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Galaxy Evolution from Halo Occupation Distribution Modeling of DEEP2 and SDSS Galaxy ClusteringMar 16 2007Oct 05 2007We model the luminosity-dependent projected two-point correlation function of DEEP2 (z~1) and SDSS (z~0) galaxies within the Halo Occupation Distribution (HOD) framework. At both epochs, there is a tight correlation between central galaxy luminosity and ... More

Spatial clustering and halo occupation distribution modeling of local AGN via cross-correlation measurements with 2MASS galaxiesOct 16 2017Nov 30 2017We present the clustering properties and halo occupation distribution (HOD) modelling of very low redshift, hard X-ray-detected active galactic nuclei (AGN) using cross-correlation function measurements with Two-Micron All Sky Survey galaxies. Spanning ... More

The Kinematics of CIV in Star-Forming Galaxies at z~1.2Apr 13 2016Jul 18 2016We present the first statistical sample of rest-frame far-UV spectra of star-forming galaxies at z~1. These spectra are unique in that they cover the high-ionization CIV{\lambda}{\lambda}1548, 1550 doublet. We also detect low-ionization features such ... More

PRIMUS: Clustering of Star-forming and Quiescent Central Galaxies at $0.2 < z < 0.9$Mar 07 2019Previous work has demonstrated that at a given stellar mass, quiescent galaxies are more strongly clustered than star-forming galaxies. The contribution to this signal from central, as opposed to satellite, galaxies is not known, which has strong implications ... More

Large Scale Structure of the UniverseFeb 29 2012Jun 20 2012Galaxies are not uniformly distributed in space. On large scales the Universe displays coherent structure, with galaxies residing in groups and clusters on scales of ~1-3 Mpc/h, which lie at the intersections of long filaments of galaxies that are >10 ... More

PRIMUS: The relationship between Star formation and AGN accretionJul 08 2014May 28 2015We study the evidence for a connection between active galactic nuclei (AGN) fueling and star formation by investigating the relationship between the X-ray luminosities of AGN and the star formation rates (SFRs) of their host galaxies. We identify a sample ... More

Clustering Measurements of broad-line AGNs: Review and FutureAug 27 2013Despite substantial effort, the precise physical processes that lead to the growth of super-massive black holes in the centers of galaxies are still not well understood. These phases of black hole growth are thought to be of key importance in understanding ... More

X-rays across the galaxy population - III. The incidence of AGN as a function of star formation rateOct 10 2018Jan 09 2019We map the co-eval growth of galaxies and their central supermassive black holes in detail by measuring the incidence of Active Galactic Nuclei (AGN) in galaxies as a function of star formation rate (SFR) and redshift (to z~4). We combine large galaxy ... More

Mock Catalogs for the DEEP2 redshift surveyNov 10 2003Feb 12 2004We present a set of mock redshift catalogs, constructed from N-body simulations, designed to mimic the DEEP2 survey. Galaxies with a range of luminosities are placed within virialized halos in the simulation using a variant of the halo model. The halo ... More

PRIMUS: Constraints on Star Formation Quenching and Galaxy Merging, and the Evolution of the Stellar Mass Function From z=0-1Jan 08 2013Mar 28 2013We measure the evolution of the stellar mass function (SMF) from z=0-1 using multi-wavelength imaging and spectroscopic redshifts from the PRism MUlti-object Survey (PRIMUS) and the Sloan Digital Sky Survey (SDSS). From PRIMUS we construct an i<23 flux-limited ... More

PRIMUS: An observationally motivated model to connect the evolution of the AGN and galaxy populations out to z~1Jan 08 2013Jul 30 2013We present an observationally motivated model to connect the AGN and galaxy populations at 0.2<z<1.0 and predict the AGN X-ray luminosity function (XLF). We start with measurements of the stellar mass function of galaxies (from the Prism Multi-object ... More

PRIMUS: Enhanced Specific Star Formation Rates In Close Galaxy PairsDec 06 2010Tidal interactions between galaxies can trigger star formation, which contributes to the global star formation rate density of the universe and could be a factor in the transformation of blue, star-forming galaxies to red, quiescent galaxies over cosmic ... More

