Astrophysics and Astronomy Commons^™

The Globular Cluster System Of Ngc 1316 - Ii. The Extraordinary Object Sh2, T. Richtler, B. Kumar, L. Bassino, B. Dirsch, Aaron J. Romanowsky

Faculty Publications

Context. SH2 has been described as an isolated HII-region, located about 6.5′ south of the nucleus of NGC 1316 (Fornax A), a merger remnant in the the outskirts of the Fornax cluster of galaxies. Aims. We give a first, preliminary description of the stellar content and environment of this remarkable object. Methods. We used photometric data in the Washington system and HST photometry from the Hubble Legacy Archive for a morphological description and preliminary aperture photometry. Low-resolution spectroscopy provides radial velocities of the brightest star cluster in SH2 and a nearby intermediate-age cluster. Results. SH2 is not a normal HII-region, …

Kinematic Properties Of The Field Elliptical Ngc 7507, R. Salinas, T. Richtler, L. P. Bassino, Aaron J. Romanowsky, Y. Schuberth

Faculty Publications

The dark matter (DM) halos of field elliptical galaxies have not been well-studied and their properties appear controversial in the literature. While some galaxies appear to be nearly devoid of DM, others show clear evidence of its presence. Furthermore, modified Newtonian dynamics (MOND), which has been found to have predictive power in the domain of disk galaxies, has not yet been investigated for isolated elliptical galaxies. We study the kinematics of the isolated elliptical NGC 7507, which has been claimed as a clear example of DM presence in early-type galaxies. We obtained major and minor axis long-slit spectroscopy of NGC …

Repeatability Of The Seasonal Variations Of Ozone Near The Mesopause From Observations Of The 11.072-Ghz Line, Alan E. E. Rogers, P. P. Erickson, V. L. Fish, J. J. Kittredge, S. S. Danford, J. M. Marr, Martina Arndt, J. Sarabia, D. Costa, S. K. May

Physics Faculty Publications

Ground-based observations of the 11.072-GHz line of ozone were made from January 2008 through the middle of September 2011 to estimate the maximum in the nighttime ozone in the upper mesosphere at an altitude of about 95 km for a region centered at 38°N, 290°E. The measurements show seasonal variation with a high degree of repeatability with peaks in ozone concentration about a month following each equinox. A significant increase in ozone concentration above the yearly trend occurred in 2010 from mid-November until the end of December, which the authors attribute to delay in the start of the meridional circulation …

The Hubble Space Telescope Cluster Supernova Survey: V. Improving The Dark Energy Constraints Above Z>1 And Building An Early-Type-Hosted Supernova Sample, N Suzuki, D Rubin, C Lidman, G Aldering, R Amanullah, K Barbary, L F. Barrientos, J Botyanszki, M Brodwin, N Connolly, K S. Dawson, A Dey, M Doi, M Donahue, S Deustua, P Eisenhardt, E Ellingson, L Faccioli, V Fadeyev, H K. Fakhouri, A S. Fruchter, D G. Gilbank, M D. Gladders, G Goldhaber, A H. Gonzalez, A Goobar, A Gude, T Hattori, H Hoekstra, E Y. Hsiao, Xiaosheng Huang, Y Ihara, M J. Jee, D Johnston, K Kashikawa, B Koester, K Konishi, M Kowalski, E V. Linder, L Lubin, J Melbourne, J Meyers, T Morokuma, F Munshi, C Mullis, T Oda, N Panagia, S Perlmutter, M Postman, T Pritchard, J Rhodes, P Ripoche, P Rosati, D J. Schlegel, A Spadafora, S A. Stanford, V Stanishev, D Stern, M Strovink, N Takanashi, K Tokita, M Wagner, L Wang, N Yasuda, H. K. C. Yee, Supernova Cosmology Project

Physics and Astronomy

We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe Ia were discovered over the redshift interval 0.623 < z < 1.415. of these sne ia, 14 pass our strict selection cuts and are used in combination with the world's sample of sne ia to derive the best current constraints on dark energy. of our new sne ia, 10 are beyond redshift z = 1, thereby nearly doubling the statistical weight of hst-discovered sne ia beyond this redshift. our detailed analysis corrects for the recently identified correlation between sn ia luminosity and host galaxy mass and corrects the nicmos zero point at the count rates appropriate for very …

