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San Jose State University

Faculty Publications

2016

Articles 1 - 30 of 38

Full-Text Articles in Physical Sciences and Mathematics

Transport And Optical Conductivity In The Hubbard Model: A High-Temperature Expansion Perspective, Edward Perepelitsky, Andrew Galatas, Jernej Mravlje, Rok Žitko, Ehsan Khatami, B. Shastry, Antoine Georges Dec 2016

Transport And Optical Conductivity In The Hubbard Model: A High-Temperature Expansion Perspective, Edward Perepelitsky, Andrew Galatas, Jernej Mravlje, Rok Žitko, Ehsan Khatami, B. Shastry, Antoine Georges

Faculty Publications

We derive analytical expressions for the spectral moments of the dynamical response functions of the Hubbard model using the high-temperature series expansion. We consider generic dimension d as well as the infinite-d limit, arbitrary electron density n, and both finite and infinite repulsion U. We use moment-reconstruction methods to obtain the one-electron spectral function, the self-energy, and the optical conductivity. They are all smooth functions at high temperature and, at large U, they are featureless with characteristic widths of the order of the lattice hopping parameter t. In the infinite-d limit, we compare the series expansion results with accurate numerical …

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A Multi-Value Sequence Generated By Power Residue Symbol And Trace Function Over Odd Characteristic Field, Yasuyuki Nogami, Satoshi Uehara, Kazuyoshi Tsuchiya, Nasima Begum, Hiroto Ino, Robert Morelos-Zaragoza Dec 2016

A Multi-Value Sequence Generated By Power Residue Symbol And Trace Function Over Odd Characteristic Field, Yasuyuki Nogami, Satoshi Uehara, Kazuyoshi Tsuchiya, Nasima Begum, Hiroto Ino, Robert Morelos-Zaragoza

Faculty Publications

This paper proposes a new multi-value sequence generated by utilizing primitive element, trace, and power residue symbol over odd characteristic finite field. In detail, let p and k be an odd prime number as the characteristic and a prime factor of p-1, respectively. Our proposal generates k-value sequence T={ti | ti=fk(Tr(ωi)+A)}, where ω is a primitive element in the extension field $\F{p}{m}$, Tr(⋅) is the trace function that maps $\F{p}{m} \rightarrow \f{p}$, A is a non-zero scalar in the prime field $\f{p}$, and fk(⋅) is a certain mapping function based on k-th power residue symbol. Thus, the proposed sequence has …

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Connecting Self-Efficacy And Views About Nature Of Science In Undergraduate Research Experiences, Gina Quan, Andrew Elby Nov 2016

Connecting Self-Efficacy And Views About Nature Of Science In Undergraduate Research Experiences, Gina Quan, Andrew Elby

Faculty Publications

Undergraduate research can support students’ more central participation in physics. We analyze markers of two coupled shifts in participation: changes in students’ views about the nature of science coupled to shifts in self-efficacy toward physics research. Students in the study worked with faculty and graduate student mentors on research projects while also participating in a seminar where they learned about research and reflected on their experiences. In classroom discussions and in clinical interviews, students described gaining more nuanced views about the nature of science, specifically related to who can participate in research and what participation in research looks like. This …

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A Discrete Chemo-Dynamical Model Of The Giant Elliptical Galaxy Ngc 5846: Dark Matter Fraction, Internal Rotation, And Velocity Anisotropy Out To Six Effective Radii, Ling Zhu, Aaron Romanowsky, Glenn Van De Ven, R. Long, Laura Watkins, Vincenzo Pota, Nicola Napolitano, Duncan Forbes, Jean Brodie, Caroline Foster Nov 2016

A Discrete Chemo-Dynamical Model Of The Giant Elliptical Galaxy Ngc 5846: Dark Matter Fraction, Internal Rotation, And Velocity Anisotropy Out To Six Effective Radii, Ling Zhu, Aaron Romanowsky, Glenn Van De Ven, R. Long, Laura Watkins, Vincenzo Pota, Nicola Napolitano, Duncan Forbes, Jean Brodie, Caroline Foster

