mass star forming regions. Using the JVLA, we have mapped the hot and dense molecular gas in W51 Main, with about 0.2 arcsec angular resolution, in five highly-excited ... More
There are no starless massive proto-clusters in the first quadrant of the GalaxyAug 20 2012Aug 22 2012We search the lambda = 1.1 mm Bolocam Galactic Plane Survey for clumps containing sufficient mass to form ~10^4 M\odot star clusters. 18 candidate massive proto-clusters are identified in the first Galactic quadrant outside of the central kiloparsec. ... More
Variability of Hypervelocity StarsFeb 07 2013We present time-series photometry of 11 hypervelocity stars (HVSs) to constrain their nature. Known HVSs are mostly late-B spectral type objects that may be either main-sequence (MS) or evolved blue horizontal branch (BHB) stars. Fortunately, MS stars ... More
Molecular gas kinematics within the central 250 pc of the Milky WayJan 14 2016Feb 10 2016Using spectral-line observations of HNCO, N2H+, and HNC, we investigate the kinematics of dense gas in the central ~250 pc of the Galaxy. We present SCOUSE (Semi-automated multi-COmponent Universal Spectral-line fitting Engine), a line fitting algorithm ... More
Accretion and outflow structures within 1000 AU from high-mass protostars with ALMA longest baselinesMay 14 2018Understanding the formation of massive stars is one of the unsolved problems in modern astronomy. The main difficulty is that the intense radiation from the high-luminosity stars and the thermal pressure from the resulting ionized gas (both insignificant ... More
A nebular analysis of the central Orion Nebula with MUSENov 05 2015Dec 09 2015A nebular analysis of the central Orion Nebula and its main structures is presented. We exploit MUSE integral field observations in the wavelength range 4595-9366 \r{A} to produce the first O, S and N ionic and total abundance maps of a region spanning ... More
'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016Feb 07 2019In this paper we provide a comprehensive description of the internal dynamics of G0.253+0.016 (a.k.a. 'the Brick'); one of the most massive and dense molecular clouds in the Galaxy to lack signatures of widespread star formation. As a potential host to ... More
Achievement of Ultra-High Quality Factor in Prototype Cryomodule for LCLS-IIDec 21 2018Jan 08 2019Quality factor is a primary cost driver for high energy, continuous wave (CW) SRF linacs like the LCLS-II X-ray free electron laser currently under construction. Taking this into account, several innovations were introduced in the LCLS-II cryomodule design ... More
Protoplanetary Disks in the Orion OMC1 Region Imaged with ALMAApr 11 2016We present ALMA observations of the Orion Nebula that cover the OMC1 outflow region. Our focus in this paper is on compact emission from protoplanetary disks. We mosaicked a field containing $\sim 600$ near-IR-identified young stars, around which we can ... More
Distributed star formation throughout the Galactic Center cloud Sgr B2Jan 15 2018We report ALMA observations with resolution $\approx0.5$" at 3 mm of the extended Sgr B2 cloud in the Central Molecular Zone (CMZ). We detect 271 compact sources, most of which are smaller than 5000 AU. By ruling out alternative possibilities, we conclude ... More
The Survey of Water and Ammonia in the Galactic Center (SWAG): Molecular Cloud Evolution in the Central Molecular ZoneOct 18 2017The Survey of Water and Ammonia in the Galactic Center (SWAG) covers the Central Molecular Zone (CMZ) of the Milky Way at frequencies between 21.2 and 25.4 GHz obtained at the Australia Telescope Compact Array at $\sim 0.9$ pc spatial and $\sim 2.0$ km ... More
Temperature structures in Galactic Center clouds - Direct evidence for gas heating via turbulenceJul 12 2016The Central Molecular Zone (CMZ) at the center of our Galaxy is the best template to study star formation processes under extreme conditions, similar to those in high-redshift galaxies. We observed on-the-fly maps of para-H$_{2}$CO transitions at 218 ... More
