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2015

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Articles 181 - 210 of 460

Full-Text Articles in Astrophysics and Astronomy

The Spitzer Survey Of Stellar Structure In Galaxies (S4g): Stellar Masses, Sizes, And Radial Profiles For 2352 Nearby Galaxies, Juan Carlos Muñoz-Mateos, Kartik Sheth, Michael Regan, Trisha Mizusawa Jul 2015

The Spitzer Survey Of Stellar Structure In Galaxies (S4g): Stellar Masses, Sizes, And Radial Profiles For 2352 Nearby Galaxies, Juan Carlos Muñoz-Mateos, Kartik Sheth, Michael Regan, Trisha Mizusawa

Aerospace, Physics, and Space Science Faculty Publications

The Spitzer Survey of Stellar Structure in Galaxies is a volume, magnitude, and size-limited survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5 μm. In this paper, we describe our surface photometry pipeline and showcase the associated data products that we have released to the community. We also identify the physical mechanisms leading to different levels of central stellar mass concentration for galaxies with the same total stellar mass. Finally, we derive the local stellar mass–size relation at 3.6 μm for galaxies of different morphologies. Our radial profiles reach stellar mass surface densities below ~1 M pc-2 …

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The Sizes Of Candidate Z~9-10 Galaxies : Confirmation Of The Bright Candels Sample And Relation With Luminosity And Mass., Benne W. Holwerda, R. J. Bouwens, P. A. Oesch, R. Smit, G. D. Illingworth, I. Labbe Jul 2015

The Sizes Of Candidate Z~9-10 Galaxies : Confirmation Of The Bright Candels Sample And Relation With Luminosity And Mass., Benne W. Holwerda, R. J. Bouwens, P. A. Oesch, R. Smit, G. D. Illingworth, I. Labbe

Faculty and Staff Scholarship

Recently, a small sample of six z ∼ 9–10 candidates was discovered in CANDELS that are ~-´ 10 20 more luminous than any of the previous z ∼ 9–10 galaxies identified over the HUDF/XDF and CLASH fields. We measure the sizes of these candidates to map out the size evolution of galaxies from the earliest observable times. Their sizes are also used to provide a valuable constraint on whether these unusual galaxy candidates are at high redshift. Using galfit to derive sizes from the CANDELS F160W images of these candidates, we find a mean size of 0. 13 0. 0 …

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Origin Of The Diffuse, Far Ultraviolet Emission In The Interarm Regions Of M101., Alison F. Crocker, Rupali Chandar, Daniela Calzetti, Benne W. Holwerda, Claus Leitherer, Cristina C. Popescu, R. J. Tuffs Jul 2015

Origin Of The Diffuse, Far Ultraviolet Emission In The Interarm Regions Of M101., Alison F. Crocker, Rupali Chandar, Daniela Calzetti, Benne W. Holwerda, Claus Leitherer, Cristina C. Popescu, R. J. Tuffs

Faculty and Staff Scholarship

We present images from the Solar Blind Channel on the Hubble Space Telescope that resolve hundreds of farultraviolet (FUV) emitting stars in two ∼1 kpc2 interarm regions of the grand-design spiral M101. The luminosity functions of these stars are compared with predicted distributions from simple star formation histories, and are best reproduced when the star formation rate has recently declined (past 10–50 Myr). This pattern is consistent with stars forming within spiral arms and then streaming into the interarm regions. We measure the diffuse FUV surface brightness after subtracting all of the detected stars, clusters, and background galaxies. A residual …

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The Spitzer Survey Of Stellar Structure In Galaxies (S4g) : Stellar Masses, Sizes, And Radial Profiles For 2352 Nearby Galaxies., Juan Carlos Muñoz-Mateos, Kartik Sheth, Michael Regan, Taehyun Kim, Jarkko Laine, Santiago Erroz-Ferrer, Armando Gil De Paz, Sebastien Comeron, Joannah Hinz, Eija Laurikainen, Heikki Salo, E. Athanassoula, Albert Bosma, Alexandre Y. Bouquin, Eva Schinnerer, Luis C. Ho, Johan H. Knapen, Sharon Meidt, Miguel Querejeta, Trisha Mizusawa, Mark Seibert, Seppo Laine, Helene M. Courtois Jul 2015