Faculty Publications

We construct a suite of discrete chemo-dynamical models of the giant elliptical galaxy NGC 5846. These models are a powerful tool to constrain both the mass distribution and internal dynamics of multiple tracer populations. We use Jeans models to simultaneously fit stellar kinematics within the effective radius Re, planetary nebula (PN) radial velocities out to 3 Re, and globular cluster (GC) radial velocities and colours out to 6 Re. The best-fitting model is a cored dark matter halo which contributes ∼10 per cent of the total mass within 1 Re, and 67 per cent ± 10 per cent within 6 …

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Ultraluminous X-Ray Bursts In Two Ultracompact Companions To Nearby Elliptical Galaxies, Jimmy Irwin, W. Maksym, Gregory Sivakoff, Aaron Romanowsky, Dacheng Lin, Tyler Speegle, Ian Prado, David Mildebrath, Jay Strader, Jifeng Liu, Jon Miller Oct 2016

Ultraluminous X-Ray Bursts In Two Ultracompact Companions To Nearby Elliptical Galaxies, Jimmy Irwin, W. Maksym, Gregory Sivakoff, Aaron Romanowsky, Dacheng Lin, Tyler Speegle, Ian Prado, David Mildebrath, Jay Strader, Jifeng Liu, Jon Miller

Faculty Publications

A search of archival X-ray data for 70 nearby galaxies has yielded two flaring sources in globular clusters or ultracompact dwarf companions of parent elliptical galaxies. One source flared once, and the other five times. When not flaring, these sources appear to be normal accreting neutron-star or black-hole X-ray binaries. Unlike magnetars and other bodies that produce repetitive flares of similar luminosity, they are located in old stellar populations.

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Alongcoast Structure And Interannual Variability Of Seasonal Midshelf Water Properties And Velocity In The Northern California Current System, B. Hickey, S. Geier, N. Kachel, S. Ramp, P. Kosro, Thomas Connolly Oct 2016

Alongcoast Structure And Interannual Variability Of Seasonal Midshelf Water Properties And Velocity In The Northern California Current System, B. Hickey, S. Geier, N. Kachel, S. Ramp, P. Kosro, Thomas Connolly

Faculty Publications

Moored sensors were maintained for ∼5 years on the northern California Current System (CCS) midshelf. The alongcoast sensor array spanned the area of influence of the plume from the Columbia River, several submarine canyons, as well as a coastal promontory where the equatorward coastal jet frequently separates from the shelf. Upwelling-favorable wind stress magnitude decreases poleward by more than a factor of three over the latitudinal range and shelf width varies by a factor of two. In spite of the alongcoast structure in setting, both seasonal and interannual patterns in subsurface layer water properties were remarkably similar at all sites. …

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Observation Of Spatial Charge And Spin Correlations In The 2d Fermi-Hubbard Model, Lawrence Cheuk, Matthew Nichols, Katherine Lawrence, Melih Okan, Hao Zhang, Ehsan Khatami, Nandini Trivedi, Thereza Paiva, Marcos Rigol, Martin Zwierlein Sep 2016

Observation Of Spatial Charge And Spin Correlations In The 2d Fermi-Hubbard Model, Lawrence Cheuk, Matthew Nichols, Katherine Lawrence, Melih Okan, Hao Zhang, Ehsan Khatami, Nandini Trivedi, Thereza Paiva, Marcos Rigol, Martin Zwierlein

Faculty Publications

Strong electron correlations lie at the origin of high-temperature superconductivity. Its essence is believed to be captured by the Fermi-Hubbard model of repulsively interacting fermions on a lattice. Here we report on the site-resolved observation of charge and spin correlations in the two-dimensional (2D) Fermi-Hubbard model realized with ultracold atoms. Antiferromagnetic spin correlations are maximal at half-filling and weaken monotonically upon doping. At large doping, nearest-neighbor correlations between singly charged sites are negative, revealing the formation of a correlation hole, the suppressed probability of finding two fermions near each other. As the doping is reduced, the correlations become positive, signaling …

