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8,854 full-text articles. Page 180 of 309.

Enhancing The Science Return Of Lunar Surface Studies: Analysis Of Rediscovered Data From Apollo 17'S Lunar Seismic Profiling Experiment, Deanna Phillips, Richard Miller 2016 University of Alabama in Huntsville

Enhancing The Science Return Of Lunar Surface Studies: Analysis Of Rediscovered Data From Apollo 17'S Lunar Seismic Profiling Experiment, Deanna Phillips, Richard Miller

Von Braun Symposium Student Posters

No abstract provided.


The Intermediate-Line Region In Active Galactic Nuclei, T. P. Adhikari, A. Różańska, B. Czerny, K. Hryniewicz, Gary J. Ferland 2016 Polish Academy of Sciences, Poland

The Intermediate-Line Region In Active Galactic Nuclei, T. P. Adhikari, A. Różańska, B. Czerny, K. Hryniewicz, Gary J. Ferland

Physics and Astronomy Faculty Publications

We show that the recently observed suppression of the gap between the broad-line region (BLR) and the narrow-line region (NLR) in some active galactic nuclei (AGNs) can be fully explained by an increase of the gas density in the emitting region. Our model predicts the formation of the intermediate-line region (ILR) that is observed in some Seyfert galaxies by the detection of emission lines with intermediate-velocity FWHM ~ 700–1200 km s−1. These lines are believed to be originating from an ILR located somewhere between the BLR and NLR. As was previously proved, the apparent gap is assumed to …


Earthkam: A Classroom With The Ultimate View!, Jeremy Frost, Tyler Finley, Tim Klug, Angela Burke, Robert Griffin 2016 University of Alabama in Huntsville

Earthkam: A Classroom With The Ultimate View!, Jeremy Frost, Tyler Finley, Tim Klug, Angela Burke, Robert Griffin

Von Braun Symposium Student Posters

No abstract provided.


Improving The Efficiency Of Gravitational Wave Detection, Jessica Page, Tyson Littenberg 2016 University of Alabama in Huntsville

Improving The Efficiency Of Gravitational Wave Detection, Jessica Page, Tyson Littenberg

Von Braun Symposium Student Posters

No abstract provided.


Designing An Anti-Coincidence Shielding System For The Alfred Project, Active Luminescence For x-Ray Emission Detection (ALFRED) Team, Francis Wessling 2016 University of Alabama in Huntsville

Designing An Anti-Coincidence Shielding System For The Alfred Project, Active Luminescence For X-Ray Emission Detection (Alfred) Team, Francis Wessling

Von Braun Symposium Student Posters

No abstract provided.


Structure And Physical Conditions In The Huygens Region Of The Orion Nebula, C. R. O'Dell, Gary J. Ferland, M. Peimbert 2016 Vanderbilt University

Structure And Physical Conditions In The Huygens Region Of The Orion Nebula, C. R. O'Dell, Gary J. Ferland, M. Peimbert

Physics and Astronomy Faculty Publications

Hubble Space Telescope images, MUSE maps of emission lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the first time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photoevaporating ionization front being viewed at different angles. There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star θ1 …


Sdss-Iv Manga: Stellar Population Gradients As A Function Of Galaxy Environment, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, M. A. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann 2016 University of Portsmouth, UK

Sdss-Iv Manga: Stellar Population Gradients As A Function Of Galaxy Environment, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, M. A. Bershady, K. Bundy, N. Drory, D. Law, Renbin Yan, D. Wake, A. Weijmans, D. Bizyaev, J. Brownstein, R. R. Lane, R. Maiolino, K. Masters, M. Merrifield, C. Nitschelm, K. Pan, A. Roman-Lopes, T. Storchi-Bergmann

