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2009

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Articles 4741 - 4770 of 7615

Full-Text Articles in Physical Sciences and Mathematics

Rhodium Nanoparticle Shape Dependence In The Reduction Of No By Co, James Russell Renzas, Yawen Zhang, Wenyu Huang, Gabor Somoraji Jan 2009

Rhodium Nanoparticle Shape Dependence In The Reduction Of No By Co, James Russell Renzas, Yawen Zhang, Wenyu Huang, Gabor Somoraji

Wenyu Huang

The shape dependence of the catalytic reduction of nitric oxide by carbon monoxide on rhodium nanopoly- hedra and nanocubes was studied from 230 to 270 ° C. The nanocubes are found to exhibit higher turnover frequency and lower activation energy than the nanopolyhedra. These trends are compared to previous studies on Rh single crystals.

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Sub-10 Nm Platinum Nanocrystals With Size And Shape Control: Catalytic Study For Ethylene And Pyrrole Hydrogenation, Chia-Kuang Tsung, John N. Kuhn, Wenyu Huang, Cesar Aliaga, Ling-I Hung, Gabor A. Somorjai, Peidong Yang Jan 2009

Sub-10 Nm Platinum Nanocrystals With Size And Shape Control: Catalytic Study For Ethylene And Pyrrole Hydrogenation, Chia-Kuang Tsung, John N. Kuhn, Wenyu Huang, Cesar Aliaga, Ling-I Hung, Gabor A. Somorjai, Peidong Yang

Wenyu Huang

Platinum nanocubes and nanopolyhedra with tunable size from 5 to 9 nm were synthesized by controlling the reducing rate of metal precursor ions in a one-pot polyol synthesis. A two-stage process is proposed for the simultaneous control of size and shape. In the first stage, the oxidation state of the metal ion precursors determined the nucleation rate and consequently the number of nuclei. The reaction temperature controlled the shape in the second stage by regulation of the growth kinetics. These well-defined nanocrystals were loaded into MCF-17 mesoporous silica for examination of catalytic properties. Pt loadings and dispersions of the supported …

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Photoaffinity Labeling Via Nitrenium Ion Chemistry: Protonation Of The Nitrene Derived From 4-Amino-3-Nitrophenyl Azide To Afford Reactive Nitrenium Ion Pairs, Valentyna Voskresenska, R. Marshall Wilson, Maxim Panov, Alexander N. Tarnovsky, Jeanette A. Krause, Shubham Vyas, Arthur Winter, Christopher M. Hadad Jan 2009

Photoaffinity Labeling Via Nitrenium Ion Chemistry: Protonation Of The Nitrene Derived From 4-Amino-3-Nitrophenyl Azide To Afford Reactive Nitrenium Ion Pairs, Valentyna Voskresenska, R. Marshall Wilson, Maxim Panov, Alexander N. Tarnovsky, Jeanette A. Krause, Shubham Vyas, Arthur Winter, Christopher M. Hadad

Arthur Winter

Phenyl azides with powerful electron-donating substituents are known to deviate from the usual photochemical behavior of other phenyl azides. They do not undergo ring expansion but form basic nitrenes that protonate to form nitrenium ions. The photochemistry of the widely used photoaffinity labeling system 4-amino-3-nitrophenyl azide, 5, has been studied by transient absorption spectroscopy from femtosecond to microsecond time domains and from a theoretical perspective. The nitrene generation from azide 5 occurs on the S2 surface, in violation of Kasha’s rule. The resulting nitrene is a powerful base and abstracts protons extremely rapidly from a variety of sources to form …

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Self-Organized Ultrathin Oxide Nanocrystals, Ziyang Huo, Chia-Kuang Tsung, Wenyu Huang, Melissa Fardy, Ruoxue Yan, Xiaofeng Zhang, Yandong Li, Peidong Yang Jan 2009

Self-Organized Ultrathin Oxide Nanocrystals, Ziyang Huo, Chia-Kuang Tsung, Wenyu Huang, Melissa Fardy, Ruoxue Yan, Xiaofeng Zhang, Yandong Li, Peidong Yang

Wenyu Huang

Sub-2-nm (down to one-unit cell) uniform oxide nanocrystals and highly ordered superstructures were obtained in one step using oleylamine and oleic acid as capping and structure directing agents. The cooperative nature of the nanocrystal growth and assembly resulted in mesoscopic one-dimensional ribbon-like superstructures made of these ultrathin nanocrystals. The process reported here is general and can be readily extended to the production of many other transition metal (TiO2, ZnO, Nb2O5) and rare earth oxide (Eu2O3, Sm2O3, Er2O3, Y2O3, Tb2O3, and Yb2O3) systems.

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Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Agegnehu Atena, Mikhail Khenner Jan 2009

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Agegnehu Atena, Mikhail Khenner

Mikhail Khenner

In this paper the lubrication-type dynamical model is developed of a molten, pulsed laser-irradiated metallic film. The heat transfer problem that incorporates the absorbed heat from a single beam or interfering beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the peak laser beam intensity, the film optical thickness, the Biot and …

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Model Systems For Flavoenzyme Activity: An Investigation Of The Role Functionality Attached To The C(7) Position Of The Flavin Unit Has On Redox And Molecular Recognition Properties, St Caldwell, Lj Farrugia, Sg Hewage, N Kryvokhyzha, Vm Rotello, G Cooke Jan 2009

Model Systems For Flavoenzyme Activity: An Investigation Of The Role Functionality Attached To The C(7) Position Of The Flavin Unit Has On Redox And Molecular Recognition Properties, St Caldwell, Lj Farrugia, Sg Hewage, N Kryvokhyzha, Vm Rotello, G Cooke

Vincent Rotello

We describe the role functionality attached to the C(7) position of a family of flavin derivatives has in tuning their redox and recognition properties and the subsequent exploitation of two of these derivatives as a three-component electrochemically controllable molecular switch.