No evidence for feedback: Unexceptional Low-ionization winds in Host galaxies of Low Luminosity Active Galactic Nuclei at Redshift z ~1Apr 26 2017We study winds in 12 X-ray AGN host galaxies at z ~ 1. We find, using the low-ionization Fe II 2586 absorption in the stacked spectra, that the probability distribution function (PDF) of the centroid velocity shift in AGN has a median, 16th and 84th percentiles ... More

A massive, quiescent, population II galaxy at a redshift of 2.1Dec 06 2016Unlike spiral galaxies such as the Milky Way, the majority of the stars in massive elliptical galaxies were formed in a short period early in the history of the Universe. The duration of this formation period can be measured using the ratio of magnesium ... More

The Spatial Clustering of ROSAT All-Sky Survey AGN: I. The cross-correlation function with SDSS Luminous Red GalaxiesFeb 18 2010Mar 25 2010We investigate the clustering properties of ~1550 broad-line active galactic nuclei (AGNs) at <z>=0.25 detected in the ROSAT All-Sky Survey (RASS) through their measured cross-correlation function with ~46,000 Luminous Red Galaxies (LRGs) in the Sloan ... More

Infalling Gas Towards the Galactic CenterSep 05 1998Oct 16 1998VLA maps of ammonia emission were made for the Galactic Center region. The NH3(1,1) and NH3(2,2) transitions were observed in three 2' x 2' fields covering Sgr A* and the region 3' immediately south of it. In the central 3 parsecs surrounding Sgr A* we ... More

Galaxy Correlation Statistics of Mock Catalogs for the DEEP2 SurveyJul 27 2001The DEEP2 project will obtain redshifts for ~60,000 galaxies between z~0.7-1.5 in a comoving volume of 7 10^6 Mpc/h^3 for an LCDM universe. The survey will map four separate 2 by 0.5 degree strips of the sky. To study the expected clustering, we have ... More

Dramatic X-ray spectral variability of a Compton-thick type-1 QSO at $z\sim 1$Aug 15 2018We report on the discovery of a dramatic X-ray spectral variability event observed in a $z\sim 1$ broad line type-1 QSO. The XMM-Newton spectrum from the year 2000 is characterized by an unobscured power-law spectrum with photon index of $\Gamma\sim 2$, ... More

NH3 in the Central 10 pc of the Galaxy I: General Morphology and Kinematic Connections Between the CND and GMCsMay 16 2001New VLA images of NH3 (1,1), (2,2), and (3,3) emission in the central 10 parsecs of the Galaxy trace filamentary streams of gas, several of which appear to feed the circumnuclear disk (CND). The NH3 images have a spatial resolution of 16.5''x14.5'' and ... More

The Spatial Clustering of ROSAT All-Sky Survey AGNs III. Expanded Sample and Comparison with Optical AGNsOct 25 2011This is the third paper in a series that reports on our investigation of the clustering properties of AGNs identified in the ROSAT All-Sky Survey (RASS) and Sloan Digital Sky Survey (SDSS). In this paper, we extend the redshift range to 0.07<z<0.50 and ... More

The Dark Matter Haloes and Host Galaxies of MgII Absorbers at z~1Jun 08 2011Strong foreground absorption features from singly-ionized Magnesium (Mg II) are commonly observed in the spectra of quasars and are presumed to probe a wide range of galactic environments. To date, measurements of the average dark matter halo masses of ... More

X-ray Surface Brightness Profiles of Active Galactic Nuclei in the Extended Groth Strip: Implications for AGN FeedbackOct 02 2013May 07 2015Using data from the All Wavelength Extended Groth Strip International Survey (AEGIS) we statistically detect the extended X-ray emission in the interstellar medium (ISM)/intra-cluster medium (ICM) in both active and normal galaxies at 0.3 <= z <= 1.3. ... More

Spectral Reduction Software for the DEEP2 Redshift SurveySep 10 2001The DEEP2/DEIMOS redshift survey, which will begin observing in the Spring of 2002, will gather high quality spectra on ~60000 galaxies in order to study the evolution of the properties and large scale clustering of galaxies at z~1. The data rate from ... More

Three-Dimensional Identification and Reconstruction of Galaxy Systems within Deep Redshift SurveysDec 15 2001We have developed a new geometrical method for identifying and reconstructing a homogeneous and highly complete set of galaxy groups in the next generation of deep, flux-limited redshift surveys. Our method combines information from the three-dimensional ... More