High-Resolution Structure and Intermolecular Interactions between L-type Straight Flagellar FilamentsNov 12 2016Bacterial mobility is powered by rotation of helical flagellar filaments driven by rotary motors. Flagellin isolated from {\it Salmonella Typhimurium} SJW1660 strain, which differs by a point mutation from the wild-type strain, assembles into straight ... More
The Peculiar Balmer Decrement of SN 2009ip: Constraints on Circumstellar GeometryNov 19 2012Nov 09 2013We present optical and near-IR spectroscopic observations of the luminous blue variable SN 2009ip during its remarkable photometric evolution of 2012. The spectra sample three key points in the SN 2009ip lightcurve, corresponding to its initial brightening ... More
A Brief Update on the CMZoom SurveyOct 18 2016The inner few hundred parsecs of the Milky Way, the Central Molecular Zone (CMZ), is our closest laboratory for understanding star formation in the extreme environments (hot, dense, turbulent gas) that once dominated the universe. We present an update ... More
Hypervelocity Collisions of Binary Stars at the Galactic CentreSep 15 2006Jan 11 2007Recent surveys have identified seven hypervelocity stars (HVSs) in the halo of the Milky Way. Most of these stars may have originated from the breakup of binary star systems by the nuclear black hole SgrA*. In some instances, the breakup of the binary ... More
Shielding Studies for Superconducting RF Cavities at FermilabFeb 07 2012A semi-empirical method that allows us to predict intensity of generated field emission in superconducting RF cavities is described. Spatial, angular and energy distributions of the generated radiation are calculated with the FISHPACT code. The Monte ... More
The Pillars of Creation revisited with MUSE: gas kinematics and high-mass stellar feedback traced by optical spectroscopyApr 13 2015Integral field unit (IFU) data of the iconic Pillars of Creation in M16 are presented. The ionisation structure of the pillars was studied in great detail over almost the entire visible wavelength range, and maps of the relevant physical parameters, e.g. ... More
Kinematics and H_2 morphology of the multipolar Post-AGB star IRAS 16594-4656Jan 04 2008context: The spectrum of IRAS 16594-4656 shows shock excited H_2 emission and collisionally excited emission lines such as[O I],[C I],and [Fe II]. aim: The goal is to determine the location of the H_2 and [Fe II] shock emission, to determine the shock ... More
The Fate of Former Companions to Hypervelocity Stars Originating at the Galactic CenterOct 19 2005Jan 20 2006The hypervelocity star SDSS J090745.0+024507 in the halo of the Milky Way galaxy (Brown et al. 2005) most likely originated from the breakup of a binary star system by the central black hole, SgrA* (Hills 1988). We examine the fate of former binary companions ... More
Comparison of Batch Normalization and Weight Normalization Algorithms for the Large-scale Image ClassificationSep 24 2017Oct 07 2017Batch normalization (BN) has become a de facto standard for training deep convolutional networks. However, BN accounts for a significant fraction of training run-time and is difficult to accelerate, since it is a memory-bandwidth bounded operation. Such ... More
Training Deep AutoEncoders for Collaborative FilteringAug 05 2017Oct 10 2017This paper proposes a novel model for the rating prediction task in recommender systems which significantly outperforms previous state-of-the art models on a time-split Netflix data set. Our model is based on deep autoencoder with 6 layers and is trained ... More
Factorization tricks for LSTM networksMar 31 2017Feb 24 2018We present two simple ways of reducing the number of parameters and accelerating the training of large Long Short-Term Memory (LSTM) networks: the first one is "matrix factorization by design" of LSTM matrix into the product of two smaller matrices, and ... More
Transits Probabilities Around Hypervelocity and Runaway StarsSep 13 2016In the blooming field of exoplanetary science, NASA's Kepler Space Telescope has revolutionized our understanding of exoplanets. Kepler's very precise and long-duration photometry is ideal for detecting planetary transits around Sun-like stars. The forthcoming ... More
