Physics Commons^™

Vimos Ultra-Deep Survey (Vuds): Witnessing The Assembly Of A Massive Cluster At Z ~ 3.3, B. C. Lemaux, O. Cucciati, L. A. M. Tasca, O. Le Fèvre, G. Zamorani, P. Cassata, B. Garilli, V. Le Brun, D. Maccagni, L. Pentericci, R. Thomas, E. Vanzella, R. Amorín, S. Bardelli, P. Capak, L. P. Cassarà, M. Castellano, A. Cimatti, J. G. Cuby, S. De La Torre, A. Durkalec, A. Fontana, M. Giavalisco, A. Grazian, N. P. Hathi, O. Ilbert, C. Moreau, S. Paltani, B. Ribeiro, M. Salvato, D. Schaerer, M. Scodeggio, V. Sommariva, M. Talia, Y. Taniguchi, L. Tresse, D. Vergani, P. W. Wang, S. Charlot, T. Contini, S. Fotopoulou, R. R. Gal, Dale D. Kocevski, C. López-Sanjuan, L. M. Lubin, Y. Mellier, T. Sadibekova, N. Scoville

Physics and Astronomy Faculty Publications

Using new spectroscopic observations obtained as part of the VIMOS Ultra-Deep Survey (VUDS), we performed a systematic search for overdense environments in the early universe (z> 2) and report here on the discovery of Cl J0227-0421, a massive protocluster at z = 3.29. This protocluster is characterized by both the large overdensity of spectroscopically confirmed members, δ_gal = 10.5 ± 2.8, and a significant overdensity in photometric redshift members. The halo mass of this protocluster is estimated by a variety of methods to be ~3 × 10¹⁴ℳ_⊙ at z ~ 3.3, which, evolved to z …

Hidden Starbursts And Active Galactic Nuclei At 0 < Z < 4 From The Herschel-Vvds-Cfhtls-D1 Field: Inferences On Coevolution And Feedback, B. C. Lemaux, E. Le Foc'h, O. Le Fèvre, O. Ilbert, L. Tresse, L. M. Lubin, G. Zamorani, R. R. Gal, P. Ciliegi, P. Cassata, Dale D. Kocevski, E. J. Mcgrath, S. Bardelli, E. Zucca, G. K. Squires

Physics and Astronomy Faculty Publications

We investigate of the properties of ~2000 Herschel/SPIRE far-infrared-selected galaxies from 0 < z < 4 in the CFHTLS-D1 field. Using a combination of extensive spectroscopy from the VVDS and ORELSE surveys, deep multiwavelength imaging from CFHT, VLA, Spitzer, XMM-Newton, and Herschel, and well-calibrated spectral energy distribution fitting, Herschel-bright galaxies are compared to optically-selected galaxies at a variety of redshifts. Herschel-selected galaxies are observed to span a range of stellar masses, colors, and absolute magnitudes equivalent to galaxies undetected in SPIRE. Though many Herschel galaxies appear to be in transition, such galaxies are largely consistent with normal star-forming galaxies when rest-frame colors are utilized. The nature of the star-forming “main sequence” is studied and we warn against adopting this …

Improved Upper Limits On The Stochastic Gravitational-Wave Background From 2009–2010 Ligo And Virgo Data, J. Aasi, B. P. Abbott, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Joseph D. Romano, Robert Stone, Cristina V. Torres, G. Valdes

Physics and Astronomy Faculty Publications and Presentations

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of ΩGWðfÞ ¼ Ωαðf=fref Þα, we place …

Line-Driven Radiative Outflows In Luminous Quasars, Rebecca A. A. Bowler, Paul C. Hewett, James T. Allen, Gary J. Ferland

Physics and Astronomy Faculty Publications

An analysis of ≃19 500 narrow ( ≲ 200 km s⁻¹) C iv λλ1548.2,1550.8 absorbers in ≃34 000 Sloan Digital Sky Survey quasar spectra is presented. The statistics of the number of absorbers as a function of outflow velocity shows that in approximately two-thirds of outflows, with multiple C iv absorbers present, absorbers are line-locked at the 500 km s⁻¹ velocity separation of the C iv absorber doublet; appearing as ‘triplets’ in the quasar spectra. Line-locking is an observational signature of radiative line-driving in outflowing material, where the successive shielding of ‘clouds’ of material in the outflow …

The Optical Luminosity Function Of Gamma-Ray Bursts Deduced From Rotse-Iii Observations, X. H. Cui, X. F. Wu, J. J. Wei, F. Yuan, W. K. Zheng, E. W. Liang, C. W. Akerlof, M. C. B. Ashley, H A. Flewelling, E. Göǧüş, T. Güver, Ü. Kızıloǧlu, T. A. Mckay, S. B. Pandey, E. S. Rykoff, W. Rujopakarn, B. E. Schaefer, J. C. Wheeler, Sarah A. Yost

