Astrophysics and Astronomy Commons^™

Search For Gravitational Waves From Binary Black Hole Inspiral Merger And Ringdown In Ligo-Virgo Data From 2009-2010, J. Aasi, J. Abadie, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report a search for gravitational waves from the inspiral, merger and ringdown of binary black holes (BBH) with total mass between 25 and 100 solar masses, in data taken at the LIGO and Virgo observatories between July 7, 2009 and October 20, 2010. The maximum sensitive distance of the detectors over this period for a (20,20)⁢M⊙ coalescence was 300 Mpc. No gravitational wave signals were found. We thus report upper limits on the astrophysical coalescence rates of BBH as a function of the component masses for nonspinning components, and also evaluate the dependence of the search sensitivity on component …

Class Of Ferromagnetic Semiconductors, Larysa Shlyk, Sergiy A. Kryukov, Lance E. De Long, Barbara Schüpp-Niewa, Rainer Niewa

Physics and Astronomy Faculty Patents

Single crystal and polycrystal oxoruthenates having the generalized compositions (Ba_z,Sr_1−z)Fe_xCo_yRu_6−(x+y)O₁₁ (1≦(x+y)≦5; 0≦z≦1) and (Ba,Sr)M_2±xRu_4∓xO₁₁ (M=Fe,Co) belong to a novel class of ferromagnetic semiconductors with applications in spin-based field effect transistors, spin-based light emitting diodes, and magnetic random access memories.

Non-Equilibrium Casimir Force Between Vibrating Plates, Andreas Hanke

Physics & Astronomy Faculty Publications

We study the fluctuation-induced, time-dependent force between two plates confining a correlated fluid which is driven out of equilibrium mechanically by harmonic vibrations of one of the plates. For a purely relaxational dynamics of the fluid we calculate the fluctuation-induced force generated by the vibrating plate on the plate at rest. The time-dependence of this force is characterized by a positive lag time with respect to the driving. We obtain two distinctive contributions to the force, one generated by diffusion of stress in the fluid and another related to resonant dissipation in the cavity. The relation to the dynamic Casimir …

Discovery Of A Magnetic Field In The Rapidly-Rotating O-Type Secondary Of The Colliding-Wind Binary Hd 47129 (Plaskett’S Star)., J. Grunhut, G. Wade, M. Leutenegger, V. Petit, G. Rauw, C. Neiner, F. Martins, D. Cohen, M. Gagné, Richard Ignace, S. Mathis, S. De Mink, A. Moffat, S. Owocki, M. Shultz, J. Sundqvist, Mimes Collaboration

ETSU Faculty Works

We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for the Observations of Stars (ESPaDOnS) spectropolarimeter at the Canada–France–Hawaii Telescope and the Narval spectropolarimeter at the Télescope Bernard Lyot. Using least-squares deconvolution we obtain definite detections of signal in Stokes V in three observations. No significant signal is detected in the diagnostic null (N) spectra. The Zeeman signatures are broad and …

Rapid Tev Gamma-Ray Flaring Of Bl Lacertae, P. T. Reynolds, Veritas

Physical Sciences Publications

We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 ± 0.6) × 10–6 photons m–2 s–1, roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 ± 4 minutes, …

Limits On The Stochastic Gravitational Wave Background From The North American Nanohertz Observatory For Gravitational Waves, P. B. Demorest, R. D. Ferdman, M. E. Gonzalez, D. Nice, S. Ransom, I. H. Stairs, Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, Fredrick Jenet

Physics & Astronomy Faculty Publications

We present an analysis of high-precision pulsar timing data taken as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We have observed 17 pulsars for a span of roughly five years using the Green Bank and Arecibo radio telescopes. We analyze these data using standard pulsar timing models, with the addition of time-variable dispersion measure and frequency-variable pulse shape terms. Sub-microsecond timing residuals are obtained in nearly all cases, and the best rms timing residuals in this set are &thk30-50 ns. We present methods for analyzing post-fit timing residuals for the presence of a gravitational wave …

The X-Ray Evolution Of Hickson Compact Groups, Christopher Fuse, Emma Broming

Student-Faculty Collaborative Research Publications

The Hickson compact groups, displaying regions of high galaxy densities, should provide environments where galaxy evolution occurs rapidly. The repeated galaxy interactions and mergers present in compact groups increase the rate of star formation and increase the number of X-ray binaries. A fraction of the Hi gas will also become heated via stirring and shocks, which yields extended diffuse, hot gas halos that can encompass all members of a compact group. Using a sample of 16 Hickson compact groups from the Chandra X-Ray Observatory archives, we report on a correlation between the diffuse X-ray gas and the total X-ray point …

Sfa Star Charts, W D. Bruton

Faculty Publications

The SFA Start Charts are designed to work anywhere on Earth. Instructions are included on the last two pages. The constellations lines are based in part on those in a book called The Stars by H. A. Rey. These constellation patterns were adopted by Google Sky.