Angular Momentum And Galaxy Formation Revisited, Aaron J. Romanowsky, S. M. Fall

Faculty Publications

Motivated by a new wave of kinematical tracers in the outer regions of early-type galaxies (ellipticals and lenticulars), we re-examine the role of angular momentum in galaxies of all types. We present new methods for quantifying the specific angular momentum j, focusing mainly on the more challenging case of early-type galaxies, in order to derive firm empirical relations between stellar j sstarf and mass M sstarf (thus extending earlier work by Fall). We carry out detailed analyses of eight galaxies with kinematical data extending as far out as 10 effective radii, and find that data at two effective radii are …

Interferometric, Astrometric, And Photometric Studies Of Epsilon Aurigae: Seeing The Disk Around A Distant Star, Brian Keith Kloppenborg

Electronic Theses and Dissertations

Epsilon (ε) Aurigae is a binary star system that has baffled astronomers for 170 years. In 1821 it was first noticed that the star system had dimmed by nearly 50%. After many decades of photometric monitoring, the 27.1 year period was finally established in 1903. A few years later, in 1912, Henry Norris Russell published the first analytic methods for binary star analysis. Later application of these formulae came to an interesting conclusion; the system was composed of two stars: the visible F-type supergiant, and an equally massive, but yet photometrically and spectroscopically invisible, companion.

Several theories were advanced to …

Spider - Vi. The Central Dark Matter Content Of Luminous Early-Type Galaxies: Benchmark Correlations With Mass, Structural Parameters And Environment, C. Tortora, F. La Barbera, N. R. Napolitano, R. R. De Carvalho, Aaron J. Romanowsky

Faculty Publications

We analyze the central dark-matter (DM) content of \sim 4,500 massive (M* \gsim 10^{10} Msun), low-redshift (z<0.1), early-type galaxies (ETGs), with high-quality ugrizYJHK photometry and optical spectroscopy from SDSS and UKIDSS. We estimate the "central" fraction of DM within the K-band effective radius, \Re, using spherically symmetric isotropic galaxy models. We discuss the role of systematics. The main results of the present work are the following: (1) DM fractions increase systematically with both structural parameters and mass proxies, as in previous studies, and decrease with central stellar density. 2) All correlations involving DM fractions are caused by two fundamental ones with galaxy effective radius and central velocity dispersion. These correlations are independent of each other, so that ETGs populate a central-DM plane (DMP), i.e. a correlation among fraction of total-to-stellar mass, effective radius, and velocity dispersion, whose scatter along the total-to-stellar mass axis amounts to \sim 0.15 dex. (3) In general, under the assumption of an isothermal or a constant M/L profile for the total mass distribution, a Chabrier IMF is favoured with respect to a bottom-heavier Salpeter IMF, as the latter produces negative (i.e. unphysical) DM fractions for more than 50% of the galaxies in our sample. For a Chabrier IMF, the DM estimates agree with \LambdaCDM toy-galaxy models based on contracted DM-halo density profiles. We also find agreement with predictions from hydrodynamical simulations. (4) The central DM content of ETGs does not depend significantly on the environment where galaxies reside, with group and field ETGs having similar DM trends.

Short-Range Correlations And Cooling Of Ultracold Fermions In The Honeycomb Lattice, Baoming Tang, Thereza Paiva, Ehsan Khatami, Marcos Rigol

Faculty Publications

We use determinantal quantum Monte Carlo simulations and numerical linked-cluster expansions to study thermodynamic properties and short-range spin correlations of fermions in the honeycomb lattice. We find that, at half filling and finite temperatures, nearest-neighbor spin correlations can be stronger in this lattice than in the square lattice, even in regimes where the ground state in the former is a semimetal or a spin liquid. The honeycomb lattice also exhibits a more pronounced anomalous region in the double occupancy that leads to stronger adiabatic cooling than in the square lattice. We discuss the implications of these findings for optical lattice …

Ua94/6/8 Student / Alumni Personal Papers Wku Terry Wilcutt, Wku Archives

WKU Archives Collection Inventories

Records created by and about Terry Wilcutt and manned space flights.