Physics Faculty Publications

We present the optical luminosity function (LF) of gamma-ray bursts (GRBs) estimated from a uniform sample of 58 GRBs from observations with the Robotic Optical Transient Search Experiment III (ROTSE-III). Our GRB sample is divided into two sub-samples: detected afterglows (18 GRBs) and those with upper limits (40 GRBs). We derive R-band fluxes for these two sub-samples 100 s after the onset of the burst. The optical LFs at 100 s are fitted by assuming that the co-moving GRB rate traces the star formation rate. While fitting the optical LFs using Monte Carlo simulations, we take into account the …

Candels/Goods-S, Cdfs, And Ecdfs: Photometric Redshifts For Normal And X-Ray-Detected Galaxies, Li-Ting Hsu, Mara Salvato, Kirpal Nandra, Marcella Brusa, Ralf Bender, Johannes Buchner, Jennifer L. Dooley, Dale D. Kocevski, Yicheng Guo, Nimish P. Hathi, Cyprian Rangel, S. P. Willner, Murray Brightman, Antonis Georgakakis, Tamás Budavári, Alexander S. Szalay, Matthew L.N. Ashby, Guillermo Barro, Tomas Dahlen, Sandra M. Faber, Henry C. Ferguson, Audrey Galametz, Andrea Grazian, Norman A. Grogin, Kuang-Han Huang, Anton M. Koekemoer, Ray A. Lucas, Elizabeth Mcgrath, Bahram Mobasher, Michael Peth, David J. Rosario, Jonathan R. Trump

Physics and Astronomy Faculty Publications

We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). This work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy Survey (CANDELS) and the Taiwan ECDFS Near-Infrared Survey (TENIS) in addition to other data. We also revisit multi-wavelength counterparts for published X-ray sources from the 4 Ms CDFS and 250 ks ECDFS surveys, finding reliable counterparts for 1207 out of 1259 sources (~96%). Data used for photometric redshifts include intermediate-band photometry deblended using the TFIT method, which is used for the first time in …

Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized 3He Target, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted

Physics and Astronomy Faculty Publications

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized ³He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1<x_bj<0.4 for K⁺ and K⁻ production. While the Collins and Sivers moments for K⁺ are consistent with zero within the experimental uncertainties, both moments for K⁻ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the …

The Mass Evolution Of The First Galaxies: Stellar Mass Functions And Star Formation Rates At 4 < Z < 7 In The Candels Goods-South Field, K. Duncan, C. J. Conselice, A. Mortlock, W. G. Hartley, Y. Guo, H. C. Ferguson, R. Davé, Y. Lu, J. Owensworth, M. L. N. Ashby, A. Dekel, M. Dickinson, S. Faber, M. Giavalisco, N. Grogin, Dale D. Kocevski, A. Koekemoer, R. S. Somerville, C. E. White

Physics and Astronomy Faculty Publications

We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ∼ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed M_{UV …}

Measurement Of “Pretzelosity” Asymmetry Of Charged Pion Production In Semi-Inclusive Deep Inelastic Scattering On A Polarized 3He Target, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. Zhang, X. Qian, J. Huang, J. Katich, Y. Wang, K. Aniol, J. R. M. Annand, T. Averett

Physics and Astronomy Faculty Publications

An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Laboratory in the kinematic region of 0.16<x<0.35 and 1.42<2.7 GeV² Pretzelosity asymmetries on ³He, which are expressed as the convolution of the h^⊥_1T transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured ³He asymmetries and cross-section ratios between the proton and ³He. Our results show that both …

Keck-I Mosfire Spectroscopy Of Compact Star-Forming Galaxies At Z ≳ 2: High Velocity Dispersions In Progenitors Of Compact Quiescent Galaxies, Guillermo Barro, Jonathan R. Trump, David C. Koo, Avishai Dekel, Susan A. Kassin, Dale D. Kocevski, Sandra M. Faber, Arjen Van Der Wel, Yicheng Guo, Pablo G. Pérez-González, Elisa Toloba, Jerome J. Fang, Camilla Pacifici, Raymond Simons, Randy D. Campbell, Daniel Ceverino, Steven L. Finkelstein, Bob Goodrich, Marc Kassis, Anton M. Koekemoer, Nicholas P. Konidaris, Rachel C. Livermore, James E. Lyke, Bahram Mobasher, Hooshang Nayyeri, Michael Peth, Joel R. Primack, Luca Rizzi, Rachel S. Somerville, Gregory D. Wirth, Adi Zolotov

Physics and Astronomy Faculty Publications

We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift 2 ≤ z ≤ 2.5 with star formation rates of SFR ~ 100 M _☉ yr^–1 and masses of log(M/M _☉) ~10.8. . . .