Physics and Astronomy Faculty Publications

We study the internal radial gradients of stellar population properties within 1.5 Re and analyse the impact of galaxy environment. We use a representative sample of 721 galaxies with masses ranging between 109 M⊙ and 1011.5 M⊙ from the SDSS-IV survey MaNGA. We split this sample by morphology into early-type and late-type galaxies. Using the full spectral fitting code firefly, we derive the light and mass-weighted stellar population properties, age and metallicity, and calculate the gradients of these properties. We use three independent methods to quantify galaxy environment, namely the Nth nearest neighbour, the …


Improved Analysis Of Gw150914 Using A Fully Spin-Precessing Waveform Model, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepańczyk, M. Zanolin, et al. 2016 California Institute of Technology

Improved Analysis Of Gw150914 Using A Fully Spin-Precessing Waveform Model, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-one-body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessing-spin waveform model (precessing EOBNR) developed within the EOB formalism. (See article for remainder of abstract.)


Ultraluminous X-Ray Bursts In Two Ultracompact Companions To Nearby Elliptical Galaxies, Jimmy Irwin, W. Maksym, Gregory Sivakoff, Aaron Romanowsky, Dacheng Lin, Tyler Speegle, Ian Prado, David Mildebrath, Jay Strader, Jifeng Liu, Jon Miller 2016 University of Alabama - Tuscaloosa

Ultraluminous X-Ray Bursts In Two Ultracompact Companions To Nearby Elliptical Galaxies, Jimmy Irwin, W. Maksym, Gregory Sivakoff, Aaron Romanowsky, Dacheng Lin, Tyler Speegle, Ian Prado, David Mildebrath, Jay Strader, Jifeng Liu, Jon Miller

Faculty Publications

A search of archival X-ray data for 70 nearby galaxies has yielded two flaring sources in globular clusters or ultracompact dwarf companions of parent elliptical galaxies. One source flared once, and the other five times. When not flaring, these sources appear to be normal accreting neutron-star or black-hole X-ray binaries. Unlike magnetars and other bodies that produce repetitive flares of similar luminosity, they are located in old stellar populations.


Deep Chandra Observations Of The Compact Starburst Galaxy Henize 2–10: X-Rays From The Massive Black Hole, Amy E. Reines, Mark T. Reynolds, Jon M. Miller, Gregory R. Sivakoff, Jenny E. Greene, Ryan C. Hickox, Kelsey E. Johnson 2016 National Optical Astronomy Observatory

Deep Chandra Observations Of The Compact Starburst Galaxy Henize 2–10: X-Rays From The Massive Black Hole, Amy E. Reines, Mark T. Reynolds, Jon M. Miller, Gregory R. Sivakoff, Jenny E. Greene, Ryan C. Hickox, Kelsey E. Johnson

Dartmouth Scholarship

We present follow-up X-ray observations of the candidate massive black hole (BH) in the nucleus of the low-mass, compact starburst galaxy Henize 2–10. Using new high-resolution observations from the Chandra X-ray Observatory totaling 200 ks in duration, as well as archival Chandraobservations from 2001, we demonstrate the presence of a previously unidentified X-ray point source that is spatially coincident with the known nuclear radio source in Henize 2–10 (i.e., the massive BH). We show that the hard X-ray emission previously identified in the 2001 observation is dominated by a source that is distinct from the nucleus, with the properties …


The Growth Of The Central Region By Acquisition Of Counterrotating Gas In Star-Forming Galaxies, Yan-Mei Chen, Yong Shi, Christy A. Tremonti, Matt Bershady, Michael Merrifield, Eric Emsellem, Yi-Fei Jin, Song Huang, Hai Fu, David A. Wake, Kevin Bundy, David Stark, Lihwai Lin, Maria Argudo-Fernandez, Thaisa Storchi Bergmann, Dmitry Bizyaev, Joel Brownstein, Martin Bureau, John Chisholm, Niv Drory, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, Alexandre Roman Lopes, Kai-Ke Pan, Rogemar A Riffel, Daniel Thomas, Lan Wang, Renbin Yan 2016 Nanjing University, China