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Sniffing Out Cancer Using "Chemical Nose" Sensors, V Rotello Jan 2009

Sniffing Out Cancer Using "Chemical Nose" Sensors, V Rotello

Vincent Rotello

No abstract provided.

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Engineered Nanoparticle Surfaces For Improved Mass Spectrometric Analyses, Zj Zhu, Vm Rotello, Rw Vachet Jan 2009

Engineered Nanoparticle Surfaces For Improved Mass Spectrometric Analyses, Zj Zhu, Vm Rotello, Rw Vachet

Vincent Rotello

Engineering of nanoparticle surface functionality provides controlled interactions with biomolecules such as cell membrane lipids, proteins and nucleic acids. Concurrently, this surface chemistry control also opens up new avenues for improving mass spectral analyses. In this Minireview, we highlight some of the emerging work that integrates surface-engineered nanoparticles with mass spectrometry to improve the analysis of a wide variety of chemical and biological systems.

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Beyond Molecular Recognition: Using A Repulsive Field To Tune Interfacial Valency And Binding Specificity Between Adhesive Surfaces, Mm Santore, J Zhang, S Srivastava, Vm Rotello Jan 2009

Beyond Molecular Recognition: Using A Repulsive Field To Tune Interfacial Valency And Binding Specificity Between Adhesive Surfaces, Mm Santore, J Zhang, S Srivastava, Vm Rotello

Vincent Rotello

Surface-bound biomolecular fragments enable “smart” materials to recognize cells and other particles in applications ranging from tissue engineering and medical diagnostics to colloidal and nanoparticle assembly. Such smart surfaces are, however, limited in their design to biomolecular selectivity. This feature article demonstrates, using a completely nonbiological model system, how specificity can be achieved for particle (and cell) binding, employing surface designs where immobilized nanoscale adhesion elements are entirely nonselective. Fundamental principles are illustrated by a model experimental system where 11 nm cationic nanoparticles on a planar negative silica surface interact with flowing negative silica microspheres having 1.0 and 0.5 μm …

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Self-Assembly Of Fluorocarbon-Coated Fept Nanoparticles For Controlling Structure And Wettability Of Surfaces, B Samanta, Y Ofir, D Patra, Vm Rotello Jan 2009

Self-Assembly Of Fluorocarbon-Coated Fept Nanoparticles For Controlling Structure And Wettability Of Surfaces, B Samanta, Y Ofir, D Patra, Vm Rotello

Vincent Rotello

Controlled self-assembly of fluorinated FePt nanoparticles from different solvent mixtures has been used to create superhydrophobic surfaces with varying topology and stickiness towards water. The ability to tune surface stickiness provides a means for fluid handling, as demonstrated by surface-to-surface transfer of water droplets.

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Gold Nanoparticle-Ppe Constructs As Biomolecular Material Mimics: Understanding The Electrostatic And Hydrophobic Interactions, Rl Phillips, Or Miranda, De Mortenson, C Subramani, Vm Rotello, Uhf Bunz Jan 2009

Gold Nanoparticle-Ppe Constructs As Biomolecular Material Mimics: Understanding The Electrostatic And Hydrophobic Interactions, Rl Phillips, Or Miranda, De Mortenson, C Subramani, Vm Rotello, Uhf Bunz

Vincent Rotello

Eleven cationic, monolayer-protected quaternary ammonium-functionalized gold nanoparticles (ANPs) were prepared and investigated for their ability to quench the fluorescence of a poly(p-phenyleneethynylene) (PPE) that features carboxylate groups to enable electrostatic interactions with the ANPs. Depending upon their structures, the ANPs displayed binding constants to the PPE from 8 × 107 to 1010 M−1, with particularly high affinity observed with aromatic functionalized ANPs capable of aromatic stacking. These binding constants were obtained by analyzing the quenching data using a modified Stern–Volmer formalism.

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Beyond Diffusion-Limited Aggregation Kinetics In Microparticle Suspensions, Rm Erb, Md Krebs, E Alsberg, B Samanta, Vm Rotello, Bb Yellen Jan 2009

Beyond Diffusion-Limited Aggregation Kinetics In Microparticle Suspensions, Rm Erb, Md Krebs, E Alsberg, B Samanta, Vm Rotello, Bb Yellen

Vincent Rotello

Aggregation in nondiffusion limited colloidal particle suspensions follows a temporal power-law dependence that is consistent with classical diffusion limited cluster aggregation models; however, the dynamic scaling exponents observed in these systems are not adequately described by diffusion limited cluster aggregation models, which expect these scaling exponents to be constant over all experimental conditions. We show here that the dynamic scaling exponents for 10 μm particles increase with the particle concentration and the particle-particle free energy of interaction. We provide a semiquantitative explanation for the scaling behavior in terms of the long-ranged particle-particle interaction potential.

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Molecular Recognition At The Liquid-Liquid Interface Of Colloidal Microcapsules, D Patra, C Pagliuca, C Subramani, B Samanta, Ss Agasti, N Zainalabdeen, St Caldwell, G Cooke, Vm Rotello Jan 2009

Molecular Recognition At The Liquid-Liquid Interface Of Colloidal Microcapsules, D Patra, C Pagliuca, C Subramani, B Samanta, Ss Agasti, N Zainalabdeen, St Caldwell, G Cooke, Vm Rotello

Vincent Rotello

Dithiocarbamate chemistry is used as a crosslinking tool to fabricate FePt colloidal microcapsules which provide a versatile scaffold for “host–guest” recognition at the liquid–liquid interface.

