Open Access. Powered by Scholars. Published by Universities.®

Astrophysics and Astronomy Commons™

Open Access. Powered by Scholars. Published by Universities.®

2011

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 331 - 354 of 354

Full-Text Articles in Astrophysics and Astronomy

Why Is An Einstein Ring Blue?, Jonathan Blackledge Jan 2011

Why Is An Einstein Ring Blue?, Jonathan Blackledge

Articles

Albert Einstein predicted the existence of `Einstein rings' as a consequence of his general theory of relativity. The phenomenon is a direct result of the idea that if a mass warps space-time then light (and other electromagnetic waves) will be `lensed' by the strong gravitational field produced by a large cosmological body such as a galaxy. Since 1998, when the first complete Einstein ring was observed, many more complete or partially complete Einstein rings have been observed in the radio and infrared spectra, for example, and by the Hubble Space Telescope in the optical spectrum. However, in the latter case, …

Go to article

Grb071028b, A Burst Behind Large Amounts Of Dust In An Unabsorbed Galaxy, C. Clemens, J. Greiner, T. Krühler, D. Pierini, S. Savaglio, S. Klose, P.M.J. Afonso, R. Filgas, F.E. Olivares, A. Rau, P. Schady, A. Rossi, A. Küpcü Yoldas, Adria Updike, A. Yoldas Jan 2011

Grb071028b, A Burst Behind Large Amounts Of Dust In An Unabsorbed Galaxy, C. Clemens, J. Greiner, T. Krühler, D. Pierini, S. Savaglio, S. Klose, P.M.J. Afonso, R. Filgas, F.E. Olivares, A. Rau, P. Schady, A. Rossi, A. Küpcü Yoldas, Adria Updike, A. Yoldas

Arts & Sciences Faculty Publications

No abstract provided.

Go to article

Grb 091127: The Cooling Break Race On Magnetic Fuel, R. Filgas, J. Greiner, P. Schady, T. Krühler, Adria Updike, S. Klose, M. Nardini, D.A. Kann, A. Rossi, V. Sudilovsky, P.M.J. Afonso, C. Clemens, J. Elliott, A. Nicuesa Guelbenzu, F. Olivares E., A. Rau Jan 2011

Grb 091127: The Cooling Break Race On Magnetic Fuel, R. Filgas, J. Greiner, P. Schady, T. Krühler, Adria Updike, S. Klose, M. Nardini, D.A. Kann, A. Rossi, V. Sudilovsky, P.M.J. Afonso, C. Clemens, J. Elliott, A. Nicuesa Guelbenzu, F. Olivares E., A. Rau

Arts & Sciences Faculty Publications

No abstract provided.

Go to article

On The Nature Of The Extremely Fast Optical Rebrightening Of The Afterglow Of Grb 081029, M. Nardini, J. Greiner, T. Krühler, R. Filgas, S. Klose, P. Afonso, C. Clemens, A. N. Guelbenzu, F. Olivares E., A. Rau, A. Rossi, Adria Updike, A. Küpcü Yoldas, A. Yoldas, D. Burlon, J. Elliott, D. A. Kann Jan 2011

On The Nature Of The Extremely Fast Optical Rebrightening Of The Afterglow Of Grb 081029, M. Nardini, J. Greiner, T. Krühler, R. Filgas, S. Klose, P. Afonso, C. Clemens, A. N. Guelbenzu, F. Olivares E., A. Rau, A. Rossi, Adria Updike, A. Küpcü Yoldas, A. Yoldas, D. Burlon, J. Elliott, D. A. Kann

Arts & Sciences Faculty Publications

Context. After the launch of the Swift satellite, the gamma-ray burst (GRB) optical light-curve smoothness paradigm has been questioned thanks to the faster and better sampled optical follow-up, which has unveiled a very complex behaviour. This complexity is triggering the interest of the whole GRB community. The GROND multi-channel imager is used to study optical and near-infrared (NIR) afterglows of GRBs with unprecedented optical and near-infrared temporal and spectral resolution. The GRB 081029 has a very prominent optical rebrightening event and is an outstanding example of the application of the multi-channel imager to GRB afterglows. Aims. Here we exploit the …

Go to article

Photometric Redshifts For Gamma-Ray Burst Afterglows From Grond And Swift/Uvot, T. Krühler, P. Schady, J. Greiner, P. Afonso, E. Bottacini, C. Clemens, R. Filgas, S. Klose, T. S. Koch, A. Küpcü-Yoldas, S. R. Oates, F. Olivares E., M. J. Page, S. Mcbreen, M. Nardini, A. Nicuesa Guelbenzu, A. Rau, P. W.A. Roming, A. Rossi, Adria Updike, A. Yoldas Jan 2011