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Metallicity And Age Of The Stellar Stream Around The Disk Galaxy Ngc 5907, Seppo Laine, Carl Grillmair, Peter Capak, Richard Arendt, Aaron Romanowsky, David Martínez-Delgado, Matthew Ashby, James Davies, Stephen Majewski, Jean Brodie, R. Gabany, Jacob Arnold Sep 2016

Metallicity And Age Of The Stellar Stream Around The Disk Galaxy Ngc 5907, Seppo Laine, Carl Grillmair, Peter Capak, Richard Arendt, Aaron Romanowsky, David Martínez-Delgado, Matthew Ashby, James Davies, Stephen Majewski, Jean Brodie, R. Gabany, Jacob Arnold

Faculty Publications

Stellar streams have become central to studies of the interaction histories of nearby galaxies. To characterize the most prominent parts of the stellar stream around the well-known nearby (d = 17 Mpc) edge-on disk galaxy NGC 5907, we have obtained and analyzed new, deep gri Subaru/Suprime-Cam and 3.6 μm Spitzer/Infrared Array Camera observations. Combining the near-infrared 3.6 μm data with visible-light images allows us to use a long wavelength baseline to estimate the metallicity and age of the stellar population along an ~60 kpc long segment of the stream. We have fitted the stellar spectral energy distribution with a single-burst …

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The Mass Discrepancy Acceleration Relation In Early-Type Galaxies: Extended Mass Profiles And The Phantom Menace To Mond, Joachim Janz, Michele Cappellari, Aaron Romanowsky, Luca Ciotti, Adebusola Alabi, Duncan Forbes Sep 2016

The Mass Discrepancy Acceleration Relation In Early-Type Galaxies: Extended Mass Profiles And The Phantom Menace To Mond, Joachim Janz, Michele Cappellari, Aaron Romanowsky, Luca Ciotti, Adebusola Alabi, Duncan Forbes

Faculty Publications

The dark matter (DM) haloes around spiral galaxies appear to conspire with their baryonic content: empirically, significant amounts of DM are inferred only below a universal characteristic acceleration scale. Moreover, the discrepancy between the baryonic and dynamical mass, which is usually interpreted as the presence of DM, follows a very tight mass discrepancy acceleration (MDA) relation. Its universality, and its tightness in spiral galaxies, poses a challenge for the DM interpretation and was used to argue in favour of MOdified Newtonian Dynamics (MOND). Here, we test whether or not this applies to early-type galaxies. We use the dynamical models of …

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Three-Dimensional Hubbard Model In The Thermodynamic Limit, Ehsan Khatami Sep 2016

Three-Dimensional Hubbard Model In The Thermodynamic Limit, Ehsan Khatami

Faculty Publications

We employ the numerical linked-cluster expansion to study finite-temperature properties of the uniform cubic lattice Hubbard model in the thermodynamic limit for a wide range of interaction strengths and densities. We carry out the expansion to the 9th order and find that the convergence of the series extends to lower temperatures as the strength of the interaction increases, giving us access to regions of the parameter space that are difficult to reach by most other numerical methods. We study the precise trends in the specific heat, the double occupancy, and magnetic correlations at temperatures as low as 0.2 of the …

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The Sluggs Survey: The Mass Distribution In Early-Type Galaxies Within Five Effective Radii And Beyond, Adebusola Alabi, Duncan Forbes, Aaron Romanowsky, Jean Brodie, Jay Strader, Joachim Janz, Vincenzo Pota, Nicola Pastorello, Christopher Usher, Lee Spitler, Caroline Foster, Zachary Jennings, Alexa Villaume, Sreeja Kartha Aug 2016

