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Articles 1951 - 1980 of 2944

Full-Text Articles in Astrophysics and Astronomy

The Energy Source Of The Filaments Around The Giant Galaxy Ngc 1275, A. C. Fabian, J. S. Sanders, R. J. R. Williams, A. Lazarian, Gary J. Ferland, R. M. Johnstone Jan 2011

The Energy Source Of The Filaments Around The Giant Galaxy Ngc 1275, A. C. Fabian, J. S. Sanders, R. J. R. Williams, A. Lazarian, Gary J. Ferland, R. M. Johnstone

Physics and Astronomy Faculty Publications

The brightest galaxy in the nearby Perseus cluster, NGC 1275, is surrounded by a network of filaments. These were first observed through their Hα emission but are now known to have a large molecular component with a total mass approaching 1011 M⊙ of gas. The filaments are embedded in hot intracluster gas and stretch over 80 kpc. They have an unusually low excitation spectrum which is well modelled by collisional heating and ionization by secondary electrons. Here we note that the surface radiative flux from the outer filaments is close to the energy flux impacting on them from …

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Herschel Observations Of The Centaurus Oluster - The Dynamics Of Cold Gas In A Cool Core, R. Mittal, C. P. O'Dea, Gary J. Ferland, J. B. R. Oonk, A. C. Edge, R. E. A. Canning, H. Russell, S. A. Baum, H. Böhringer, F. Combes, M. Donahue, A. C. Fabian, N. A. Hatch, A. Hoffer, R. Johnstone, B. R. Mcnamara, P. Salomé, G. Tremblay Jan 2011

Herschel Observations Of The Centaurus Oluster - The Dynamics Of Cold Gas In A Cool Core, R. Mittal, C. P. O'Dea, Gary J. Ferland, J. B. R. Oonk, A. C. Edge, R. E. A. Canning, H. Russell, S. A. Baum, H. Böhringer, F. Combes, M. Donahue, A. C. Fabian, N. A. Hatch, A. Hoffer, R. Johnstone, B. R. Mcnamara, P. Salomé, G. Tremblay

Physics and Astronomy Faculty Publications

Brightest cluster galaxies (BCGs) in the cores of galaxy clusters have distinctly different properties from other low-redshift massive ellipticals. The majority of the BCGs in cool-core clusters show signs of active star formation. We present observations of NGC 4696, the BCG of the Centaurus galaxy cluster, at far-infrared (FIR) wavelengths with theHerschel space telescope. Using the PACS spectrometer, we detect the two strongest coolants of the interstellar medium, [C II] at 157.74 μm and [O I] at 63.18 μm, and in addition [N II] at 121.90 μm. The [C II] emission is extended over a region of 7 kpc …

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A Deep Spectroscopic Study Of The Filamentary Nebulosity In Ngc 4696, The Brightest Cluster Galaxy In The Centaurus Cluster, R. E. A. Canning, A. C. Fabian, R. M. Johnstone, J. S. Sanders, C. S. Crawford, Gary J. Ferland, N. A. Hatch Jan 2011

A Deep Spectroscopic Study Of The Filamentary Nebulosity In Ngc 4696, The Brightest Cluster Galaxy In The Centaurus Cluster, R. E. A. Canning, A. C. Fabian, R. M. Johnstone, J. S. Sanders, C. S. Crawford, Gary J. Ferland, N. A. Hatch

Physics and Astronomy Faculty Publications

We present results of deep integral-field spectroscopy observations using high-resolution optical (4150–7200 Å) VLT VIsible MultiObject Spectrograph spectra of NGC 4696, the dominant galaxy in the Centaurus cluster (Abell 3526). After the Virgo cluster, this is the second nearest (z= 0.0104) example of a cool-core cluster. NGC 4696 is surrounded by a vast, luminous Hα emission-line nebula (LHα= 2.2 × 1040 erg s−1). We explore the origin and excitation of the emission-line filaments and find their origin consistent with being drawn out, under rising radio bubbles, into the intracluster medium as in …

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Unidirectional Invisibility Induced By Pt-Symmetric Periodic Structures, Zin Lin, Hamidreza Ramezani Jan 2011

Unidirectional Invisibility Induced By Pt-Symmetric Periodic Structures, Zin Lin, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

Parity-time (PT) symmetric periodic structures, near the spontaneous PT-symmetry breaking point, can act as unidirectional invisible media. In this regime, the reflection from one end is diminished while it is enhanced from the other. Furthermore, the transmission coefficient and phase are indistinguishable from those expected in the absence of a grating. The phenomenon is robust even in the presence of Kerr nonlinearities, and it can also effectively suppress optical bistabilities.