Photometric Redshifts For Gamma-Ray Burst Afterglows From Grond And Swift/Uvot, T. Krühler, P. Schady, J. Greiner, P. Afonso, E. Bottacini, C. Clemens, R. Filgas, S. Klose, T. S. Koch, A. Küpcü-Yoldas, S. R. Oates, F. Olivares E., M. J. Page, S. Mcbreen, M. Nardini, A. Nicuesa Guelbenzu, A. Rau, P. W.A. Roming, A. Rossi, Adria Updike, A. Yoldas

Arts & Sciences Faculty Publications

No abstract provided.

Go to article

The Seds And Host Galaxies Of The Dustiest Grb Afterglows, T. Krühler, J. Greiner, P. Schady, S. Savaglio, P. M.J. Afonso, C. Clemens, J. Elliott, R. Filgas, D. Gruber, D. A. Kann, S. Klose, A. Küpcü-Yoldas, S. Mcbreen, F. Olivares, D. Pierini, A. Rau, A. Rossi, M. Nardini, A. Nicuesa Guelbenzu, V. Sudilovsky, Adria Updike Jan 2011

The Seds And Host Galaxies Of The Dustiest Grb Afterglows, T. Krühler, J. Greiner, P. Schady, S. Savaglio, P. M.J. Afonso, C. Clemens, J. Elliott, R. Filgas, D. Gruber, D. A. Kann, S. Klose, A. Küpcü-Yoldas, S. Mcbreen, F. Olivares, D. Pierini, A. Rau, A. Rossi, M. Nardini, A. Nicuesa Guelbenzu, V. Sudilovsky, Adria Updike

Arts & Sciences Faculty Publications

No abstract provided.

Go to article

Spitzer 24Μm Survey For Dust Disks Around Hot White Dwarfs, You-Hua Chu, Kate Y.L. Su, Jana Bilikova, Robert A. Gruendl, Orsola De Marco, Martin A. Guerrero, Adria Updike, Kevin Volk, Thomas Rauch Jan 2011

Spitzer 24Μm Survey For Dust Disks Around Hot White Dwarfs, You-Hua Chu, Kate Y.L. Su, Jana Bilikova, Robert A. Gruendl, Orsola De Marco, Martin A. Guerrero, Adria Updike, Kevin Volk, Thomas Rauch

Arts & Sciences Faculty Publications

No abstract provided.

Go to article

Precise Measurements Of Beam Spin Asymmetries In Semi-Inclusive Π0 Production, M. Aghasyan, H. Avakian, P. Rossi, E. De Sanctis, D. Hasch, M. Mirazita, D. Adikaram, M. J. Amaryan, M. Anghinolfi, H. Baghdasaryan, R. P. Bennett, S. Bültmann, G. E. Dodge, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, L. B. Weinstein Jan 2011

Precise Measurements Of Beam Spin Asymmetries In Semi-Inclusive Π0 Production, M. Aghasyan, H. Avakian, P. Rossi, E. De Sanctis, D. Hasch, M. Mirazita, D. Adikaram, M. J. Amaryan, M. Anghinolfi, H. Baghdasaryan, R. P. Bennett, S. Bültmann, G. E. Dodge, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, L. B. Weinstein

Physics Faculty Publications

We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sin phi(h) amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle φh of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations. (C) 2011 Elsevier B.V.

Go to article

Evolution Of The Differential Transverse Momentum Correlation Function With Centrality In Au + Au Collisions At √Snn = 200 Gev, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, B. D. Anderson, C. D. Anson, D. Arhipkin, G. S. Averichev, S. Bültmann, D. Plyku Jan 2011

Evolution Of The Differential Transverse Momentum Correlation Function With Centrality In Au + Au Collisions At √Snn = 200 Gev, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, B. D. Anderson, C. D. Anson, D. Arhipkin, G. S. Averichev, S. Bültmann, D. Plyku

Physics Faculty Publications

We present first measurements of the evolution of the differential transverse momentum correlation function, C, with collision centrality in Au + Au interactions at √sNN = 200 GeV. This observable exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of C with increasing centrality to estimate the ratio of the shear viscosity to entropy density, η / s , of the matter formed in central Au + Au interactions. We obtain an upper limit estimate of η / s …

Go to article

Photon Impact Factor In The Next-To-Leading Order, Ian Balitsky, Giovanni A. Chirilli Jan 2011

Photon Impact Factor In The Next-To-Leading Order, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

An analytic coordinate-space expression for the next-to-leading order photon impact factor for small-x deep inelastic scattering is calculated using the operator expansion in Wilson lines.