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(+-)-3-Carboxy-2-(Imidazol-3-Ium-1-Yl)- Propanoate, Sara A. Reeb, Marlesa C. Shields, Kraig A. Wheeler Jan 2009

(+-)-3-Carboxy-2-(Imidazol-3-Ium-1-Yl)- Propanoate, Sara A. Reeb, Marlesa C. Shields, Kraig A. Wheeler

Kraig A. Wheeler

The title compound, C7H8N2O4, crystallizes as a zwitterion, with molecules organized into molecular sheets via carboxyl– carboxylate and N+—H_ _ _carboxylate contacts. These sheets are constructed from translationally related molecules that further link to neighboring motifs via _-stacking [centroid– centroid distance 3.504 (3) A ° ] and weak C—H_ _ _O contacts.

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A New Era In Extragalactic Background Light Measurements: The Cosmic History Of Accretion, Nucleosynthesis And Reionization, Asantha Cooray, Alexandre Amblard, Charles Beichman, Dominic Benford, Rebecca Bernstein, James J. Bock, Mark Brodwin, Volker Bromm, Renyue Cen, Ranga R. Chary, Mark Devlin, Timothy Dolch, Hervé Dole, Eli Dwek, David Elbaz, Michael Fall, Giovanni Fazio, Henry Ferguson, Steven Furlanetto, Jonathan Gardner, Mauro Giavalisco, Rudy Gilmore, Nickolay Gnedin, Anthony Gonzalez, Zoltan Haiman, Michael Hauser, Jiasheng Huang, Sergei Ipatov, Alexander Kashlinsky, Brian Keating, Thomas Kelsall, Eiichiro Komatsu, Guilaine Lagache, Louis R. Levenson, Avi Loeb, Piero Madau, John C. Mather, Toshio Matsumoto, Shuji Matsuura, Kalevi Mattila, Harvey Moseley, Leonidas Moustakas, S. Peng Oh, Larry Petro, Joel Primack, William Reach, Tom Renbarger, Paul Shapiro, Daniel Stern, Ian Sullivan, Aparna Venkatesan, Michael Werner, Rogier Windhorst, Edward L. Wright, Michael Zemcov Jan 2009

A New Era In Extragalactic Background Light Measurements: The Cosmic History Of Accretion, Nucleosynthesis And Reionization, Asantha Cooray, Alexandre Amblard, Charles Beichman, Dominic Benford, Rebecca Bernstein, James J. Bock, Mark Brodwin, Volker Bromm, Renyue Cen, Ranga R. Chary, Mark Devlin, Timothy Dolch, Hervé Dole, Eli Dwek, David Elbaz, Michael Fall, Giovanni Fazio, Henry Ferguson, Steven Furlanetto, Jonathan Gardner, Mauro Giavalisco, Rudy Gilmore, Nickolay Gnedin, Anthony Gonzalez, Zoltan Haiman, Michael Hauser, Jiasheng Huang, Sergei Ipatov, Alexander Kashlinsky, Brian Keating, Thomas Kelsall, Eiichiro Komatsu, Guilaine Lagache, Louis R. Levenson, Avi Loeb, Piero Madau, John C. Mather, Toshio Matsumoto, Shuji Matsuura, Kalevi Mattila, Harvey Moseley, Leonidas Moustakas, S. Peng Oh, Larry Petro, Joel Primack, William Reach, Tom Renbarger, Paul Shapiro, Daniel Stern, Ian Sullivan, Aparna Venkatesan, Michael Werner, Rogier Windhorst, Edward L. Wright, Michael Zemcov

Mauro Giavalisco

(Brief Summary) What is the total radiative content of the Universe since the epoch of recombination? The extragalactic background light (EBL) spectrum captures the redshifted energy released from the first stellar objects, protogalaxies, and galaxies throughout cosmic history. Yet, we have not determined the brightness of the extragalactic sky from UV/optical to far-infrared wavelengths with sufficient accuracy to establish the radiative content of the Universe to better than an order of magnitude. Among many science topics, an accurate measurement of the EBL spectrum from optical to far-IR wavelengths, will address: What is the total energy released by stellar nucleosynthesis over …

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The Relative Abundance Of Compact And Normal Massive Early-Type Galaxies And Its Evolution From Redshift Z~2 To The Present, P. Cassata, Mauro Giavalisco, Yicheng Guo, A. Renzini, H. Ferguson, A. M. Koekemoer, S. Salimbeni, C. Scarlata, N. A. Grogin, C. J. Conselice, T. Dahlen, J. M. Lotz, M. Dickinson, Lihwai Lin Jan 2009

The Relative Abundance Of Compact And Normal Massive Early-Type Galaxies And Its Evolution From Redshift Z~2 To The Present, P. Cassata, Mauro Giavalisco, Yicheng Guo, A. Renzini, H. Ferguson, A. M. Koekemoer, S. Salimbeni, C. Scarlata, N. A. Grogin, C. J. Conselice, T. Dahlen, J. M. Lotz, M. Dickinson, Lihwai Lin

Mauro Giavalisco

We report on the evolution of the number density and size of early-type galaxies from z~2 to z~0. We select a sample of 563 massive (M>10^{10} Msun), passively evolving (SSFR<10^{-2} Gyr^{-1}) and morphologically spheroidal galaxies at 01.2 and z<1.2, respectively). We measure a significant evolution of the mass-size relation of early-type galaxies, with the fractional increment that is almost independent on the stellar mass. Early-type galaxies (ETGs) formed at z>1 appear to be preferentially small, and the evolution of the mass-size relation at z<1 is driven by both the continuous size growth of the compact galaxies and the appearance of new ETGs with large sizes. We also find that the number density of all passive early-type galaxies increases rapidly, by a factor of 5, from z~2 to z~1, and then more mildly by another factor of 1.5 from z~1 to z~0. We interpret these results as the evidence that the bulk of the ETGs are formed at 1