The Spitzer Survey Of Stellar Structure In Galaxies (S4g) : Stellar Masses, Sizes, And Radial Profiles For 2352 Nearby Galaxies., Juan Carlos Muñoz-Mateos, Kartik Sheth, Michael Regan, Taehyun Kim, Jarkko Laine, Santiago Erroz-Ferrer, Armando Gil De Paz, Sebastien Comeron, Joannah Hinz, Eija Laurikainen, Heikki Salo, E. Athanassoula, Albert Bosma, Alexandre Y. Bouquin, Eva Schinnerer, Luis C. Ho, Johan H. Knapen, Sharon Meidt, Miguel Querejeta, Trisha Mizusawa, Mark Seibert, Seppo Laine, Helene M. Courtois

Faculty and Staff Scholarship

The Spitzer Survey of Stellar Structure in Galaxies is a volume, magnitude, and size-limited survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5 μm. In this paper, we describe our surface photometry pipeline and showcase the associated data products that we have released to the community. We also identify the physical mechanisms leading to different levels of central stellar mass concentration for galaxies with the same total stellar mass. Finally, we derive the local stellar mass–size relation at 3.6 μm for galaxies of different morphologies. Our radial profiles reach stellar mass surface densities below ~1 pc M …

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Beam-Energy-Dependent Two-Pion Interferometry And The Freeze-Out Eccentricity Of Pions Measured In Heavy Ion Collisions At The Star Detector, J. Kevin Adkins, Renee Fatemi, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin Jul 2015

Beam-Energy-Dependent Two-Pion Interferometry And The Freeze-Out Eccentricity Of Pions Measured In Heavy Ion Collisions At The Star Detector, J. Kevin Adkins, Renee Fatemi, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin

Physics and Astronomy Faculty Publications

We present results of analyses of two-pion interferometry in Au+Au collisions at √SNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown–Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive …

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Double Spin Asymmetries Of Inclusive Hadron Electroproduction From A Transversely Polarized 3He Target, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. X. Zhao, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted, A. Camsonne Jul 2015

Double Spin Asymmetries Of Inclusive Hadron Electroproduction From A Transversely Polarized 3He Target, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. X. Zhao, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted, A. Camsonne

Physics and Astronomy Faculty Publications

We report the measurement of beam-target double spin asymmetries (ALT) in the inclusive production of identified hadrons, e⃗ + 3He↑→h+X, using a longitudinally polarized 5.9-GeV electron beam and a transversely polarized 3He target. Hadrons (π±,K±, and proton) were detected at 16∘ with an average momentum ⟨Ph⟩=2.35 GeV/c and a transverse momentum (pT) coverage from 0.60 to 0.68 GeV/c. Asymmetries from the 3He target were observed to be nonzero for π± production when the target …

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Evolution Of Magnetism In Single-Crystal Ca2Ru1−XIrXO4(0≤X≤0.65), Shujuan Yuan, Jsaminka Terzic, J. C. Wang, L. Li, Saicharan Aswartham, W. H. Song, F. Ye, Gang Cao Jul 2015

Evolution Of Magnetism In Single-Crystal Ca2Ru1−XIrXO4(0≤X≤0.65), Shujuan Yuan, Jsaminka Terzic, J. C. Wang, L. Li, Saicharan Aswartham, W. H. Song, F. Ye, Gang Cao

Physics and Astronomy Faculty Publications

We report structural, magnetic, transport, and thermal properties of single-crystal Ca2Ru1−xIrxO4(0≤x≤0.65). Ca2RuO4 is a structurally driven Mott insulator with a metal-insulator transition at TMI=357K, which is well separated from antiferromagnetic order at TN=110K. Substitution of a 5d element, Ir, for Ru enhances spin-orbit coupling and locking between the structural distortions and magnetic moment canting. Ir doping intensifies the distortion or rotation of Ru/IrO6 octahedra and induces weak ferromagnetic behavior along the c axis. In particular, Ir doping suppresses TN but …