Go to article

Ultra-Sensitive High-Precision Spectroscopy Of A Fast Molecular Ion Beam, A. Mills, B. Stiller, M. Porambo, Manori Perera, H. Kreckel, B. Mccall Jan 2011

Ultra-Sensitive High-Precision Spectroscopy Of A Fast Molecular Ion Beam, A. Mills, B. Stiller, M. Porambo, Manori Perera, H. Kreckel, B. Mccall

Scholarship

Direct spectroscopy of a fast molecular ion beam offers many advantages over competing techniques, including the generality of the approach to any molecular ion, the complete elimination of spectral confusion due to neutral molecules, and the mass identification of individual spectral lines. The major challenge is the intrinsic weakness of absorption or dispersion signals resulting from the relatively low number density of ions in the beam. Direct spectroscopy of an ion beam was pioneered by Saykally and co-workers in the late 1980s, but has not been attempted since that time. Here, we present the design and construction of an ion …

Go to article

The Core Collapse Supernova Rate In The Sdss-Ii Supernova Survey, Matthew Frederick Taylor Jan 2011

The Core Collapse Supernova Rate In The Sdss-Ii Supernova Survey, Matthew Frederick Taylor

Wayne State University Dissertations

The Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN), though designed as a type Ia supernova search for cosmology, also discovered a large sample of core collapse supernovae (CCSN). I use the SDSS-II SN data to measure the volumetric CCSN rate in the redshift range (0.03 < z < 0.09), finding a volume-averaged rate of 0.98±0.18 ×10⊃−4⊃h⊂70⊂⊃3⊃yr⊃−1⊃Mpc⊃−3⊃. The CCSN luminosity function is also extracted from the data, and its implications on the cosmic star formation history are considered.

Go to article

Two-Body Photodisintegration Of 3he Between 7 And 16 Mev, W. Tornow, H. J. Karwowski, J. H. Kelley, R. Raut, G. Rusev, S. C. Stave, A. P. Tonchev, A. Deltuva, A. C. Fonseca, L. E. Marcucci, R. Schiavilla Jan 2011

Two-Body Photodisintegration Of 3he Between 7 And 16 Mev, W. Tornow, H. J. Karwowski, J. H. Kelley, R. Raut, G. Rusev, S. C. Stave, A. P. Tonchev, A. Deltuva, A. C. Fonseca, L. E. Marcucci, R. Schiavilla

Physics Faculty Publications

A comprehensive data set is reported for the two-body photodisintegration cross section of 3He using mono-energetic photon beams at eleven energies between 7.0 and 16.0 MeV. A 3He + Xe high-pressure gas scintillator served as target and detector. Although our data are in much better agreement with our state-of-the-art theoretical calculations than the majority of the previous data, these calculations underpredict the new data by about 10%. This disagreement suggests an incomplete understanding of the dynamics of the three-nucleon system and its response to electromagnetic probes.

Go to article

Using Observations Of Distant Quasars To Constrain Quantum Gravity, Eric S. Perlman, Yeejack Ng, David J.E. Floyd, Wayne A. Christiansen Jan 2011

Using Observations Of Distant Quasars To Constrain Quantum Gravity, Eric S. Perlman, Yeejack Ng, David J.E. Floyd, Wayne A. Christiansen

Aerospace, Physics, and Space Science Faculty Publications

Aims. The small-scale nature of spacetime can be tested with observations of distant quasars. We comment on a recent paper by Tamburini et al. (2011, A&A, 533, A71) which claims that Hubble Space Telescope (HST) observations of the most distant quasars place severe constraints on models of foamy spacetime. Methods. If space is foamy on the Planck scale, photons emitted from distant objects will accumulate uncertainties in distance and propagation directions thus affecting the expected angular size of a compact object as a function of redshift. We discuss the geometry of foamy spacetime, and the appropriate distance measure for calculating …

Go to article

The Period And Amplitude Changes In The Coolest Gw Virginis Variable Star (Pg 1159-Type) Pg 0122+200, Gérard P. Vauclair, Jianning Fu, Jan Erik Solheim, Seunglee Kim, Noël Dolez, M Chevreton, Li Chen, Matt A. Wood, Isaac M. Silver, Zs Bognár, Margit Paparó, Alejandro H. Córsico Jan 2011