The Growth Of The Central Region By Acquisition Of Counterrotating Gas In Star-Forming Galaxies, Yan-Mei Chen, Yong Shi, Christy A. Tremonti, Matt Bershady, Michael Merrifield, Eric Emsellem, Yi-Fei Jin, Song Huang, Hai Fu, David A. Wake, Kevin Bundy, David Stark, Lihwai Lin, Maria Argudo-Fernandez, Thaisa Storchi Bergmann, Dmitry Bizyaev, Joel Brownstein, Martin Bureau, John Chisholm, Niv Drory, Qi Guo, Lei Hao, Jian Hu, Cheng Li, Ran Li, Alexandre Roman Lopes, Kai-Ke Pan, Rogemar A Riffel, Daniel Thomas, Lan Wang, Renbin Yan

Physics and Astronomy Faculty Publications

Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Here, based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations …


Exoplanet Research: Differential Photometry For Kepler 6b, Garrett T. Benson, Charlotte Alexandra Olsen 2016 Humboldt State University

Exoplanet Research: Differential Photometry For Kepler 6b, Garrett T. Benson, Charlotte Alexandra Olsen

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

No abstract provided.


Three Temperate Neptunes Orbiting Nearby Stars, Benjamin J. Fulton, Andrew W. Howard, Lauren M. Weiss, Evan Sinukoff, Erik A. Petigura, Howard Isaacson, Lea A. Hirsch, Geoffrey W. Marcy, Gregory W. Henry, Samuel K. Grunblatt, Daniel Huber, Kaspar von Braun, Tabetha S. Boyajian, Stephen R. Kane, Justin Wittrock, Elliott P. Horch, David R. Ciardi, Steve B. Howell, Jason T. Wright, Eric B. Ford 2016 University of Hawaii

Three Temperate Neptunes Orbiting Nearby Stars, Benjamin J. Fulton, Andrew W. Howard, Lauren M. Weiss, Evan Sinukoff, Erik A. Petigura, Howard Isaacson, Lea A. Hirsch, Geoffrey W. Marcy, Gregory W. Henry, Samuel K. Grunblatt, Daniel Huber, Kaspar Von Braun, Tabetha S. Boyajian, Stephen R. Kane, Justin Wittrock, Elliott P. Horch, David R. Ciardi, Steve B. Howell, Jason T. Wright, Eric B. Ford

Information Systems and Engineering Management Research Publications

We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of 15.4 ± 2.4 ${M}_{\oplus }$, a semimajor axis of 0.55 au, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 (ρ CrB). The new planet orbiting HD 164922 has a minimum mass of 12.9 ± 1.6 ${M}_{\oplus }$ and orbits interior to the previously known Jovian mass planet …


An Eccentric Binary Millisecond Pulsar With A Helium White Dwarf Companion In The Galactic Field, John Antoniadis, David L. Kaplan, Kevin Stovall, Paulo C.C. Freire, Julia S. Deneva, Detlev Koester, Fredrick Jenet, Jose G. Martinez 2016 The University of Texas Rio Grande Valley

An Eccentric Binary Millisecond Pulsar With A Helium White Dwarf Companion In The Galactic Field, John Antoniadis, David L. Kaplan, Kevin Stovall, Paulo C.C. Freire, Julia S. Deneva, Detlev Koester, Fredrick Jenet, Jose G. Martinez

Physics & Astronomy Faculty Publications

Low-mass white dwarfs (LMWDs) are believed to be exclusive products of binary evolution, as the universe is not old enough to produce them from single stars. Because of the strong tidal forces operating during the binary interaction phase, the remnant systems observed today are expected to have negligible eccentricities. Here, we report on the first unambiguous identification of an LMWD in an eccentric (e = 0.13) orbit around the millisecond pulsar PSR J2234+0511, which directly contradicts this picture. We use our spectra and radio-timing solution (derived elsewhere) to infer the WD temperature (Teff = 8600 ±190 K), and peculiar systemic …


Magnetic Reconnection With A Fast Perpendicular Sheared Flow, Xuanye Ma, Antonius Otto, Peter A. Delamere 2016 University of Alaska, Fairbanks