The Spatial Clustering of ROSAT All-Sky Survey AGNs II. Halo Occupation Distribution Modeling of the Cross Correlation FunctionOct 26 2010Nov 03 2010This is the second paper of a series that reports on our investigation of the clustering properties of AGNs in the ROSAT All-Sky Survey (RASS) through cross-correlation functions (CCFs) with Sloan Digital Sky Survey (SDSS) galaxies. In this paper, we ... More

PRIMUS + DEEP2: Clustering of X-ray, Radio and IR-AGN at z~0.7Apr 23 2015Feb 26 2016We measure the clustering of X-ray, radio, and mid-IR-selected active galactic nuclei (AGN) at 0.2 < z < 1.2 using multi-wavelength imaging and spectroscopic redshifts from the PRIMUS and DEEP2 redshift surveys, covering 7 separate fields spanning ~10 ... More

The MOSDEF Survey: First Measurement of Nebular Oxygen Abundance at $z>4$Jul 17 2017Aug 23 2017We present the first spectroscopic measurement of multiple rest-frame optical emission lines at $z>4$. During the MOSFIRE Deep Evolution Field (MOSDEF) survey, we observed the galaxy GOODSN-17940 with the Keck I/MOSFIRE spectrograph. The K-band spectrum ... More

3D Identification and Reconstruction of z~1 Clusters: Prospects for the DEEP2 Redshift SurveySep 10 2001We have developed a geometrical method based on 3D Voronoi polyhedra and Delaunay tessellation for identifying and reconstructing clusters of galaxies in the next generation of deep, flux-limited redshift surveys. We here describe this algorithm and tests ... More

Measuring the Cosmic Equation of State with Galaxy Clusters in the DEEP2 Redshift SurveySep 07 2001The abundances of groups and clusters of galaxies are expected to have changed substantially since high redshift, with the strength of this evolution dependent upon fundamental cosmological parameters. Upcoming large redshift surveys of distant galaxies ... More

Chemical Abundances of DEEP2 Star-forming Galaxies at 1.0<z<1.5Sep 05 2005We present the results of near-infrared spectroscopic observations for a sample of 12 star-forming galaxies at 1.0<z<1.5, drawn from the DEEP2 Galaxy Redshift Survey. H-beta, [OIII], H-alpha, and [NII] emission-line fluxes are measured for these galaxies. ... More

The CDF L2 XFT Trigger UpgradeOct 18 2008Oct 22 2008We briefly present the eXtremely Fast Tracker stereo track upgrade for the CDF Level 2 trigger system. This upgrade enabled full 3D track reconstruction at Level 2 of the 3-Level CDF online triggering system. Using information provided by the stereo layers ... More

Blue Straggler Formation in ClustersSep 10 2010Blue stragglers are thought to be formed from the merger or coalescence of two stars, but the details of their formation in clusters has been difficult to disentangle. We discuss the two main formation mechanisms for blue stragglers (stellar collisions ... More

Some remarks on a result of Jensen and tilting modules for $\SL_3(k)$ and $q$-$\GL_3(k)$Sep 12 2008Aug 25 2010This paper reviews a result of Jensen on characters of some tilting modules for $\SL_3(k)$, where $k$ has characteristic at least five and fills in some gaps in the proof of this result. We then apply the result to finding some decomposition numbers for ... More

Searches for Massive tprime quarks decaying to W + q at the TevatronJan 31 2011Feb 01 2011We present searches for pair-production of fourth generation tprime quarks in their decays to Wq. We analyse 4.6 fb-1 and 4.3 fb-1 of data collected by the CDF and D0 detectors, respectively, at the Fermilab Tevatron collider at a centre-of-mass energy ... More

Models of Individual Blue StragglersJun 13 2014This chapter describes the current state of models of individual blue stragglers. Stellar collisions, binary mergers (or coalescence), and partial or ongoing mass transfer have all been studied in some detail. The products of stellar collisions retain ... More

Good l-filtrations for q-GL_3(k)Aug 22 2005Let $k$ be an algebraically closed field of characteristic $p$, possibly zero, and $G=q$-$\GL_3(k)$, the quantum group of three by three matrices as defined by Dipper and Donkin. We may also take $G$ to be $\GL_3(k)$. We first determine the extensions ... More