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Moments Of The Neutron G2 Structure Function At Intermediate Q2, Wolfgang Korsch, P. Solvignon, N. Liyanage, J.-P. Chen, Seonho Choi, K. Slifer, K. Aniol, T. Averett, W. Boeglin, A. Camsonne, G. D. Cates Jul 2015

Moments Of The Neutron G2 Structure Function At Intermediate Q2, Wolfgang Korsch, P. Solvignon, N. Liyanage, J.-P. Chen, Seonho Choi, K. Slifer, K. Aniol, T. Averett, W. Boeglin, A. Camsonne, G. D. Cates

Physics and Astronomy Faculty Publications

We present new experimental results for the 3He spin structure function g2 in the resonance region at Q2 values between 1.2 and 3.0(GeV/c)2. Spin dependent moments of the neutron were extracted. Our main result, the inelastic contribution to the neutron d2 matrix element, was found to be small at ⟨Q2⟩=2.4(GeV/c)2 and in agreement with the lattice QCD calculation. The Burkhardt-Cottingham sum rule for 3He and the neutron was tested with the measured data and using the Wandzura-Wilczek relation for the low x unmeasured region.

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Hard Three-Loop Corrections To Hyperfine Splitting In Positronium And Muonium, Michael I. Eides, Valery A. Shelyuto Jul 2015

Hard Three-Loop Corrections To Hyperfine Splitting In Positronium And Muonium, Michael I. Eides, Valery A. Shelyuto

Physics and Astronomy Faculty Publications

We consider hard three-loop corrections to hyperfine splitting in muonium and positronium generated by the diagrams with closed electron loops. There are six gauge-invariant sets of such diagrams that generate corrections of order mα7. The contributions of these diagrams are calculated for an arbitrary electron-muon mass ratio without expansion in the small mass ratio. We obtain the formulas for contributions to hyperfine splitting that in the case of a small mass ratio describe corrections for muonium and in the case of equal masses describe corrections for positronium. The first few terms of the expansion of hard corrections in …

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A Sensitive Faraday Rotation Setup Using Triple Modulation, G. Phelps, Josh Abney, Mark Broering, Wolfgang Korsch Jul 2015

A Sensitive Faraday Rotation Setup Using Triple Modulation, G. Phelps, Josh Abney, Mark Broering, Wolfgang Korsch

Physics and Astronomy Faculty Publications

The utilization of polarized targets in scattering experiments has become a common practice in many major accelerator laboratories. Noble gases are especially suitable for such applications, since they can be easily hyper-polarized using spin exchange or metastable pumping techniques. Polarized helium-3 is a very popular target because it often serves as an effective polarized neutron due to its simple nuclear structure. A favorite cell material to generate and store polarized helium-3 is GE-180, a relatively dense aluminosilicate glass. In this paper, we present a Faraday rotation method, using a new triple modulation technique, where the measurement of the Verdet constants …

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Observing Strategy For The Sdss-Iv/Manga Ifu Galaxy Survey, David R. Law, Renbin Yan, Matthew A. Bershady, Kevin Bundy, Brian Cherinka, Niv Drory, Nicholas Macdonald, José R. Sánchez-Gallego, David R. Wake, Anne-Marie Weijmans, Michael R. Blanton, Mark A. Klaene, Sean M. Moran, Sebastian F. Sanchez, Kai Zhang Jul 2015

Observing Strategy For The Sdss-Iv/Manga Ifu Galaxy Survey, David R. Law, Renbin Yan, Matthew A. Bershady, Kevin Bundy, Brian Cherinka, Niv Drory, Nicholas Macdonald, José R. Sánchez-Gallego, David R. Wake, Anne-Marie Weijmans, Michael R. Blanton, Mark A. Klaene, Sean M. Moran, Sebastian F. Sanchez, Kai Zhang

Physics and Astronomy Faculty Publications

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an integral-field spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). MaNGA's 17 pluggable optical fiber-bundle integral field units (IFUs) will observe a sample of 10,000 nearby galaxies distributed throughout the SDSS imaging footprint (focusing particularly on the North Galactic Cap). In each pointing these IFUs are deployed across a 3° field; they yield spectral coverage 3600−10300 Å at a typical resolution R ~ 2000, and sample the sky with 2'' diameter fiber apertures with a total bundle fill factor of 56%. Observing …