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Candels: The Contribution Of The Observed Galaxy Population To Cosmic Reionization, Steven L. Finkelstein, Casey Papovich, Russel E, Ryan Jr., Andreas H. Pawlik, Mark Dickinson, Henry C. Ferguson, Kristian Finlator, Anton M. Koekemoer, Mauro Giavalisco, Mauro Giavalisco, Asantha Cooray, James S. Dunlop, Sandy M. Faber, Norman A. Grogin, Dale D. Kocevski, Jeffrey A. Newman Jan 2009

Candels: The Contribution Of The Observed Galaxy Population To Cosmic Reionization, Steven L. Finkelstein, Casey Papovich, Russel E, Ryan Jr., Andreas H. Pawlik, Mark Dickinson, Henry C. Ferguson, Kristian Finlator, Anton M. Koekemoer, Mauro Giavalisco, Mauro Giavalisco, Asantha Cooray, James S. Dunlop, Sandy M. Faber, Norman A. Grogin, Dale D. Kocevski, Jeffrey A. Newman

Mauro Giavalisco

We present measurements of the specific ultraviolet luminosity density from a sample of 483 galaxies at 6 . z . 8. These galaxies were selected from new deep near-infrared Hubble Space Telescope imaging from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble UltraDeep Field 2009 and WFC3 Early Release Science programs. In contrast to the majority of previous analyses, which assume that the distribution of galaxy ultraviolet (UV) luminosities follows a Schechter distribution, and that the distribution continues to luminosities far below our observable limit, we investigate the contribution to reionization from galaxies which we can observe, free from …

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Candels: Constraining The Agn-Merger Connection With Host Morphologies At Z~2, Dale D. Kocevski, S. M. Faber, Mark Mozena, Anton M. Koekemoer, Kirpal Nandra, Cyprian Rangel, Elise S. Laird, Marcella Brusa, Stijn Wuyts, Jonathan R. Trump, David C. Koo, Rachel S. Somerville, Eric F. Bell, Jennifer M. Lotz, David M. Alexander, Frederic Bournaud, Christopher J. Conselice, Tomas Dahlen, Avashi Dekel, Jennifer L. Donley, James S. Dunlop, Alexis Finoguenov, Antonis Georgakakis, Mauro Giavalisco, Yicheng Guo, Norman A. Grogin, Nimish P. Hathi, Stéphanie Juneau, Jeyhan S. Kartaltepe, Ray A. Lucas, Elizabeth J. Mcgrath, Daniel H. Mcintosh, Bahram Mobasher, Aday R. Robaina, David Rosario, Amber N. Straughn, Arjen Van Der Wel, Carolin Villforth Jan 2009

Candels: Constraining The Agn-Merger Connection With Host Morphologies At Z~2, Dale D. Kocevski, S. M. Faber, Mark Mozena, Anton M. Koekemoer, Kirpal Nandra, Cyprian Rangel, Elise S. Laird, Marcella Brusa, Stijn Wuyts, Jonathan R. Trump, David C. Koo, Rachel S. Somerville, Eric F. Bell, Jennifer M. Lotz, David M. Alexander, Frederic Bournaud, Christopher J. Conselice, Tomas Dahlen, Avashi Dekel, Jennifer L. Donley, James S. Dunlop, Alexis Finoguenov, Antonis Georgakakis, Mauro Giavalisco, Yicheng Guo, Norman A. Grogin, Nimish P. Hathi, Stéphanie Juneau, Jeyhan S. Kartaltepe, Ray A. Lucas, Elizabeth J. Mcgrath, Daniel H. Mcintosh, Bahram Mobasher, Aday R. Robaina, David Rosario, Amber N. Straughn, Arjen Van Der Wel, Carolin Villforth

Mauro Giavalisco

Using HST/WFC3 imaging taken as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), we examine the role that major galaxy mergers play in triggering active galactic nuclei (AGN) activity at z~2. Our sample consists of 72 moderate-luminosity (Lx ~ 1E42-1E44 erg/s) AGN at 1.5

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The Redshift Search Receiver Observations Of 12co J = 1 → 0 In 29 Ultraluminous Infrared Galaxies, Aeree Chung, Gopal Narayanan, Min S. Yun, Mark Heyer, Neal R. Erickson Jan 2009

The Redshift Search Receiver Observations Of 12co J = 1 → 0 In 29 Ultraluminous Infrared Galaxies, Aeree Chung, Gopal Narayanan, Min S. Yun, Mark Heyer, Neal R. Erickson

Gopal Narayanan

We present 12CO J = 1 → 0 observations of ultraluminous infrared galaxies (ULIRGs) obtained using the Redshift Search Receiver (RSR) on the 14 m telescope of the Five College Radio Astronomy Observatory. The RSR is a novel, dual-beam, dual-polarization receiver equipped with an ultra-wideband spectrometer backend that is being built as a facility receiver for the Large Millimeter Telescope. Our sample consists of 29 ULIRGs in the redshift range of 0.04–0.11, including 10 objects with no prior 12CO measurements. We have detected 27 systems (a detection rate of 93%), including 9 ULIRGs that are detected in CO for the …

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Expanding The Search For Galaxies At Z ~7-10 With New Nicmos Parallel Fields, Alaina L. Henry, Brian Siana, Matthew A. Malkan, Matthew L. N. Ashby, Carrie R. Bridge, Ranga-Ram Chary, James W. Colbert, Mauro Giavalisco, Harry I. Teplitz, Patrick J. Mccarthy Jan 2009

