High-Excitation Emission Lines Near Eta Carinae, And Its Likely Companion Star,
2010
University of Minnesota
High-Excitation Emission Lines Near Eta Carinae, And Its Likely Companion Star, Andrea Mehner, Kris Davidson, Gary J. Ferland, Roberta M. Humphreys
Physics and Astronomy Faculty Publications
In order to study the distribution of gas and ionizing radiation around η Car and their implications for its likely companion star, we have examined high-excitation emission lines of [Ne III], [Fe III], etc., in spectra obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph instrument during 1998-2004. Our principal results, some of them unexpected, are as follows. (1) The high-excitation fluxes varied systematically and non-trivially throughout η Car's 5.5 year spectroscopic cycle. Instead of rising to a plateau after the 1998 ''event,'' they changed continuously with a maximum in mid-cycle. (2) At one significant location a brief, strong …
An Analytical And Numerical Treatment Of The Carter Constant For Inclined Elliptical Orbits About A Massive Kerr Black Hole,
2010
The University of Western Ontario
An Analytical And Numerical Treatment Of The Carter Constant For Inclined Elliptical Orbits About A Massive Kerr Black Hole, Peter Komorowski, Sree Ram Valluri, Martin Houde
WORLDiscoveries Research Showcase
In an extreme binary black hole system, an orbit will increase its angle of inclination (i) as it evolves in Kerr spacetime. We focus our attention on the behaviour of the Carter constant (Q) for near-polar orbits. The value of Q for bound orbits is non-negative; and an increase in Q corresponds to an increase in i. For a Schwarzschild black hole, the polar orbit represents the boundary between the prograde and retrograde orbits at which Q is at its maximum value. The introduction of spin (S = |J|/M2) to the massive black hole causes this boundary, or Abutment, to …
Recent Discoveries Of Supersoft X-Ray Sources In M 31,
2010
Max-Planck-Instiut für Extraterrestrische Physik, Giessenbachstraße
Recent Discoveries Of Supersoft X-Ray Sources In M 31, M. Henze, W. Pietsch, E. Haberl, G. Sala, M. Hernanz, D. Hartzidimitriou, A. Rau, Dieter H. Hartmann, J. Greiner, M. Orio, H Stiele, M.J. Freyberg
Publications
Classical novae (CNe) have recently been reported to represent the major class of supersoft X-ray sources (SSSs) in the central area of our neighbouring galaxy M 31. This paper presents a review of results from recent X-ray observations of M 31 with XMM-Newton and Chandra. We carried out a dedicated optical and X-ray monitoring program of CNe and SSSs in the central area of M 31. We discovered the first SSSs in M 31 globular clusters (GCs) and their connection to the very first discovered CN in a M 31 GC. This result may have an impact on the CN …
Constraining The Black Hole Mass Spectrum With Gravitational Wave Observations – I. The Error Kernel,
2010
Utah State University
Constraining The Black Hole Mass Spectrum With Gravitational Wave Observations – I. The Error Kernel, Danny C. Jacobs, Joseph E. Plowman, Ronald W. Hellings, Sachiko Tsuruta, Shane L. Larson
All Physics Faculty Publications
Many scenarios have been proposed for the origin of the supermassive black holes (SMBHs) that are found in the centres of most galaxies. Many of these formation scenarios predict a high-redshift population of intermediate-mass black holes (IMBHs), with masses M• in the range 102≲M•≲ 105 M⊙. A powerful way to observe these IMBHs is via gravitational waves the black holes emit as they merge. The statistics of the observed black hole population should, in principle, allow us to discriminate between competing astrophysical scenarios for the origin and formation of SMBHs. However, …
Dynamics Of Strong Radio Sources With Umrt-Ii.,
2010
Universiti Malaya
Dynamics Of Strong Radio Sources With Umrt-Ii., Mohammed Awid Al-Amri
Student Works (2010-2019)
Radio astronomy is a new field in Southeast Asia. University Malaya Radio Telescope UMRT-II is located on the roof of Block B in the Department of Physics, University of Malaya to detect neutral hydrogen emission line. Doppler shift of 1420.4 MHz for different radio sources were observed to determine their dynamics. By measuring the Doppler shift, the velocity V, of each radio source can be determined. Hence the dynamic of radio source can be deduced. The radio spectrum of Coma Cluster was also analyzed and its dark matter content was estimated. The observation time effort was investigated for Coma Cluster …
Gamma-Ray Spectroscopy: Meteorite Samples And The Search For 98tc,
2010
California Polytechnic State University - San Luis Obispo
Gamma-Ray Spectroscopy: Meteorite Samples And The Search For 98tc, Kristopher L. Merolla
Physics
The focus of this project is low-count-level gamma-ray spectroscopy on meteorite samples in search of a particular isotope of Technetium (98Tc), which according to stellar theory, should be present in the universe. The spectral lines for 99Tc have, however, been observed in S-, M-, and N- type stars, which makes finding 98Tc created naturally a possibility, and thus a search can be justified.