Evidence Of Light-Bending Effects And Its Implication For Spectral State Transitions, R. C. Reis, J. M. Miller, M. T. Reynolds, A. C. Fabian, D. J. Walton, E. Cackett, J. F. Steiner

Physics and Astronomy Faculty Research Publications

It has long been speculated that the nature of the hard X-ray corona may be an important second driver of black hole state transitions, in addition to the mass accretion rate through the disk. However, a clear physical picture of coronal changes has not yet emerged. We present results from a systematic analysis of Rossi X-Ray Timing Explorer observations of the stellar-mass black hole binary XTE J1650-500. All spectra with significant hard X-ray detections were fit using a self-consistent, relativistically blurred disk reflection model suited to high ionization regimes. Importantly, we find evidence that both the spectral and timing properties …

Regulation Of Black Hole Winds And Jets Across The Mass Scale, A. L. King, J. M. Miller, J. Raymond, A. C. Fabian, C. S. Reynolds, K. Gültekin, E. M. Cackett, S. W. Allen, D. Proga, T. R. Kallman

Physics and Astronomy Faculty Research Publications

We present a study of the mechanical power generated by both winds and jets across the black hole mass scale. We begin with the study of ionized X-ray winds and present a uniform analysis using Chandra grating spectra. The high-quality grating spectra facilitate the characterization of the outflow velocity, ionization, and column density of the absorbing gas. We find that the kinetic power of the winds, derived from these observed quantities, scales with increasing bolometric luminosity as log (L _{wind, 42}/C_v ) = (1.58 ± 0.07)log (L _{Bol, 42}) - (3.19 ± 0.19). This suggests that supermassive …

The Planetary Nebula Spectrograph Survey Of S0 Galaxy Kinematics. Data And Overview, A. Cortesi, M. Arnaboldi, L. Coccato, M. R. Merrifield, O. Gerhard, S. Bamford, Aaron J. Romanowsky, N. R. Napolitano, N. G. Douglas, K. Kuiijken, M. Capaccioli, K. C. Freeman, A. L. Chies-Santos, V. Pota

Faculty Publications

The origins of S0 galaxies remain obscure, with various mechanisms proposed for their formation, likely depending on environment. These mechanisms would imprint different signatures in the galaxies' stellar kinematics out to large radii, offering a method for distinguishing between them. We aim to study a sample of six S0 galaxies from a range of environments, and use planetary nebulae (PNe) as tracers of their stellar populations out to very large radii, to determine their kinematics in order to understand their origins. Using a special-purpose instrument, the Planetary Nebula Spectrograph, we observe and extract PNe catalogues for these six systems*. We …

The Sluggs Survey: Wide Field Imaging Of The Globular Cluster System Of Ngc 4278, C. Usher, D. A. Forbes, L. R. Spitler, J. P. Brodie, Aaron J. Romanowsky, J. Strader, K. A. Woodley

Faculty Publications

We use multipointing Hubble Space Telescope Advanced Camera for Surveys and wide field Subaru Suprime-Cam imaging to study the globular cluster system of the L* elliptical galaxy NGC 4278. We have also obtained a handful of new globular cluster spectra with the Keck Deep Imaging Multi-Object Spectrograph. We determine the globular cluster surface density profile and use it to calculate the total number of globular clusters, finding the system to be slightly more populous than average for galaxies of its luminosity. We find clear evidence for bimodality in the globular cluster colour distribution and for a colour–magnitude relation in the …

Mond And Imf Variations In Early-Type Galaxies From Atlas3d, C. Tortora, Aaron J. Romanowsky, V. F. Cardone, N. R. Napolitano, Ph Jetzer

Faculty Publications

No abstract provided.

The Sluggs Survey: Outer Triaxiality In The Fast Rotator Elliptical Ngc 4473, C. Foster, J. A. Arnold, D. A. Forbes, N. Pastorello, Aaron J. Romanowsky, L. R. Spitler, J. Strader, J. P. Brodie

Faculty Publications

Systematic surveys of nearby early-type galaxies using integral field unit (IFU) spectrograph data have revealed that galaxies can hide interesting structures only visible through kinematic studies. As part of their pioneering work, the ATLAS3D team have shown that most morphologically elliptical galaxies are centrally kinematically disc like. Hence, while global morphology suggests that ellipticals are ellipsoidal/triaxial in shape, their central kinematics may be consistent with (inclined) oblate systems. Here, we study the fast rotator elliptical galaxy: NGC 4473. Using slitlets, we obtain galaxy light kinematics out to unprecedentedly large galactocentric radii (2.5 effective radii). While we confirm the IFU results …

Filling The Gap: A New Class Of Old Star Cluster?, D. A. Forbes, V. Pota, C. Usher, Aaron J. Romanowsky, J. Strader, J. P. Brodie, J. A. Arnold, L. R. Spitler