The optically bright post-AGB population of the LMCApr 12 2011The detected variety in chemistry and circumstellar shell morphology of the limited sample of Galactic post-AGB stars is so large that there is no consensus yet on how the different objects are linked by evolutionary channels. The evaluation is complicated ... More
Fermilab experience of post-annealing losses in SRF niobium cavities due to furnace contamination and the ways to its mitigation: a pathway to processing simplification and quality factor improvementMay 09 2013May 16 2013We investigate the effect of high temperature treatments followed by only high-pressure water rinse (HPR) of superconducting radio frequency (SRF) niobium cavities. The objective is to provide a cost effective alternative to the typical cavity processing ... More
Connecting the dots: a correlation between ionising radiation and cloud mass-loss rate traced by optical integral field spectroscopyJul 29 2016We present an analysis of the effect of feedback from O- and B-type stars with data from the integral field spectrograph MUSE mounted on the Very Large Telescope of pillar-like structures in the Carina Nebular Complex, one of the most massive star-forming ... More
SWAG Water Masers in the Galactic CenterNov 06 2017The Galactic Center contains large amounts of molecular and ionized gas as well as a plethora of energetic objects. Water masers are an extinction-insensitive probe for star formation and thus ideal for studies of star formation stages in this highly ... More
Fire in the Heart: A Characterization of the High Kinetic Temperatures and Heating Sources in the Nucleus of NGC253Dec 21 2018Jan 18 2019The nuclear starburst within the central $\sim 15^{\prime\prime}$ ($\sim 250$ pc; $1^{\prime\prime} \simeq 17$ pc) of NGC253 has been extensively studied as a prototype for the starburst phase in galactic evolution. Atacama Large Millimeter/submillimeter ... More
Characterizing Precursors to Stellar Clusters with HerschelJan 24 2011Context: Despite their profound effect on the universe, the formation of massive stars and stellar clusters remains elusive. In the past decade, compelling evidence has emerged that suggests Infrared Dark Clouds (IRDCs) may be precursors to stellar clusters. ... More
Triple Disruptions in The Galactic Centre: Captured and Ejected Binaries, Rejuvenated Stars, and Correlated OrbitsSep 11 2011The disruption of a binary star by a massive black hole (MBH) typically leads to the capture of one component around the MBH and the ejection of its companion at a high velocity, possibly producing a hypervelocity star. The high fraction of observed triples ... More
Star Formation Rates of Massive Molecular Clouds in the Central Molecular ZoneJan 23 2019We investigate star formation at very early evolutionary phases in five massive clouds in the inner 500 pc of the Galaxy, the Central Molecular Zone. Using interferometer observations of H$_2$O masers and ultra-compact H II regions, we find evidence of ... More
Water, methanol and dense gas tracers in the local ULIRG Arp 220: Results from the new SEPIA Band 5 Science Verification campaignJun 20 2016We present a line survey of the ultra-luminous infrared galaxy Arp 220, taken with the newly installed SEPIA Band 5 instrument on APEX. We illustrate the capacity of SEPIA to detect the 183.3 GHz H2O 31,3-22,0 line against the atmospheric H2O absorption ... More
Large Batch Training of Convolutional NetworksAug 13 2017Sep 13 2017A common way to speed up training of large convolutional networks is to add computational units. Training is then performed using data-parallel synchronous Stochastic Gradient Descent (SGD) with mini-batch divided between computational units. With an ... More
The Orion fingers: Near-IR spectral imaging of an explosive outflowApr 15 2016We present near-IR (1.1-2.4 micron) position-position-velocity cubes of the 500-year-old Orion BN/KL explosive outflow with spatial resolution 1" and spectral resolution 86 km/s. We construct integrated intensity maps free of continuum sources of 15 H2 ... More
JCMT HARP CO 3-2 Observations of Molecular Outflows in W5Jun 07 2011Jul 20 2011New JCMT HARP CO 3-2 observations of the W5 star forming complex are presented, totaling an area of 12000 arcmin^2 with sensitivity better than 0.1 K per 0.4 km/s channel. We discovered 55 CO outflow candidates, of which 40 are associated with W5 and ... More