Starships & The Physics Of Interstellar Travel,
2010
Utah State University
Starships & The Physics Of Interstellar Travel, Shane L. Larson
Public Talks
No abstract provided.
Connections To The Cosmos: The Search For Life Beyond Earth,
2010
Utah State University
Connections To The Cosmos: The Search For Life Beyond Earth, Shane L. Larson
Public Talks
No abstract provided.
The California Planet Survey. Ii. A Saturn-Mass Planet Orbiting The M Dwarf Gl 6491,
2010
California Institute of Technology
The California Planet Survey. Ii. A Saturn-Mass Planet Orbiting The M Dwarf Gl 6491, John Asher Johnson, Andrew W. Howard, Geoffrey W. Marcy, Brendan P. Bowler, Gregory W. Henry, Debra A. Fischer, Kevin Apps, Howard Isaacson, Jason T. Wright
Information Systems and Engineering Management Research Publications
We report precise Doppler measurements of the nearby (d = 10.34 pc) M dwarf Gl 649 that reveal the presence of a planet with a minimum mass MP sin i = 0.328 MJup in an eccentric (e = 0.30), 598.3 day orbit. Our photometric monitoring reveals Gl 649 to be a new variable star with brightness changes on both rotational and decadal timescales. However, neither of these timescales are consistent with the 600 day Doppler signal and so provide strong support for planetary reflex motion as the best interpretation of the observed radial velocity variations. Gl …
Ordered Magnesium-Lithium Alloys: First-Principles Predictions,
2010
Brigham Young University
Ordered Magnesium-Lithium Alloys: First-Principles Predictions, Richard H. Taylor, Gus L. W. Hart, Stefano Curtarolo
Faculty Publications
Magnesium-lithium (Mg-Li) alloys are among the lightest structural materials. Although considerable work has been done on the Mg-Li system, little is known regarding potential ordered phases. A first and rapid analysis of the system with the high-throughput method reveals an unexpected wealth of potentially stable low-temperature phases. Subsequent cluster expansions constructed for bcc and hcp superstructures extend the analysis and verify our high-throughput results. Of particular interest are those structures with greater than 13 at. % lithium, as they exhibit either partial or complete formation as a cubic structure. Order-disorder transition temperatures are predicted by Monte Carlo simulations to be …
Chasing Cosmic Bullets: The Pierre Auger Experiment,
2010
Illinois Math and Science Academy
Chasing Cosmic Bullets: The Pierre Auger Experiment, Angela Olinto
IMSA Great Minds Program ®
The most energetic particles in the universe are ultra-high energy cosmic rays. Millions of times more powerful than anything produced by man-made accelerators, their origin has been a mystery for about a century. Over the last several years, an international collaboration of 18 countries joined forces to solve this mystery by building the Pierre Auger Observatory. Spread over 3,000 square kilometers in western Argentina, the observatory was recently inaugurated. During its construction, the observatory gathered enough of these rare particles to find the first clues to their origin. The most energetic of these particles tend to point to cosmologically nearby …
Refined Stellar, Orbital And Planetary Parameters Of The Eccentric Hat-P-2 Planetary System,
2010
Harvard-Smithsonian Center for Astrophysics
Refined Stellar, Orbital And Planetary Parameters Of The Eccentric Hat-P-2 Planetary System, András Pál, Gáspár Á. Bakos, Guillermo Torres, Robert W. Noyes, Debra A. Fischer, John A. Johnson, Gregory W. Henry, R. Paul Butler, Geoffrey W. Marcy, Andrew W. Howard, Brigitta Sipőcz, David W. Latham, Gilbert A. Esquerdo
Information Systems and Engineering Management Research Publications