Expanding The Search For Galaxies At Z ~7-10 With New Nicmos Parallel Fields, Alaina L. Henry, Brian Siana, Matthew A. Malkan, Matthew L. N. Ashby, Carrie R. Bridge, Ranga-Ram Chary, James W. Colbert, Mauro Giavalisco, Harry I. Teplitz, Patrick J. Mccarthy

Mauro Giavalisco

We have carried out a search for galaxies at z ~ 7-10 in ~14.4 sq. arcmin of new NICMOS parallel imaging taken in the Great Observatories Origins Deep Survey (GOODS, 5.9 sq. arcmin), the Cosmic Origins Survey (COSMOS, 7.2 sq. arcmin), and SSA22 (1.3 sq. arcmin). These images reach 5 sigma sensitivities of J110 = 26.0-27.5 (AB), and combined they increase the amount of deep near-infrared data by more than 60% in fields where the investment in deep optical data has already been made. We find no z>7 candidates in our survey area, consistent with the Bouwens et al. …

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Spectroscopic Observations Of Lyman-Break Galaxies At Redshift ~ 4, 5 And 6 In The Goods-South Field, E. Vanzella, Mauro Giavalisco, M. Dickinson, S. Cristiani, M. Nonino, H. Kuntschner, P. Popesso, P, Rosati, A. Renzini, D. Stern, C. Cesarsky, H. C. Ferguson, R. A. E. Fosbury, The Goods Team Jan 2009

Spectroscopic Observations Of Lyman-Break Galaxies At Redshift ~ 4, 5 And 6 In The Goods-South Field, E. Vanzella, Mauro Giavalisco, M. Dickinson, S. Cristiani, M. Nonino, H. Kuntschner, P. Popesso, P, Rosati, A. Renzini, D. Stern, C. Cesarsky, H. C. Ferguson, R. A. E. Fosbury, The Goods Team

Mauro Giavalisco

We report on observations of Lyman-break galaxies (LBGs) selected from the Great Observatories Origins Deep Survey at mean redshift z~4, 5 and 6, obtained with FORS2 spectrograph at the ESO-VLT.This program has yielded spectroscopic identifications for 114 galaxies of which 51 are at z~4, 31 at z~5, and 32 at z~6. The adopted selection criteria are effective, identifying galaxies at the expected redshift with minimal foreground contamination. Once selection effects are properly accounted for, the rest-frame UV spectra of the higher-redshift LBGs appear to be similar to their counterparts at z~3. As at z~3, LBGs at z~4 and z~5 show …

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Spectroscopy Of Luminous Z>7 Galaxy Candidates And Sources Of Contamination In Z>7 Galaxy Searches, P. Capak, B. Mobasher, N. Z. Scoville, H. Mccracken, O. Ilbert, M. Salvato, K. Menéndez-Delmestre, H. Aussel, C. Carilli, F. Civano, M. Elvis, Mauro Giavalisco, E. Jullo, J. Kartaltepe, A. Leauthaud, A. M. Koekemoer, J.-P. Kneib, E. Lefloch, D. B. Sanders, E. Schinnerer, Y. Shioya, P. Shopbell, Y. Tanaguchi, D. Thompson, C. J. Willcott Jan 2009

Spectroscopy Of Luminous Z>7 Galaxy Candidates And Sources Of Contamination In Z>7 Galaxy Searches, P. Capak, B. Mobasher, N. Z. Scoville, H. Mccracken, O. Ilbert, M. Salvato, K. Menéndez-Delmestre, H. Aussel, C. Carilli, F. Civano, M. Elvis, Mauro Giavalisco, E. Jullo, J. Kartaltepe, A. Leauthaud, A. M. Koekemoer, J.-P. Kneib, E. Lefloch, D. B. Sanders, E. Schinnerer, Y. Shioya, P. Shopbell, Y. Tanaguchi, D. Thompson, C. J. Willcott

Mauro Giavalisco

We present three bright z+ dropout candidates selected from deep Near-Infrared (NIR) imaging of the COSMOS 2 square degree field. All three objects match the 0.8-8um colors of other published z>7 candidates but are three magnitudes brighter, facilitating further study. Deep spectroscopy of two of the candidates covering 0.64-1.02um with Keck-DEIMOS and all three covering 0.94-1.10um and 1.52-1.80um with Keck-NIRSPEC detects weak spectral features tentatively identified as Ly-alpha at z=6.95 and z=7.69 in two of the objects. The third object is placed at z~1.6 based on a 24um and weak optical detection. A comparison with the spectral energy distributions …

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Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, Masami Ouchi, Bahram Mobasher, Kazuhiro Shimasaku, Henry C. Ferguson, S. Michael Fall, Yoshiaki Ono, Nobunari Kashikawa, Tomoki Morokuma, Kimihiko Nakajima, Sadanori Okamura, Mark Dickinson, Mauro Giavalisco, Kouji Ohta Jan 2009

Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, Masami Ouchi, Bahram Mobasher, Kazuhiro Shimasaku, Henry C. Ferguson, S. Michael Fall, Yoshiaki Ono, Nobunari Kashikawa, Tomoki Morokuma, Kimihiko Nakajima, Sadanori Okamura, Mark Dickinson, Mauro Giavalisco, Kouji Ohta

Mauro Giavalisco

We present results of our large-area survey for z'-band dropout galaxies at z=7 in a 1568 arcmin^2 sky area covering the SDF and GOODS-N fields. Combining our ultra-deep Subaru/Suprime-Cam z'- and y-band (lambda_eff=1um) images with legacy data of Subaru and HST, we have identified 22 bright z-dropout galaxies down to y=26, one of which has a spectroscopic redshift of z=6.96 determined from Lya emission. The z=7 luminosity function (LF) yields the best-fit Schechter parameters of phi*=0.69 +2.62/-0.55 x10^(-3) Mpc^(-3), Muv*=-20.10 +/-0.76 mag, and alpha=-1.72 +/-0.65, and indicates a decrease from z=6 at a >95% confidence level. This decrease is beyond …