The Sluggs Survey: The Mass Distribution In Early-Type Galaxies Within Five Effective Radii And Beyond, Adebusola Alabi, Duncan Forbes, Aaron Romanowsky, Jean Brodie, Jay Strader, Joachim Janz, Vincenzo Pota, Nicola Pastorello, Christopher Usher, Lee Spitler, Caroline Foster, Zachary Jennings, Alexa Villaume, Sreeja Kartha

Faculty Publications

We study mass distributions within and beyond 5 effective radii (Re) in 23 early-type galaxies from the SAGES Legacy Unifying Globulars and Galaxies Survey, using their globular cluster (GC) kinematic data. The data are obtained with Keck/DEep Imaging Multi-Object Spectrograph, and consist of line-of-sight velocities for ∼3500 GCs, measured with a high precision of ∼15 km s−1 per GC and extending out to ∼13 Re. We obtain the mass distribution in each galaxy using the tracer mass estimator of Watkins et al. and account for kinematic substructures, rotation of the GC systems and galaxy flattening in our mass estimates. The …

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Attending To Scientific Practices Within Undergraduate Research Experiences, Gina Quan, Chandra Turpen, Andrew Elby Jul 2016

Attending To Scientific Practices Within Undergraduate Research Experiences, Gina Quan, Chandra Turpen, Andrew Elby

Faculty Publications

Ford (2015) argues for viewing "scientific practice" not as a list of particular skills, but rather, as "sets of regularities of behaviors and social interactions" among scientists. This conceptualization of scientific practices foregrounds how they 1) meaningfully connect to one another, 2) are purposefully employed in their ability to explain nature and 3) prospectively adapt based on critique. While Ford focused on practices in K-12 classrooms, we apply this framework to understand how undergraduate physics majors do or do not make progress toward more central participation in physics research experiences. Using video from interviews with students and research mentors, and …

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The Sluggs Survey*: Exploring The Globular Cluster Systems Of The Leo Ii Group And Their Global Relationships, Sreeja Kartha, Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Lee Spitler, Zachary Jennings, Joel Roediger May 2016

The Sluggs Survey*: Exploring The Globular Cluster Systems Of The Leo Ii Group And Their Global Relationships, Sreeja Kartha, Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Lee Spitler, Zachary Jennings, Joel Roediger

Faculty Publications

We present an investigation of the globular cluster (GC) systems of NGC 3607 and NGC 3608 as part of the ongoing SLUGGS (SAGES Legacy Unifying Globulars and GalaxieS) survey. We use wide-field imaging data from the Subaru telescope in the g, r and i filters to analyse the radial density, colour and azimuthal distributions of both GC systems. With the complementary kinematic data obtained from the Keck II telescope, we measure the radial velocities of a total of 81 GCs. Our results show that the GC systems of NGC 3607 and NGC 3608 have a detectable spatial extent of ∼15 …

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The Sluggs Survey: Globular Clusters And The Dark Matter Content Of Early-Type Galaxies, Duncan Forbes, Adebusola Alabi, Aaron Romanowsky, Jean Brodie, Jay Strader, Christopher Usher, Vincenzo Pota May 2016

The Sluggs Survey: Globular Clusters And The Dark Matter Content Of Early-Type Galaxies, Duncan Forbes, Adebusola Alabi, Aaron Romanowsky, Jean Brodie, Jay Strader, Christopher Usher, Vincenzo Pota

Faculty Publications

No abstract provided.

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The Chromatic Number Of The Square Of Subcubic Planar Graphs, Stephen Hartke, Sogol Jahanbekam, Brent Thomas Apr 2016

The Chromatic Number Of The Square Of Subcubic Planar Graphs, Stephen Hartke, Sogol Jahanbekam, Brent Thomas

Faculty Publications

Wegner conjectured in 1977 that the square of every planar graph with maximum degree at most 3 is 7-colorable. We prove this conjecture using the discharging method and computational techniques to verify reducible configurations.