The DEEP2 Galaxy Redshift Survey: Clustering of Quasars and Galaxies at z=1Jul 20 2006Sep 12 2006We present the clustering of DEEP2 galaxies at 0.7<z<1.4 around quasars identified using both the SDSS and DEEP2 surveys. We measure the two-point cross-correlation of a sample of 36 optically-selected, spectroscopically-identified quasars from the SDSS ... More

Calibrating the Star Formation Rate at z=1 from Optical DataAug 11 2011We present a star-formation rate calibration based on optical data that is consistent with average observed rates in both the red and blue galaxy populations at z~1. The motivation for this study is to calculate SFRs for DEEP2 Redshift Survey galaxies ... More

Outflowing Galactic Winds in Post-starburst and AGN Host Galaxies at 0.2<z<0.8Apr 04 2011Sep 23 2011We present Keck/LRIS-B spectra for a sample of ten AEGIS X-ray AGN host galaxies and thirteen post-starburst galaxies from SDSS and DEEP2 at 0.2<z<0.8 in order to investigate the presence, properties, and influence of outflowing galactic winds at intermediate ... More

Scattered Emission from z~1 Galactic OutflowsApr 23 2013May 17 2013Mapping Mg II resonance emission scattered by galactic winds offers a means to determine the spatial extent and density of the warm outflow. Using Keck/LRIS spectroscopy, we have resolved scattered Mg II emission to the east of 32016857, a star-forming ... More

Direct Observations of the Ionizing Star in the UC HII Region G29.96-0.02: A Strong Constraint on the Stellar Birth Line for Massive StarsMay 01 1997We have observed the ultracompact HII region G29.96-0.02 in the near infrared J, H, and K bands and in the Br-gamma line. By comparison with radio observations, we determine that the extinction to the nebula is AK = 2.14 with a 3 sigma uncertainty of ... More

Extended Photometry for the DEEP2 Galaxy Redshift Survey: A Testbed for Photometric Redshift ExperimentsOct 08 2012Jan 31 2013This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys; the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky ... More

AEGIS: The Morphologies of Green Galaxies at 0.4<z<1.2Jan 17 2011May 13 2011We present quantitative morphologies of ~300 galaxies in the optically-defined green valley at 0.4<z<1.2, in order to constrain the mechanism(s) responsible for quenching star formation in the bulk of this population. The sample is selected from galaxies ... More

The DEEP2 Galaxy Redshift Survey: Clustering Dependence on Galaxy Stellar Mass and Star Formation Rate at z~1Oct 24 2012Feb 25 2013We present DEEP2 galaxy clustering measurements at z~1 as a function of stellar mass, star formation rate (SFR), and specific SFR (sSFR). We find a strong positive correlation between stellar mass and clustering amplitude on 1-10 h^-1 Mpc scales for blue, ... More

CIII] Emission in Star-forming Galaxies at z ~ 1Dec 20 2016Mar 04 2017The CIII]{\lambda}{\lambda}1907, 1909 rest-frame UV emission doublet has recently been detected in galaxies during the epoch of reionization (z > 6), with high equivalent width (>10 {\AA}, rest frame). Currently, it is possible to obtain much more detailed ... More

The evolution of the X-ray luminosity functions of unabsorbed and absorbed AGNs out to z~5Mar 03 2015May 08 2015We present new measurements of the evolution of the X-ray luminosity functions (XLFs) of unabsorbed and absorbed Active Galactic Nuclei (AGNs) out to z~5. We construct samples containing 2957 sources detected at hard (2-7 keV) X-ray energies and 4351 ... More

Parallel HOP: A Scalable Halo Finder for Massive Cosmological Data SetsJan 19 2010Jun 17 2010Modern N-body cosmological simulations contain billions ($10^9$) of dark matter particles. These simulations require hundreds to thousands of gigabytes of memory, and employ hundreds to tens of thousands of processing cores on many compute nodes. In order ... More

The MOSDEF Survey: Stellar Continuum Spectra and Star Formation Histories of Active, Transitional, and Quiescent Galaxies at 1.4$<$\lowercase{z}$<$2.6Oct 16 2018Oct 18 2018Using the MOSDEF rest-frame optical spectroscopic survey, we investigate the star-formation histories (SFHs) of different galaxy types, ranging from actively star forming to quiescent at $1.4\leq~z\leq2.6$. SFHs are constrained utilizing stellar continuum ... More