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The Study Of Variability In Four Oxygen-Rich Proto-Planetary Nebulae, Kristie Shaw Jan 2011

The Study Of Variability In Four Oxygen-Rich Proto-Planetary Nebulae, Kristie Shaw

Symposium on Research and Creative Expression (SORCE)

This summer, I have been working on a project to study the variability of four proto-planetary nebulae. Proto-planetary nebulae (PPNe) are evolved stellar objects that are in the process of losing their outer layers and in transition from a red giant star to a planetary nebula. Oxygen-rich PPNe, specifically, have a higher oxygen content in their nebula than they do carbon, and this occurs mainly in lower mass stars. This project includes combining our data from the VU Observatory with other published data, analyzing light curves of brightness versus time and looking for patterns, and performing period analysis using a …

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Searching For Binary Stars In Planetary Nebulae Using The Isis Image Subtraction Software, Samantha Schwartz Jan 2011

Searching For Binary Stars In Planetary Nebulae Using The Isis Image Subtraction Software, Samantha Schwartz

Symposium on Research and Creative Expression (SORCE)

We explored the theory that binary central stars of planetary nebulae may be contributing factor in the formation of planetary nebulae. We searched for this photometric variability in central stars of planetary nebulae because consistent periodic variability is indicative of a close binary system. The variability of our targets was assessed with the image subtraction software, ISIS. We found that the central stars of the planetary nebulae Hen 2-84, NGC 6326, and K 1-22 showed clear variability. A preliminary light curve for Hen 2-84 showed periodic behavior, suggesting a binary system. Of the remaining targets observed, with sufficient data, five …

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Calibrating The Star Endcap Electromagnetic Calorimeter Using π-0'S, Benjamin Barber Jan 2011

Calibrating The Star Endcap Electromagnetic Calorimeter Using π-0'S, Benjamin Barber

Symposium on Research and Creative Expression (SORCE)

The STAR Endcap ElectroMagnetic Calorimeter (EEMC) is an important tool for identifying the particles produced in the forward direction of the STAR detector. These particles are used in the study of the proton's intrinsic angular momentum. Current calibrations of the EEMC have relied on the energy deposition of minimally ionizing particles (MIPs). To verify the MIP-based calibration, we are re-calibrating it using the energy deposition of the di-photon pairs created by Ï€-0 decays. Using the position and initial energy calibration of the two photon events, we can reconstruct the invariant mass of the parent particle. When this analysis is performed …

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Initial Studies Of The Forward Gem Tracker, Malorie Stowe, David Grosnik Jan 2011

Initial Studies Of The Forward Gem Tracker, Malorie Stowe, David Grosnik

Symposium on Research and Creative Expression (SORCE)

The spin of the proton is known to be produced by several constituents including quarks, antiquarks, and gluons. It has been the goal of STAR to measure the contribution of gluons and various sea quarks to the proton spin. The Forward GEM Tracker (FGT) is a newly constructed detector to be placed into STAR, which is located at the RHIC collider at Brookhaven National Laboratory. The FGT serves to track the position of forward going charged particles, produced in proton-proton collisions, as they travel towards the Endcap Electromagnetic Calorimeter (EEMC). This information will be critical in helping to determine the …

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Radon Concentration In Basements, Joel Rogers Jan 2011

Radon Concentration In Basements, Joel Rogers

Symposium on Research and Creative Expression (SORCE)

This summer I am studying radon gas concentrations in basements in the Valparaiso community area. Radon is known to be the second leading cause of lung cancer after smoking. After several years (more than twenty) of continuous radon inhalation, the human lungs can be impaired and can become cancerous. This study will help people be aware of a potential radon problem in their homes. The EPA recommends having a concentration of four picocuries per liter or less in each home. The experiment is performed by using an EPA approved radon testing apparatus that records the concentration each hour for up …

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A Mip-Based Energy Calibration Of The Star Endcap Electromagnetic Calorimeter, Zachary Nault Jan 2011