Gravitational Waves and Intermediate-mass Black Hole Retention in Globular ClustersNov 01 2017Mar 27 2018The recent discovery of gravitational waves has opened new horizons for physics. Current and upcoming missions, such as LIGO, VIRGO, KAGRA, and LISA, promise to shed light on black holes of every size from stellar mass (SBH) sizes up to supermassive black ... More
Deep-Inelastic e^+p Scattering at Very High Q^2 from ZEUS at HERAMay 25 1999Neutral-current and charged-current deep-inelastic scattering at very high four-momentum transfer squared (Q^2) have been studied in positron-proton collisions at center-of-mass energy 300 GeV using the ZEUS detector at HERA. An integrated luminosity ... More
A measurement of the turbulence-driven density distribution in a non-star-forming molecular cloudOct 02 2013Oct 04 2013Molecular clouds are supersonically turbulent. This turbulence governs the initial mass function and the star formation rate. In order to understand the details of star formation, it is therefore essential to understand the properties of turbulence, in ... More
Ending AIDS in Gabon: How long will it take? How much will it cost?Mar 26 2014The prevalence of HIV in West Africa is lower than elsewhere in Africa but Gabon has one of the highest rates of HIV in that region. Gabon has a small population and a high per capita gross domestic product making it an ideal place to carry out a programme ... More
Using young massive star clusters to understand star formation and feedback in high-redshift-like environmentsJan 11 2016The formation environment of stars in massive stellar clusters is similar to the environment of stars forming in galaxies at a redshift of 1 - 3, at the peak star formation rate density of the Universe. As massive clusters are still forming at the present ... More
VLASSICK: The VLA Sky Survey in the Central KiloparsecJan 15 2014At a distance of 8 kpc, the center of our Galaxy is the nearest galactic nucleus, and has been the subject of numerous key projects undertaken by great observatories such as Chandra, Spitzer, and Herschel. However, there are still no surveys of molecular ... More
Nonparametric Reduced-Rank Regression for Multi-SNP, Multi-Trait Association MappingDec 08 2015Genome-wide association studies have proven to be essential for understanding the genetic basis of disease. However, many complex traits---personality traits, facial features, disease subtyping---are inherently high-dimensional, impeding simple approaches ... More
High Gradient Tests of the Fermilab SSR1 CavityJan 23 2013In Fermilab we are build and tested several superconducting Single Spoke Resonators (SSR1, \beta=0.22) which can be used for acceleration of low beta ions. Fist two cavities performed very well during cold test in Vertical Test Station at FNAL. One dressed ... More
Forming Super Star Clusters in the Central Starburst of NGC 253Apr 05 2018Oct 24 2018NGC 253 hosts the nearest nuclear starburst. Previous observations show a region rich in molecular gas, with dense clouds associated with recent star formation. We used ALMA to image the 350 GHz dust continuum and molecular line emission from this region ... More
Absorption Filaments Towards the Massive Clump G0.253+0.016Sep 12 2014ALMA HCO+ observations of the infrared dark cloud G0.253+0.016 located in the Central Molecular Zone of the Galaxy are presented. The 89 GHz emission is area-filling, optically thick, and sub-thermally excited. Two types of filaments are seen in absorption ... More
Thermal Feedback in the high-mass star and cluster forming region W51Apr 05 2017May 17 2017High-mass stars have generally been assumed to accrete most of their mass while already contracted onto the main sequence, but this hypothesis has not been observationally tested. We present ALMA observations of a 3 x 1.5 pc area in the W51 high-mass ... More
The Molecular Gas Environment in the 20 km s$^{-1}$ Cloud in the Central Molecular ZoneMar 20 2017We recently reported a population of protostellar candidates in the 20 km s$^{-1}$ cloud in the Central Molecular Zone of the Milky Way, traced by H$_2$O masers in gravitationally bound dense cores. In this paper, we report high-angular-resolution ($\sim$3'') ... More