PRIMUS+DEEP2: The Dependence of Galaxy Clustering on Stellar Mass and Specific Star Formation Rate at 0.2 < z < 1.2Sep 28 2016We present results on the clustering properties of galaxies as a function of both stellar mass and specific star formation rate (sSFR) using data from the PRIMUS and DEEP2 galaxy redshift surveys spanning 0.2 < z < 1.2. We use spectroscopic redshifts ... More

Metallicities and Physical Conditions in Star-forming Galaxies at z~1.0-1.5Jan 10 2008Apr 01 2008We present a study of the mass-metallicity (M-Z) relation and H II region physical conditions in a sample of 20 star-forming galaxies at 1.0<z<1.5 drawn from the DEEP2 Galaxy Redshift Survey. Our analysis indicates that the zero point of the M-Z relationship ... More

The spatial clustering of ROSAT All-Sky Survey Active Galactic Nuclei IV. More massive black holes reside in more massive dark matter halosSep 03 2015Dec 14 2015This is the fourth paper in a series that reports on our investigation of the clustering properties of active galactic nuclei (AGN) identified in the ROSAT All-Sky Survey (RASS) and Sloan Digital Sky Survey (SDSS). In this paper we investigate the cause ... More

Rotational circulant graphsFeb 27 2013Sep 03 2013A Frobenius group is a transitive permutation group which is not regular but only the identity element can fix two points. Such a group can be expressed as the semi-direct product $G = K \rtimes H$ of a nilpotent normal subgroup $K$ and another group ... More

Finding White Dwarfs with Transit SearchesMar 20 2003Apr 18 2003We make predictions for the rate of discovery of eclipsing white dwarf-main sequence (WD-MS) binaries in terrestrial-planet transit searches, taking the planned Kepler and Eddington missions as examples. We use a population synthesis model to characterize ... More

Quantum work distribution for a driven diatomic moleculeSep 02 2014Nov 13 2014We compute the quantum work distribution for a driven Morse oscillator. To this end, we solve the time-dependent dynamics for a scale-invariant process, from which the exact expressions for the transition probabilities are found. Special emphasis is put ... More

Simulations of Stellar Collisions Involving Pre-Main Sequence StarsMar 21 2005In this paper, we present the results of smoothed particle hydrodynamic (SPH) simulations of collisions between pre-main sequence stars and a variety of other kinds of stars. Simulations over a range of impact parameters and velocities were performed. ... More

Optical Variability of Infrared Power Law-Selected Galaxies & X-ray Sources in the GOODS-South FieldMay 07 2007We investigate the use of optical variability to identify and study Active Galactic Nuclei (AGN) in the GOODS-South field. A sample of 22 mid-infrared power law sources and 102 X-ray sources with optical counterparts in the HST ACS images were selected. ... More

Cauchy Pairs and Cauchy MatricesOct 08 2014Let $\mathbb{K}$ denote a field and let $\mathfrak{X}$ denote a finite non-empty set. Let $\text{Mat}_\mathfrak{X}(\mathbb{K})$ denote the $\mathbb{K}$-algebra consisting of the matrices with entries in $\mathbb{K}$ and rows and columns indexed by $\mathfrak{X}$. ... More

An Erdős-Ko-Rado theorem for multisetsNov 18 2011Let $k$ and $m$ be positive integers. A collection of $k$-multisets from $\{1,..., m \}$ is intersecting if every pair of multisets from the collection is intersecting. We prove that for $m \geq k+1$, the size of the largest such collection is $\binom{m+k-2}{k-1}$ ... More

Intersection theorems for multisetsApr 24 2015May 26 2015Let $k$, $t$ and $m$ be positive integers. A $k$-multiset of $[m]$ is a collection of $k$ integers from the set $\{1,...,m\}$ in which the integers can appear more than once. We use graph homomorphisms and existing theorems for intersecting and $t$-intersecting ... More

The Universality of Initial Conditions for Globular Cluster FormationMar 09 2004We investigate a simple model for globular cluster (GC) formation. We simulate the violent relaxation of initially homogeneous isothermal stellar spheres and show that it leads to the formation of clusters with radial density profiles that match the observed ... More

An Analytic Technique for Constraining the Dynamical Origins of Multiple Star Systems Containing Merger ProductsSep 02 2010Oct 14 2010We present a technique to identify the most probable dynamical formation scenario for an observed binary or triple system containing one or more merger products or, alternatively, to rule out the possibility of a dynamical origin. Our method relies on ... More