A Mip-Based Energy Calibration Of The Star Endcap Electromagnetic Calorimeter, Zachary Nault

Symposium on Research and Creative Expression (SORCE)

One of the main goals of the STAR Spin Collaboration is to understand the intrinsic angular momentum of the proton. An integral part of this experiment is the Endcap Electromagnetic Calorimeter (EEMC). The EEMC is used in detecting particles produced from hard proton-proton collisions that end up in the forward direction or 'end' of the experimental apparatus. In order to use properly the data collected, the energy and position measurements in the EEMC need to be well-known. To accomplish this, an energy calibration of the EEMC was performed using minimum ionizing particles (MIPs). The important property of MIPs utilized was …

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Verification Of Monte-Carlo Simulation For Star Endcap Electromagnetic Calorimeter, Kevin Miller Jan 2011

Verification Of Monte-Carlo Simulation For Star Endcap Electromagnetic Calorimeter, Kevin Miller

Symposium on Research and Creative Expression (SORCE)

The STAR experiment at Brookhaven National Laboratory seeks to measure the source of the protons spin, a fundamental property of matter. To accomplish this measurement, a simulation method called Monte-Carlo will be used to model the true detector responses to proton-proton collisions. My work is to confirm the accuracy of the Monte-Carlo simulation for the Endcap Electromagnetic Calorimeter (EEMC). By comparing histograms of fundamental parameters from the Monte-Carlo simulated data and true data from 2006 experimentation, we will be able to test the simulations accuracy. When validated, the Monte-Carlo simulation will be used to achieve a greater understanding of the …

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The Reduction And Reporting Of Data On Proto-Planetary Nebulae From Two Observatories, Wesley Cheek Jan 2011

The Reduction And Reporting Of Data On Proto-Planetary Nebulae From Two Observatories, Wesley Cheek

Symposium on Research and Creative Expression (SORCE)

I am documenting the light variability in a sample of proto-planetary nebulae (PPNs) observed from two observatories. PPNs are stars in the stage of evolution between the AGB and planetary nebula phases. I analyzed the digital images of the data taken on 34 nights from the SARA-South observatory located in Cerro Tololo, Chile along with data taken from the SARA-North Observatory located in Tuscon, Arizona. This was done to obtain quantitative measurements of the brightness variations over time. Once I had this information for each object, I plotted light curves, which can be used to document the amplitudes and possible …

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Spitzer Reveals What Is Behind Orion's Bar, Robert H. Rubin, Janet P. Simpson, C. R. O'Dell, Ian A. Mcnabb, Sean W. J. Colgan, Scott Y. Zhuge, Gary J. Ferland, Sergio A. Hidalgo Jan 2011

Spitzer Reveals What Is Behind Orion's Bar, Robert H. Rubin, Janet P. Simpson, C. R. O'Dell, Ian A. Mcnabb, Sean W. J. Colgan, Scott Y. Zhuge, Gary J. Ferland, Sergio A. Hidalgo

Physics and Astronomy Faculty Publications

We present Spitzer Space Telescope observations of 11 regions south-east (SE) of the Bright Bar in the Orion Nebula, along a radial from the exciting star θ1 Ori C, extending from 2.6 to 12.1 arcmin. Our Cycle 5 programme obtained deep spectra with matching Infrared Spectrograph (IRS) short-high (SH) and long-high (LH) aperture grid patterns. Most previous IR missions observed only the inner few arcmin (the ‘Huygens’ Region). The extreme sensitivity of Spitzer in the 10–37 μm spectral range permitted us to measure many lines of interest to much larger distances from θ1 Ori C. Orion is the …

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Detection Of Optical Coronal Emission From 106-K Gas In The Core Of The Centaurus Cluster, R. E. A. Canning, A. C. Fabian, R. M. Johnstone, J. S. Sanders, C. S. Crawford, N. A. Hatch, Gary J. Ferland Jan 2011

Detection Of Optical Coronal Emission From 106-K Gas In The Core Of The Centaurus Cluster, R. E. A. Canning, A. C. Fabian, R. M. Johnstone, J. S. Sanders, C. S. Crawford, N. A. Hatch, Gary J. Ferland