The Period And Amplitude Changes In The Coolest Gw Virginis Variable Star (Pg 1159-Type) Pg 0122+200, Gérard P. Vauclair, Jianning Fu, Jan Erik Solheim, Seunglee Kim, Noël Dolez, M Chevreton, Li Chen, Matt A. Wood, Isaac M. Silver, Zs Bognár, Margit Paparó, Alejandro H. Córsico

Aerospace, Physics, and Space Science Faculty Publications

Context: The PG 1159 pre-white dwarf stars experiment a rapidly cooling phase with a time scale of a few 106 years. Theoretical models predict that the neutrinos produced in their core should play a dominant role in the cooling, mainly at the cool end of the PG 1159 sequence. Measuring the evolutionary time scale of the coolest PG 1159 stars could offer a unique opportunity to empirically constrain the neutrino emission rate. Aims. A subgroup of the PG 1159 stars are nonradial pulsators, the GW Vir type of variable stars. They exhibit g-mode pulsations with periods of a few hundred …

Go to article

The Increasing Rotation Period Of Comet 10p/Tempel 2, Matthew M. Knight, Tony L. Farnham, David G. Schleicher, Edward W. Schwieterman Jan 2011

The Increasing Rotation Period Of Comet 10p/Tempel 2, Matthew M. Knight, Tony L. Farnham, David G. Schleicher, Edward W. Schwieterman

Aerospace, Physics, and Space Science Faculty Publications

We imaged comet 10P/Tempel 2 on 32 nights from 1999 April through 2000 March. R-band light curves were obtained on 11 of these nights from 1999 April through 1999 June, prior to both the onset of significant coma activity and perihelion. Phasing of the data yields a double-peaked light curve and indicates a nucleus rotational period of 8.941 ± 0.002 hr with a peak-to-peak amplitude of ∼0.75 mag. Our data are sufficient to rule out all other possible double-peaked solutions as well as the single- and triple-peaked solutions. This rotation period agrees with one of five possible solutions found in …

Go to article

Suppression Of Away-Side Jet Fragments With Respect To The Reaction Plane In Au + Au Collisions At √Snn=200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Szabolcs Rembeczki, Marcus Hohlmann Jan 2011

Suppression Of Away-Side Jet Fragments With Respect To The Reaction Plane In Au + Au Collisions At √Snn=200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Szabolcs Rembeczki, Marcus Hohlmann

Aerospace, Physics, and Space Science Faculty Publications

Pair correlations between large transverse momentum neutral pion triggers (pT=4 - 7 GeV/c) and charged hadron partners (pT=3 - 7 GeV/c) in central (0%-20%) and midcentral (20%-60%) Au+Au collisions at √sNN=200 GeV are presented as a function of trigger orientation with respect to the reaction plane. The particles are at larger momentum than where jet shape modifications have been observed, and the correlations are sensitive to the energy loss of partons traveling through hot dense matter. An out-of-plane trigger particle produces only 26±20% of the away-side pairs that are observed opposite of an in-plane trigger particle for midcentral (20%-60%) collisions. …

Go to article

Suppression Of Away-Side Jet Fragments With Respect To The Reaction Plane In Au + Au Collisions At √Snn=200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Szabolcs Rembeczki, Marcus Hohlmann, Phenix Collaboration Jan 2011

Suppression Of Away-Side Jet Fragments With Respect To The Reaction Plane In Au + Au Collisions At √Snn=200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Szabolcs Rembeczki, Marcus Hohlmann, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

Pair correlations between large transverse momentum neutral pion triggers (pT=4 - 7 GeV/c) and charged hadron partners (pT=3 - 7 GeV/c) in central (0%-20%) and midcentral (20%-60%) Au+Au collisions at √sNN=200 GeV are presented as a function of trigger orientation with respect to the reaction plane. The particles are at larger momentum than where jet shape modifications have been observed, and the correlations are sensitive to the energy loss of partons traveling through hot dense matter. An out-of-plane trigger particle produces only 26±20% of the away-side pairs that are observed opposite of an in-plane trigger particle for midcentral (20%-60%) collisions. …