Globular Clusters with Dark Matter Halos. I. Initial RelaxationSep 26 2004In a series of two papers, we test the primordial scenario of globular cluster formation using results of high-resolutions N-body simulations. In this first paper we study the initial relaxation of a stellar core inside a live dark matter minihalo in ... More

Higher extensions between modules for SL_2Aug 09 2005Aug 25 2010We calculate Ext^*_{SL_2(k)}(\Delta(\lambda), \Delta(\mu)), Ext^*_{SL_2(k)}(L(\lambda), \Delta(\mu)), Ext^*_{SL_2(k)}(\Delta(\lambda), L(\mu)), and Ext^*_{SL_2(k)}(L(\lambda), L(\mu)), where \Delta(\lambda) is the Weyl module of highest weight \lambda, ... More

Asymptotics for the number of Simple $(4a+1)$-Knots of Genus 1May 10 2019We investigate the asymptotics of the total number of simple $4a+1$-knots with Alexander polynomial of the form $mt^2 +(1-2m) t + m$ for some $m \in [-X, X]$. Using Kearton and Levine's classification of simple knots, we give equivalent algebraic and ... More

Ovopub: Modular data publication with minimal provenanceMay 29 2013With the growth of the Semantic Web as a medium for creating, consuming, mashing up and republishing data, our ability to trace any statement(s) back to their origin is becoming ever more important. Several approaches have now been proposed to associate ... More

What does mathoverflow tell us about the production of mathematics?May 04 2013The highest level of mathematics research is traditionally seen as a solitary activity. Yet new innovations by mathematicians themselves are starting to harness the power of social computation to create new modes of mathematical production. We study the ... More

Mathematical practice, crowdsourcing, and social machinesMay 04 2013The highest level of mathematics has traditionally been seen as a solitary endeavour, to produce a proof for review and acceptance by research peers. Mathematics is now at a remarkable inflexion point, with new technology radically extending the power ... More

Globular Clusters with Dark Matter Halos. II. Evolution in Tidal FieldSep 26 2004In this second paper in our series, we continue to test primordial scenarios of globular cluster formation which predict that globular clusters formed in the early universe in the potential of dark matter minihalos. In this paper we use high-resolution ... More

Multiple Populations in Globular Clusters: The Possible Contributions of Stellar CollisionsApr 23 2010Globular clusters were thought to be simple stellar populations, but recent photometric and spectroscopic evidence suggests that the clusters' early formation history was more complicated. In particular, clusters show star-to-star abundance variations, ... More

Scaling limits of weakly asymmetric interfacesMar 10 2014Dec 12 2014We consider three models of evolving interfaces intimately related to the weakly asymmetric simple exclusion process with $N$ particles on a finite lattice of $2N$ sites. Our Model 1 defines an evolving bridge on $[0,1]$, our Model 1-w an evolving excursion ... More

Homomorphisms and Higher Extensions for Schur algebras and symmetric groupsAug 26 2005This paper surveys, and in some cases generalises, many of the recent results on homomorphisms and the higher Ext groups for q-Schur algebras and for the Hecke algebra of type A. We review various results giving isomorphisms between Ext groups in the ... More

Homomorphisms between Weyl modules for SL_3(k)Aug 26 2005We classify all homomorphisms between Weyl modules for SL_3(k) when k is an algebraically closed field of characteristic at least three, and show that the Hom-spaces are all at most one-dimensional. As a corollary we obtain all homomorphisms between Specht ... More

Frobenius circulant graphs of valency six, Eisenstein-Jacobi networks, and hexagonal meshesMay 26 2012Nov 13 2013A Frobenius group is a transitive but not regular permutation group such that only the identity element can fix two points. A finite Frobenius group can be expressed as $G = K \rtimes H$ with $K$ a nilpotent normal subgroup. A first-kind $G$-Frobenius ... More

The positive even subalgebra of $U_q(\mathfrak{sl}_2)$ and its finite-dimensional irreducible modulesJun 05 2015The equitable presentation of $U_q(\mathfrak{sl}_2)$ was introduced in 2006 by Ito, Terwilliger, and Weng. This presentation involves some generators $x, y, y^{-1}, z$. It is known that $\{x^r y^s z^t : r, t \in \mathbb{N}, s \in \mathbb{Z}\}$ is a basis ... More