Dense gas kinematics and a narrow filament in the Orion A OMC1 region using NH3Jun 05 2018Dec 18 2018We present combined observations of the NH3 (J,K) = (1,1) and (2,2) inversion transitions towards OMC1 in Orion A obtained by the Karl G. Jansky Very Large Array (VLA) and the 100 m Robert C. Byrd Green Bank Telescope (GBT). With an angular resolution ... More
A Keplerian disk around Orion Source I, a ~15 Msun YSOApr 27 2018We report ALMA long-baseline observations of Orion Source I (SrcI) with resolution 0.03-0.06" (12-24 AU) at 1.3 and 3.2 mm. We detect both continuum and spectral line emission from SrcI's disk. We also detect a central weakly resolved source that we interpret ... More
The Orion Fingers: Near-IR Adaptive Optics Imaging of an Explosive Protostellar OutflowFeb 16 2015Feb 18 2015Aims. Adaptive optics images are used to test the hypothesis that the explosive BN/KL outflow from the Orion OMC1 cloud core was powered by the dynamical decay of a non-hierarchical system of massive stars. Methods. Narrow-band H2, [Fe II], and broad-band ... More
Investigating fragmentation of gas structures in OB cluster-forming molecular clump G33.92+0.11 with 1000 AU resolution observations of ALMAAug 23 2018Dec 05 2018We report new, $\sim$1000 AU spatial resolution observations of 225 GHz dust continuum emission towards the OB cluster-forming molecular clump G33.92+0.11. On parsec scales, this molecular clump presents a morphology with several arm-like dense gas structures ... More
Training Neural Speech Recognition Systems with Synthetic Speech AugmentationNov 02 2018Building an accurate automatic speech recognition (ASR) system requires a large dataset that contains many hours of labeled speech samples produced by a diverse set of speakers. The lack of such open free datasets is one of the main issues preventing ... More
Galactic H2CO Densitometry I: Pilot survey of Ultracompact HII regions and methodologyJun 07 2011Jul 26 2011We present a pilot survey of 21 lines of sight towards UCHII regions in the H2CO 1-1 (6cm) and 2-2 (2cm) transitions, using the H2CO centimeter lines as a molecular gas densitometer. Using Arecibo and Green Bank beam-matched observations, we measure the ... More
The Orion fingers: H$_2$ temperatures and excitation in an explosive outflowMar 05 2018We measure H$_2$ temperatures and column densities across the Orion BN/KL explosive outflow from a set of thirteen near-IR H$_2$ rovibrational emission lines observed with the TripleSpec spectrograph on Apache Point Observatory's 3.5-meter telescope. ... More
Detecting Stars at the Galactic Centre via Synchrotron EmissionSep 21 2015Stars orbiting within 1$\arcsec$ of the supermassive black hole in the Galactic Centre, Sgr A*, are notoriously difficult to detect due to obscuration by gas and dust. We show that some stars orbiting this region may be detectable via synchrotron emission. ... More
SEBOOST - Boosting Stochastic Learning Using Subspace Optimization TechniquesSep 02 2016We present SEBOOST, a technique for boosting the performance of existing stochastic optimization methods. SEBOOST applies a secondary optimization process in the subspace spanned by the last steps and descent directions. The method was inspired by the ... More
Tidal Disruption Events and Gravitational Waves from Intermediate-mass Black Holes in Evolving Globular Clusters Across Space and TimeJun 21 2018Nov 01 2018We present a semi-analytic model for self-consistently evolving a population of globular clusters (GCs) in a given host galaxy across cosmic time. We compute the fraction of GCs still hosting intermediate-mass black holes (IMBHs) at a given redshift in ... More
Herschel Observations of the W43 "mini-starburst"May 21 2010Aims: To explore the infrared and radio properties of one of the closest Galactic starburst regions. Methods: Images obtained with the Herschel Space Observatory at wavelengths of 70, 160, 250, 350, and 500 microns using the PACS and SPIRE arrays are ... More
