Astrophysics and Astronomy Commons^™

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 …}

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 …

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 …

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 …

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 …

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 . …

No More Active Galactic Nuclei In Clumpy Disks Than In Smooth Galaxies At Z ~ 2 In Candels/3d-Hst*, Jonathan R. Trump, Guillermo Barro, Stéphanie Juneau, Benjamin J. Weiner, Bin Luo, Gabriel B. Brammer, Eric F. Bell, W. N. Brandt, Avishai Dekel, Yicheng Guo, Philip F. Hopkins, David C. Koo, Dale D. Kocevski, Daniel H. Mcintosh, Ivelina Momcheva, S. M. Faber, Henry C. Ferguson, Norman A. Grogin, Jeyhan Kartaltepe, Anton M. Koekemoer, Jennifer Lotz, Michael Maseda, Mark Mozena, Kirpal Nandra, David J. Rosario, Gergory R. Zeimann

Physics and Astronomy Faculty Publications

We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3 < z < 2.4. We select galaxies undergoing gravitational instabilities using the number of clumps and degree of patchiness as proxies. The CANDELS visual classification system is used to identify 44 clumpy disk galaxies, along with mass-matched comparison samples of smooth and intermediate morphology galaxies. We note that despite being mass-matched and having similar star formation rates, the smoother galaxies tend to be smaller disks with more prominent bulges compared to the clumpy galaxies. The lack of smooth extended disks is probably a general feature of the z ~ 2 galaxy population, and means we cannot directly compare with the clumpy and smooth extended disks observed at lower redshift. We find that z ~ 2 clumpy galaxies have slightly enhanced AGN fractions selected by integrated line ratios (in the mass-excitation method), but the spatially resolved line ratios indicate this is likely due to extended phenomena rather than nuclear AGNs. Meanwhile, the X-ray data show that …

Alleviating Polarity-Conflict At The Heterointerfaces Of Ktao3/Gdsco3 Polar Complex-Oxides, Justin K. Thompson, J. Hwang, John Nichols, John G. Connell, S. Stemmer, Sung S. Ambrose Seo

Physics and Astronomy Faculty Publications

We have synthesized and investigated the heterointerfaces of KTaO₃ (KTO) and GdScO₃ (GSO), which are both polar complex-oxides along the pseudo-cubic [001] direction. Since their layers have the same, conflicting net charges at interfaces, i.e., KO(−1)/ScO₂(−1) or TaO₂(+1)/GdO(+1), forming the heterointerface of KTO/GSO should be forbidden due to strong Coulomb repulsion, the so-called polarity conflict. However, we have discovered that atomic reconstruction occurs at the heterointerfaces between KTO thin-films and GSO substrates, which effectively alleviates the polarity conflict without destroying the hetero-epitaxy. Our result demonstrates one of the important ways to create artificial heterostructures …

Tunable Magnetic Properties Of Transition Metal Doped Mos2, Antonis N. Andiotis, Madhu Menon

Physics and Astronomy Faculty Publications

We report a detailed investigation of the electronic and magnetic properties of the transition metal (TM) doped two-dimensional (2D) MoS₂ using ab initio calculations. The doping is achieved by substituting two or more Mo atoms by TM atoms of the 3d series. Additionally, the effect of codoping on the 2D MoS₂ by cation-cation and cation-anion pairs is also investigated. Our results demonstrate that the TM doping of 2D MoS₂ leads to a significant reduction of the energy gap and the appearance of magnetic features whose major characteristic is the ferromagnetic coupling of the TM dopants. The …

On The Momentum Dependence Of The Flavor Structure Of The Nucleon Sea, Jen-Chieh Peng, Wen-Chen Chang, Hai-Yang Cheng, Tie-Jiun Hou, Keh-Fei Liu, Jian-Wei Qiu

Physics and Astronomy Faculty Publications

Difference between the u¯ and d¯ sea quark distributions in the proton was first observed in the violation of the Gottfried sum rule in deep-inelastic scattering (DIS) experiments. The parton momentum fraction x dependence of this difference has been measured over the region 0.02 < x < 0.35 from Drell–Yan and semi-inclusive DIS experiments. The Drell–Yan data suggested a possible sign-change for d¯(x) − u¯ (x) near x ~ 0.3, which has not yet been explained by existing theoretical models. We present an independent evidence for the d¯(x) − u¯ (x) sign-change at x ~ 0.3 from an analysis of the DIS data. We further discuss the x …

Recent Ideas On The Calculation Of Lepton Anomalous Magnetic Moments, Michael I. Eides

Physics and Astronomy Faculty Publications

We discuss the recent claim [G. Mishima, arXiv:1311.7109; M. Fael and M. Passera, arXiv:1402.1575 [Phys. Rev. D (to be published)]] about discovery of a nonperturbative quantum-electrodynamic contribution of order (α/π)⁵ to lepton anomalous magnetic moments. We explain why this nonperturbative correction does not exist.

