Results for "John Gallagher"

total 19399took 0.27s
Collaborative Dense SLAMNov 19 2018Nov 21 2018In this paper, we present a new system for live collaborative dense surface reconstruction. Cooperative robotics, multi participant augmented reality and human-robot interaction are all examples of situations where collaborative mapping can be leveraged ... More
Populations of Dwarfs in Clusters of Galaxies: Environmental ConnectionsAug 01 2001Despite their apparent fragile appearance, dwarf spheroidals are the most common galaxy type in clusters. In this paper we consider some of the issues associated with two major models for the origin of these dwarfs: primeval galaxies which formed with ... More
Constraining Stellar Feedback: Shock-ionized Gas in Nearby Starburst GalaxiesSep 02 2013(abridged) We investigate the properties of feedback-driven shocks in 8 nearby starburst galaxies using narrow-band imaging data from the Hubble Space Telescope (HST). We identify the shock--ionized component via the line diagnostic diagram \oiii/\hb ... More
A Web-based Tool Combining Different Type AnalysesJan 17 2007There are various kinds of type analysis of logic programs. These include for example inference of types that describe an over-approximation of the success set of a program, inference of well-typings, and abstractions based on given types. Analyses can ... More
Detecting and Diagnosing Energy Issues for Mobile ApplicationsJan 04 2019Energy efficiency is an important criterion to judge the quality of mobile apps, but one third of our randomly sampled apps are suffering from energy issues that can quickly drain battery. To understand these issues, we conducted an empirical study on ... More
The Star Formation History of the Large Magellanic CloudSep 25 2001Using WFPC2 aboard the Hubble Space Telescope, we have created deep color-magnitude diagrams in the V and I passbands for approximately 100,000 stars in a field at the center of the LMC bar and another in the disk. The main--sequence luminosity functions ... More
Proceedings of the 19th Workshop on Logic-based methods in Programming Environments (WLPE 2009)Feb 24 2010This volume contains the papers presented at the 19th Workshop on Logic- based methods in Programming Environments (WLPE'09), which was held in Pasadena, USA, on July 14th, 2009. WLPE aims at providing an informal meeting for researchers working on logic-based ... More
Proceedings 3rd Workshop on Horn Clauses for Verification and SynthesisJul 14 2016This volume contains the proceedings of HCVS 2016, the Third Workshop on Horn Clauses for Verification and Synthesis which was held on April 3, 2016 in Eindhoven, The Netherlands as a satellite event of the European Joint Conferences on Theory and Practice ... More
Convex polyhedral abstractions, specialisation and property-based predicate splitting in Horn clause verificationDec 03 2014We present an approach to constrained Horn clause (CHC) verification combining three techniques: abstract interpretation over a domain of convex polyhedra, specialisation of the constraints in CHCs using abstract interpretation of query-answer transformed ... More
Analysis and Transformation Tools for Constrained Horn Clause VerificationMay 15 2014Several techniques and tools have been developed for verification of properties expressed as Horn clauses with constraints over a background theory (CHC). Current CHC verification tools implement intricate algorithms and are often limited to certain subclasses ... More
Interpolant Tree Automata and their Application in Horn Clause VerificationJan 25 2016Jul 10 2016This paper investigates the combination of abstract interpretation over the domain of convex polyhedra with interpolant tree automata, in an abstraction-refinement scheme for Horn clause verification. These techniques have been previously applied separately, ... More
A Source-level Energy Optimization Framework for Mobile ApplicationsAug 18 2016Energy efficiency can have a significant influence on user experience of mobile devices such as smartphones and tablets. Although energy is consumed by hardware, software optimization plays an important role in saving energy, and thus software developers ... More