The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated cloudsFeb 05 2019Feb 07 2019The evolution of molecular clouds in galactic centres is thought to differ from that in galactic discs due to a significant influence of the external gravitational potential. We present a set of numerical simulations of molecular clouds orbiting on the ... More
Young massive star cluster formation in the Galactic Centre is driven by global gravitational collapse of high-mass molecular cloudsMar 14 2019Young massive clusters (YMCs) are the most compact, high-mass stellar systems still forming at the present day. The precursor clouds to such systems are, however, rare due to their large initial gas mass reservoirs and rapid dispersal timescales due to ... More
High-mass star-forming cloud G0.38+0.04 in the Galactic Center Dust Ridge contains H2CO and SiO masersOct 21 2015Nov 16 2015We have discovered a new H$_2$CO (formaldehyde) $1_{1,0}-1_{1,1}$ 4.82966 GHz maser in Galactic Center Cloud C, G0.38+0.04. At the time of acceptance, this is the eighth region containing an H$_2$CO maser detected in the Galaxy. Cloud C is one of only ... More
The CARMA-NRO Orion Survey: The filamentary structure as seen in C$^{18}$O emissionJan 01 2019We present an initial overview of the filamentary structure in the Orion A molecular cloud utilizing a high angular and velocity resolution C$^{18}$O(1-0) emission map that was recently produced as part of the CARMA-NRO Orion Survey. The main goal of ... More
Star formation in a high-pressure environment: An SMA view of the Galactic centre dust ridgeNov 02 2017The star formation rate in the Central Molecular Zone (CMZ) is an order of magnitude lower than predicted according to star formation relations that have been calibrated in the disc of our own and nearby galaxies. Understanding how and why star formation ... More
Dense gas in the Galactic central molecular zone is warm and heated by turbulenceSep 04 2015The Galactic center is the closest region in which we can study star formation under extreme physical conditions like those in high-redshift galaxies. We measure the temperature of the dense gas in the central molecular zone (CMZ) and examine what drives ... More
A spatially resolved study of photoelectric heating and [CII] cooling in the LMCDec 12 2008(abridged) We study photoelectric heating throughout the Large Magellanic Cloud. We quantify the importance of the [CII] cooling line and the photoelectric heating process of various environments in the LMC and investigate which parameters control the ... More
The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the Gould BeltApr 20 2017We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with $A_V \gtrsim 7$ mag visible from ... More
The Green Bank Ammonia Survey: Observations of Hierarchical Dense Gas Structures in Cepheus-L1251Oct 13 2017We use Green Bank Ammonia Survey observations of NH$_3$ (1,1) and (2,2) emission with 32'' FWHM resolution from a ~ 10 pc$^{2}$ portion of the Cepheus-L1251 molecular cloud to identify hierarchical dense gas structures. Our dendrogram analysis of the ... More
The Green Bank Ammonia Survey: Dense Cores Under Pressure in Orion AAug 17 2017We use gas temperature and velocity dispersion data from the Green Bank Ammonia Survey and core masses and sizes from the James Clerk Maxwell Telescope Gould Belt Survey to estimate the virial states of dense cores within the Orion A molecular cloud. ... More
Herschel Reveals Massive Cold Clumps in NGC 7538Jun 28 2013We present the first overview of the Herschel observations of the nearby high-mass star-forming region NGC 7538, taken as part of the Herschel imaging study of OB Young Stellar objects (HOBYS) Key Programme. These PACS and SPIRE maps cover an approximate ... More
Orion Source I's disk is saltyJan 14 2019We report the detection of NaCl, KCl, and their $^{37}$Cl and $^{41}$K isotopologues toward the disk around Orion SrcI. About 60 transitions of these molecules were identified. This is the first detection of these molecules in the interstellar medium ... More
Outflows and Massive Stars in the protocluster IRAS 05358+3543Oct 15 2009Sep 25 2013We present new near-IR H2, CO J=2-1, and CO J = 3-2 observations to study outflows in the massive star forming region IRAS 05358+3543. The Canada-France-Hawaii Telescope H2 images and James Clerk Maxwell Telescope CO data cubes of the IRAS 05358 region ... More