Faculty Publications

It is not understood whether long-lived star clusters possess a continuous range of sizes and masses (and hence densities) or if rather, they should be considered as distinct types with different origins. Utilizing the Hubble Space Telescope to measure sizes and long exposures on the Keck 10 m telescope to obtain distances, we have discovered the first confirmed star clusters that lie within a previously claimed size–luminosity gap dubbed the ‘avoidance zone’ by Hwang et al. The existence of these star clusters extends the range of sizes, masses and densities for star clusters, and argues against current formation models that …

The Sluggs Survey: The Globular Cluster Systems Of Three Early-Type Galaxies Using Wide-Field Imaging, S. S. Kartha, D. A. Forbes, L. R. Spitler, Aaron J. Romanowsky, J. A. Arnold, J. P. Brodie

Faculty Publications

We present the results from a wide-field imaging study of globular cluster (GC) systems in three early-type galaxies. Combinations of Subaru/Suprime-Cam, CFHT/MegaCam and HST/WFPC2/ACS data were used to determine the GC system properties of three highly flattened galaxies NGC 720, NGC 1023 and NGC 2768. This work is the first investigation of the GC system in NGC 720 and NGC 2768 to very large galactocentric radius (∼ 100 kpc). The three galaxies have clear blue and red GC subpopulations. The radial surface densities of the GC systems are fitted with Sersic profiles, and detected out to 15, 8 and 10 …

Abundance Patterns In The Spiral Galaxy Messier 33, Melissa A. Siemer, Ravi Sankrit

STAR Program Research Presentations

Messier 33 (M33) is a spiral disk galaxy, similar to our galaxy, approximately 3 million light-years from Earth. Because of its proximity to Earth and face-on viewing angle, it is easy to see individual objects. Consequently, M33 is in an ideal position for obtaining data on elemental abundances. By studying M33, we learn how galaxies like our own form and change over time.

We use published optical spectroscopic data, obtained and assembled from online sources, to map the abundances of various elements (Helium, Nitrogen, Oxygen, Neon, Argon, Sulfur) in the planetary nebula and HII region populations of M33. We classify …

Seeing Through A Cloudy Glass: Putting Limits On Planetary Nebulae Abundances Using Photoionization Modeling., Peter R. Sullivan, Ravi Sankrit

STAR Program Research Presentations

Planetary nebulae (PNe) form around low to intermediate mass stars transitioning from the giant branch to white dwarf phase. The outer layer of the star is ejected during the transition and this gas, ionized by the central star, emits a line-spectrum. This spectrum traces the chemical abundances that were characteristic of the interstellar medium in which the star formed (e.g. oxygen) as well as of the elements created by these progenitor stars (e.g. nitrogen) aiding our understanding of chemical evolution of galaxies. In this project, we use modeling of the emission lines of PNe to determine the accuracy of direct …

Chemical Compatibility Study Of Anti-Corrosive Materials For Stratospheric Observatory For Infrared Astronomy (Sofia), Belyn Nicole Grant, Zaheer Ali, Greg Perryman, Stefan Teufel, Brian Eney

STAR Program Research Presentations

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a telescope designed to capture infrared light from deep space, mounted in a highly modified Boeing 747 SP. Portions of the aircraft interior are showing signs of corrosion, and need to be coated with a material that will prevent further corrosion. Up to date, current anti-corrosive materials commonly used on aircrafts are incompatible with the very thin aluminum surface of the telescope mirrors. The purpose of our study is to find an effective corrosion preventive material with low outgassing properties.

Precision Measurement Of The Most Distant Spectroscopically Confirmed Supernova Ia With The Hubble Space Telescope, D Rubin, R A. Knop, E Rykoff, G Aldering, R Amanullah, K Barbary, M S. Burns, A Conley, N Connolly, S Deustua, V Fadeyev, H K. Fakhouri, A S. Fruchter, R A. Gibbons, G Goldhaber, A Goobar, E Y. Hsiao, Xiaosheng Huang, M Kowalski, C Lidman, J Meyers, J Nordin, S Perlmutter, C Saunders, A Spadafora, V Stanishev, N Suzuki, L Wang, Supernova Cosmology Project

Physics and Astronomy

We report the discovery of a redshift 1.71 supernova in the GOODS North field. The Hubble Space Telescope (HST) ACS spectrum has almost negligible contamination from the host or neighboring galaxies. Although the rest frame sampled range is too blue to include any Si ii line, a principal component analysis allows us to confirm it as a Type Ia supernova with 92% confidence. A recent serendipitous archival HST WFC3 grism spectrum contributed a key element of the confirmation by giving a host-galaxy redshift of 1.713 +/- 0.007. In addition to being the most distant SN Ia with spectroscopic confirmation, this …