Practical Methods For Continuous Gravitational Wave Detection Using Pulsar Timing Data,
2012
University of Texas Rio Grande Valley
Practical Methods For Continuous Gravitational Wave Detection Using Pulsar Timing Data, J. A. Ellis, F. A. Jenet, M. A. Mclaughlin
Physics & Astronomy Faculty Publications
Gravitational waves (GWs) are tiny ripples in the fabric of space time predicted by Einstein's general relativity. Pulsar timing arrays (PTAs) are well poised to detect low-frequency (10-9-10-7 Hz) GWs in the near future. There has been a significant amount of research into the detection of a stochastic background of GWs from supermassive black hole binaries (SMBHBs). Recent work has shown that single continuous sources standing out above the background may be detectable by PTAs operating at a sensitivity sufficient to detect the stochastic background. The most likely sources of continuous GWs in the pulsar timing frequency band are extremely …
Discovery Of The Optical/Ultraviolet/Gamma-Ray Counterpart To The Eclipsing Millisecond Pulsar J1816+4510,
2012
The University of Texas Rio Grande Valley
Discovery Of The Optical/Ultraviolet/Gamma-Ray Counterpart To The Eclipsing Millisecond Pulsar J1816+4510, D. L. Kaplan, Kevin Stovall, S. M. Ransom, M. S. R. Robers, R. Kotulla, Anne M. Archibald, C. M. Biwer, Anthony J. Ford, Fredrick Jenet
Physics & Astronomy Faculty Publications
The energetic, eclipsing millisecond pulsar J1816+4510 was recently discovered in a low-frequency radio survey with the Green Bank Telescope. With an orbital period of 8.7 hr and a minimum companion mass of 0.16 M☉, it appears to belong to an increasingly important class of pulsars that are ablating their low-mass companions. We report the discovery of the γ-ray counterpart to this pulsar and present a likely optical/ultraviolet counterpart as well. Using the radio ephemeris, we detect pulsations in the unclassified γ-ray source 2FGL J1816.5+4511, implying an efficiency of ∼25% in converting the pulsar's spin-down luminosity into γ-rays and adding PSR …
Entropic Measure For Localized Energy Configurations: Kinks, Bounces, And Bubbles,
2012
Dartmouth College
Entropic Measure For Localized Energy Configurations: Kinks, Bounces, And Bubbles, Marcelo Gleiser, Nikitas Stamatopoulos
Dartmouth Scholarship
No abstract provided.
The Gas/Dust Ratio Of Circumstellar Disks: Testing Models Of Planetesimal Formation,
2012
University of Missouri-St. Louis
The Gas/Dust Ratio Of Circumstellar Disks: Testing Models Of Planetesimal Formation, David Horne, Erika Gibb, Terrence Rettig, Sean Brittain, David Tilley, Dinshaw Balsara
Physics Faculty Works
We present high-resolution, near-infrared NIRSPEC observations of CO absorption toward six class II T Tauri stars: AA Tau, DG Tau, IQ Tau, RY Tau, CW Tau, and Haro 6-5b. 12CO overtone absorption lines originating from the circumstellar disk of each object were used to calculate line-of-sight gas column densities toward each source. We measured the gas/dust ratio as a function of disk inclination, utilizing measured visual extinctions and inclinations for each star. The majority of our sources show further evidence for a correlation between the gas/dust column density ratio and disk inclination similar to that found by Rettig et al.
Elastic Properties Of The Zintl Ferromagnet Yb14mnsb11,
2012
University of Tennessee
Elastic Properties Of The Zintl Ferromagnet Yb14mnsb11, Sriparna Bhattacharya, D C. Marinescu, James R. Morris, Ivan A. Sergienko, Brian Sales, David Madrus, Veerle Keppens
Publications
We report measurements of the elastic moduli as a function of temperature (5–300) K and magnetic field (0–2 T) for the Zintl ferromagnet Yb14MnSb11, which is believed to be a rare example of an underscreened Kondo lattice. The elastic moduli measured below the Curie temperature in this complex ferromagnet exhibit unusual lattice stiffening that is independent of the magnetic field and can be adequately modeled using the Landau theory.