Graph-based interpretation of the Molecular Interstellar Medium SegmentationOct 14 2015We present a generalization of the Giant Molecular Cloud (GMC) identification problem based on cluster analysis. The method we designed, SCIMES (Spectral Clustering for Interstellar Molecular Emission Segmentation) considers the dendrogram of emission ... More
SWAG: Distribution and Kinematics of an Obscured AGB Population toward the Galactic CenterOct 30 2018Nov 13 2018Outflows from AGB stars enrich the Galactic environment with metals and inject mechanical energy into the ISM. Radio spectroscopy can recover both properties through observations of molecular lines. We present results from SWAG: "Survey of Water and Ammonia ... More
Early stage massive star formation near the Galactic Center: Sgr CSep 02 2013We present near-infrared spectroscopy and 1 mm line and continuum observations of a recently identified site of high mass star formation likely to be located in the Central Molecular Zone near Sgr C. Located on the outskirts of the massive evolved HII ... More
An Infrared through Radio Study of the Properties and Evolution of IRDC ClumpsAug 04 2010We examine the physical properties and evolutionary stages of a sample of 17 clumps within 8 Infrared Dark Clouds (IRDCs) by combining existing infrared, millimeter, and radio data with new Bolocam Galactic Plane Survey (BGPS) 1.1 mm data, VLA radio continuum ... More
How to Find Young Massive Cluster ProgenitorsAug 16 2012Aug 22 2012We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up, enabling star formation ... More
Commissioning And First Results From The Fermilab Cryomodule Test StandMay 07 2018A new test stand dedicated to Superconducting Radiofrequency (SRF) cryomodule testing, CMTS1, has been commissioned and is now in operation at Fermilab. The first device to be cooled down and powered in this facility is the prototype 1.3 GHz cryomodule ... More
The Ring Nebula Around the Blue Supergiant SBW1: Pre-Explosion Snapshot of a SN 1987A TwinNov 19 2012Nov 24 2012SBW1 is a B supergiant surrounded by a ring nebula that is a nearby twin of SN 1987A. We present images and spectra of SBW1 obtained with HST, Spitzer, and Gemini South. HST images of SBW1 do not exhibit long Rayleigh-Taylor fingers, which are presumed ... More
Outflows, Dusty Cores, and a Burst of Star Formation in the North America and Pelican NebulaeSep 23 2014We present observations of near-infrared 2.12 micro-meter molecular hydrogen outflows emerging from 1.1 mm dust continuum clumps in the North America and Pelican Nebula (NAP) complex selected from the Bolocam Galactic Plane Survey (BGPS). Hundreds of ... More
Direct Conversion Pulsed UWB Transceiver ArchitectureOct 25 2007Ultra-wideband (UWB) communication is an emerging wireless technology that promises high data rates over short distances and precise locationing. The large available bandwidth and the constraint of a maximum power spectral density drives a unique set ... More
The Comparison of Physical Properties Derived from Gas and Dust in a Massive Star-Forming RegionMay 13 2014We explore the relationship between gas and dust in massive star-forming regions by comparing physical properties derived from each. We compare the temperatures and column densities in a massive star-forming Infrared Dark Cloud (IRDC, G32.02+0.05), which ... More
Star-forming Region Sh 2-233IR I. Deep NIR Observations toward the Embedded Stellar ClustersJul 14 2011We observed the Sh 2-233IR (S233IR) region with better sensitivity in near-infrared than previous studies for this region. By applying statistical subtraction of the back- ground stars, we identified member sources and derived the age and mass of three ... More
The Cultural Evolution of National ConstitutionsNov 18 2017We explore how ideas from infectious disease and genetics can be used to uncover patterns of cultural inheritance and innovation in a corpus of 591 national constitutions spanning 1789 - 2008. Legal "Ideas" are encoded as "topics" - words statistically ... More