An Energy-Aware Programming Approach for Mobile Application Development Guided by a Fine-Grained Energy ModelMay 17 2016Energy efficiency has a significant influence on user experience of battery-driven devices such as smartphones and tablets. It is shown that software optimization plays an important role in reducing energy consumption of system. However, in mobile devices, ... More
Fine-Grained Energy Modeling for the Source Code of a Mobile ApplicationOct 14 2015May 18 2016Energy efficiency has a significant influence on user experience of battery-driven devices such as smartphones and tablets. The goal of an energy model for source code is to lay a foundation for the application of energy-saving techniques during software ... More
Galaxy Aggregates in the Coma ClusterJan 16 1998Feb 05 1998We present evidence for a new morphologically defined form of small-scale substructure in the Coma Cluster, which we call galaxy aggregates. These aggregates are dominated by a central galaxy, which is on average three magnitudes brighter than the smaller ... More
B and V CCD Photometry of Southern, Extreme Late-Type Spiral GalaxiesSep 15 1997We present B and V CCD aperture photometry for a morphologically-selected sample of forty-nine southern, extreme late-type spiral galaxies. All objects are moderate-to-low surface brightness Local Supercluster field galaxies that were detected previously ... More
Impact of Reionization on the Stellar Populations of Nearby Dwarf GalaxiesJul 06 2004Cold dark matter models for galaxy formation predict that low-mass systems will be the first sites of star formation. As these objects have shallow gravitational potential wells, the subsequent growth of their stellar populations may be halted by heating ... More
Optical Structure and Evolution of the Arp 104 Interacting Galaxy SystemSep 01 2010Arp 104 is a pair of luminous interacting galaxies consisting of NGC 5216, an elliptical, and NGC 5218, a disturbed disk galaxy and joined by a stellar bridge. We obtained optical imaging to support photometric and color studies of the system. NGC 5216 ... More
Extragalactic Star Clusters: Speculations on the FutureSep 04 2001We discuss the future possibilities for extragalactic star cluster research with the expected new ground-based and space-based telescopes and instrumentation. Significant gains are expected due to improved angular resolution, sensitivity, and area coverage ... More
An Optimised Algorithm for Determinisation and Completion of Finite Tree AutomataNov 11 2015Determinisation is an important concept in the theory of finite tree automata. However the complexity of the textbook procedure for determinisation is such that it is not viewed as a being a practical procedure for manipulating tree automata, even fairly ... More
Decomposition by tree dimension in Horn clause verificationDec 12 2015In this paper we investigate the use of the concept of tree dimension in Horn clause analysis and verification. The dimension of a tree is a measure of its non-linearity - for example a list of any length has dimension zero while a complete binary tree ... More
Tides, Interactions, and Fine-Scale Substructures in Galaxy ClustersSep 29 1998We present the results of a study on galaxy interactions, tides, and other processes which produce luminous fine-scale substructures in the galaxy clusters: Coma, Perseus, Abell 2199, AWM 3 and AWM 5. All unusual structures in these clusters can be categorized ... More
Stellar Populations and Ages of M82 Super Star ClustersDec 09 1998We present high signal-to-noise optical spectra of two luminous super star clusters in the starburst galaxy M82. The data for cluster F and the nearby, highly reddened cluster L were obtained with the William Herschel Telescope (WHT) at a resolution of ... More
Tree dimension in verification of constrained Horn clausesMar 05 2018Mar 06 2018In this paper, we show how the notion of tree dimension can be used in the verification of constrained Horn clauses (CHCs). The dimension of a tree is a numerical measure of its branching complexity and the concept here applies to Horn clause derivation ... More
Anomalous Evolution of the Dwarf Galaxy HIPASS J1321-31Aug 21 2003We present HST/WFPC2 observations of the dwarf galaxy HIPASS J1321-31. This unusual galaxy lies in the direction of the Centaurus A group of galaxies, and has a color-magnitude diagram with a distinctive red plume of luminous stars. This feature could ... More