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Smooth And Fast Versus Instantaneous Quenches In Quantum Field Theory, Sumit R. Das, Damián A. Galante, Robert C. Myers Jul 2015

Smooth And Fast Versus Instantaneous Quenches In Quantum Field Theory, Sumit R. Das, Damián A. Galante, Robert C. Myers

Physics and Astronomy Faculty Publications

We examine in detail the relationship between smooth fast quantum quenches, characterized by a time scale δt, and instantaneous quenches, within the framework of exactly solvable mass quenches in free scalar field theory. Our earlier studies [1, 2] highlighted that the two protocols remain distinct in the limit δt → 0 because of the relation of the quench rate to the UV cut-off, i.e., 1/δt ≪ Λ always holds in the fast smooth quenches while 1/δt ∼ Λ for instantaneous quenches. Here we study UV finite quantities like correlators at …

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The Spitzer Survey Of Stellar Structure In Galaxies (S4g) : Precise Stellar Mass Distributions From Automated Dust Correction At 3.6 Μm., Miguel Querejeta, Sharon Meidt, Eva Schinnerer, Mauricio Cisternas, Juan Carlos Muñoz-Mateos, Kartik Sheth, Johan H. Knapen, Glenn Van De Ven, Mark A. Norris, Reynier Peletier, Eija Laurikainen, Heikki Salo, Benne W. Holwerda, E. Athanassoula, Albert Bosma, Brent Groves, Luis C. Ho, Dimitri A. Gadotti, Dennis Zaritsky, Michael Regan, Joannah Hinz, Armando Gil De Paz, Karin Menendez-Delmestre, Mark Seibert, Trisha Mizusawa, Taehyun Kim, Santiago Erroz-Ferrer, Jarkko Laine, Sebastien Comeron Jul 2015

The Spitzer Survey Of Stellar Structure In Galaxies (S4g) : Precise Stellar Mass Distributions From Automated Dust Correction At 3.6 Μm., Miguel Querejeta, Sharon Meidt, Eva Schinnerer, Mauricio Cisternas, Juan Carlos Muñoz-Mateos, Kartik Sheth, Johan H. Knapen, Glenn Van De Ven, Mark A. Norris, Reynier Peletier, Eija Laurikainen, Heikki Salo, Benne W. Holwerda, E. Athanassoula, Albert Bosma, Brent Groves, Luis C. Ho, Dimitri A. Gadotti, Dennis Zaritsky, Michael Regan, Joannah Hinz, Armando Gil De Paz, Karin Menendez-Delmestre, Mark Seibert, Trisha Mizusawa, Taehyun Kim, Santiago Erroz-Ferrer, Jarkko Laine, Sebastien Comeron

Faculty and Staff Scholarship

The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6 mm IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old stellar flux at 3.6 μm and obtain stellar mass maps for more than 1600 galaxies available from the Spitzer Survey of Stellar Structure in Galaxies (S4 G). This survey consists of images in two infrared bands (3.6 and 4.5 mm ), and we use the Independent Component Analysis (ICA) method presented in Meidt et al. to separate …

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Analysis Of Angular Momentum In Planetary Systems And Host Stars, Stacy Ann Irwin Jul 2015

Analysis Of Angular Momentum In Planetary Systems And Host Stars, Stacy Ann Irwin