For the remainder of the abstract, please visit:

http://dx.doi.org/10.1088/0004-637X/795/2/145

The Decomposed Bulge And Disc Size–Mass Relations Of Massive Galaxies At 1 < Z < 3 In Candels, V. A. Bruce, J. S. Dunlop, R. J. Mclure, M. Cirasuolo, F. Buitrago, R. A. A. Bowler, T. A. Targett, E. F. Bell, D. H. Mcintosh, A. Dekel, S. M. Faber, H. C. Ferguson, N. A. Grogin, W. Hartley, Dale D. Kocevski, A. M. Koekemoer, D. C. Koo, E. J. Mcgrath

Physics and Astronomy Faculty Publications

We have constructed a mass-selected sample of M_* > 10¹¹ M_⊙ galaxies at 1 < z < 3 in the CANDELS UKIDSS UDS and COSMOS fields and have decomposed these systems into their separate bulge and disc components according to their H₁₆₀-band morphologies. By extending this analysis to multiple bands, we have been able to conduct individual bulge and disc component SED fitting which has provided us with stellar-mass and star formation rate estimates for the separate bulge and disc components. Having utilized the new decomposed stellar-mass estimates, we confirm that the bulge components display a stronger size evolution than the discs. The median sizes of the bulge components is 3.09 ± 0.20 times smaller than similarly massive local galaxies over the …

The Bulge–Disc Decomposed Evolution Of Massive Galaxies At 1 < Z < 3 In Candels, V. A. Bruce, J. S. Dunlop, R. J. Mclure, M. Cirasuolo, F. Buitrago, R. A. A. Bowler, T. A. Targett, E. F. Bell, D. H. Mcintosh, A. Dekel, S. M. Faber, H. C. Ferguson, N. A. Grogin, W. Hartley, Dale D. Kocevski, A. M. Koekemoer, D. C. Zoo, E. J. Mcgrath

Physics and Astronomy Faculty Publications

We present the results of a new and improved study of the morphological and spectral evolution of massive galaxies over the redshift range 1 < z < 3. Our analysis is based on a bulge–disc decomposition of 396 galaxies with M_* > 10¹¹ M_⊙ uncovered from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) Wide Field Camera 3 (WFC3)/IR imaging within the Cosmological Evolution Survey (COSMOS) and UKIRT Infrared Deep Sky Survey (UKIDSS) UDS survey fields. We find that, by modelling the H₁₆₀ image of each galaxy with a combination of a de Vaucouleurs bulge (Sérsic index n = 4) and an exponential disc (n = 1), we can then …

Optimization Of Nanograv's Time Allocation For Maximum Sensitivity To Single Sources, Brian Christy, Ryan Anella, Andrea N. Lommen, Lee Samuel Finn, Richard S. Camuccio, Emma Handzo

Physics and Astronomy Faculty Publications and Presentations

Pulsar timing arrays (PTAs) are a collection of precisely timed millisecond pulsars (MSPs) that can search for gravitational waves (GWs) in the nanohertz frequency range by observing characteristic signatures in the timing residuals. The sensitivity of a PTA depends on the direction of the propagating GW source, the timing accuracy of the pulsars, and the allocation of the available observing time. The goal of this paper is to determine the optimal time allocation strategy among the MSPs in the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) for a single source of GW under a particular set of assumptions. We …

Lattice-Tuned Magnetism Of Ru4+(4D4) Ions In Single Crystals Of The Layered Honeycomb Ruthenates Li2Ruo3 And Na2Ruo3, J. C. Wang, Jsaminka Terzic, T. F. Qi, Feng Ye, Shujuan Yuan, Saicharan Aswartham, S. V. Streltsov, D. I. Khomskii, Ribku K. Kaul, Gang Cao

Physics and Astronomy Faculty Publications

We synthesize and study single crystals of the layered honeycomb lattice Mott insulators Na₂RuO₃ and Li₂RuO₃ with magnetic Ru⁴⁺(4d⁴) ions. The newly found Na₂RuO₃ features a nearly ideal honeycomb lattice and orders antiferromagnetically at 30 K. Single crystals of Li₂RuO₃ adopt a honeycomb lattice with either C2/m or more distorted P2₁/m below 300 K, depending on detailed synthesis conditions. We find that Li₂RuO₃ in both structures hosts a well-defined magnetic state, in contrast to …