Magnetic Reconnection With A Fast Perpendicular Sheared Flow, Xuanye Ma, Antonius Otto, Peter A. Delamere

Publications

Magnetic reconnection at the Earth's low‐latitude magnetopause near the flank region is likely associated with a large sheared flow, being frequently quasi‐perpendicular to the antiparallel magnetic field components. The magnitude of a fast sheared flow can be super‐Alfvénic and even overcome the local fast mode speed. A scaling analysis implies a contradiction between the Walén relation and the balance of the total pressure for magnetic reconnection with a supercritical perpendicular sheared flow. This study uses one‐ and two‐dimensional magnetohydrodynamic (MHD) simulations to demonstrate that the traditional reconnection layer violates the Walén relation but still maintains the total pressure balance in …


Very Low-Mass Stellar And Substellar Companions To Solar-Like Stars From Marvels. Vi. A Giant Planet And A Brown Dwarf Candidate In A Close Binary System Hd 87646, Bo Ma, Jian Ge, Alex Wolszczan, Matthew W. Muterspaugh, Brian Lee, Gregory W. Henry, Donald P. Schneider, Eduardo L. Martín, Andrzej Niedzielski, Jiwei Xie, Scott W. Fleming, Neil Thomas, Michael Williamson, Zhaohuan Zhu, Eric Agol, Dmitry Bizyaev, Luiz Nicolaci da Costa, Peng Jiang, Aldo Fabricio Martinez Fiorenzano, Jonay I. González Hernández, Pengcheng Guo, Nolan Grieves, Rui Li, Jane Liu, Suvrath Mahadevan, Tsevi Mazeh, Duy Cuong Nguyen, Martin Paegert, Sirinrat Sithajan, Keivan Stassun, Sivarani Thirupathi, Julian C. van Eyken, Xiaoke Wan, Ji Wang, John P. Wisniewski, Bo Zhao, Shay Zucker 2016 University of Florida

Very Low-Mass Stellar And Substellar Companions To Solar-Like Stars From Marvels. Vi. A Giant Planet And A Brown Dwarf Candidate In A Close Binary System Hd 87646, Bo Ma, Jian Ge, Alex Wolszczan, Matthew W. Muterspaugh, Brian Lee, Gregory W. Henry, Donald P. Schneider, Eduardo L. Martín, Andrzej Niedzielski, Jiwei Xie, Scott W. Fleming, Neil Thomas, Michael Williamson, Zhaohuan Zhu, Eric Agol, Dmitry Bizyaev, Luiz Nicolaci Da Costa, Peng Jiang, Aldo Fabricio Martinez Fiorenzano, Jonay I. González Hernández, Pengcheng Guo, Nolan Grieves, Rui Li, Jane Liu, Suvrath Mahadevan, Tsevi Mazeh, Duy Cuong Nguyen, Martin Paegert, Sirinrat Sithajan, Keivan Stassun, Sivarani Thirupathi, Julian C. Van Eyken, Xiaoke Wan, Ji Wang, John P. Wisniewski, Bo Zhao, Shay Zucker

Information Systems and Engineering Management Research Publications

We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using the Exoplanet Tracker at the Kitt Peak National Observatory, the High Resolution Spectrograph at the Hobby Eberley telescope, the "Classic" spectrograph …


Fluctuations In A Cosmology With A Spacelike Singularity And Their Gauge Theory Dual Description, Robert H. Brandenberger, Elisa G. M. Ferreira, Ian A. Morrison, Yi-Fu Cai, Sumit R. Das, Yi Wang 2016 McGill University, Canada

Fluctuations In A Cosmology With A Spacelike Singularity And Their Gauge Theory Dual Description, Robert H. Brandenberger, Elisa G. M. Ferreira, Ian A. Morrison, Yi-Fu Cai, Sumit R. Das, Yi Wang

