The Carter Constant For Inclined Orbits About A Massive Kerr Black Hole: Near-Circular, Near-Polar Orbits,
2012
University of Western Ontario
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 (QX) 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,
2012
IAPS-INAF & INFN
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,
2012
Clemson University
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,
2012
Gettysburg College
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,
2012
Butler University
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,
2012
Butler University
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,
2012
Merrimack
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,
2012
University of Durham
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, …
Joint Astrophysics Nascent Universe Satellite:. Utilizing Grbs As High Redshift Probes,
2012
Southwest Research Institute
Joint Astrophysics Nascent Universe Satellite:. Utilizing Grbs As High Redshift Probes, P. W. A. Roming, S. G. Bilen, D. N. Burrows, A Falcone, D. B. Fox, T. L. Herter, J. A. Kennea, Mark L. Mcconnell, J. A. Nousek
Physics & Astronomy
The Joint Astrophysics Nascent Universe Satellite (JANUS) is a multiwavelength cosmology mission designed to address fundamental questions about the cosmic dawn. It has three primary science objectives: (1) measure the massive star formation rate over 5 ≤ z ≤ 12 by discovering and observing high-z gamma-ray bursts (GRBs) and their afterglows, (2) enable detailed studies of the history of reionization and metal enrichment in the early Universe, and (3) map the growth of the first supermassive black holes by discovering and observing the brightest quasars at z ≥ 6. A rapidly slewing spacecraft and three science instruments – the X-ray …
Hydrogen Two-Photon Continuum Emission From The Horseshoe Filament In Ngc 1275,
2012
University of Cambridge, UK
Hydrogen Two-Photon Continuum Emission From The Horseshoe Filament In Ngc 1275, R. M. Johnstone, R. E.A. Canning, A. C. Fabian, Gary J. Ferland, Matt Lykins, R. L. Porter, P. A.M. Vanhoof, R. J.R. Williams
Physics and Astronomy Faculty Publications
Far-ultraviolet emission has been detected from a knot of Hα emission in the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected relative to the brightness of the Hα line in the same spatial region is very close to that expected from hydrogen two-photon continuum emission in the particle heating model of Ferland et al. if reddening internal to the filaments is taken into account. We find no need to invoke other sources of far-ultraviolet emission such as hot stars or emission lines from C IV in intermediate-temperature gas to explain these data.
Intervening Broad-Line Region Clouds' Effects On The Optical/Ultraviolet Spectrum,
2012
University of Kentucky
Intervening Broad-Line Region Clouds' Effects On The Optical/Ultraviolet Spectrum, Ye Wang, Gary J. Ferland, Chen Hu, Jian-Min Wang, Pu Du
Physics and Astronomy Faculty Publications
Recent X-ray observations of Mrk 766 suggest that broad emission-line region clouds cross our line of sight and produce variable X-ray absorption. Here we investigate what optical/ultraviolet (UV) spectroscopic features would be produced by such ‘intervening broad-line region (BLR) clouds' (IBC) crossing our line of sight to the accretion disc, the source of the optical/UV continuum. Although the emission spectrum produced by intervening clouds is identical to the standard BLR model, they may produce absorption features on the optical or UV continuum. Single clouds will have little effect on the optical/UV spectrum because BLR clouds are likely to be much …
The Characterization Of Virgo Data And Its Impact On Gravitational-Wave Searches,
2012
The University of Texas Rio Grande Valley
The Characterization Of Virgo Data And Its Impact On Gravitational-Wave Searches, J. Aasi, J. Abadie, Matthew Benacquista, G. Cagnoli, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Cristina V. Torres
Physics & Astronomy Faculty Publications
Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing …
Exceptional-Point Dynamics In Photonic Honeycomb Lattices With Pt Symmetry,
2012
The University of Texas Rio Grande Valley
Exceptional-Point Dynamics In Photonic Honeycomb Lattices With Pt Symmetry, Hamidreza Ramezani, Tsampikos Kottos, Vassilios Kovanis, Demetrios N. Christodoulides
Physics & Astronomy Faculty Publications
We theoretically investigate the flow of electromagnetic waves in complex honeycomb photonic lattices with local PT symmetries. Such PT structure is introduced via a judicious arrangement of gain and loss across the honeycomb lattice, characterized by a gain and loss parameter γ. We found a class of conical diffraction phenomena where the formed cone is brighter and travels along the lattice with a transverse speed proportional to √γ.