We present refined parameters for the extrasolar planetary system HAT-P-2 (also known as HD 147506), based on new radial velocity and photometric data. HAT-P-2b is a transiting extrasolar planet that exhibits an eccentric orbit. We present a detailed analysis of the planetary and stellar parameters, yielding consistent results for the mass and radius of the star, better constraints on the orbital eccentricity and refined planetary parameters. The improved parameters for the host star are M★= 1.36 ± 0.04 M⊙ and R★= 1.64 ± 0.08 R⊙, while the planet has a mass of Mp= 9.09 ± 0.24 MJup and radius of …
Simulating The Fticr-Ms Signal Of A Decaying Beryllium-7 Ion Plasma In A 2d Electrostatic Pic Code,
2010
Brigham Young University - Provo
Simulating The Fticr-Ms Signal Of A Decaying Beryllium-7 Ion Plasma In A 2d Electrostatic Pic Code, Michael Takeshi Nakata
Theses and Dissertations
Beryllium-7 (Be-7) only decays by electron capture into lithium-7 (Li-7) with a half life of 53 days. We study the effect of ionization on this decay rate. We do so by trapping a Be-7 ion plasma in a cylindrical Malmberg-Penning trap and measuring Be-7 and Li-7 concentrations as functions of time by using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). We have simulated these signals in a 2-dimensional electrostatic particle-in-cell (PIC) code. The two spectrum peaks merge at high ion densities whereas at low ion densities they can be resolved. The merged peak shifts linearly according to the relative …
Discovery Of Variability In The Very High Energy Gamma-Ray Emission Of 1es 1218+304 With Veritas,
2010
Department of Physical Sciences, Cork Institute of Technology, Bishopstown, Cork, Ireland
Discovery Of Variability In The Very High Energy Gamma-Ray Emission Of 1es 1218+304 With Veritas, P. T. Reynolds, Et Al
Physical Sciences Publications
We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ~6% of the Crab Nebula flux, the new VERITAS data reveal a prominent flare reaching ~20% of the Crab. While very high energy (VHE) flares are quite common in many nearby blazars, the case of 1ES 1218+304 (redshift z = 0.182) is particularly interesting since it belongs to a group of blazars that exhibit unusually hard VHE spectra considering their redshifts. When correcting the measured …
The Acs Survey Of Galactic Globular Clusters. Viii. Effects Of Environment On Globular Cluster Global Mass Functions,
2010
Whitman College
The Acs Survey Of Galactic Globular Clusters. Viii. Effects Of Environment On Globular Cluster Global Mass Functions, Nathaniel E. Q. Paust, I. Neill Reid, Giampaolo Piotto, Antonio Aparicio, Jay Anderson, Ata Sarajedini, Luigi R. Bedin, Brian Chaboyer
Dartmouth Scholarship
We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic Globular Clusters to construct global present-day mass functions for 17 globular clusters utilizing multi-mass King models to extrapolate from our observations to the global cluster behavior. The global present-day mass functions for these clusters are well matched by power laws from the turnoff, ≈0.8 M ☉, to 0.2-0.3 M ☉ on the lower main sequence. The slopes of those power-law fits, α, have been correlated with an extensive set of intrinsic and extrinsic cluster properties to investigate which parameters may influence the form …
The Determination Of Reddening From Intrinsic Vr Colors Of Rr Lyrae Stars,
2010
Dartmouth College
The Determination Of Reddening From Intrinsic Vr Colors Of Rr Lyrae Stars, Andrea Kunder, Brian Chaboyer, Andrew Layden
Dartmouth Scholarship
New R-band observations of 21 local field RR Lyrae variable stars are used to explore the reliability of minimum light (V – R) colors as a tool for measuring interstellar reddening. For each star, R-band intensity mean magnitudes and light amplitudes are presented. Corresponding V-band light curves from the literature are supplemented with the new photometry, and (V – R) colors at minimum light are determined for a subset of these stars as well as for other stars in the literature. Two different definitions of minimum light color are examined, one which uses …
