Astrophysics and Astronomy Commons^™

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. …

The Structure Of X-Ray Emissions Fromtriggered Lightning Leadersmeasured By A Pinhole-Type X-Ray Camera, M. M. Schaal, J. R. Dwyer, S. Arabshahi, E. S. Cramer, R. J. Lucia, N. Y. Liu, H. K. Rassoul, D. M. Smith, J. W. Matten, A. G. Reid, J. D. Hill, D. M. Jordan, M. A. Uman

Aerospace, Physics, and Space Science Faculty Publications

We investigate the structure of X-ray emissions from downward triggered lightning leaders using a pinhole-type X-ray camera (XCAM) located at the International Center for Lightning Research and Testing. This study builds on the work of Dwyer et al. (2011), which reported results from XCAM data from the 2010 summer lightning season. Additional details regarding the 2010 data are reported here. During the 2011 summer lightning season, the XCAM recorded 12 out of 17 leaders, 5 of which show downward leader propagation. Of those five leaders, one dart-stepped leader and two chaotic dart leaders are the focus of this paper. These …

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 …

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 …

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 …

Observational Studies Of Proto-Planetary Nebulae At The Valparaiso University Observatory, Christopher Miko, Rachael Jensema

Symposium on Research and Creative Expression (SORCE)

We are observing the light variation with time of a sample of 26 proto-planetary nebulae (PPNe) using Valparaiso University’s 16-inch computer-controlled reflector telescope and CCD digital camera. PPNe are evolved stars late in their lifetime, in between the red giant and planetary nebula phase. The resulting images are analyzed and properly calibrated to produce quantitative measurements of light intensity with respect to time. We are particularly analyzing nine PPNe and their light variations through time to quantify variability and search for periods to their variability. Of the nine, all are variable over a range of 10-50%. Five demonstrate an approximate …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

On The Clustering Of Sub-Millimeter Galaxies, Christina Williams, Mauro Giavalisco, Cristiano Porciani, Min Yun, Alexandra Pope, Kimberly Scott, Jason Austermann, Itziar Aretxaga, Bunyo Hatsukade, Kyoung-Soo Lee, Grant Wilson, J. Ryan Cybulski, David Hughes, Ryo Kawabe, Kotaro Kohno, Thushara Perera, F. Peter Schloerb

Scholarship

We measure the angular two-point correlation function of sub-millimeter galaxies (SMGs) from 1.1-millimeter imaging of the COSMOS field with the AzTEC camera and ASTE 10-meter telescope. These data yields one of the largest contiguous samples of SMGs to date, covering an area of 0.72 degrees^2 down to a 1.26 mJy/beam (1-sigma) limit, including 189 (328) sources with S/N greater than 3.5 (3). We can only set upper limits to the correlation length r_0, modeling the correlation function as a power-law with pre-assigned slope. Assuming existing redshift distributions, we derive 68.3% confidence level upper limits of r_0 < 6-8 h^-1 Mpc at 3.7 mJy, and r_0 < 11-12 h^-1 Mpc at 4.2 mJy. Although consistent with most previous estimates, these upper limits imply that the real r_0 is likely smaller. This casts doubts on the robustness of claims that SMGs are characterized by significantly stronger spatial clustering, (and thus larger mass), than differently selected galaxies at high-redshift. Using Monte Carlo simulations we show that even strongly clustered distributions of galaxies can appear unclustered when sampled with limited sensitivity and coarse angular resolution common to current sub-millimeter surveys. The simulations, however, also show that unclustered distributions can appear strongly clustered under these circumstances. From the simulations, we predict that at our survey depth, a mapped area of two degrees^2 is needed to reconstruct the correlation function, assuming smaller beam sizes of future surveys (e.g. the Large Millimeter Telescope's 6" beam size). At present, robust measures of the clustering strength of bright SMGs appear to be below the reach of most observations.

High-Order Finite Difference Methods With Subcell Resolution For 2d Detonation Waves, W. Wang, C.-W. Shu, Helen Yee, Bjorn Sjögreen

United States National Aeronautics and Space Administration: Publications

In simulating hyperbolic conservation laws in conjunction with an inhomogeneous stiff source term, if the solution is discontinuous, spurious numerical results may be produced due to the different time scales of the transport part and the source term. This numerical issue often arises in combustion and high-speed chemical reacting flows.

Our objective in this study is to extend this method to two-dimensional reactive Euler equations. The first step of the proposed fractional step method is the convection step which solves the homogeneous hyperbolic conservation law in which any high-resolution shock-capturing method can be used. The aim in this step is …

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 …

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 …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

President's Message, Justin K. Wyatt

Journal of the South Carolina Academy of Science

No abstract provided.