Isometries And Spontaneous Lorentz Violation In General Relativity,
2012
Colby College
Isometries And Spontaneous Lorentz Violation In General Relativity, Greg Merritt
Honors Theses
General Relativity, or GR, is a theory which describes gravity as a manifestation of the curvature of space and time. While the other three fundamental forces in nature are represented as field theories, GR is a geometric theory. In the search for a way to reconcile the field theories for the electromagnetic, strong, and weak forces with the gravitational force, a logical place to start is by re-expressing GR as a field theory. In doing so, we find that the theory contains a number of symmetries. When we solve the equations in GR, we find that by choosing certain solutions …
The Late-Time Afterglow Of The Extremely Energetic Short Burst Grb 090510 Revisited,
2012
Roger Williams University
The Late-Time Afterglow Of The Extremely Energetic Short Burst Grb 090510 Revisited, A. Nicuesa Guelbenzu, S. Klose, T. Krühler, J. Greiner, A. Rossi, D.A. Kann, F. Olivares, A. Rau, P.M.J. Afonso, J. Elliott, R. Filgas, A. Küpcü Yoldas, S. Mcbreen, M. Nardini, P. Schady, S. Schmidl, V. Sudilovsky, Adria Updike, A. Yoldas
Arts & Sciences Faculty Publications
No abstract provided.
The Fast Evolution Of Sn 2010bh Associated With Xrf 100316d,
2012
Roger Williams University
The Fast Evolution Of Sn 2010bh Associated With Xrf 100316d, F. Olivares E., J. Greiner, P. Schady, A. Rau, S. Klose, T. Krühler, P.M.J. Afonso, Adria Updike, M. Nardini, R. Filgas, A. Nicuesa Guelbenzu, C. Clemens, J. Elliott, D.A. Kann, A. Rossi, V. Sudilovsky
Arts & Sciences Faculty Publications
No abstract provided.
Bl Lacertae Objects Beyond Redshift 1.3 – Uv-To-Nir Photometry And Photometric Redshift For Fermi/Lat Blazars,
2012
Roger Williams University
Bl Lacertae Objects Beyond Redshift 1.3 – Uv-To-Nir Photometry And Photometric Redshift For Fermi/Lat Blazars, A. Rau, P. Schady, J. Greiner, M. Salvato, M. Ajello, E. Bottacini, N. Gehrels, P.M.J. Afonso, J. Elliott, R. Filgas, D.A. Kann, S. Klose, T. Krühler, M. Nardini, A. Nicuesa Guelbenzu, F. Olivares E., A. Rossi, V. Sudilovsky, Adria Updike, D.H. Hartmann
Arts & Sciences Faculty Publications
Context. Observations of the γ-ray sky with Fermi led to significant advances towards understanding blazars, the most extreme class of active galactic nuclei. A large fraction of the population detected by Fermi is formed by BL Lacertae (BL Lac) objects, whose sample has always suffered from a severe redshift incompleteness due to the quasi-featureless optical spectra. Aims. Our goal is to provide a significant increase of the number of confirmed high-redshift BL Lac objects contained in the 2 LAC Fermi/LAT cataloge.Methods. For 103 Fermi/LAT blazars, photometric redshifts using spectral energy distribution fitting have been obtained.The photometry includes 13 broad-band filters …
Phase Estimation With Two-Mode Squeezed Vacuum And Parity Detection: Bayesian Analysis,
2012
Louisiana State University
Phase Estimation With Two-Mode Squeezed Vacuum And Parity Detection: Bayesian Analysis, Keith Motes
Honors Capstones
No abstract provided.
H2 Temperatures In The Crab Nebula,
2012
Michigan State University
H2 Temperatures In The Crab Nebula, E. D. Loh, J. A. Baldwin, Gary J. Ferland, Z. K. Curtis, C. T. Richardson, A. C. Fabian, P. Salomé
Physics and Astronomy Faculty Publications
We used K-band spectra to measure the H2 excitation temperatures in six molecular knots associated with the filaments in the Crab Nebula. The temperatures are quite high – in the range T∼ 2000–3000 K, just below the H2 dissociation temperature. This is the temperature range over which the H2 1–0 S(1) line at λ2.121 μm has its maximum emissivity per unit mass, so there may be many additional H2 cores with lower temperatures that are too faint to detect. We also measured the electron density in adjacent ionized gas, which on the assumption of …
Near Infrared Hydrogen Emission Line Ratios As Diagnostics Of The Broad Emission Line Region,
2012
University of Melbourne, Australia
Near Infrared Hydrogen Emission Line Ratios As Diagnostics Of The Broad Emission Line Region, Andrea J. Ruff, David J. E. Floyd, Kirk T. Korista, Rachel L. Webster, Ryan Lucian Porter, Gary J. Ferland
Physics and Astronomy Faculty Publications
Broad emission line flux ratios are a powerful diagnostic of the physical conditions of the broad-line region gas in Active Galactic Nuclei. With recent advances in infrared spectroscopy, previously unstudied emission lines provide a new means to investigate the physical nature of the BELR gas. The hydrogen emission lines are particularly sensitive to the upper limits of both the radius from the central ionising source and the number density of the gas. Using an existing subset of near-infrared quasar spectra from the Glikman et al. (2006) sample [1] together with Cloudy photoionization simulations, we confirm the Locally Optimally emitting Cloud …