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The Morphology Of Passively Evolving Galaxies At Z ~ 2 From Hst/Wfc3 Deep Imaging In The Hubble Ultradeep Field, P. Cassata, Mauro Giavalisco, Yicheng Guo, H. Ferguson, A. Koekemoer, A. Renzini, A. Fontana, S. Salimbeni, M. Dickinson, S. Casertano, C. J. Conselice, N. Grogin, J. M. Lotz, C. Papovich, R. A. Lucas, A. Straughn, Jonathan P. Gardner, L. Moustakas Jan 2009

The Morphology Of Passively Evolving Galaxies At Z ~ 2 From Hst/Wfc3 Deep Imaging In The Hubble Ultradeep Field, P. Cassata, Mauro Giavalisco, Yicheng Guo, H. Ferguson, A. Koekemoer, A. Renzini, A. Fontana, S. Salimbeni, M. Dickinson, S. Casertano, C. J. Conselice, N. Grogin, J. M. Lotz, C. Papovich, R. A. Lucas, A. Straughn, Jonathan P. Gardner, L. Moustakas

Mauro Giavalisco

We present near-IR images, obtained with the Hubble Space Telescope (HST) and the WFC3/IR camera, of six passive and massive galaxies at redshift 1.3

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Photometric Properties Of Ly Alpha Emitters At Z=4.86 In The Cosmos 2 Square Degree Field, Y. Shioya, Y. Taniguchi, S. S. Sasaki, T. Nagao, T. Murayama, T. Saito, Y. Ideue, A. Nakajima, K. L. Matsuoka, J. Trump, N. Z. Scoville, D. B. Sanders, B. Mobasher, H. Aussel, P. Capak, J. Kartaltepe, A. Koekemoer, C. Carilli, R. S. Ellis, B. Garilli, Mauro Giavalisco, M. G. Kitzbichler, C. Impey, O. Lefevre, E. Schinnerer, V. Smolcic Jan 2009

Photometric Properties Of Ly Alpha Emitters At Z=4.86 In The Cosmos 2 Square Degree Field, Y. Shioya, Y. Taniguchi, S. S. Sasaki, T. Nagao, T. Murayama, T. Saito, Y. Ideue, A. Nakajima, K. L. Matsuoka, J. Trump, N. Z. Scoville, D. B. Sanders, B. Mobasher, H. Aussel, P. Capak, J. Kartaltepe, A. Koekemoer, C. Carilli, R. S. Ellis, B. Garilli, Mauro Giavalisco, M. G. Kitzbichler, C. Impey, O. Lefevre, E. Schinnerer, V. Smolcic

Mauro Giavalisco

We present results of a survey for Ly alpha emitters at z=4.86 based on optical narrowband (lambda_c=7126 angstrom, Delta lambda=73 angstrom) and broadband (B, V, r', i', and z') observations of the Cosmic Evolution Survey (COSMOS) field using Suprime-Cam on the Subaru Telescope. We find 79 LAE candidates at z=4.86 over a contiguous survey area of 1.83 deg^2, down to the Ly alpha line flux of 1.47 x 10^-17 ergs s^-1 cm^-2. We obtain the Ly alpha luminosity function with a best-fit Schechter parameters of log L^*=42.9^+0.5_-0.3 ergs s^-1 and phi^* = 1.2^+8.0_-1.1 x 10^-4 Mpc^-3 for alpha=-1.5 (fixed). The …

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The Udf05 Follow-Up Of The Hubble Ultra Deep Field. Iii. The Luminosity Function At Z~6, Jian Su, Massimo Stiavelli, Pascal Oesch, Michele Trenti, Eddie Bergeron, Larry Bradley, Marcella Carollo, Tomas Dahlen, Henry C. Ferguson, Mauro Giavalisco, Anton Koekemoer, Simon Lilly, Ray A. Lucas, Bahram Mobasher, Nino Panagia, Cheryl Pavlovsky Jan 2009

The Udf05 Follow-Up Of The Hubble Ultra Deep Field. Iii. The Luminosity Function At Z~6, Jian Su, Massimo Stiavelli, Pascal Oesch, Michele Trenti, Eddie Bergeron, Larry Bradley, Marcella Carollo, Tomas Dahlen, Henry C. Ferguson, Mauro Giavalisco, Anton Koekemoer, Simon Lilly, Ray A. Lucas, Bahram Mobasher, Nino Panagia, Cheryl Pavlovsky

Mauro Giavalisco

In this paper, we present a derivation of the rest-frame 1400A luminosity function (LF) at redshift six from a new application of the maximum likelihood method by exploring the five deepest HST/ACS fields, i.e., the HUDF, two UDF05 fields, and two GOODS fields. We work on the latest improved data products, which makes our results more robust than those of previous studies. We use un-binned data and thereby make optimal use of the information contained in the dataset. We focus on the analysis to a magnitude limit where the completeness is larger than 50% to avoid possibly large errors in …