Multimessenger Astronomy: Modeling Gravitational And Electromagnetic Radiations From A Stellar Binary System, Kevin Kern

Bridges: A Journal of Student Research

Our Sun is one of roughly 100 billion other stars that make up the Milky Way Galaxy. Two-thirds of all stars are paired off, with a gravitational bond between the two stars. Such systems are known as stellar binaries. Although these binaries are very common in the galaxy, there is much yet to be learned about their formation, evolution, and interactions. The approach taken in this thesis is to produce simulated data representing the expected measurements that an observational astronomer would collect. We attempt to simulate three different stellar binary star systems: an eclipsing binary, a spectroscopic binary, and a …

Photocatalytic Hydrogen Production At Titania-Supported Pt Nanoclusters That Are Derived From Surface-Anchored Molecular Precursors, Rony S. Khnayzer, Lucas B. Thompson, Mikhail Zamkov, Shane Ardo, Gerald J. Meyer, Catherine J. Murphy, Felix N. Castellano

Physics and Astronomy Faculty Publications

Degussa P-25 TiO2 bearing surface-anchored Pt(dcbpy)Cl-2 [dcbpy = 4,4'-dicarboxylic acid-2,2'-bipyridine] prepared with systematically varied surface coverage produced Pt-0 nanoparticles under bandgap illumination in the presence of methanol hole scavengers. Energy-dispersive X-ray spectroscopy confirmed the presence of elemental platinum in the newly formed nanoparticles during scanning transmission electron microscopy (STEM) eleriments. According to the statistical analysis of numerous STEM images, the Pt-0 nanoclusters were distributed in a segregated manner throughout the titania surface, ranging in size from 1 to 3 nm in diameter. The final achieved nanoparticle size and net hydrogen production were determined as a function of the Pt(dcbpy)Cl-2 surface …

Dwarfs Gobbling Dwarfs: A Stellar Tidal Stream Around Ngc 4449 And Hierarchical Galaxy Formation On Small Scales, D. Mart´Inez-Delgado, Aaron J. Romanowsky, R. J. Gabany, F. Annibali, J. A. Arnold, J. Fliri, S. Zibetti, R. P. Van Der Marel, H. W. Rix, T. S. Chonis, J. A. Carballo-Bello, A. Aloisi, A. V. Macci`O, J. Gallego-Laborda, J. P. Brodie, M. R. Merrifield

Faculty Publications

A candidate diffuse stellar substructure was previously reported in the halo of the nearby dwarf starburst galaxy NGC 4449 by Karachentsev et al. We map and analyze this feature using a unique combination of deep integrated-light images from the BlackBird 0.5 m telescope, and high-resolution wide-field images from the 8 m Subaru Telescope, which resolve the nebulosity into a stream of red giant branch stars, and confirm its physical association with NGC 4449. The properties of the stream imply a massive dwarf spheroidal progenitor, which after complete disruption will deposit an amount of stellar mass that is comparable to the …

The Carter Constant For Inclined Orbits About A Massive Kerr Black Hole: Near-Circular, Near-Polar Orbits, Sree Ram Valluri, Peter Komorowski, Martin Houde

Physics and Astronomy Publications

In an extreme mass-ratio binary black hole system, a non-equatorial orbit will list (i.e. increase its angle of inclination, iota) as it evolves in Kerr spacetime. The abutment, a set of evolving, near-polar, retrograde orbits, for which the instantaneous Carter constant (Q) is at its maximum value (Q_X) for given values of latus rectum (˜l) and eccentricity (e), has been introduced as a laboratory in which the consistency of dQ/dt with corresponding evolution equations for d˜l/dt and de/dt might be tested independently of a specific radiation back-reaction model. To demonstrate the use of the abutment as such a …

Loft: The Observatory For X-Ray Timing, M. Feroci, J. W. Den Herder, E. Bozzo, D. Barret, S. Brandt, M. Hernanz, M. Van Der Klis, M. Pohl, A. Santangelo, L Stella, A Watts, J Wilms, S Zane