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Erratum: The Sluggs Survey: The Globular Cluster Systems Of Three Early-Type Galaxies Using Wide-Field Imaging, Sreeja Kartha, Duncan Forbes, Lee Spitler, Aaron Romanowsky, Jacob Arnold, Jean Brodie Apr 2016

Erratum: The Sluggs Survey: The Globular Cluster Systems Of Three Early-Type Galaxies Using Wide-Field Imaging, Sreeja Kartha, Duncan Forbes, Lee Spitler, Aaron Romanowsky, Jacob Arnold, Jean Brodie

Faculty Publications

The paper ‘The SLUGGS survey: the globular cluster systems of three early-type galaxies using wide-field imaging’ was published in Monthly Notices of the Royal Astronomical Society, 437, 273 – 292 (2014).

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The Sluggs Survey: The Assembly Histories Of Individual Early-Type Galaxies, Duncan Forbes, Aaron Romanowsky, Nicola Pastorello, Caroline Foster, Jean Brodie, Jay Strader, Christopher Usher, Vincenzo Pota Apr 2016

The Sluggs Survey: The Assembly Histories Of Individual Early-Type Galaxies, Duncan Forbes, Aaron Romanowsky, Nicola Pastorello, Caroline Foster, Jean Brodie, Jay Strader, Christopher Usher, Vincenzo Pota

Faculty Publications

Early-type (E and S0) galaxies may have assembled via a variety of different evolutionary pathways. Here, we investigate these pathways by comparing the stellar kinematic properties of 24 early-type galaxies from the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey with the hydrodynamical simulations of Naab et al. In particular, we use the kinematics of starlight up to 4 effective radii (Re) as diagnostics of galaxy inner and outer regions, and assign each galaxy to one of six Naab et al. assembly classes. The majority of our galaxies (14/24) have kinematic characteristics that indicate an assembly history dominated by gradual …

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Discovery Of An Ultra-Diffuse Galaxy In The Pisces-Perseus Supercluster, David Martínez-Delgado, Ronald Läsker, Margarita Sharina, Elisa Toloba, Jürgen Fliri, Rachael Beaton, David Valls-Gabaud, Igor Karachentsev, Taylor Chonis, Eva Grebel, Duncan Forbes, Aaron Romanowsky, J. Gallego-Laborda, Karel Teuwen, M. Gómez-Flechoso, Jie Wang, Puragra Guhathakurta, Serafim Kaisin, Nhung Ho Mar 2016

Discovery Of An Ultra-Diffuse Galaxy In The Pisces-Perseus Supercluster, David Martínez-Delgado, Ronald Läsker, Margarita Sharina, Elisa Toloba, Jürgen Fliri, Rachael Beaton, David Valls-Gabaud, Igor Karachentsev, Taylor Chonis, Eva Grebel, Duncan Forbes, Aaron Romanowsky, J. Gallego-Laborda, Karel Teuwen, M. Gómez-Flechoso, Jie Wang, Puragra Guhathakurta, Serafim Kaisin, Nhung Ho

Faculty Publications

We report the discovery of DGSAT I, an ultra-diffuse, quenched galaxy located 10fdg4 in projection from the Andromeda galaxy (M31). This low-surface brightness galaxy (μV = 24.8 mag arcsec−2), found with a small amateur telescope, appears unresolved in sub-arcsecond archival Subaru/Suprime-Cam images, and hence has been missed by optical surveys relying on resolved star counts, in spite of its relatively large effective radius (Re(V) = 12'') and proximity (15') to the well-known dwarf spheroidal galaxy And II. Its red color (V − I = 1.0), shallow Sérsic index (nV = 0.68), and the absence of detectable Hα emission are typical …