Large-scale filaments associated with Milky Way spiral armsApr 02 2015Jul 08 2015The ubiquity of filamentary structure at various scales through out the Galaxy has triggered a renewed interest in their formation, evolution, and role in star formation. The largest filaments can reach up to Galactic scale as part of the spiral arm structure. ... More
The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark CloudMay 13 2014We present new NH3 (1,1), (2,2), and (4,4) observations from the Karl G. Jansky Very Large Array (VLA) compiled with work in the literature to explore the range of conditions observed in young, massive star-forming regions. To sample the effects of evolution ... More
Latent protein treesAug 11 2011Dec 05 2013Unbiased, label-free proteomics is becoming a powerful technique for measuring protein expression in almost any biological sample. The output of these measurements after preprocessing is a collection of features and their associated intensities for each ... More
The road toward a full, high resolution Molecular Cloud catalog of the GalaxyOct 19 2015The statistical description of Giant Molecular Cloud (GMC) properties relies heavily on the performance of automatic identification algorithms, which are often seriously affected by the survey design. The algorithm we designed, SCIMES (Spectral Clustering ... More
The ALMA View of the OMC1 Explosion in OrionJan 08 2017Feb 01 2017Most massive stars form in dense clusters where gravitational interactions with other stars may be common. The two nearest forming massive stars, the BN object and Source I, located behind the Orion Nebula, were ejected with velocities of $\sim$29 and ... More
Mixed-Precision Training for NLP and Speech Recognition with OpenSeq2SeqMay 25 2018Nov 21 2018We present OpenSeq2Seq - a TensorFlow-based toolkit for training sequence-to-sequence models that features distributed and mixed-precision training. Benchmarks on machine translation and speech recognition tasks show that models built using OpenSeq2Seq ... More
SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar mediumJan 17 2017The origin and life-cycle of molecular clouds are still poorly constrained, despite their importance for understanding the evolution of the interstellar medium. We have carried out a systematic, homogeneous, spectroscopic survey of the inner Galactic ... More
Droplets I: Pressure-Dominated Sub-0.1 pc Coherent Structures in L1688 and B18Sep 26 2018We present the observation and analysis of newly discovered coherent structures in the L1688 region of Ophiuchus and the B18 region of Taurus. Using data from the Green Bank Ammonia Survey (GAS; Friesen et al. 2017), we identify regions of high density ... More
Reverberation Mapping Results for Five Seyfert 1 GalaxiesJun 27 2012We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140-day span beginning ... More
The dense gas mass fraction in the W51 cloud and its protoclustersNov 06 2014Jan 07 2015We present new 2 cm and 6 cm maps of H2CO, radio recombination lines, and the radio continuum in the W51 star forming complex acquired with Arecibo and the Green Bank Telescope at ~50" resolution. We use H2CO absorption to determine the relative line-of-sight ... More
The Structure of the Broad Line Region in AGN: I. Reconstructed Velocity-Delay MapsOct 08 2012Dec 11 2012We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum-entropy method for four objects: Mrk 335, Mrk 1501, 3C120, and PG2130+099. For the fifth, Mrk 6, we were only able to ... More
Next Generation Very Large Array Memo No. 6, Science Working Group 1: The Cradle of LifeOct 21 2015This paper discusses compelling science cases for a future long-baseline interferometer operating at millimeter and centimeter wavelengths, like the proposed Next Generation Vary Large Array (ngVLA). We report on the activities of the Cradle of Life science ... More
A Reverberation Lag for the High-Ionization Component of the Broad Line Region in the Narrow-Line Seyfert 1 Mrk 335Oct 27 2011Nov 28 2011We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 galaxy Mrk 335, collected over a 120-day span in the fall of 2010. From these data we measure the lag in the He II 4686 broad ... More