Polygonal Dissections and Reversions of SeriesJan 28 2014The Catalan numbers $C_k$ were first studied by Euler, in the context of enumerating triangulations of polygons $P_{k+2}$. Among the many generalizations of this sequence, the Fuss-Catalan numbers $C^{(d)}_k$ count enumerations of dissections of polygons ... More

Magnetic braking in ultracompact binariesJun 21 2010Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether magnetically ... More

On the good filtration dimension of Weyl modules for a linear algebraic groupJul 27 2005Let G be a linear algebraic group over an algebraically closed field of characteristic p whose corresponding root system is irreducible. In this paper we calculate the Weyl filtration dimension of the induced G-modules, \nabla(\lambda) and the simple ... More

The Global Dimension of Schur Algebras for GL_2 and GL_3Jul 26 2005We first define the notion of good filtration dimension and Weyl filtration dimension in a quasi-hereditary algebra. We calculate these dimensions explicitly for all irreducible modules in SL_2 and SL_3. We use these to show that the global dimension ... More

Saturn in hot water: viscous evolution of the Enceladus torusJun 09 2008The detection of outgassing water vapor from Enceladus is one of the great breakthroughs of the Cassini mission. The fate of this water once ionized has been widely studied; here we investigate the effects of purely neutral-neutral interactions within ... More

Stellar Encounters with Multiple Star Systems and the Blue Straggler ProblemSep 23 2010We present a technique to identify the most probable dynamical formation scenario for an observed binary or triple system containing one or more merger products or, alternatively, to rule out the possibility of a dynamical origin. Our method relies on ... More

A family of Koszul self-injective algebras with finite Hochschild cohomologyMay 11 2011This paper presents an infinite family of Koszul self-injective algebras whose Hochschild cohomology ring is finite-dimensional. Moreover, for each $N \geq 5$ we give an example where the Hochschild cohomology ring has dimension $N$. This family of algebras ... More

Spectral decomposition of entangled photons with an arbitrary pumpDec 22 2010We calculate the bi-photon state generated by spontaneous parametric down conversion in a thin crystal and under collinear phase matching conditions using a pump consisting of any superposition of Laguerre-Gauss modes. The result has no restrictions on ... More

Galaxies and Supermassive Black Holes at z <= 0.1: The Velocity Dispersion FunctionMar 31 2019We study the distribution of central velocity dispersion, sigma, for >100000 galaxies in the SDSS at 0.01 <= z <= 0.1. We construct the velocity dispersion function (VDF) from samples complete for all sigma, where galaxies with sigma greater than the ... More

The exact bound for the Erdős-Ko-Rado theorem for $t$-cycle-intersecting permutationsAug 17 2012Mar 01 2013In this paper we adapt techniques used by Ahlswede and Khachatrian in their proof of the Complete Erd\H{o}s-Ko-Rado Theorem to show that if $n \geq 2t+1$, then any pairwise $t$-cycle-intersecting family of permutations has cardinality less than or equal ... More

Rotational circulant graphsFeb 27 2013Sep 26 2018A Frobenius group is a transitive permutation group which is not regular but only the identity element can fix two points. Such a group can be expressed as the semi-direct product $G = K \rtimes H$ of a nilpotent normal subgroup $K$ and another group ... More

Evolution and Color-Dependence of the Galaxy Angular Correlation Function: 350,000 Galaxies in 5 Square DegreesMar 17 2004Dec 02 2004When applied to deep photometric catalogs, the two-point angular correlation function, w(theta), is a sensitive probe of the evolution of galaxy clustering properties. Here we present measurements of w(theta) as a function of I_AB magnitude and (R-I) ... More

Tracing the Filamentary Structure of the Galaxy Distribution at z~0.8Mar 16 2010We study filamentary structure in the galaxy distribution at z ~ 0.8 using data from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey and its evolution to z ~ 0.1 using data from the Sloan Digital Sky Survey (SDSS). We trace individual ... More

Galaxies Probing Galaxies in PRIMUS - I. Sample, Spectroscopy, and Characteristics of the z~0.5 MgII-Absorbing Circumgalactic MediumNov 23 2017Spectroscopy of background QSO sightlines passing close to foreground galaxies is a potent technique for studying the circumgalactic medium (CGM). QSOs are effectively point sources, however, limiting their potential to constrain the size of circumgalactic ... More