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Candels: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey, Norman A. Grogin, Dale D. Kocevski, S. M. Faber, Henry C. Ferguson, Anton M. Koekemoer, Adam G. Riess, Viviana Acquaviva, David M. Alexander, Omar Almaini, Matthew L. N. Ashby, Marco Barden, Eric F. Bell, Frédéric Bournaud, Thomas M. Brown, Karina I. Caputi, Stefano Casertano, Paolo Cassata, Marco Castellano, Peter Challis, Ranga-Ram Chary, Edmond Cheung, Michele Cirasuolo, Christopher J. Conselice, Asantha Roshan Cooray, Darren J. Croton, Emanuele Daddi, Tomas Dahlen, Romeel Davé, Duília F. De Mello, Avishai Dekel, Mark Dickinson, Timothy Dolch, Jennifer L. Donley, James S. Dunlop, Aaron A. Dutton, David Elbaz, Giovanni G. Fazio, Alexei V. Filippenko, Steven L. Finkelstein, Adriano Fontana, Jonathan P. Gardner, Peter M. Garnavich, Eric Gawiser, Mauro Giavalisco, Andrea Grazian, Yicheng Guo, Nimish P. Hathi, Boris Häussler, Philip F. Hopkins, Jia-Sheng Huang, Kuang-Han Huang, Saurabh W. Jha, Jeyhan S. Kartaltepe, Robert P. Kirshner, David C. Koo, Kamson Lai, Kyoung-Soo Lee, Weidong Li, Jennifer M. Lotz, Ray A. Lucas, Piero Madau, Patrick J. Mccarthy, Elizabeth J. Mcgrath, Daniel H. Mcintosh, Ross J. Mclure, Bahram Mobasher, Leonidas A. Moustakas, Mark Mozena, Kirpal Nandra, Jeffrey A. Newman, Sami-Matias Niemi, Kai G. Noeske, Casey J. Papovich, Laura Pentericci, Alexandra Pope, Joel R. Primack, Abhijith Rajan, Swara Ravindranath, Naveen A. Reddy, Alvio Renzini, Hans-Walter Rix, Aday R. Robaina, Steven A. Rodney, David J. Rosario, Piero Rosati, Sara Salimbeni, Claudia Scarlata, Brian Siana, Luc Simard, Joseph Smidt, Rachel S. Somerville, Hyron Spinrad, Amber N. Straughn, Louis-Gregory Strolger, Olivia Telford, Harry I. Teplitz, Jonathan R. Trump, Arjen Van Der Wel, Carolin Villforth, Risa H. Wechsler, Benjamin J. Weiner, Tommy Wiklind, Vivienne Wild, Grant Wilson, Stijn Wuyts, Hao-Jing Yan, Min S. Yun Jan 2009

Candels: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey, Norman A. Grogin, Dale D. Kocevski, S. M. Faber, Henry C. Ferguson, Anton M. Koekemoer, Adam G. Riess, Viviana Acquaviva, David M. Alexander, Omar Almaini, Matthew L. N. Ashby, Marco Barden, Eric F. Bell, Frédéric Bournaud, Thomas M. Brown, Karina I. Caputi, Stefano Casertano, Paolo Cassata, Marco Castellano, Peter Challis, Ranga-Ram Chary, Edmond Cheung, Michele Cirasuolo, Christopher J. Conselice, Asantha Roshan Cooray, Darren J. Croton, Emanuele Daddi, Tomas Dahlen, Romeel Davé, Duília F. De Mello, Avishai Dekel, Mark Dickinson, Timothy Dolch, Jennifer L. Donley, James S. Dunlop, Aaron A. Dutton, David Elbaz, Giovanni G. Fazio, Alexei V. Filippenko, Steven L. Finkelstein, Adriano Fontana, Jonathan P. Gardner, Peter M. Garnavich, Eric Gawiser, Mauro Giavalisco, Andrea Grazian, Yicheng Guo, Nimish P. Hathi, Boris Häussler, Philip F. Hopkins, Jia-Sheng Huang, Kuang-Han Huang, Saurabh W. Jha, Jeyhan S. Kartaltepe, Robert P. Kirshner, David C. Koo, Kamson Lai, Kyoung-Soo Lee, Weidong Li, Jennifer M. Lotz, Ray A. Lucas, Piero Madau, Patrick J. Mccarthy, Elizabeth J. Mcgrath, Daniel H. Mcintosh, Ross J. Mclure, Bahram Mobasher, Leonidas A. Moustakas, Mark Mozena, Kirpal Nandra, Jeffrey A. Newman, Sami-Matias Niemi, Kai G. Noeske, Casey J. Papovich, Laura Pentericci, Alexandra Pope, Joel R. Primack, Abhijith Rajan, Swara Ravindranath, Naveen A. Reddy, Alvio Renzini, Hans-Walter Rix, Aday R. Robaina, Steven A. Rodney, David J. Rosario, Piero Rosati, Sara Salimbeni, Claudia Scarlata, Brian Siana, Luc Simard, Joseph Smidt, Rachel S. Somerville, Hyron Spinrad, Amber N. Straughn, Louis-Gregory Strolger, Olivia Telford, Harry I. Teplitz, Jonathan R. Trump, Arjen Van Der Wel, Carolin Villforth, Risa H. Wechsler, Benjamin J. Weiner, Tommy Wiklind, Vivienne Wild, Grant Wilson, Stijn Wuyts, Hao-Jing Yan, Min S. Yun

Mauro Giavalisco

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8--1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z>1.5 to test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to …

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The Evolution Of The Galaxy Rest-Frame Ultraviolet Luminosity Function Over The First Two Billion Years, Steven L. Finkelstein, Russell E. Ryan Jr., Casey Papovich, Mark Dickinson, Mimi Song, Rachel Somerville, Herny C. Ferguson, Brett Salmon, Mauro Giavalisco, Anton M. Koekemoer, Matthew L. N. Ashby, Peter Behroozi, Marco Castellano, James S. Dunlop, Sandy M. Faber, Giovanni G. Fazio, Adriano Fontana, Norman A. Grogin, Nimish Hathi, Jason Jaacks, Dale D. Kocevski, Rachel Livermore, Ross J. Mclure, Emiliano Merlin, Bahram Mobasher, Jeffrey A. Newman, Marc Rafelski, Vithal Tilvi, S.P. Willner Jan 2009