Theses and Dissertations

The spin angular momentum of single Main Sequence stars has long been shown to follow a primary power law of stellar mass, J ∝ Mα, excluding stars of <2 solar masses. Lower mass stars rotate more slowly with and have smaller moments of inertia, and as a result they contain much less spin angular momentum. A secondary power law describes the upper bound of angular momenta of these less massive stars with a steeper slope. The Solar System’s orbital angular momentum, however, is of the same order of magnitude as the primary law, whereas the Sun’s spin angular momentum is consistent with the secondary relationship. This suggests that planets are an important clue to answering questions about stellar angular momentum loss and transfer. With recent advances in exoplanet discovery and characterization, the angular momenta of exoplanetary systems can now be determined. A method is developed to calculate planetary system angular momenta from the spin and orbital angular momenta of a sample including 426 host stars and 532 planets. To maximize the size of the working sample, systems discovered by both the transit and radial velocity methods are included, and the biases of both techniques are identified. Self-consistent stellar moment of inertia parameters are interpolated from grids of stellar evolutionary models. Main Sequence host stars range from 0.6 to 1.7 solar masses, and their angular momenta are shown to agree well with previous studies of stellar angular momentum, generally falling on or below the appropriate power law, and exhibiting detection method biases. The systems’ angular momenta, including both the planetary orbital and stellar spin components, are widely spread above and below the primary power law, but on average agree well with the primary relationship. The results indicate that the primary power law describes angular momenta of stars of <2 solar masses well, when planetary angular momentum is included. This relationship also holds across host star evolutionary classifications. For 90% of the systems, the angular momentum contained in the planets is greater than the spin angular momentum of the host star, a characteristic shared by the Solar System. Undetected planets contribute significant bias to the system angular momentum as well as to the proportion of angular momentum contained in the planets. This bias is used to identify systems which are likely to harbor additional planets in already known planetary systems, assuming the Solar System’s proportions are typical.

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A Search For Planets And Brown Dwarfs Around Post Main Sequence Stars, Tomomi Otani Jul 2015

A Search For Planets And Brown Dwarfs Around Post Main Sequence Stars, Tomomi Otani

Theses and Dissertations

So far, the most promising theory for the existence of subdwarf B (sdB) stars is that they were formed during binary star evolution. This research was conducted to test this theory by searching for companions around six sdB pulsators (V391 Peg, HS 0702+6043, EC 20117-4014, PG 1219+534, PG 0911+456, and PG 1613+426) using the Observed-minus-Calculated (O-C) method. A star’s position in space will wobble due to the gravitational forces of any companion. If the star is emitting a periodic signal, the orbital motion of the star around the system’s center of mass causes periodic changes in the light pulse arrival …

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Solubility And Detectability Of Hydrocarbons On The Surface Of Titan, Sandeep Singh Jul 2015

Solubility And Detectability Of Hydrocarbons On The Surface Of Titan, Sandeep Singh

Graduate Theses and Dissertations

Titan’s thick atmosphere is enriched with organic compounds and its surface holds reservoirs of hydrocarbons. This makes Titan the only other candidate in our solar system (apart from Earth) to have stable liquid at the surface. The stability and characteristics of liquid and ices on the surface of Titan are of high importance in understanding its surface-atmosphere interactions. Titan’s hydrological cycle is similar to what we see on Earth, with the exception of methane (CH4) and ethane (C2H6) taking the place of water. The smoggy atmosphere veils the surface of Titan from the view of Cassini spacecraft, except at seven …

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Coexisting Charge And Magnetic Orders In The Dimer-Chain Iridate Ba5Alir2O11, Jsaminka Terzic, J. C. Wang, Feng Ye, W. H. Song, Shujuan Yuan, Saicharan Aswartham, Lance E. De Long, S. V. Streltsov, D. I. Khomskii, Gang Cao Jun 2015

Coexisting Charge And Magnetic Orders In The Dimer-Chain Iridate Ba5Alir2O11, Jsaminka Terzic, J. C. Wang, Feng Ye, W. H. Song, Shujuan Yuan, Saicharan Aswartham, Lance E. De Long, S. V. Streltsov, D. I. Khomskii, Gang Cao

Physics and Astronomy Faculty Publications

We have synthesized and studied single-crystal Ba5AlIr2O11 that features dimer chains of two inequivalent octahedra occupied by tetravalent Ir4+(5d5) and pentavalent Ir5+(5d4) ions, respectively. Ba5AlIr2O11 is a Mott insulator that undergoes a subtle structural phase transition near TS=210K and a magnetic transition at TM=4.5K; the latter transition is surprisingly resistant to applied magnetic fields μoH≤12T but more sensitive to modest applied pressure (dTM/dp≈+0.61K/GPa). All results indicate that the …

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Solar Wind Energy Input To The Magnetosheath And At The Magnetopause, T. I. Pulkkinen, A. P. Dimmock, A. Osmane, K. Nykyri Jun 2015