Experiments with a Convex Polyhedral Analysis Tool for Logic ProgramsDec 17 2007Convex polyhedral abstractions of logic programs have been found very useful in deriving numeric relationships between program arguments in order to prove program properties and in other areas such as termination and complexity analysis. We present a ... More
Solving non-linear Horn clauses using a linear Horn clause solverJul 15 2016In this paper we show that checking satisfiability of a set of non-linear Horn clauses (also called a non-linear Horn clause program) can be achieved using a solver for linear Horn clauses. We achieve this by interleaving a program transformation with ... More
On the convergence of smooth solutions from Boltzmann to Navier-StokesMar 06 2019In this work, we are interested in the link between strong solutions of the Boltzmann and the Navier-Stokes equations. To justify this connection, our main idea is to use information on the limit system (for instance the fact that the Navier-Stokes equations ... More
Stellar Populations at the Center of IC 1613May 27 1999We have observed the center of the Local Group dwarf irregular galaxy IC 1613 with WFPC2 aboard the Hubble Space Telescope in the F439W, F555W, and F814W filters. We find a dominant old stellar population (aged ~7 Gyr), identifiable by the strong red ... More
The Star Cluster System of the NGC 7673 StarburstJun 11 2002We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The ... More
Dusty Superwind from a Galaxy with a Compact Obscured Nucleus: Optical Spectroscopic Study of NGC 4418Dec 21 2018We report our optical spectroscopic study of the nucleus and its surrounding region of a nearby luminous infrared galaxy NGC 4418. This galaxy has been known to host a compact obscured nucleus, showing distinct characteristics such as a very compact ($\sim ... More
Compact HI clouds from the GALFA-HI surveyAug 07 2010The Galactic Arecibo L-band Feed Array HI (GALFA-HI) survey is mapping the entire Arecibo sky at 21-cm, over a velocity range of -700 to +700 km/s (LSR), at a velocity resolution of 0.18 km/s and a spatial resolution of 3.5 arcmin. The unprecedented resolution ... More
Dynamics and the Origin of Low-Mass Galaxies in the Virgo ClusterMay 29 2001Early-type dwarfs are the most common galaxy in the local universe, yet their origin and evolution remain a mystery. Various cosmological scenarios predict that dwarf-like galaxies in dense areas are the first to form and hence should be the oldest stellar ... More
Dwarf Spheroidal Galaxies : Keystones of Galaxy EvolutionNov 16 1994Dwarf spheroidal galaxies are the most insignificant extragalactic stellar systems in terms of their visibility, but potentially very significant in terms of their role in the formation and evolution of much more luminous galaxies. We discuss the present ... More
WIYN Survey for Carbon Stars in the M31 and Cetus Dwarf Spheroidal Galaxies: Evolutionary ImplicationsJan 28 2004We report results of a photometric survey with the WIYN telescope for carbon stars in the M 31 dwarf spheroidal (dSph) companions And III, And V, And VI, and And VII, as well as in the relatively isolated Local Group dSph Cetus. We find three carbon-star ... More
On the Nature of the NGC 1275 SystemAug 01 2001Sub-arcsecond images, taken in B, R, and H-Alpha filters, and area spectroscopy obtained with the WIYN 3.5-m telescope provide the basis for an investigation of the unusual structures in the stellar body and ionized gas in and around the Perseus cluster ... More
The Nature of Low-Density Star FormationMar 13 2019How do stars manage to form within low-density, HI-dominated gas? Such environments provide a laboratory for studying star formation with physical conditions distinct from starbursts and the metal-rich disks of spiral galaxies where most effort has been ... More
The Dynamical Origin of Early-Type Dwarfs in Galaxy Clusters: A Theoretical InvestigationDec 08 2014Dec 30 2014Observations of early-type dwarf galaxies in clusters often show that cluster dwarf members have significantly higher velocities and less symmetric distributions than cluster giant ellipticals, suggesting that these dwarfs are recently accreted galaxies, ... More