A Hybrid Particle-Continuum Method For Hydrodynamics Of Complex Fluids,
2010
San Jose State University
A Hybrid Particle-Continuum Method For Hydrodynamics Of Complex Fluids, Alejandro Garcia, A. Donev, J. B. Bell, B. Alder
Faculty Publications
A previously developed hybrid particle-continuum method [J. B. Bell, A. Garcia, and S. A. Williams, Multiscale Model. Simul., 6 (2008), pp. 1256–1280] is generalized to dense fluids and two- and three-dimensional flows. The scheme couples an explicit fluctuating compressible Navier–Stokes solver with the isotropic direct simulation Monte Carlo (DSMC) particle method [A. Donev, A. L. Garcia, and B. J. Alder, J. Stat. Mech. Theory Exp., 2009 (2009), article P11008]. To achieve bidirectional dynamic coupling between the particle (microscale) and continuum (macroscale) regions, the continuum solver provides state-based boundary conditions to the particle subdomain, while the particle solver provides flux-based boundary …
The Globular Cluster System Of Ngc 1399. V. Dynamics Of The Cluster System Out To 80 Kpc,
2010
Argelander-Institut für Astronomie
The Globular Cluster System Of Ngc 1399. V. Dynamics Of The Cluster System Out To 80 Kpc, Y. Schuberth, T. Richtler, M. Hilker, B. Dirsch, L. Bassino, Aaron J. Romanowsky, L. Infante
Faculty Publications
Globular clusters (GCs) are tracers of the gravitational potential of their host galaxies. Moreover, their kinematic properties may provide clues for understanding the formation of GC systems and their host galaxies. We use the largest set of GC velocities obtained so far of any elliptical galaxy to revise and extend the previous investigations (Richtler et al. 2004) of the dynamics of NGC 1399, the central dominant galaxy of the nearby Fornax cluster of galaxies. The GC velocities are used to study the kinematics, their relation with population properties, and the dark matter halo of NGC 1399. We have obtained 477 …
Central Dark Matter Content Of Early-Type Galaxies: Scaling Relations And Connections With Star Formation Histories, N. R. Napolitano, Aaron J. Romanowsky, A. J. Tortora
Faculty Publications
We examine correlations between masses, sizes and star formation histories for a large sample of low-redshift early-type galaxies, using a simple suite of dynamical and stellar population models. We confirm an anticorrelation between the size and stellar age and go on to survey for trends with the central content of dark matter (DM). An average relation between the central DM density and galaxy size of 〈ρDM〉∝R−2eff provides the first clear indication of cuspy DM haloes in these galaxies – akin to standard Λ cold dark matter haloes that have undergone adiabatic contraction. The DM density scales with galaxy mass as …
A Long-Period Planet Orbiting A Nearby Sun-Like Star,
2010
University of Hertfordshire
A Long-Period Planet Orbiting A Nearby Sun-Like Star, Hugh R. A. Jones, R. Paul Butler, Chris Tinney, Simon O'Toole, Rob Wittenmyer, Gregory W. Henry, Stefano Meschiari, Steve Vogt, Eugenio Rivera, Greg Laughlin, Brad D. Carter, Jeremy Bailey, James S. Jenkins
Information Systems and Engineering Management Research Publications
The Doppler wobble induced by the extra-solar planet HD 134987b was first detected by data from the Keck Telescope nearly a decade ago, and was subsequently confirmed by data from the Anglo-Australian Telescope (AAT). However, as more data have been acquired for this star over the years since, the quality of a single Keplerian fit to that data has been getting steadily worse. The best-fitting single Keplerian to the 138 Keck and AAT observations now in hand has an root-mean-square (rms) scatter of 6.6 m s−1. This is significantly in excess of both the instrumental precision achieved by both the …