Publications

The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultradense matter. These primary science goals will be addressed by a payload composed of a Large Area Detector (LAD) and a Wide Field Monitor …

Measuring The Stellar Accretion Rates Of Herbig Ae/Be Stars, Brian Donehew, Sean D. Brittain

Publications

The accretion rate of young stars is a fundamental characteristic of these systems.While accretion onto T Tauri stars has been studied extensively, little work has been done on measuring the accretion rate of their intermediate-mass analogs, the Herbig Ae/Be stars. Measuring the stellar accretion rate of Herbig Ae/Bes is not straightforward both because of the dearth of metal absorption lines available for veiling measurements and the intrinsic brightness of Herbig Ae/Be stars at ultraviolet wavelengths where the brightness of the accretion shock peaks. Alternative approaches to measuring the accretion rate of young stars by measuring the luminosity of proxies such …

A Possible Detection Of Occultation By A Proto-Planetary Clump In Gm Cephei, W. P. Chen, S. C.-L. Hu, R. Errmann, Ch. Adam, Laurence A. Marschall

Physics and Astronomy Faculty Publications

GM Cep in the young (~ 4 Myr) open cluster Trumpler 37 has been known to be an abrupt variable and to have a circumstellar disk with very active accretion. Our monitoring observations in 2009–2011 revealed the star to show sporadic ?are events, each with brightening of . 0.5 mag lasting for days. These brightening events, associated with a color change toward the blue, should originate from an increased accretion activity. Moreover, the star also underwent a brightness drop of ~ 1 mag lasting for about a month, during which the star became bluer when fainter. Such brightness drops seem …

8077 Hoyle: A Short Period Asteroid, Daniel A. Klinglesmith Iii, Ethan Risley, Janek Turk, Angelica Vargas, Xianming Han, Orry R. Heffner, Adam W. Kidd, Bradley J. Magnetta, Frederick W. Rastede

Scholarship and Professional Work - LAS

The main-belt asteroid 8077 Hoyle was observed on 13 nights over a span of 47 days in 2012 April-May. A bimodal synodic period of 2.7454 ± 0.0002 h and an amplitude of 0.20 ± 0.02 mag. were obtained.

Period Determination For Nea (162421) 2000 Et70, Eduardo Manuel Alvarez, Julian Oey, Xianming Han, Orry R. Heffner, Adam W. Kidd, Bradley J. Magnetta, Frederick W. Rastede

Scholarship and Professional Work - LAS

Lightcurve analysis for (162421) 2000 ET70 was performed in collaboration with observers in Uruguay, Australia, and the United States from observations obtained during the asteroid’s favorable opposition in 2012. The synodic rotation period was found to be 8.947 ± 0.001 h and the lightcurve amplitude was 0.60 ± 0.07 mag.

Topspin Networks In Loop Quantum Gravity, Christopher L. Duston

Physics Faculty Publications

We discuss the extension of loop quantum gravity to topspin networks, a proposal which allows topological information to be encoded in spin networks. We will show that this requires minimal changes to the phase space, C*-algebra and Hilbert space of cylindrical functions. We will also discuss the area and Hamiltonian operators, and show how they depend on the topology. This extends the idea of 'background independence' in loop quantum gravity to include topology as well as geometry. It is hoped this work will confirm the usefulness of the topspin network formalism and open up several new avenues for research into …

Identifying A New Intermediate Polar Using Xmm-Newton And Integral, Matthew J. Middleton, Edward M. Cackett, Craig Shaw, Gavin Ramsay, Timothy P. Roberts, Peter J. Wheatley

Physics and Astronomy Faculty Research Publications

The bright X-ray source 2XMMi J180438.7-145647 is fortunate to have long baseline observations in INTEGRAL that complement observations taken by other missions. Optical spectroscopy of this object has suggested a distance of ˜7 kpc and an identification with a low-mass X-ray binary. We instead use the X-ray data from 0.3 to 40 keV to identify the source as a bright intermediate polar (IP) with an estimate for the white dwarf mass of ˜0.60 M_⊙. This identification is supported by the presence of an iron triplet, the component lines of which are some of the strongest seen in IPs, …