Physics and Astronomy Faculty Publications

We report a detection (3.5 × 1037± 5.6 × 1036 erg s−1) of the optical coronal emission line [Fe X] λ6374 and upper limits of four other coronal lines using high-resolution VIMOS spectra centred on NGC 4696, the brightest cluster galaxy in the Centaurus cluster. Emission from these lines is indicative of gas at temperatures between 1 × 106−5 × 106 K, so traces the interstellar gas in NGC 4696. The rate of cooling derived from the upper limits is consistent with the cooling rate from X-ray observations (∼10 M⊙ yr …

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Table Of Contents Jan 2011

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

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President's Message, Justin K. Wyatt Jan 2011

President's Message, Justin K. Wyatt

Journal of the South Carolina Academy of Science

No abstract provided.

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Scas Officers And Council Members 2010 - 2011 Jan 2011

Scas Officers And Council Members 2010 - 2011

Journal of the South Carolina Academy of Science

No abstract provided.

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Properties And Uses Of Sodium Titanates And Peroxotitanates, David Hobbs Jan 2011

Properties And Uses Of Sodium Titanates And Peroxotitanates, David Hobbs

Journal of the South Carolina Academy of Science

No abstract provided.

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Overview Of Hybrid Microwave Technology, Rebecca Schulz, George Wicks, Diane Folz, David Clark Jan 2011

Overview Of Hybrid Microwave Technology, Rebecca Schulz, George Wicks, Diane Folz, David Clark

Journal of the South Carolina Academy of Science

No abstract provided.

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Removal And Sequestration Of Iodide From Alkaline Solutions Using Silver-Doped Carbon Nanotubes, Adrian L. Pishko, Steven M. Serkiz, Apparao M. Rao Jan 2011

Removal And Sequestration Of Iodide From Alkaline Solutions Using Silver-Doped Carbon Nanotubes, Adrian L. Pishko, Steven M. Serkiz, Apparao M. Rao

Journal of the South Carolina Academy of Science

No abstract provided.

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Table Of Contents Jan 2011

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

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Scas Officers And Council Members 2010-2011 Jan 2011

Scas Officers And Council Members 2010-2011

Journal of the South Carolina Academy of Science

No abstract provided.

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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.

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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 …

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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.

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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.

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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.

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Magnetic-Field Induced Stability In Two-Flavor Color Superconductivity, Churna B. Bhandari Jan 2011

Magnetic-Field Induced Stability In Two-Flavor Color Superconductivity, Churna B. Bhandari

Open Access Theses & Dissertations

It has long been understood that the ground state of a superdense quark system, a Fermi liquid of weakly interacting quarks, is unstable with respect to the formation of diquark condensates. This nonperturbative phenomenon is essentially equivalent to the Cooper instability of conventional BCS superconductivity. As the quark pairs have nonzero color charge, this kind of superconductivity breaks the SU(3) color gauge symmetry, thus it is called color superconductivity. A peculiar feature of spin-zero color superconductivity is the lack of Meissner effect for a combination of the regular electromagnetic field and one of the gluon fields. This combination behaves as …

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Fine-Scale Structures In Saturn's Rings Waves, Wakes And Ghosts, Kevin Baille Jan 2011

Fine-Scale Structures In Saturn's Rings Waves, Wakes And Ghosts, Kevin Baille

Electronic Theses and Dissertations

The Cassini mission provided wonderful tools to explore Saturn, its satellites and its rings system. The UVIS instrument allowed stellar occultation observations of structures in the rings with the best resolution available (around 10 meters depending on geometry and navigation), bringing our understanding of the physics of the rings to the next level. In particular, we have been able to observe, dissect, model and test the interactions between the satellites and the rings. We first looked at kilometer-wide structures generated by resonances with satellites orbiting outside the main rings. The observation of structures in the C ring and their association …

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Superluminal Neutrinos At Opera Confront Pion Decay Kinematics, Ramanath Cowsick, Shmuel Nussinov, Utpal Sarkar Jan 2011

Superluminal Neutrinos At Opera Confront Pion Decay Kinematics, Ramanath Cowsick, Shmuel Nussinov, Utpal Sarkar

Mathematics, Physics, and Computer Science Faculty Articles and Research

Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits alpha = (upsilon(v) - c)/c < 4 x 10(-6). We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (upsilon - c)/c < 10(-12).

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