Physics and Astronomy Faculty Publications

We consider a time-dependent deformation of anti–de Sitter (AdS) space-time which contains a spacelike “singularity”—a spacelike region of high curvature. Making use of the AdS/CFT correspondence we can map the bulk dynamics onto the boundary. The boundary theory has a time dependent coupling constant which becomes small at times when the bulk space-time is highly curved. We investigate the propagation of small fluctuations of a test scalar field from early times before the bulk singularity to late times after the singularity. Under the assumption that the AdS/CFT correspondence extends to deformed AdS space-times, we can map the bulk evolution of …


Large Linear Magnetoresistance In Heavily-Doped Nb:Srtio3 Epitaxial Thin Films, Hyunwoo Jin, Keundong Lee, Seung-Hyub Baek, Jin-Sang Kim, Byung-Ki Cheong, Bae Ho Park, Sungwon Yoon, B. J. Suh, Changyoung Kim, Sung S. Ambrose Seo, Suyoun Lee 2016 Korea Institute of Science and Technology, South Korea

Large Linear Magnetoresistance In Heavily-Doped Nb:Srtio3 Epitaxial Thin Films, Hyunwoo Jin, Keundong Lee, Seung-Hyub Baek, Jin-Sang Kim, Byung-Ki Cheong, Bae Ho Park, Sungwon Yoon, B. J. Suh, Changyoung Kim, Sung S. Ambrose Seo, Suyoun Lee

Physics and Astronomy Faculty Publications

Interaction between electrons has long been a focused topic in condensed-matter physics since it has led to the discoveries of astonishing phenomena, for example, high-Tc superconductivity and colossal magnetoresistance (CMR) in strongly-correlated materials. In the study of strongly-correlated perovskite oxides, Nb-doped SrTiO3 (Nb:SrTiO3) has been a workhorse not only as a conducting substrate, but also as a host possessing high carrier mobility. In this work, we report the observations of large linear magnetoresistance (LMR) and the metal-to-insulator transition (MIT) induced by magnetic field in heavily-doped Nb:STO (SrNb0.2Ti0.8O3) epitaxial thin …


Optimizing The Telescope Assembly Alignment Simulator For Sofia, Zoe E. Sharp, Alex QuyenVo, Jennifer Briggs, Brian Eney 2016 Cal Poly, San Luis Obispo

Optimizing The Telescope Assembly Alignment Simulator For Sofia, Zoe E. Sharp, Alex Quyenvo, Jennifer Briggs, Brian Eney

STAR Program Research Presentations

The Stratospheric Observatory for Infrared Astronomy (SOFIA) conducts research on a modified Boeing 747sp aircraft. By using a variety of infrared science instruments mounted on a 2.7 meter telescope, researchers can make discoveries about the galactic center, star formation, and various topics associated with a deeper understanding of our universe. To efficiently collect data through the SOFIA instruments, the instruments must be tested and prepared prior to being placed on the aircraft. Therefore, with the use of the Telescope Assembly Alignment Simulator (TAAS), researchers can design and construct improvements needed for these instruments to efficiently perform while in flight. The …


Measurement And Modeling Of Cosmic Ray Exposure For Supercdms Dark Matter Detectors., Kameron McCall, John Orrell, Jared Yamaoka 2016 University of Houston - Main

Measurement And Modeling Of Cosmic Ray Exposure For Supercdms Dark Matter Detectors., Kameron Mccall, John Orrell, Jared Yamaoka

STAR Program Research Presentations

Dark matter is an unknown type of matter that composes roughly 27% of the observable universe and, as cosmological structure models suggest, the earth should be passing through a “dark halo” of this unknown matter present in the Milky Way galaxy. As we pass through this halo, the Super Cryogenic Dark Matter Search (SuperCDMS) experiment aims to directly detect dark -matter particles. Though many dark matter particle candidates exist, SuperCDMS focuses on the detection of particles called WIMPS (weakly interacting massive particles) as predicted by super-symmetric theories beyond the standard model. Due to the high-sensitivity of the germanium detectors employed, …


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