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The Sluggs Survey: Chromodynamical Modelling Of The Lenticular Galaxy Ngc 1023, Arianna Cortesi, Ana Chies-Santos, Vincenzo Pota, Caroline Foster, Lodovico Coccato, Claudia Mendes De Oliveira, Duncan Forbes, Michael Merrifield, Steven Bamford, Aaron Romanowsky, Jean Brodie, Sreeja Kartha, Adebusola Alabi, Robert Proctor, Andres Almeida Mar 2016

The Sluggs Survey: Chromodynamical Modelling Of The Lenticular Galaxy Ngc 1023, Arianna Cortesi, Ana Chies-Santos, Vincenzo Pota, Caroline Foster, Lodovico Coccato, Claudia Mendes De Oliveira, Duncan Forbes, Michael Merrifield, Steven Bamford, Aaron Romanowsky, Jean Brodie, Sreeja Kartha, Adebusola Alabi, Robert Proctor, Andres Almeida

Faculty Publications

Globular clusters (GCs) can be considered discrete, long-lived, dynamical tracers that retain crucial information about the assembly history of their parent galaxy. In this paper, we present a new catalogue of GC velocities and colours for the lenticular galaxy NGC 1023, we study their kinematics and spatial distribution, in comparison with the underlying stellar kinematics and surface brightness profile, and we test a new method for studying GC properties. Specifically, we decompose the galaxy light into its spheroid (assumed to represent the bulge+halo components) and disc components and use it to assign to each GC a probability of belonging to …

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The Sluggs Survey: Stellar Kinematics, Kinemetry And Trends At Large Radii In 25 Early-Type Galaxies, Caroline Foster, Nicola Pastorello, Joel Roediger, Jean Brodie, Duncan Forbes, Sreeja Kartha, Vincenzo Pota, Aaron Romanowsky, Lee Spitler, Jay Strader, Christopher Usher, Jacob Arnold Mar 2016

The Sluggs Survey: Stellar Kinematics, Kinemetry And Trends At Large Radii In 25 Early-Type Galaxies, Caroline Foster, Nicola Pastorello, Joel Roediger, Jean Brodie, Duncan Forbes, Sreeja Kartha, Vincenzo Pota, Aaron Romanowsky, Lee Spitler, Jay Strader, Christopher Usher, Jacob Arnold

Faculty Publications

Due to longer dynamical time-scales, the outskirts of early-type galaxies retain the footprint of their formation and assembly. Under the popular two-phase galaxy formation scenario, an initial in situ phase of star formation is followed by minor merging and accretion of ex situ stars leading to the expectation of observable transitions in the kinematics and stellar populations on large scales. However, observing the faint galactic outskirts is challenging, often leaving the transition unexplored. The large-scale, spatially resolved stellar kinematic data from the SAGES Legacy Unifying Galaxies and GlobularS (SLUGGS) survey are ideal for detecting kinematic transitions. We present kinematic maps …

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Satellite Accretion In Action: A Tidally Disrupting Dwarf Spheroidal Around The Nearby Spiral Galaxy Ngc 253, Aaron Romanowsky, David Martínez-Delgado, Nicolas Martin, Gustavo Morales, Zachary Jennings, R. Gabany, Jean Brodie, Eva Grebel, Johannes Schedler, Michael Sidonio Mar 2016

Satellite Accretion In Action: A Tidally Disrupting Dwarf Spheroidal Around The Nearby Spiral Galaxy Ngc 253, Aaron Romanowsky, David Martínez-Delgado, Nicolas Martin, Gustavo Morales, Zachary Jennings, R. Gabany, Jean Brodie, Eva Grebel, Johannes Schedler, Michael Sidonio

Faculty Publications

No abstract provided.