Solar Wind Energy Input To The Magnetosheath And At The Magnetopause, T. I. Pulkkinen, A. P. Dimmock, A. Osmane, K. Nykyri

Publications

Using Time History of Events and Macroscale Interactions During Substorms observations, we show that the efficiency of the energy entry through the magnetopause as measured by the Poynting vector normal component depends on the combination of the solar wind speed and the southward component of the interplanetary magnetic field (IMF): Most efficient energy transfer occurs when the IMF BZ is only moderately negative, and the solar wind speed is high. This means that for the same level of solar wind driver parameters (electric field, epsilon, or other), different combinations of V and BZ will produce different driving at the magnetopause. …

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Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa Jun 2015

Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa

2017 Academic High Altitude Conference

Since the time of Victor Hess and his balloon flight that demonstrated that cosmic rays increased with altitude, new detection methods have become widely available to be used on current day flights. One such method is to utilize CCDs with long duration exposures. During the exposures the CCD is exposed to cosmic rays which then leave a track. This phenomenon is caused by the CCD's inability to distinguish between photons of light and charged particles. Such tracks can then be separated from the CCD's background noise and classified.

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Observation Of Charge Asymmetry Dependence Of Pion Elliptic Flow And The Possible Chiral Magnetic Wave In Heavy-Ion Collisions, J. Kevin Adkins, Renee Fatemi, Suvarna Ramachandran, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev Jun 2015

Observation Of Charge Asymmetry Dependence Of Pion Elliptic Flow And The Possible Chiral Magnetic Wave In Heavy-Ion Collisions, J. Kevin Adkins, Renee Fatemi, Suvarna Ramachandran, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev

Physics and Astronomy Faculty Publications

We present measurements of π− and π+ elliptic flow, v2, at midrapidity in Au+Au collisions at √SNN=200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV, as a function of event-by-event charge asymmetry, Ach, based on data from the STAR experiment at RHIC. We find that π− (π+) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at √SNN=27  GeV and higher. At √SNN=200  GeV, the slope of the difference of v2 between π− and π+ …

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Directional Camera Control On High Altitude Balloons, Matthew M. Plewa, Brent Scharlau Jun 2015

Directional Camera Control On High Altitude Balloons, Matthew M. Plewa, Brent Scharlau

2017 Academic High Altitude Conference

The research reported in this paper examined the design and control of a gimbal for solar eclipse tracking and video recording. The gimbal design required 3 axes of rotation to allow for full range of motion. Utilizing individual brushless motors for each of the axes ensure minimum rotational requirements on each axes. In controlling the gimbal, both a mathematical and visual method were utilized. The mathematical method is a modified version of what is currently used for solar array pointing. The visual method looks at where the position of the sun is within the image and determines what angle changes …

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Double Compact Objects. Iii. Gravitational-Wave Detection Rates, Michal Dominik, Emanuele Berti, Richard O'Shaughnessy, Ilya Mandel, Krzysztof Belczynski, Christopher Fryer, Daniel E. Holz, Tomasz Bulik, Francesco Pannarale Jun 2015

Double Compact Objects. Iii. Gravitational-Wave Detection Rates, Michal Dominik, Emanuele Berti, Richard O'Shaughnessy, Ilya Mandel, Krzysztof Belczynski, Christopher Fryer, Daniel E. Holz, Tomasz Bulik, Francesco Pannarale

Physics & Astronomy Faculty Publications

The unprecedented range of second-generation gravitational-wave (GW) observatories calls for refining the predictions of potential sources and detection rates. The coalescence of double compact objects (DCOs)—i.e., neutron star–neutron star (NS–NS), black hole–neutron star (BH–NS), and black hole–black hole (BH–BH) binary systems—is the most promising source of GWs for these detectors. We compute detection rates of coalescing DCOs in second-generation GW detectors using the latest models for their cosmological evolution, and implementing inspiral-merger-ringdown gravitational waveform models in our signal-to-noise ratio calculations. We find that (1) the inclusion of the merger/ringdown portion of the signal does not significantly affect rates for NS–NS …

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Cosmic Ray Air Shower Lateral Coincidences, Gordon C. Mcintosh Jun 2015