The Evolution Of The Galaxy Rest-Frame Ultraviolet Luminosity Function Over The First Two Billion Years, Steven L. Finkelstein, Russell E. Ryan Jr., Casey Papovich, Mark Dickinson, Mimi Song, Rachel Somerville, Herny C. Ferguson, Brett Salmon, Mauro Giavalisco, Anton M. Koekemoer, Matthew L. N. Ashby, Peter Behroozi, Marco Castellano, James S. Dunlop, Sandy M. Faber, Giovanni G. Fazio, Adriano Fontana, Norman A. Grogin, Nimish Hathi, Jason Jaacks, Dale D. Kocevski, Rachel Livermore, Ross J. Mclure, Emiliano Merlin, Bahram Mobasher, Jeffrey A. Newman, Marc Rafelski, Vithal Tilvi, S.P. Willner

Mauro Giavalisco

No abstract provided.

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Accessibility Of Cylindrical Channels Within Patterned Mesoporous Silica Films Using Nanoparticle Diffusion, Ht Chen, Ta Crosby, Mh Park, S Nagarajan, Vm Rotello, Jj Watkins Jan 2009

Accessibility Of Cylindrical Channels Within Patterned Mesoporous Silica Films Using Nanoparticle Diffusion, Ht Chen, Ta Crosby, Mh Park, S Nagarajan, Vm Rotello, Jj Watkins

Vincent Rotello

Mesoporous silica films with well ordered nanochannels (approximately 7 nm in diameter) oriented parallel to the substrate were synthesized using supercritical carbon dioxide mediated silica deposition within templates comprised of triblock copolymers blended with strongly associating homopolymers. The films were patterned at the device level by conventional lithography and etched to yield periodic circular features approximately 20 µm in diameter. The nanoscale channels remained accessible to penetrant diffusion as shown by dye uptake experiments. The nanochannel arrays were used as miniature size exclusion columns to mediate nanoparticle diffusion.

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Advanced Technology Large-Aperture Space Telescope (Atlast): A Technology Roadmap For The Next Decade, Vic Argabright, Bill Arnold, David Aronstein, Paul Atcheson, Morley Blouke, Tom Brown, Daniela Calzetti, Webster Cash, Mark Clampin, Dave Content, Dean Dailey, Rolf Danner, Rodger Doxsey, Dennis Ebbets, Peter Eisenhardt, Lee Feinberg, Andrew Fruchter, Mauro Giavalisco, Tiffany Glassman, Qian Gong, James Green, John Grunsfeld, Ted Gull, Greg Hickey, Randall Hopkins, John Hraba, Tupper Hyde, Ian Jordan, Jeremy Kasdin, Steve Kendrick, Steve Kilston, Anton Koekemoer, Bob Korechoff, John Krist, John Mather, Chuck Lillie, Amy Lo, Rick Lyon, Peter Mccullough, Gary Mosier, Matt Mountain, Bill Oegerle, Bert Pasquale, Lloyd Purves, Cecelia Penera, Ron Polidan, Dave Redding, Kailash Sahu, Babak Saif, Ken Sembach, Mike Shull, Scott Smith, George Sonneborn, David Spergel, Phil Stahl, Karl Stapelfeldt, Harley Thronson, Gary Thronton, Jackie Townsend, Wesley Traub, Steve Unwin, Jeff Valenti, Robert Vanderbei, Michael Werner, Richard Wesenberg, Jennifer Wiseman, Bruce Woodgate Jan 2009

Advanced Technology Large-Aperture Space Telescope (Atlast): A Technology Roadmap For The Next Decade, Vic Argabright, Bill Arnold, David Aronstein, Paul Atcheson, Morley Blouke, Tom Brown, Daniela Calzetti, Webster Cash, Mark Clampin, Dave Content, Dean Dailey, Rolf Danner, Rodger Doxsey, Dennis Ebbets, Peter Eisenhardt, Lee Feinberg, Andrew Fruchter, Mauro Giavalisco, Tiffany Glassman, Qian Gong, James Green, John Grunsfeld, Ted Gull, Greg Hickey, Randall Hopkins, John Hraba, Tupper Hyde, Ian Jordan, Jeremy Kasdin, Steve Kendrick, Steve Kilston, Anton Koekemoer, Bob Korechoff, John Krist, John Mather, Chuck Lillie, Amy Lo, Rick Lyon, Peter Mccullough, Gary Mosier, Matt Mountain, Bill Oegerle, Bert Pasquale, Lloyd Purves, Cecelia Penera, Ron Polidan, Dave Redding, Kailash Sahu, Babak Saif, Ken Sembach, Mike Shull, Scott Smith, George Sonneborn, David Spergel, Phil Stahl, Karl Stapelfeldt, Harley Thronson, Gary Thronton, Jackie Townsend, Wesley Traub, Steve Unwin, Jeff Valenti, Robert Vanderbei, Michael Werner, Richard Wesenberg, Jennifer Wiseman, Bruce Woodgate

Mauro Giavalisco

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a set of mission concepts for the next generation of UVOIR space observatory with a primary aperture diameter in the 8-m to 16-m range that will allow us to perform some of the most challenging observations to answer some of our most compelling questions, including "Is there life elsewhere in the Galaxy?" We have identified two different telescope architectures, but with similar optical designs, that span the range in viable technologies. The architectures are a telescope with a monolithic primary mirror and two variations of a telescope with a large segmented primary …

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