Beam Energy Dependence Of Moments Of The Net-Charge Multiplicity Distributions In Au+Au Collisions At Rhic, J. Kevin Adkins, Renee Fatemi, Wolfgang Korsch, 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 measurements of the moments—mean (M), variance (σ²), skewness (S), and kurtosis (κ)—of the net-charge multiplicity distributions at midrapidity in Au+Au collisions at seven energies, ranging from √^S_NN=7.7 to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, σ²/M, Sσ, and κσ², with the expectations …

Thermal Diffusivities Of Functionalized Pentacene Semiconductors, Hao Zhang, Yulong Yao, Marcia M. Payne, John E. Anthony, Joseph W. Brill

Physics and Astronomy Faculty Publications

We have measured the interlayer and in-plane (needle axis) thermal diffusivity of 6,13-bis(triisopropylsilylethynyl) pentacene. The needle axis value is comparable to the phonon thermal diffusivities of quasi-one dimensional organic metals with excellent π-orbital overlap, and its value suggests that a significant fraction of heat is carried by optical phonons. Furthermore, the interlayer (c-axis) thermal diffusivity is at least an order of magnitude larger, and this unusual anisotropy implies very strong dispersion of optical modes in the interlayer direction, presumably due to interactions between the silyl-containing side groups. Similar values for both in-plane and interlayer diffusivities have been observed for several …

The Meaning Of Wise Colours – I. The Galaxy And Its Satellites, Robert Nikutta, Nicholas Hunt-Walker, Maia M. Nenkova, Željko Ivezić, Moshe Elitzur

Physics and Astronomy Faculty Publications

Through matches with the Sloan Digital Sky Survey (SDSS) catalogue we identify the location of various families of astronomical objects in WISE colour space. We identify reliable indicators that separate Galactic/local from extragalactic sources and concentrate here on the objects in our Galaxy and its closest satellites. We develop colour and magnitude criteria that are based only on WISE data to select asymptotic giant branch (AGB) stars with circumstellar dust shells, and separate them into O-rich and C-rich classes. With these criteria we produce an all-sky map for the count ratio of the two populations. The map reveals differences between …

Measurement Of Longitudinal Spin Asymmetries For Weak Boson Production In Polarized Proton-Proton Collisions At Rhic, 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 measurements of single- and double-spin asymmetries for W^± and Z/γ^∗ boson production in longitudinally polarized p+p collisions at √^S=510  GeV by the STAR experiment at RHIC. The asymmetries for W^± were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton’s polarized quark distributions at the scale of the W mass. The results are compared to theoretical predictions, constrained by polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range 0.05<x<0.2.

J/Ψ Production At Low PT In Au + Au And Cu + Cu Collisions At √SNn = 200 Gev With The Star Detector, J. Kevin Adkins, Renee Fatemi, Suvarna Ramachandran, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin

Physics and Astronomy Faculty Publications

The J/ψ p_T spectrum and nuclear modification factor (R_AA) are reported for p_T < 5 GeV/c and |y| < 1 from 0% to 60% central Au + Au and Cu + Cu collisions at √^SNN = 200 GeV at STAR. A significant suppression of p_T-integrated J/ψ production is observed in central Au + Au events. The Cu + Cu data are consistent with no suppression, although the precision is limited by the available statistics. R_AA in Au + Au collisions exhibits a strong suppression at low transverse momentum and gradually increases with p_T. The data are compared to high-p_{T …}

Star Formation Quenching In High-Redshift Large-Scale Structure: Post-Starburst Galaxies In The Ci 1604 Supercluster At Z ~ 0.9, Po-Feng Wu, Roy R. Gal, Brian C. Lemaux, Dale D. Kocevski, Lori M. Lubin, Nicholas Rumbaugh, Gordon K. Squires

Physics and Astronomy Faculty Publications

The Cl 1604 supercluster at z ~ 0.9 is one of the most extensively studied high-redshift large-scale structures, with more than 500 spectroscopically confirmed members. It consists of eight clusters and groups, with members numbering from a dozen to nearly a hundred, providing a broad range of environments for investigating the large-scale environmental effects on galaxy evolution. Here we examine the properties of 48 post-starburst galaxies in Cl 1604, comparing them to other galaxy populations in the same supercluster. Incorporating photometry from ground-based optical and near-infrared imaging, along with Spitzer mid-infrared observations, we derive stellar masses for all Cl 1604 …

Nonperturbative Renormalization Of Overlap Quark Bilinears On 2+1-Flavor Domain Wall Fermion Configurations, Zhaofeng Liu, Ying Chen, Shao-Jing Dong, Michael Glatzmaier, Ming Gong, Anyi Li, Keh-Fei Liu, Yi-Bo Yang, Jian-Bo Zhang

Physics and Astronomy Faculty Publications

We present renormalization constants of overlap quark bilinear operators on 2+1-flavor domain wall fermion configurations. . . .