The Hd 192263 System: Planetary Orbital Period And Stellar Variability Disentangled,
2012
University of British Columbia
The Hd 192263 System: Planetary Orbital Period And Stellar Variability Disentangled, Diana Dragomir, Stephen R. Kane, Gregory W. Henry, David R. Ciardi, Debra A. Fischer, Andrew W. Howard, Eric L. N. Jensen, Gregory Laughlin, Suvrath Mahadevan, Jaymie M. Matthews, Genady Pilyavsky, Kaspar Von Braun, Sharon X. Wang, Jason T. Wright
Information Systems and Engineering Management Research Publications
As part of the Transit Ephemeris Refinement and Monitoring Survey, we present new radial velocities and photometry of the HD 192263 system. Our analysis of the already available Keck-HIRES and CORALIE radial velocity measurements together with the five new Keck measurements we report in this paper results in improved orbital parameters for the system. We derive constraints on the size and phase location of the transit window for HD 192263b, a Jupiter-mass planet with a period of 24.3587 ± 0.0022 days. We use 10 years of Automated Photoelectric Telescope photometry to analyze the stellar variability and search for planetary transits. …
Herschel/Pacs Observations Of Young Sources In Taurus: The Far-Infrared Counterpart Of Optical Jets,
2012
Institut de Planetologie et d'Astrophysique de Grenoble
Herschel/Pacs Observations Of Young Sources In Taurus: The Far-Infrared Counterpart Of Optical Jets, L Podio, I Kamp, D Flower, C Howard, G Sandell, A Mora, G Aresu, Sean D. Brittain, W.R.F. Dent, C Pinte, G J. White
Publications
Context. Observations of the atomic and molecular line emission associated with jets and outflows emitted by young stellar objects provide sensitive diagnostics of the excitation conditions, and can be used to trace the various evolutionary stages they pass through as they evolve to become main sequence stars. Aims. To understand the relevance of atomic and molecular cooling in shocks, and how accretion and ejection efficiency evolves with the evolutionary state of the sources, we will study the far-infrared counterparts of bright optical jets associated with Class I and II sources in Taurus (T Tau, DG Tau A, DG Tau B, …
On The Determination Of The Spin Of The Black Hole In Cyg X-1 From X-Ray Reflection Spectra,
2012
Institute of Astronomy, Cambridge
On The Determination Of The Spin Of The Black Hole In Cyg X-1 From X-Ray Reflection Spectra, A. C. Fabian, D. R. Wilkins, J. M. Miller, R. C. Reis, C. S. Reynolds, E. M. Cackett, M. A. Nowak, G. G. Pooley, K. Pottschmidt, J. S. Sanders, R. R. Ross, J. Wilms
Physics and Astronomy Faculty Research Publications
The spin of Cygnus X-1 is measured by fitting reflection models to Suzaku data covering the energy band 0.9-400 keV. The inner radius of the accretion disc is found to lie within 2 gravitational radii (rg=GM/c2), and a value of ? is obtained for the dimensionless black hole spin. This agrees with recent measurements using the continuum fitting method by Gou et al. and of the broad iron line by Duro et al. The disc inclination is measured at ?, which is consistent with the recent optical measurement of the binary system inclination by Orosz et …
Simulated Lsst Survey Of Rr Lyrae Stars Throughout The Local Group,
2012
Florida Institute of Technology
Simulated Lsst Survey Of Rr Lyrae Stars Throughout The Local Group, Hakeem M. Oluseyi, Christopher Culliton, Muhammad Furqan, Keri L. Hoadley, Paul Regencia, Akeem J. Wells
Aerospace, Physics, and Space Science Faculty Publications
We report on a study to determine the efficiency of the Large Synoptic Survey Telescope (LSST) to recover the periods, brightnesses, and shapes of RR Lyrae stars’ light curves in the volume extending to heliocentric distances of 1.5 Mpc. We place the smoothed light curves of 30 type ab and 10 type c RR Lyrae stars in 1007 fields across the sky, each of which represents a different realization of the LSST sampling cadences, and that sample five particular observing modes. A light curve simulation tool was used to sample the idealized RR Lyrae stars’ light curves, returning each as …
Fourier Transform Infrared Spectroscopy And Wide-Angle X-Ray Scattering: Investigations On Polypropylene-Vapor-Grown Carbon Nanofiber Composites,
2012
The University of Texas Rio Grande Valley
Fourier Transform Infrared Spectroscopy And Wide-Angle X-Ray Scattering: Investigations On Polypropylene-Vapor-Grown Carbon Nanofiber Composites, Mircea Chipara, John Hamilton, Alin Cristian Chipara, Tom George, Dorina M. Chipara, Elamin Ibrahim, Karen Lozano, David J. Sellmyer
Physics & Astronomy Faculty Publications
Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray scattering (WAXS) investigations of isotactic polypropylene (iPP)-vapor-grown carbon nanofiber (VGCNF) composites containing various amounts of VGCNFs ranging between 0 and 20 wt %. are reported. The FTIR investigations were focused on the regularity bands of iPP. The FTIR data indicated a drop in the isotacticity index as the concentration of nanofibers was increased; this suggested a decrease in the crystallinity. WAXS measurements revealed a dominating α 1 phase, with a small admixture of γ phase or mesophase. The loading of the polymeric matrix with carbon nanofibers (CNFs) did not induce significant changes …
Evolution In The Dust Lane Fraction Of Edge-On L*V Spiral Galaxies Since Z = 0.8.,
2012
University of Louisville
Evolution In The Dust Lane Fraction Of Edge-On L*V Spiral Galaxies Since Z = 0.8., Benne W. Holwerda, J. J. Dalcanton, D. Radburn-Smith, R. S. De Jong, P. Guhathakurta, A. Koekemoer, R. J. Allen, T. Boker
Faculty and Staff Scholarship
The presence of a well-defined and narrow dust lane in an edge-on spiral galaxy is the observational signature of a thin and dense molecular disk, in which gravitational collapse has overcome turbulence. Using a sample of galaxies out to z ∼ 1 extracted from the COSMOS survey, we identify the fraction of massive (L∗ V ) disks that display a dust lane. Our goal is to explore the evolution in the stability of the molecular interstellar medium (ISM) disks in spiral galaxies over a cosmic timescale. We check the reliability of our morphological classifications against changes in rest-frame wavelength, resolution, …
Outer-Disk Populations In Ngc 7793 : Evidence For Stellar Radial Migration.,
2012
University of Washington - Seattle Campus
Outer-Disk Populations In Ngc 7793 : Evidence For Stellar Radial Migration., David J. Radburn-Smith, Rok Roskar, Victor P. Debattista, Julianne J. Dalcanton, David Streich, Roelof S. De Jong, Marija Vlajic, Benne W. Holwerda, Chris W. Purcell, Andrew E. Dolphin, Daniel B. Zucker
Faculty and Staff Scholarship
We analyzed the radial surface brightness profile of the spiral galaxy NGC 7793 using HST/ACS images from the GHOSTS survey and a new HST/WFC3 image across the disk break. We used the photometry of resolved stars to select distinct populations covering a wide range of stellar ages. We found breaks in the radial profiles of all stellar populations at 280 (∼5.1 kpc). Beyond this disk break, the profiles become steeper for younger populations. This same trend is seen in numerical simulations where the outer disk is formed almost entirely by radial migration. We also found that the older stars of …
3.6 And 4.5 Μm Phase Curves And Evidence For Non-Equilibrium Chemistry In The Atmosphere Of Extrasolar Planet Hd 189733b,
2012
California Institute of Technology
3.6 And 4.5 Μm Phase Curves And Evidence For Non-Equilibrium Chemistry In The Atmosphere Of Extrasolar Planet Hd 189733b, Heather A. Knutson, Nikole K. Lewis, Jonathan J. Fortney, Adam Burrows, Adam P. Showman, Nicolas B. Cowan, Eric Agol, Suzanne Aigrain, David Charbonneau, Drake Deming, Jean-Michel Désert, Gregory W. Henry, Jonathan Langton, Gregory Laughlin
Information Systems and Engineering Management Research Publications
We present new, full-orbit observations of the infrared phase variations of the canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 μm bands using the Spitzer Space Telescope. When combined with previous phase curve observations at 8.0 and 24 μm, these data allow us to characterize the exoplanet's emission spectrum as a function of planetary longitude and to search for local variations in its vertical thermal profile and atmospheric composition. We utilize an improved method for removing the effects of intrapixel sensitivity variations and robustly extracting phase curve signals from these data, and we calculate our best-fit parameters …
Bypassing The Bandwidth Theorem With Pt Symmetry,
2012
The University of Texas Rio Grande Valley
Bypassing The Bandwidth Theorem With Pt Symmetry, Hamidreza Ramezani, J. Schindler, F. M. Ellis, Uwe Günther, Tsampikos Kottos
Physics & Astronomy Faculty Publications
The beat time τ fpt associated with the energy transfer between two coupled oscillators is dictated by the bandwidth theorem which sets a lower bound τ fpt∼1/δω. We show, both experimentally and theoretically, that two coupled active LRC electrical oscillators with parity-time (PT) symmetry bypass the lower bound imposed by the bandwidth theorem, reducing the beat time to zero while retaining a real valued spectrum and fixed eigenfrequency difference δω. Our results foster design strategies which lead to (stable) pseudounitary wave evolution, and may allow for ultrafast computation, telecommunication, and signal processing. © 2012 American Physical Society.