PRIMUS: One- and Two-Halo Galactic Conformity at $0.2 < z < 1$Aug 17 2016We test for galactic conformity at $0.2<z<1.0$ to a projected distance of 5 Mpc using spectroscopic redshifts from the PRism MUlti-object Survey (PRIMUS). Our sample consists of $\sim60,000$ galaxies in five separate fields covering a total of $\sim5.5$ ... More

The Co-Formation of Spheroids and Quasars Traced in their ClusteringNov 26 2006Jun 18 2007We compare observed clustering of quasars and galaxies as a function of redshift, mass, luminosity, & color/morphology, to constrain models of quasar fueling and spheroid-BH co-evolution. High redshift quasars are shown to be drawn from progenitors of ... More

PRIMUS: One- and Two-Halo Galactic Conformity at $0.2 < z < 1$Aug 17 2016Nov 04 2016We test for galactic conformity at $0.2<z<1.0$ to a projected distance of 5 Mpc using spectroscopic redshifts from the PRism MUlti-object Survey (PRIMUS). Our sample consists of $\sim60,000$ galaxies in five separate fields covering a total of $\sim5.5$ ... More

Ultraviolet Perspectives on Diffuse Gas in the Largest Cosmic StructuresMar 14 2019The past decade has seen an explosion of discoveries and new insights into the diffuse gas within galaxies, galaxy clusters, and the filaments composing the Cosmic Web. A new decade will bring fresh opportunities to further this progress towards developing ... More

Improved Mock Galaxy Catalogs for the DEEP2 Galaxy Redshift Survey from Subhalo Abundance and Environment MatchingJul 10 2012Jun 23 2013We develop empirical methods for modeling the galaxy population and populating cosmological N-body simulations with mock galaxies according to the observed properties of galaxies in survey data. We use these techniques to produce a new set of mock catalogs ... More

Molecular Tracers of the Central 12 pc of the Galactic CenterNov 17 2000We have used the BIMA array to image the Galactic Center with a 19-pointing mosaic in HCN(1-0), HCO+(1-0), and H 42-alpha emission with 5 km/s velocity resolution and 13'' x 4'' angular resolution. The 5' field includes the circumnuclear ring (CND) and ... More

A Wide-field Hubble Space Telescope Survey of the Cluster Cl 0024+16 at z=0.4. III: Spectroscopic Signatures of Environmental Evolution in Early Type GalaxiesAug 02 2005We report results from a panoramic spectroscopic survey of 955 objects in the field of the rich cluster Cl 0024+1654 (z~0.4), complementing the HST imaging presented in the first paper in this series. Our new spectroscopic sample includes over 200 high ... More

Galaxies Probing Galaxies in PRIMUS - II. The Coherence Scale of the Cool Circumgalactic MediumJun 22 2018Sep 21 2018The circumgalactic medium (CGM) close to ~L* star-forming galaxies hosts strong MgII 2796 absorption (with equivalent width W_2796>0.1 Ang) with a near-unity covering fraction. To characterize the spatial coherence of this absorption, we analyze the W_2796 ... More

X-rays across the galaxy population I: tracing the main sequence of star formationNov 10 2016We use deep Chandra imaging to measure the distribution of X-ray luminosities (L_X) for samples of star-forming galaxies as a function of stellar mass and redshift, using a Bayesian method to push below the nominal X-ray detection limits. Our luminosity ... More

Mass Transfer in Binary Stars using SPH. II. Eccentric BinariesNov 09 2010Despite numerous efforts to better understand binary star evolution, some aspects of it remain poorly constrained. In particular, the evolution of eccentric binaries has remained elusive mainly because the Roche lobe formalism derived for circular binaries ... More

Wave damping by MHD turbulence and its effect upon cosmic ray propagation in the ISMNov 17 2003Cosmic rays scatter off magnetic irregularities (Alfven waves) with which they are resonant, that is waves of wavelength comparable to their gyroradii. These waves may be generated either by the cosmic rays themselves, if they stream faster than the Alfven ... More

The Structural Effects of Rotation in Low Mass StarsMar 08 1999We present theoretical models of rotating low mass stars (0.1 - 1.0 \Msun) to demonstrate the effect of rotation on the effective temperature and luminosity of stars. The range of rotation rates in our models corresponds to the observed rotation rates ... More