NGC 5523: An Isolated Product of Soft Galaxy Mergers?Nov 18 2016Multi-band images of the very isolated spiral galaxy NGC 5523 show a number of unusual features consistent with NGC 5523 having experienced a significant merger: (1) Near-infrared (NIR) images from the Spitzer Space Telescope (SST) and the WIYN 3.5-m ... More
Rescuing the Initial Mass Function for Arp 78Oct 09 2008We present deep R and narrow-band Halpha images of Arp 78 obtained with the WIYN 3.5-m telescope on Kitt Peak. GALEX observations had shown a very extended UV structure for this system, reaching beyond the optical radius of Arp 78 and also beyond its ... More
The Progenitors of Dwarf Spheroidal GalaxiesJan 02 2003Dwarf spheroidal (dSph) galaxies present an evolutionary puzzle that we explore in 40 early- and late-type dwarfs in the Local Group and nearby field. Although dSphs formed stars over extended periods, today all but one are free of detectable interstellar ... More
Evolutionary Status of Dwarf ``Transition'' GalaxiesOct 08 1998We present deep B, R and Halpha imaging of 3 dwarf galaxies: NGC3377A, NGC4286, and IC3475. Based on previous broadband imaging and HI studies, these mixed-morphology galaxies were proposed by Sandage & Hoffman (1991) to be, respectively, a gas-rich low ... More
Relativistic Euler Equations in cosmologies with non-linear structuresJul 04 2018We consider a new variant of cosmological perturbation theory that has been designed specifically to include non-linear density contrasts on scales 100 Mpc, while still allowing for linear fluctuations on larger scales. This theory is used to derive the ... More
Weak convergence results for inhomogeneous rotating fluid equationsFeb 10 2003We consider the equations governing incompressible, viscous fluids in three space dimensions, rotating around an inhomogeneous vector B(x): this is a generalization of the usual rotating fluid model (where B is constant). We prove the weak convergence ... More
Supernova-Driven Outflows in NGC 7552: A Comparison of H-alpha and UV TracersJul 01 2015We investigate the supernova-driven galactic wind of the barred spiral galaxy NGC 7552, using both ground-based optical nebular emission lines and far-ultraviolet absorption lines measured with the Hubble Space Telescope Cosmic Origins Spectrograph. We ... More
The Stability of Low Surface Brightness Disks Based on Multi-Wavelength ModelingJul 29 2011To investigate the structure and composition of the dusty interstellar medium (ISM) of low surface brightness (LSB) disk galaxies, we have used multiwavelength photometry to construct spectral energy distributions for three low-mass, edge-on LSB galaxies. ... More
Stacking Star Clusters in M51: Searching for Faint X-Ray BinariesDec 04 2012The population of low-luminosity (< 10^35 erg/s) X-Ray Binaries (XRBs) has been investigated in our Galaxy and M31 but not further. To address this problem, we have used data from the Chandra X-Ray Observatory and the Hubble Space Telescope to investigate ... More
On the uniqueness of the solution of the two-dimensional Navier-Stokes equation with a Dirac mass as initial vorticityOct 15 2004We propose two different proofs of the fact that Oseen's vortex is the unique solution of the two-dimensional Navier-Stokes equation with a Dirac mass as initial vorticity. The first argument, due to C.E. Wayne and the second author, is based on an entropy ... More
Perturbation theory for cosmologies with non-linear structureJul 04 2017Mar 27 2018The next generation of cosmological surveys will operate over unprecedented scales, and will therefore provide exciting new opportunities for testing general relativity. The standard method for modelling the structures that these surveys will observe ... More
Meshfree and efficient modelling of swimming cellsJan 12 2018May 11 2018Locomotion in Stokes flow is an intensively-studied problem because it describes important biological phenomena such as the motility of many species' sperm, bacteria, algae and protozoa. Numerical computations can be challenging, particularly in three ... More
On the role of quadratic oscillations in nonlinear Schrodinger equationsDec 12 2002Feb 05 2003We consider a nonlinear semi-classical Schrodinger equation for which it is known that quadratic oscillations lead to focusing at one point, described by a nonlinear scattering operator. If the initial data is an energy bounded sequence, we prove that ... More
Tail diameter upper bounds for polytopes and polyhedraMar 13 2016In 1992, Kalai and Kleitman proved a quasipolynomial upper bound on the diameters of convex polyhedra. Todd and Sukegawa-Kitahara proved tail-quasipolynomial bounds on the diameters of polyhedra. These tail bounds apply when the number of facets is greater ... More
Selection type results and fixed point property for affine bi-Lipschitz mapsFeb 28 2019We obtain a refinement of a selection principle for $(\mathcal{K}, \lambda)$-wide-$(s)$ sequences in Banach spaces due to Rosenthal. This result is then used to show that if $C$ is a bounded, non-weakly compact, closed convex subset of a Banach space ... More
What Happened to My Dog in That Network: Unraveling Top-down Generators in Convolutional Neural NetworksNov 23 2015Top-down information plays a central role in human perception, but plays relatively little role in many current state-of-the-art deep networks, such as Convolutional Neural Networks (CNNs). This work seeks to explore a path by which top-down information ... More
A Stochastic Process Model of Classical SearchNov 27 2015Among classical search algorithms with the same heuristic information, with sufficient memory A* is essentially as fast as possible in finding a proven optimal solution. However, in many situations optimal solutions are simply infeasible, and thus search ... More
Active Galactic Nuclei, Neutrinos, and Interacting Cosmic Rays in NGC 253 & NGC 1068Nov 21 2013The galaxies M82, NGC 253, NGC 1068, and NGC 4945 have been detected in gamma-rays by Fermi. Previously, we developed and tested a model for cosmic ray interactions in the starburst galaxy M82. Now, we aim to explore the differences between starburst ... More
Probing the Structure and Kinematics of the transition Layer between the Magellanic Stream and the Halo in HIOct 10 2012The Magellanic Stream (MS) is a nearby laboratory for studying the fate of cool gas streams injected into a gaseous galactic halo. We investigate properties of the boundary layer between the cool MS gas and the hot Milky Way halo with 21 cm HI observations ... More
After the interaction: an efficiently star-forming molecular disk in NGC5195Jun 24 2016Aug 07 2016We present new molecular gas maps of NGC5195 (alternatively known as M51b) from the Combined Array for Research in Millimeter Astronomy (CARMA), including 12CO(1-0), 13CO(1-0), CN(1-0), and CS(2-1). NGC5195 has also been detected in 3mm continuum. NGC5195 ... More
II Zwicky 23 and FamilyMar 12 2006II Zwicky 23 (UGC 3179) is a luminous, nearby compact narrow emission line starburst galaxy with blue optical colors and strong emission lines. We present a photometric and morphological study of II Zw 23 and its interacting companions using data obtained ... More
Galaxy Populations and Evolution in Clusters IV: Deep HI Observations of Dwarf Ellipticals in the Virgo ClusterMar 09 2003We present in this paper the deepest Arecibo HI observations of Virgo cluster dwarf ellipticals (dEs) taken to date. Based on this data we argue that a significant fraction of Virgo cluster dEs recently underwent evolution. Our new observations consist ... More
Galaxy Populations and Evolution in Clusters II: Defining Cluster PopulationsFeb 27 2002This paper presents quantitative techniques for studying, in an unbiased manner, the photometric and structural properties of galaxies in clusters, including a means to identify likely background objects in the absence of redshift information. We develop ... More
Galaxy Populations and Evolution in Clusters III. The Origin of Low-Mass Galaxies in Clusters: Constraints from Stellar PopulationsOct 02 2002Low-mass galaxies in nearby clusters are the most numerous galaxy type in the universe, yet their origin and properties remain largely unknown. To study basic questions concerning these galaxies we present the results of a survey designed to constrain ... More
From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal TailsSep 13 2000Star clusters can be found in galaxy mergers, not only in central regions, but also in the tidal debris. In both the Eastern and Western tidal tails of NGC 3256 there are dozens of young star clusters, confirmed by their blue colors and larger concentration ... More
Deep Optical Imaging of Starbursting "Transition" Dwarf GalaxiesOct 22 2007A subgroup of dwarf galaxies have characteristics of a possible evolutionary transition between star-forming systems and dwarf ellipticals. These systems host significant starbursts in combination with smooth, elliptical outer envelopes and small HI content; ... More
Model-based image analysis of a tethered Brownian fibre for shear stress sensingAug 02 2017The measurement of shear stress acting on a biologically relevant surface is a challenging problem, particularly in the complex environment of, for example, the vasculature. While an experimental method for the direct detection of wall shear stress via ... More
The Active Assembly of the Virgo Cluster: Indications for Recent Group Infall From Early-Type Dwarf GalaxiesAug 14 2018Virgo is a dynamically young galaxy cluster with substructure in its spatial and kinematic distribution. Here, we simultaneously study the phase-space distribution and the main characteristics of Virgo's galaxies, particularly its most abundant galaxy ... More
Equipartition and Cosmic Ray Energy Densities in Central Molecular Zones of StarburstsDec 02 2015The energy densities in magnetic fields and cosmic rays (CRs) in galaxies are often assumed to be in equipartition, allowing for an indirect estimate of the magnetic field strength from the observed radio synchrotron spectrum. However, both primary and ... More
Dwarf Elliptical Galaxies in the Perseus ClusterOct 21 1999Dwarf ellipticals have the lowest stellar densities of any galaxies, but paradoxically are most common in the densest regions of the universe, and are especially frequent in rich clusters of galaxies. Simple estimates suggest that low luminosity dwarf ... More
NGC 3310 and Its Tidal Debris: Remnants of Galaxy EvolutionJul 05 2006NGC 3310 is a local galaxy with an intense, ongoing starburst thought to result from a merger with a companion galaxy. It has several known tidal features in the northwest and southern regions around the main galactic disc, as well as a closed, tidal ... More
Starbursts and the Evolution of Gas-Rich GalaxiesSep 22 2000Moderately luminous starbursts in the nearby universe often occur in disk galaxies that are at most subject to mild external perturbations. An investigation of this type of galaxy leads to a better understanding of starburst triggering mechanisms and ... More
Examining the Role of Environment in a Comprehensive Sample of Compact GroupsJan 05 2012(Abridged) Compact groups, with their high number densities, small velocity dispersions, and an interstellar medium that has not been fully processed, provide a local analog to conditions of galaxy interactions in the earlier universe. The frequent and ... More
Cosmic Rays, Gamma-Rays, and Neutrinos in the Starburst Nuclei of Arp 220Jun 16 2015Jul 27 2015The cores of Arp 220, the closest ultra-luminous infrared starburst galaxy, provide an opportunity to study interactions of cosmic rays under extreme conditions. In this paper, we model the populations of cosmic rays produced by supernovae in the central ... More
Winds, Clumps, and Interacting Cosmic Rays in M82Mar 18 2013We construct a family of models for the evolution of energetic particles in the starburst galaxy M82 and compare them to observations to test the calorimeter assumption that all cosmic ray energy is radiated in the starburst region. Assuming constant ... More
The Fossil Starburst in M82Mar 11 1999We present high-resolution optical and near-infrared HST observations of two adjacent regions in the fossil starburst region in M82, M82 B1 and B2. The presence of both the active and the fossil starburst in M82 provides a unique physical environment ... More
Five Years of Magellanic Clouds Research: A Newsletter Editors' PerspectiveJul 08 2001We analyze the topical and demographic evolution of Magellanic Clouds research over the past five years based on submissions of abstracts of refereed papers to the electronic Magellanic Clouds Newsletter (http://www.astro.uiuc.edu/projects/mcnews/MCNews.html). ... More
The Fossil Starburst in M82Oct 02 2000(Abridged) We present high-resolution HST imaging in the optical (WFPC2) and near-infrared (NICMOS) of a disk region 1 kpc NE of the starburst core in the nearby galaxy M82. This region, M82 ``B,'' has been suspected to be a fossil starburst site in which ... More
WFPC2 Observations of the Cooling Flow Elliptical in Abell 1795Jun 22 1996We present WFPC2 images of the core of the cooling flow cD galaxy in Abell 1795. An irregular, asymmetric dust lane extends 7 \h75 kpc in projection to the north-northwest. The dust shares the morphology observed in the H$\alpha$ and excess UV emission. ... More
The Measurement of Disk Ellipticity in Nearby Spiral GalaxiesMar 13 2001We have measured the intrinsic disk ellipticity for 7 nearby, nearly face-on spiral galaxies by combining Densepak integral-field spectroscopy with I-band imaging from the WIYN telescope. Initially assuming an axisymmetric model, we determine kinematic ... More
Giant Galaxies, Dwarfs, and Debris Survey. I. Dwarf Galaxies and Tidal Features Around NGC 7331Nov 15 2012The Giant GAlaxies, Dwarfs, and Debris Survey concentrates on the nearby universe to study how galaxies have interacted in groups of different morphology, density, and richness. In these groups we select the dominant spiral galaxy and search its surroundings ... More
Gamma-Ray Puzzles in Cygnus X: Implications for High-Energy NeutrinosMar 07 2017Aug 10 2017The Cygnus X region contains giant molecular cloud complexes and populous associates of massive young stars. The discovery of spatially extended, hard gamma-ray emission in Cygnus X by both Milagro and Fermi indicates that Cygnus X is also a potential ... More
The Milky Way's Kiloparsec Scale Wind: A Hybrid Cosmic-Ray and Thermally Driven OutflowOct 19 2007We apply a wind model, driven by combined cosmic-ray and thermal-gas pressure, to the Milky Way, and show that the observed Galactic diffuse soft X-ray emission can be better explained by a wind than by previous static gas models. We find that cosmic-ray ... More
Hubble Space Telescope survey of the Perseus Cluster -III: The effect of local environment on dwarf galaxiesJan 11 2010Aug 10 2010We present the results of a Hubble Space Telescope (HST) study of dwarf galaxies in the outer regions of the nearby rich Perseus Cluster, down to M_V = -12, and compare these with the dwarf population in the cluster core from our previous HST imaging. ... More
New Results from the MINOS ExperimentSep 30 2008In this paper we present the latest results from the MINOS Experiment. This includes a new measurement of the atmospheric neutrino oscillation parameters based on 3.36 x 10^20 protons-on-target of data and a first analysis of neutral current events in ... More
A Hadronization Model for Few-GeV Neutrino InteractionsApr 26 2009We present a detailed description of a new hadronic multiparticle production model for use in neutrino interaction simulations. Its validity spans a wide invariant mass range starting from pion production threshold. This model focuses on the low invariant ... More
The Ionized Gas in Local Starburst Galaxies: Global and Small--Scale Feedback from Star FormationDec 15 2003Abridged: The small-- and intermediate--scale structure and the fraction of the ISM ionized by non--radiative processes is investigated in a small sample of four local starburst galaxies, imaged with the HST WFPC2. The sample comprises three dwarf galaxies, ... More
Detection of a ~20 kpc coherent magnetic field in the outskirt of merging spirals: the Antennae galaxiesSep 14 2016We present a study of the magnetic field properties of NGC 4038/9 (the `Antennae' galaxies), the closest example of a late stage merger of two spiral galaxies. Wideband polarimetric observations were performed using the Karl G. Jansky Very Large Array ... More
A Systematic Study of the Stellar Populations and ISM in Galaxies out to the Virgo ClusterApr 13 2009We present a compelling case for a systematic and comprehensive study of the resolved and unresolved stellar populations, ISM, and immediate environments of galaxies throughout the local volume, defined here as D < 20 Mpc. This volume is our cosmic backyard ... More
Supernova Remnants in the Fossil Starburst in M82Oct 04 1999Oct 27 1999We report the discovery of ten compact H-alpha-bright sources in the post-starburst region northeast of the center of M82, ``M82 B.'' These objects have H alpha luminosities and sizes consistent with Type II supernova remnants (SNRs). They fall on the ... More
Inferring Parametric Energy Consumption Functions at Different Software Levels: ISA vs. LLVM IRNov 04 2015The static estimation of the energy consumed by program executions is an important challenge, which has applications in program optimization and verification, and is instrumental in energy-aware software development. Our objective is to estimate such ... More
Ballistic miniband conduction in a graphene superlatticeMar 03 2016Rational design of artificial lattices yields effects unavailable in simple solids, and vertical superlattices of multilayer semiconductors are already used in optical sensors and emitters. Manufacturing lateral superlattices remains a much bigger challenge, ... More
Spotting Suspicious Link Behavior with fBox: An Adversarial PerspectiveOct 15 2014How can we detect suspicious users in large online networks? Online popularity of a user or product (via follows, page-likes, etc.) can be monetized on the premise of higher ad click-through rates or increased sales. Web services and social networks which ... More
Sharp quadrature error bounds for the nearest-neighbor discretization of the regularized stokeslet boundary integral equationJun 05 2018The method of regularized stokeslets is a powerful numerical method to solve the Stokes flow equations for problems in biological fluid mechanics. A recent variation of this method incorporates a nearest-neighbor discretization to improve accuracy and ... More
Solar Hard X-ray Source Sizes in a Beam-Heated and Ionised ChromosphereNov 19 2014Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by using the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) have ... More
Optimal Bacon-Shor codesSep 04 2012We study the performance of Bacon-Shor codes, quantum subsystem codes which are well suited for applications to fault-tolerant quantum memory because the error syndrome can be extracted by performing two-qubit measurements. Assuming independent noise, ... More
Deep Chandra Monitoring Observations of NGC 4649: II. Wide-Field Hubble Space Telescope Imaging of the Globular ClustersOct 12 2012We present g and z photometry and size estimates for globular clusters (GCs) in the massive Virgo elliptical NGC 4649 (M60) using a five-pointing Hubble Space Telescope/Advanced Camera for Surveys mosaic. The metal-poor GCs show a monotonic negative metallicity ... More
Faint Stars in the Ursa Minor Dwarf Spheroidal Galaxy: Implications for the Low-Mass Stellar Initial Mass Function at High RedshiftJun 10 2002The stellar initial mass function at high redshift is an important defining property of the first stellar systems to form and may also play a role in various dark matter problems. We here determine the faint stellar luminosity function in an apparently ... More
Structural Parameters of Seven SMC Intermediate-Age and Old Star ClustersSep 07 2009We present structural parameters for the seven intermediate-age and old star clusters NGC121, Lindsay 1, Kron 3, NGC339, NGC416, Lindsay 38, and NGC419 in the Small Magellanic Cloud. We fit King profiles and Elson, Fall, and Freeman profiles to both surface-brightness ... More
A population of faint low surface brightness galaxies in the Perseus cluster coreMay 26 2017Jun 13 2017We present the detection of 89 low surface brightness (LSB), and thus low stellar density galaxy candidates in the Perseus cluster core, of the kind named "ultra-diffuse galaxies", with mean effective V-band surface brightnesses 24.8-27.1 mag arcsec$^{-2}$, ... More
Sizes and Shapes of Young Star Cluster Light Profiles in M83Jun 05 2015We measure the radii and two-dimensional light profiles of a large sample of young, massive star clusters in M83 using archival HST/WFC3 imaging of seven adjacent fields. We use GALFIT to fit the two-dimensional light profiles of the clusters, from which ... More
Mid-Infrared Evidence for Accelerated Evolution in Compact Group GalaxiesAug 26 2010Compact galaxy groups are at the extremes of the group environment, with high number densities and low velocity dispersions that likely affect member galaxy evolution. To explore the impact of this environment in detail, we examine the distribution in ... More