Analysis Of The Early-Time Optical Spectra Of Sn 2011fe In M101,
2012
Dartmouth College
Analysis Of The Early-Time Optical Spectra Of Sn 2011fe In M101, J. T. Parrent, D. A. Howell, B. Friesen, R. C. Thomas
Dartmouth Scholarship
The nearby Type Ia supernova SN 2011fe in M101 (cz=241 km s^-1) provides a unique opportunity to study the early evolution of a "normal" Type Ia supernova, its compositional structure, and its elusive progenitor system. We present 18 high signal-to-noise spectra of SN 2011fe during its first month beginning 1.2 days post-explosion and with an average cadence of 1.8 days. This gives a clear picture of how various line-forming species are distributed within the outer layers of the ejecta, including that of unburned material (C+O). We follow the evolution of C II absorption features until they diminish near maximum light, …
All-Sky Search For Gravitational-Wave Bursts In The Second Joint Ligo-Virgo Run,
2012
The University of Texas Rio Grande Valley
All-Sky Search For Gravitational-Wave Bursts In The Second Joint Ligo-Virgo Run, J. Abadie, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano
Physics & Astronomy Faculty Publications
We present results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010: data are analyzed when at least two of the three LIGO-Virgo detectors are in coincident operation, with a total observation time of 207 days. The analysis searches for transients of duration -1s over the frequency band 64-5000 Hz, without other assumptions on the signal waveform, polarization, direction or occurrence time. All identified events are consistent with the expected accidental background. We set frequentist upper limits on the rate of gravitational-wave bursts by combining …
Findchirp: An Algorithm For Detection Of Gravitational Waves From Inspiraling Compact Binaries,
2012
Max-Planck-Institut fur Gravitationsphysik
Findchirp: An Algorithm For Detection Of Gravitational Waves From Inspiraling Compact Binaries, Bruce Allen, Warren G. Anderson, Patrick R. Brady, Duncan A. Brown, Jolien D E Creighton
Physics - All Scholarship
Matched-filter searches for gravitational waves from coalescing compact binaries by the LIGO Scientific Collaboration use the FINDCHIRP algorithm: an implementation of the optimal filter with innovations to account for unknown signal parameters and to improve performance on detector data that has nonstationary and non-Gaussian artifacts. We provide details on the FINDCHIRP algorithm as used in the search for subsolar mass binaries, binary neutron stars, neutron star-black hole binaries, and binary black holes.
The Hidden “Agn Main Sequence”: Evidence For A Universal Black Hole Accretion To Star Formation Rate Ratio Since Z ∼ 2 Producing An M Bh - M * Relation,
2012
CEA-Saclay
The Hidden “Agn Main Sequence”: Evidence For A Universal Black Hole Accretion To Star Formation Rate Ratio Since Z ∼ 2 Producing An M Bh - M * Relation, J. R. Mullaney, E. Daddi, M. Béthermin, D. Elbaz, S. Juneau, M. Pannella, M. T. Sargent, D. M. Alexander, R. C. Hickox
Dartmouth Scholarship
Using X-ray stacking analyses we estimate the average amounts of supermassive black hole (SMBH) growth taking place in star-forming galaxies at z ~ 1 and z ~ 2 as a function of galaxy stellar mass (M *). We find that the average SMBH growth rate follows remarkably similar trends with M * and redshift as the average star formation rates (SFRs) of their host galaxies (i.e., \dot{M}_BH vprop M * 0.86 ± 0.39 for the z ~ 1 sample and \dot{M}_BH vprop M * 1.05 ± 0.36 for the z ~ 2 sample). It follows that the ratio of …
Flux And Photon Spectral Index Distributions Of Fermi-Lat Blazars And Contribution To The Extragalactic Gamma-Ray Background,
2012
University of Richmond
Flux And Photon Spectral Index Distributions Of Fermi-Lat Blazars And Contribution To The Extragalactic Gamma-Ray Background, Jack Singal, V. Petrosian, M. Ajello
Physics Faculty Publications
We present a determination of the distributions of the photon spectral index and gamma-ray flux—the so-called log N–log S relation—for the 352 blazars detected with a greater than approximately 7σ detection threshold and located above ±20◦ Galactic latitude by the Large Area Telescope of the Fermi Gamma-ray Space Telescope in its first year catalog. Because the flux detection threshold depends on the photon index, the observed raw distributions do not provide the true log N–log S counts or the true distribution of the photon index. We use the non-parametric methods developed by Efron and Petrosian to reconstruct the intrinsic distributions …
Discovery Of Tev Gamma-Ray Emission Toward Supernova Remnant Snr G78.2+2.1,
2012
Cork Institute of Technology
Discovery Of Tev Gamma-Ray Emission Toward Supernova Remnant Snr G78.2+2.1, P. T. Reynolds, Et. Al.
Physical Sciences Publications
We report the discovery of an unidentified, extended source of very-high-energy gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hr of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic …