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Erratum: Global Properties Of ‘Ordinary’ Early-Type Galaxies: Photometry And Spectroscopy Of Stars And Globular Clusters In Ngc 4494, Caroline Foster, Lee Spitler, Aaron Romanowsky, Duncan Forbes, Vincenzo Pota, Kenji Bekki, Jay Strader, Robert Proctor, Jacob Arnold, Jean Brodie Feb 2016

Erratum: Global Properties Of ‘Ordinary’ Early-Type Galaxies: Photometry And Spectroscopy Of Stars And Globular Clusters In Ngc 4494, Caroline Foster, Lee Spitler, Aaron Romanowsky, Duncan Forbes, Vincenzo Pota, Kenji Bekki, Jay Strader, Robert Proctor, Jacob Arnold, Jean Brodie

Faculty Publications

This is an erratum to the paper entitled “Global properties of ‘ordinary’ early-type galaxies: photometry and spectroscopy of stars and globular clusters in NGC 4494”, published in MNRAS, 2011, 415, 3393.

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The Aimss Project – Iii. The Stellar Populations Of Compact Stellar Systems, Joachim Janz, Mark Norris, Duncan Forbes, Avon Huxor, Aaron Romanowsky, Matthias Frank, Carlos Escudero, Favio Faifer, Juan Forte, Sheila Kannappan, Claudia Maraston, Jean Brodie, Jay Strader, Bradley Thompson Feb 2016

The Aimss Project – Iii. The Stellar Populations Of Compact Stellar Systems, Joachim Janz, Mark Norris, Duncan Forbes, Avon Huxor, Aaron Romanowsky, Matthias Frank, Carlos Escudero, Favio Faifer, Juan Forte, Sheila Kannappan, Claudia Maraston, Jean Brodie, Jay Strader, Bradley Thompson

Faculty Publications

In recent years, a growing zoo of compact stellar systems (CSSs) have been found whose physical properties (mass, size, velocity dispersion) place them between classical globular clusters (GCs) and true galaxies, leading to debates about their nature. Here we present results using a so far underutilized discriminant, their stellar population properties. Based on new spectroscopy from 8–10m telescopes, we derive ages, metallicities, and [α/Fe] of 29 CSSs. These range from GCs with sizes of merely a few parsec to compact ellipticals (cEs) larger than M32. Together with a literature compilation, this provides a panoramic view of the stellar population characteristics …

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Threshold-Bounded Influence Dominating Sets For Recommendations In Social Networks, Magdalini Eirinaki, Nuno Moniz, Katerina Potika Jan 2016

Threshold-Bounded Influence Dominating Sets For Recommendations In Social Networks, Magdalini Eirinaki, Nuno Moniz, Katerina Potika

Faculty Publications

The process of decision making in humans involves a combination of the genuine information held by the individual, and the external influence from their social network connections. This helps individuals to make decisions or adopt behaviors, opinions or products. In this work, we seek to investigate under which conditions and with what cost we can form neighborhoods of influence within a social network, in order to assist individuals with little or no prior genuine information through a two-phase recommendation process. Most of the existing approaches regard the problem of identifying influentials as a long-term, network diffusion process, where information cascading …

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Time-Based Ensembles For Prediction Of Rare Events In News Streams, Nuno Moniz, Luís Torgo, Magdalini Eirinaki Jan 2016

Time-Based Ensembles For Prediction Of Rare Events In News Streams, Nuno Moniz, Luís Torgo, Magdalini Eirinaki

Faculty Publications

Thousands of news are published everyday reporting worldwide events. Most of these news obtain a low level of popularity and only a small set of events become highly popular in social media platforms. Predicting rare cases of highly popular news is not a trivial task due to shortcomings of standard learning approaches and evaluation metrics. So far, the standard task of predicting the popularity of news items has been tackled by either of two distinct strategies related to the publication time of news. The first strategy, a priori, is focused on predicting the popularity of news upon their publication when …

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Development Of Cloud-Based Uav Monitoring And Management System, Mason Itkin, Mihui Kim, Younghee Park Jan 2016

Development Of Cloud-Based Uav Monitoring And Management System, Mason Itkin, Mihui Kim, Younghee Park