Cosmic Ray Air Shower Lateral Coincidences, Gordon C. Mcintosh

2017 Academic High Altitude Conference

At the University of Minnesota, Morris, my students and I have begun to investigate the time and altitude dependence of air showers. Air showers are cosmic ray secondaries that spread out laterally around the primary cosmic ray direction. To investigate the air showers we have been measuring the lateral coincidences among three Aware RM60 Geiger counters located at 0 cm, 15 cm, and 40 cm. Most of these measurements have been carried out at the surface. The rate of lateral, triple coincidences of Geiger counter with this configuration is 0.053 ±0.013 hr-1 at the surface. On 4 April 2015 …

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First Measurement Of The Atomic Electric Dipole Moment Of 225Ra, R. H. Parker, M. R. Dietrich, M. R. Kalita, N. D. Lemke, K. G. Bailey, M. Bishof, J. P. Greene, R. J. Holt, Wolfgang Korsch, Z.-T. Lu, P. Mueller, T. P. O'Connor, J. T. Singh Jun 2015

First Measurement Of The Atomic Electric Dipole Moment Of 225Ra, R. H. Parker, M. R. Dietrich, M. R. Kalita, N. D. Lemke, K. G. Bailey, M. Bishof, J. P. Greene, R. J. Holt, Wolfgang Korsch, Z.-T. Lu, P. Mueller, T. P. O'Connor, J. T. Singh

Physics and Astronomy Faculty Publications

The radioactive radium-225 (225Ra) atom is a favorable case to search for a permanent electric dipole moment. Because of its strong nuclear octupole deformation and large atomic mass, 225Ra is particularly sensitive to interactions in the nuclear medium that violate both time-reversal symmetry and parity. We have developed a cold-atom technique to study the spin precession of 225Ra atoms held in an optical dipole trap, and demonstrated the principle of this method by completing the first measurement of its atomic electric dipole moment, reaching an upper limit of |d(225Ra)|<5.0×10−22  e cm …

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Star Formation And Quenching Among The Most Massive Galaxies At Z ∼ 1.7, C. Mancini, A. Renzini, E. Daddi, G. Rodighiero, S. Berta, N. Grogin, Dale D. Kocevski, A. Koekemoer Jun 2015

Star Formation And Quenching Among The Most Massive Galaxies At Z ∼ 1.7, C. Mancini, A. Renzini, E. Daddi, G. Rodighiero, S. Berta, N. Grogin, Dale D. Kocevski, A. Koekemoer

Physics and Astronomy Faculty Publications

We have conducted a detailed object-by-object study of a mass-complete (M* ≥ 1011 M⊙) sample of 56 galaxies at 1.4 ≤ z ≤ 2 in the Great Observatories Origins Deep Survey-South field, showing that an accurate deblending in 24 μm images is essential to properly assign to each galaxy its own star formation rate (SFR), whereas an automatic procedure often fails. This applies especially to galaxies with SFRs below the main sequence (MS) value, which may be in their quenching phase. After that, the sample splits evenly between galaxies forming stars within a factor of …

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Einstein@ Home Discovery Of A Palfa Millisecond Pulsar In An Eccentric Binary Orbit, B. Knispel, A. G. Lyne, B. W. Stappers, P. C.C. Freire, P. Lazarus, B. Allen, C. Aulbert, O. Bock, S. Bogdanov, Fredrick Jenet Jun 2015

Einstein@ Home Discovery Of A Palfa Millisecond Pulsar In An Eccentric Binary Orbit, B. Knispel, A. G. Lyne, B. W. Stappers, P. C.C. Freire, P. Lazarus, B. Allen, C. Aulbert, O. Bock, S. Bogdanov, Fredrick Jenet

Physics & Astronomy Faculty Publications

We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 (P = 4.3 ms) in a binary system with an eccentric (e = 0.08) 22 day orbit in Pulsar Arecibo L-band Feed Array survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 Mo and is most likely a white dwarf (WD). Fully recycled MSPs like this one are thought to be old neutron stars spun-up by mass transfer from a companion star. This process should circularize the orbit, as is observed for the vast majority of binary MSPs, which predominantly have orbital eccentricities …