For the remainder of the abstract, please visit: http://dx.doi.org/10.1103/PhysRevD.90.034505

Beam-Energy Dependence Of Charge Separation Along The Magnetic Field In Au+Au Collisions At Rhic, 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

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with …

Suppression Of Υ Production In D + Au And Au + Au Collisions At √SNn = 200 Gev, James K. Adkins, Renee Fatemi, Wolfgang Korsch, Suvarna Ramachandran, L. Adamczyk, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee

Physics and Astronomy Faculty Publications

We report measurements of Υ meson production in p + p, d + Au, and Au + Au collisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au + Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Υ (1S + …

Candels+3d-Hst: Compact Sfgs At Z ~ 2-3, The Progenitors Of The First Quiescent Galaxies, G. Barro, S. M. Faber, P. G. Pérez-González, C. Pacifici, J. R. Trump, D. C. Koo, S. Wuyts, Y. Guo, E. Bell, A. Dekel, L. Porter, J. Primack, H. Ferguson, M. L. N. Ashby, K. Caputi, D. Ceverino, D. Croton, G. G. Fazio, M. Giavalisco, L. Hsu, Dalibor D. Kocevski, A. Koekemoer, P. Kurcynski, P. Kollipara, J. Lee, D. H. Mcintosh, E. Mcgrath, C. Moody, R. Somerville, C. Papovich, M. Salvato, P. Santini, T. Tal, A. Van Der Wel, C. C. Williams, S. P. Willner, A. Zolotov

Physics and Astronomy Faculty Publications

We analyze the star-forming and structural properties of 45 massive (log(M/M _☉) >10) compact star-forming galaxies (SFGs) at 2 < z < 3 to explore whether they are progenitors of compact quiescent galaxies at z ~ 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are heavily obscured. Nearly half (47%) host an X-ray-bright active galactic nucleus (AGN). In contrast, only about 10% of other massive galaxies at that time host AGNs. Compact SFGs have centrally concentrated light profiles and spheroidal morphologies similar to quiescent galaxies and are thus strikingly different from other SFGs, which typically are disk-like and sometimes clumpy or irregular. Most compact …

The Violent Youth Of Bright And Massive Cluster Galaxies And Their Maturation Over 7 Billion Years, B. Ascaso, B. C. Lemaux, L. M. Lubin, R. R. Gal, Dale D. Kocevski, N. Rumbaugh, G. Squires

Physics and Astronomy Faculty Publications

In this study, we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z ∼ 0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z ∼ 0.1) counterparts drawn from the MCXC meta-catalogue, supplemented by Sloan Digital Sky Survey imaging and spectroscopy. We observed striking differences in the morphological, colour, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broad-band colours, properties largely absent amongst …

The Gentle Growth Of Galaxies At High Redshifts In Overdense Environments, Emilio Romano-Díaz, Isaac Shlosman, Jun-Hwan Choi, Raphael Sadoun

Physics and Astronomy Faculty Publications

We have explored prevailing modes of galaxy growth for redshifts z ~ 6-14, comparing substantially overdense and normal regions of the universe, using high-resolution zoom-in cosmological simulations. Such rare overdense regions have been projected to host high-z quasars. We demonstrate that galaxies in such environments grow predominantly by a smooth accretion from cosmological filaments which dominates the mass input from major, intermediate, and minor mergers. We find that by z ~ 6, the accumulated galaxy mass fraction from mergers falls short by a factor of 10 of the cumulative accretion mass for galaxies in the overdense regions, and by …

Different Response Of Transport And Magnetic Properties Of Bairo3 To Chemical And Physical Pressure, M. A. Laguna-Marco, G. Fabbris, N. M. Souza-Neto, S. Chikara, J. S. Schilling, Gang Cao, D. Haskel

Physics and Astronomy Faculty Publications

A combination of x-ray absorption, x-ray-diffraction, and transport measurements at high pressure is used to investigate the interplay between the electronic properties of Ir 5d states and lattice degrees of freedom in the weakly ferromagnetic insulator BaIrO₃. Although the Ir 5d local magnetic moment is highly stable against lattice compression, remaining nearly unperturbed to at least 30 GPa, the weak ferromagnetism (net ordered moment) is quickly quenched by 4.5 GPa (3% volume reduction). Under chemical pressure, where Sr is substituted for the larger Ba in BaIrO₃, the local magnetic moment on Ir remains stable, …

Casimir Energy Of Smooth Compact Surfaces, Joseph P. Straley, Eugene B. Kolomeisky

Physics and Astronomy Faculty Publications

We discuss the formalism of Balian and Duplantier [Balian and Duplantier, Ann. Phys. (NY) 104, 300 (1977); Balian and Duplantier, Ann. Phys. (NY) 112, 165 (1978)] for the calculation of the Casimir energy for an arbitrary smooth compact surface and use it to give some examples: a finite cylinder with hemispherical caps, a torus, an ellipsoid of revolution, a cube with rounded corners and edges, and a drum made of disks and part of a torus. We propose a model function that approximately captures the shape dependence of the Casimir energy.