Go to article

Physical Conditions In A Galactic Star Forming Region W22, Akshaya Rane Jan 2011

Physical Conditions In A Galactic Star Forming Region W22, Akshaya Rane

University of Kentucky Master's Theses

This document describes study of an active star forming region in our galaxy (the Milky Way) known as W22. Physical conditions in these regions can help us in understanding star formation processes in the universe and hence the structure and evolution of the universe. Zeeman effect measurements in 18 cm OH absorption line were carried out in order to estimate the line of sight magnetic field strength in the molecular cloud associated with this star forming region. Other physical parameters such as hydrogen column density, optical depth, critical magnetic field were also determined from these measurements. The region was mapped …

Go to article

Teaching Introductory Undergraduate Physics Using Commercial Video Games, Soumya Mohanty, Sergio Cantu Jan 2011

Teaching Introductory Undergraduate Physics Using Commercial Video Games, Soumya Mohanty, Sergio Cantu

Physics & Astronomy Faculty Publications

Commercial video games are increasingly using sophisticated physics simulations to create a more immersive experience for players. This also makes them a powerful tool for engaging students in learning physics. We provide some examples to show how commercial off-the-shelf games can be used to teach specific topics in introductory undergraduate physics. The examples are selected from a course taught predominantly through the medium of commercial video games.

Go to article

The Effects Of Seductive Details In An Inflatable Planetarium, Sean Gillette Jan 2011

The Effects Of Seductive Details In An Inflatable Planetarium, Sean Gillette

Walden Dissertations and Doctoral Studies

Astronomy is becoming a forgotten science, which is evident by its relatively low enrollment figures compared to biology, chemistry, and physics. A portable inflatable planetarium brings relevance back to astronomy and offers support to students and educators by simulating realistic astronomical environments. This study sought to determine if learning is improved in an inflatable planetarium by adhering to the design principles of the cognitive theory of multimedia learning (CTML), specifically the coherence principle, in an authentic classroom. Two groups of 5th grade students of similar ability were purposefully assigned using a 1-teacher-to-many-students format with mean lesson lengths of 34 minutes. …

Go to article

Balloon Borne Mars Research Platforms, Sean Michael Hancock Jan 2011

Balloon Borne Mars Research Platforms, Sean Michael Hancock

Mechanical & Aerospace Engineering Theses & Dissertations

Aerial platforms can fill a measurement gap between orbiters and rovers, providing planetary scale high resolution in situ measurements, access to scientifically interesting terrain that is either inaccessible or hazardous to rovers, and serve as a planet-wide delivery platforms to deploy surface probes and rovers to areas inaccessible given existing entry, descent, and landing systems. A permanent robotic outpost on the Martian surface can utilize locally-derived hydrogen as a lifting gas for balloon systems deployed from Mars. That approach can simplify the inflation and launch of aerial vehicles while allowing for a long duration deployment campaign that is not constrained …

Go to article

A Gravitational Wave Observatory Operating Beyond The Quantum Shot-Noise Limit, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, C. Adams, R. Adhikari, C. Affeldt, P. Ajith, B. Allen, G. S. Allen, E. Amador Ceron, D. Amariutei, R. S. Amin, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, S. Ballmer, D. Barker, B. Barr, P. Barriga, L. Barsotti, Tiffany Z. Summerscales Jan 2011

A Gravitational Wave Observatory Operating Beyond The Quantum Shot-Noise Limit, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, C. Adams, R. Adhikari, C. Affeldt, P. Ajith, B. Allen, G. S. Allen, E. Amador Ceron, D. Amariutei, R. S. Amin, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, S. Ballmer, D. Barker, B. Barr, P. Barriga, L. Barsotti, Tiffany Z. Summerscales

Faculty Publications

© 2011 Macmillan Publishers Limited. All rights reserved. Around the globe several observatories are seeking the first direct detection of gravitational waves (GWs). These waves are predicted by Einstein's general theory of relativity and are generated, for example, by black-hole binary systems. Present GW detectors are Michelson-type kilometre-scale laser interferometers measuring the distance changes between mirrors suspended in vacuum. The sensitivity of these detectors at frequencies above several hundred hertz is limited by the vacuum (zero-point) fluctuations of the electromagnetic field. A quantum technology - the injection of squeezed light - offers a solution to this problem. Here we demonstrate …

Go to article

Book Review: Exploring Mars: Chronicles From A Decade Of Discovery, T. D. Oswalt Jan 2011

Book Review: Exploring Mars: Chronicles From A Decade Of Discovery, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Exploring Mars : Chronicles from a Decade of Discovery by Scott Hubbard. Arizona, 2011 194p, 9780816521111 $45.00, 9780816528967 $17.95.

Go to article

First Prev