Accurate Determination Of The Free–Free Gaunt Factor – I. Non-Relativistic Gaunt Factors, P. A. M. Van Hoof, R. J. R. Williams, K. Vollk, Marios Chatzikos, Gary J. Ferland, M. Lykins, R. L. Porter, Ye Wang

Physics and Astronomy Faculty Publications

Modern spectral synthesis codes need the thermally averaged free–free Gaunt factor defined over a very wide range of parameter space in order to produce an accurate prediction for the spectrum emitted by an ionized plasma. Until now no set of data exists that would meet this need in a fully satisfactory way. We have therefore undertaken to produce a table of very accurate non-relativistic Gaunt factors over a much wider range of parameters than has ever been produced before. We first produced a table of non-averaged Gaunt factors, covering the parameter space ¹⁰log ϵ_i = −20 to +10 …

Information-Entropic Measure Of Energy-Degenerate Kinks In Two-Field Models, R.A.C. Correa, A. De Souza Dutra, M. Gleiser

Dartmouth Scholarship

We investigate the existence and properties of kink-like solitons in a class of models with two interacting scalar fields. In particular, we focus on models that display both double and single-kink solutions, treatable analytically using the Bogomol'nyi–Prasad–Sommerfield bound (BPS). Such models are of interest in applications that include Skyrmions and various superstring-motivated theories. Exploring a region of parameter space where the energy for very different spatially-bound configurations is degenerate, we show that a newly-proposed momentum–space entropic measure called Configurational Entropy (CE) can distinguish between such energy-degenerate spatial profiles. This information-theoretic measure of spatial complexity provides a complementary perspective to situations …

Observation Of D0 Meson Nuclear Modifications In Au+Au Collisions At √SNn=200  Gev, J. Kevin Adkins, Renee Fatemi, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer

Physics and Astronomy Faculty Publications

We report the first measurement of charmed-hadron (D⁰) production via the hadronic decay channel (D⁰→K⁻+π⁺) in Au+Au collisions at √^S_NN=200  GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N_bin, from p+p to central Au+Au collisions. The D⁰ meson yields in central Au+Au collisions are strongly suppressed compared to those in p+p scaled by N_bin, for transverse momenta p_T>3  GeV/c …

Anisotropic Magnetoresistance In Antiferromagnetic Sr2Iro4, C. Wang, H. Seinige, Gang Cao, J.-S. Zhou, J. B. Goodenough, M. Tsoi

Physics and Astronomy Faculty Publications

We report point-contact measurements of anisotropic magnetoresistance (AMR) in a single crystal of antiferromagnetic Mott insulator Sr₂IrO₄. The point-contact technique is used here as a local probe of magnetotransport properties on the nanoscale. The measurements at liquid nitrogen temperature reveal negative magnetoresistances (up to 28%) for modest magnetic fields (250 mT) applied within the IrO₂ a−b plane and electric currents flowing perpendicular to the plane. The angular dependence of magnetoresistance shows a crossover from fourfold to twofold symmetry in response to an increasing magnetic field with angular variations in resistance from 1% to 14%. We …

Mapping Gravitational-Wave Backgrounds Using Methods From Cmb Analysis: Application To Pulsar Timing Arrays, Jonathan Gair, Joseph D. Romano, Stephen Taylor, Chiara M. F. Mingarelli

Physics and Astronomy Faculty Publications and Presentations

We describe an alternative approach to the analysis of gravitational-wave backgrounds, based on the formalism used to characterize the polarization of the cosmic microwave background. In contrast to standard analyses, this approach makes no assumptions about the nature of the background and so has the potential to reveal much more about the physical processes that generated it. An arbitrary background can be decomposed into modes whose angular dependence on the sky is given by gradients and curls of spherical harmonics. We derive the pulsar timing overlap reduction functions for the individual modes, which are given by simple combinations of spherical …

Characterizing The Ab Doradus Moving Group Via High-Resolution Spectroscopy And Kinematic Traceback, Kyle Mccarthy, Ronald J. Wilhelm

Physics and Astronomy Faculty Publications

We present a detailed analysis of 10 proposed F and G members of the nearby, young moving group AB Doradus (ABD). Our sample was obtained using the 2.7 m telescope at the McDonald Observatory with the coude echelle spectrograph, achieving R ~ 60,000 and signal-to-noise ratio ~200. We derive spectroscopic T _eff, log(g), [Fe/H], and microturbulance (v_t ) using a bootstrap method of the TGVIT software resulting in typical errors of 33K in T _eff, 0.08 dex in log(g), 0.03 dex in [Fe/H], and 0.13 km s^–1 in v_t . …