Faculty Publications

Unmanned aerial vehicles (UAVs) are an emerging technology with the potential to revolutionize commercial industries and the public domain outside of the military. UAVs would be able to speed up rescue and recovery operations from natural disasters and can be used for autonomous delivery systems (e.g., Amazon Prime Air). An increase in the number of active UAV systems in dense urban areas is attributed to an influx of UAV hobbyists and commercial multi-UAV systems. As airspace for UAV flight becomes more limited, it is important to monitor and manage many UAV systems using modern collision avoidance techniques. In this paper, …

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A Cloud-Based Framework For Smart Permit System For Buildings, Magdalini Eirinaki, Subhankar Dhar, Shishir Mathur Jan 2016

A Cloud-Based Framework For Smart Permit System For Buildings, Magdalini Eirinaki, Subhankar Dhar, Shishir Mathur

Faculty Publications

In this paper we propose a novel cloud-based platform for building permit system that is efficient, user-friendly, transparent, and has quick turn-around time for homeowners. Compared to the existing permit systems, the proposed smart city permit framework provides a pre-permitting decision workflow, and incorporates a data analytics and mining module that enables the continuous improvement of a) the end user experience, by analyzing explicit and implicit user feedback, and b) the permitting and urban planning process, allowing a gleaning of key insights for real estate development and city planning purposes, by analyzing how users interact with the system depending on …

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Discovery Of The Candidate Off-Nuclear Ultrasoft Hyper-Luminous X-Ray Source 3xmm J141711.1+522541, Dacheng Lin, Eleazar Carrasco, Natalie Webb, Jimmy Irwin, Renato Dupke, Aaron Romanowsky, Enrico Ramirez-Ruiz, Jay Strader, Jeroen Homan, Didier Barret, Olivier Godet Jan 2016

Discovery Of The Candidate Off-Nuclear Ultrasoft Hyper-Luminous X-Ray Source 3xmm J141711.1+522541, Dacheng Lin, Eleazar Carrasco, Natalie Webb, Jimmy Irwin, Renato Dupke, Aaron Romanowsky, Enrico Ramirez-Ruiz, Jay Strader, Jeroen Homan, Didier Barret, Olivier Godet

Faculty Publications

No abstract provided.

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An Overmassive Dark Halo Around An Ultra-Diffuse Galaxy In The Virgo Cluster, Michael Beasley, Aaron Romanowsky, Vincenzo Pota, Ignacio Navarro, David Martinez-Delgado, Fabian Neyer, Aaron Deich Jan 2016

An Overmassive Dark Halo Around An Ultra-Diffuse Galaxy In The Virgo Cluster, Michael Beasley, Aaron Romanowsky, Vincenzo Pota, Ignacio Navarro, David Martinez-Delgado, Fabian Neyer, Aaron Deich

Faculty Publications

No abstract provided.

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First Results From The Madcash Survey: A Faint Dwarf Galaxy Companion To The Low-Mass Spiral Galaxy Ngc 2403 At 3.2 Mpc*, Jeffrey Carlin, David Sand, Paul Price, Beth Willman, Ananthan Karunakaran, Kristine Spekkens, Eric Bell, Jean Brodie, Denija Crnojević, Duncan Forbes, Jonathan Hargis, Evan Kirby, Robert Lupton, Annika Peter, Aaron Romanowsky, Jay Strader Jan 2016

First Results From The Madcash Survey: A Faint Dwarf Galaxy Companion To The Low-Mass Spiral Galaxy Ngc 2403 At 3.2 Mpc*, Jeffrey Carlin, David Sand, Paul Price, Beth Willman, Ananthan Karunakaran, Kristine Spekkens, Eric Bell, Jean Brodie, Denija Crnojević, Duncan Forbes, Jonathan Hargis, Evan Kirby, Robert Lupton, Annika Peter, Aaron Romanowsky, Jay Strader

Faculty Publications

No abstract provided.

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