Results for "Alison Coil"

total 563took 0.13s
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
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
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
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
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
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
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
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 MOSDEF Survey: Measurements of Balmer Decrements and the Dust Attenuation Curve at Redshifts z~1.4-2.6Apr 10 2015We present results on the dust attenuation curve of z~2 galaxies using early observations from the MOSFIRE Deep Evolution Field (MOSDEF) survey. Our sample consists of 224 star-forming galaxies with nebular spectroscopic redshifts in the range z= 1.36-2.59 ... More
PRIMUS: Effect of Galaxy Environment on the Quiescent Fraction Evolution at z < 0.8Dec 22 2014Dec 24 2014We investigate the effects of galaxy environment on the evolution of the quiescent fraction ($f_\mathrm{Q}$) from z =0.8 to 0.0 using spectroscopic redshifts and multi-wavelength imaging data from the PRIsm MUlti-object Survey (PRIMUS) and the Sloan Digitial ... 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
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
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
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
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
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
The Persistence of Cool Galactic Winds in High Stellar Mass Galaxies Between z~1.4 and ~1Dec 13 2009We present an analysis of the MgII 2796, 2803 and FeII 2586, 2600 absorption line profiles in coadded spectra of 468 galaxies at 0.7 < z < 1.5. The galaxy sample, drawn from the Team Keck Treasury Redshift Survey of the GOODS-N field, has a range in stellar ... 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
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
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
The MOSDEF survey: AGN multi-wavelength identification, selection biases and host galaxy propertiesAug 21 2016Nov 28 2016We present results from the MOSFIRE Deep Evolution Field (MOSDEF) survey on the identification, selection biases, and host galaxy properties of 55 X-ray, IR and optically-selected active galactic nuclei (AGN) at $1.4 < z < 3.8$. We obtain rest-frame optical ... More
The MOSDEF Survey: Broad Emission Lines at z=1.4-3.8Oct 09 2017We present results from the MOSFIRE Deep Evolution Field (MOSDEF) survey on broad flux from the nebular emission lines H$\alpha$, [NII], [OIII], H$\beta$, and [SII]. The sample consists of 127 star-forming galaxies at $1.37 < z < 2.61$ and 84 galaxies ... More
The MOSDEF Survey: Electron Density and Ionization Parameter at $z\sim2.3$Sep 11 2015Oct 27 2015Using observations from the MOSFIRE Deep Evolution Field (MOSDEF) survey, we investigate the physical conditions of star-forming regions in $z\sim2.3$ galaxies, specifically the electron density and ionization state. From measurements of the [O II]$\lambda\lambda$3726,3729 ... More
Where do Wet, Dry, and Mixed Galaxy Mergers Occur? A Study of the Environments of Close Galaxy Pairs in the DEEP2 Galaxy Redshift SurveyJan 25 2010We study the environment of wet, dry, and mixed galaxy mergers at 0.75 < z < 1.2 using close pairs in the DEEP2 Galaxy Redshift Survey. We find that the typical environment of mixed and dry merger candidates is denser than that of wet mergers, mostly ... 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
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
Dark Matter Halo Models of Stellar Mass-Dependent Galaxy Clustering in PRIMUS+DEEP2 at 0.2<z<1.2Mar 02 2015Jul 20 2015We utilize $\Lambda$CDM halo occupation models of galaxy clustering to investigate the evolving stellar mass dependent clustering of galaxies in the PRIsm MUlti-object Survey (PRIMUS) and DEEP2 Redshift Survey over the past eight billion years of cosmic ... 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
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 Deep2 Galaxy Redshift Survey: Evolution of Close Galaxy Pairs and Major-Merger Rates Up to z ~ 1.2Nov 04 2004Dec 17 2004We derive the close, kinematic pair fraction and merger rate up to z ~ 1.2 from the initial data of the DEEP2 Redshift Survey. Assuming a mild luminosity evolution, the number of companions per luminous galaxy is found to evolve as (1+z)^{m}, with m = ... 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
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
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
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
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
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
The DEEP2 Galaxy Redshift Survey: Spectral classification of galaxies at z~1May 29 2003Sep 12 2003We present a Principal Component Analysis (PCA)-based spectral classification, eta, for the first 5600 galaxies observed in the DEEP2 Redshift Survey. This parameter provides a very pronounced separation between absorption and emission dominated galaxy ... 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
The DEEP2 Galaxy Redshift Survey: AEGIS Observations of a Dual AGN at z=0.7Aug 17 2006May 02 2007We present evidence for a dual Active Galactic Nucleus (AGN) within an early-type galaxy at z=0.709 in the Extended Groth Strip. The galaxy lies on the red sequence, with absolute magnitude M_B=-21.0 (AB, with h=0.7) and rest-frame color U-B=1.38. Its ... More
AEGIS: Enhancement of Dust-enshrouded Star Formation in Close Galaxy Pairs and Merging Galaxies up to z ~ 1Jul 13 2006Apr 14 2007Using data from the DEEP2 Galaxy Redshift Survey and HST/ACS imaging in the Extended Groth Strip, we select nearly 100 interacting galaxy systems including kinematic close pairs and morphologically identified merging galaxies. Spitzer MIPS 24 micron fluxes ... More
The MOSDEF Survey: Kinematic and Structural Evolution of Star-Forming Galaxies at $1.4\leq z\leq 3.8$Feb 25 2019We present ionized gas kinematics for 708 galaxies at $z\sim 1.4-3.8$ from the MOSFIRE Deep Evolution Field survey, measured using models which account for random galaxy-slit misalignments together with structural parameters derived from CANDELS Hubble ... More
Absence of Evidence Is Not Evidence of Absence: The Color-Density Relation at Fixed Stellar Mass Persists to z ~ 1Jul 12 2010We use data drawn from the DEEP2 Galaxy Redshift Survey to investigate the relationship between local galaxy density, stellar mass, and rest-frame galaxy color. At z ~ 0.9, we find that the shape of the stellar mass function at the high-mass (log (M*/Msun) ... More
The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method catalog of galaxy groupsMar 17 2012We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the DEEP2 Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or ... 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
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
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
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
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
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
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
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
Observing Galaxy Evolution in the Context of Large-Scale StructureMar 14 2019Galaxies form and evolve in the context of their local and large-scale environments. Their baryonic content that we observe with imaging and spectroscopy is intimately connected to the properties of their dark matter halos, and to their location in the ... 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
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
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
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
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
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
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
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
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
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
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
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
Widespread and Hidden Active Galactic Nuclei in Star-Forming Galaxies at Redshift > 0.3Nov 27 2012Jan 20 2013We characterize the incidence of active galactic nuclei (AGNs) is 0.3 < z < 1 star-forming galaxies by applying multi-wavelength AGN diagnostics (X-ray, optical, mid-infrared, radio) to a sample of galaxies selected at 70-micron from the Far-Infrared ... 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
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
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
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
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