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Star Formation And Relaxation In 379 Nearby Galaxy Clusters, Seth A. Cohen, Ryan C. Hickox, Gary A. Wegner Jun 2015

Star Formation And Relaxation In 379 Nearby Galaxy Clusters, Seth A. Cohen, Ryan C. Hickox, Gary A. Wegner

Dartmouth Scholarship

We investigate the relationship between star formation (SF) and level of relaxation in a sample of 379 galaxy clusters at z < 0.2. We use data from the Sloan Digital Sky Survey to measure cluster membership and level of relaxation, and to select star-forming galaxies based on mid-infrared emission detected with the Wide-Field Infrared Survey Explorer. For galaxies with absolute magnitudes Mr < −19.5, we find an inverse correlation between SF fraction and cluster relaxation: as a cluster becomes less relaxed, its SF fraction increases. Furthermore, in general, the subtracted SF fraction in all unrelaxed clusters (0.117 ± 0.003) is higher than that in all relaxed clusters (0.097 ± 0.005). We verify the validity of our SF calculation methods and membership criteria through analysis of previous work. Our results agree with previous findings that a weak correlation exists between cluster SF and dynamical state, possibly because unrelaxed clusters are less evolved relative to relaxed clusters.

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A Comprehensive Characterization Of The 70 Virginis Planetary System, Stephen R. Kane, Tabetha S. Boyajian, Gregory W. Henry, Y. Katherina Feng, Natalie R. Hinkel, Debra A. Fischer, Kaspar Von Braun, Andrew W. Howard, Jason T. Wright Jun 2015

A Comprehensive Characterization Of The 70 Virginis Planetary System, Stephen R. Kane, Tabetha S. Boyajian, Gregory W. Henry, Y. Katherina Feng, Natalie R. Hinkel, Debra A. Fischer, Kaspar Von Braun, Andrew W. Howard, Jason T. Wright

Information Systems and Engineering Management Research Publications

An on-going effort in the characterization of exoplanetary systems is the accurate determination of host star properties. This effort extends to the relatively bright host stars of planets discovered with the radial velocity method. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) is aiding in these efforts as part of its observational campaign for exoplanet host stars. One of the first known systems is that of 70 Virginis, which harbors a jovian planet in an eccentric orbit. Here we present a complete characterization of this system with a compilation of TERMS photometry, spectroscopy, and interferometry. We provide fundamental properties of …

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Models Of Time Travel And Their Consequences, Antonio M. Mantica Jun 2015

Models Of Time Travel And Their Consequences, Antonio M. Mantica

Oglethorpe Journal of Undergraduate Research

How do we travel through time? We know that we can move forward in it (we have no choice), but can we jump forward in time? Can we go backward in time? It also gives rise to other troubling questions: is time measurable in distinct increments, or does it flow continuously? In "Models of Time Travel and their Consequences," Antonio Mantica walks the reader through current understandings of how time functions in Einstein's universe and proposes three distinct models to explain it. Following that, he provides a list of experiments to credit or discredit the models. Appropriate for audiences of …

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Update On Radiation Dose From Galactic And Solar Protons At The Moon Using The Lro/Crater Microdosimeter, J. E. Mazur, Cary Zeitlin, Nathan A. Schwadron, M. D. Looper, Lawrence W. Townsend, J. B. Blake, Harlan E. Spence Jun 2015

Update On Radiation Dose From Galactic And Solar Protons At The Moon Using The Lro/Crater Microdosimeter, J. E. Mazur, Cary Zeitlin, Nathan A. Schwadron, M. D. Looper, Lawrence W. Townsend, J. B. Blake, Harlan E. Spence

Physics & Astronomy

The NASA Lunar Reconnaissance Orbiter (LRO) has been exploring the lunar surface and radiation environment since June 2009. In Mazur et al. [2011] we discussed the first 6 months of mission data from a microdosimeter that is housed within the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument onboard LRO. The CRaTER microdosimeter is an early version of what is now a commercially available hybrid that accurately measures total ionizing radiation dose in a silicon target (http://www.teledynemicro.com/product/radiation-dosimeter). This brief report updates the transition from a deep solar minimum radiation environment to the current …

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