# Astrophysics and Astronomy Commons™

## All Articles in Astrophysics and Astronomy

4,609 full-text articles. Page 1 of 119.

2016 Macalester College

#### Contributing To Astropy: A Community Python Library For Astronomers, Asra Nizami

##### Macalester Journal of Physics and Astronomy

This paper discusses the author’s contributions to two packages affiliated with Astropy, a community Python library for astronomers. The packages the author contributed to were modeling, a sub-package within the core Astropy package, and WCSAxes, an Astropy affiliated package, outside the core package.

Energetic Behavior Of Resistive Random-Access Memory Cells, 2016 Macalester College

#### Energetic Behavior Of Resistive Random-Access Memory Cells, Christopher M. Bisbee

##### Macalester Journal of Physics and Astronomy

In order to investigate the switching characteristics of Resistive Random Access Memory cells (ReRAM) in terms of their thermodynamic free energy properties, we need to build a number of models that replicate the system. This report contains the models used to investigate filament growth patterns based on different boundary conditions applied to the electrode-filament system. Using Comsol Multiphysics software, we determined that when a fixed voltage is applied to each electrode in the electrode-filament system, we should expect filament dissolution that resets our cells into the High Resistance State (HRS). If we instead fix a set amount of charge on ...

2016 University of Arkansas, Fayetteville

#### Extending The Supermassive Black Hole Mass-Pitch Angle Relation To Moderate Redshifts, Logan H. Jones

I extend the empirical correlation between central supermassive black hole mass M and spiral arm pitch angle P in spiral galaxies to intermediate redshifts using a sample of 14 type 1 Seyfert galaxies. Nuclear black hole masses are measured from the widths and luminosities of the broad Hβ and MgII emission lines, and pitch angles are measured using two independent image analysis techniques. I find the best-fit relation log(M/M☉) = (8.31 ± 0.28) − (0.058 ± 0.016)P, which indicates little to no evolution compared to the published M-P relation for local spirals.

The Inner Gaseous Disks Of Herbig Be Stars, 2016 The University of Western Ontario

#### The Inner Gaseous Disks Of Herbig Be Stars, Parshati Patel

##### Electronic Thesis and Dissertation Repository

Herbig Ae/Be stars are intermediate mass (~2 to 20Msun) pre-main sequence stars that inherit a circumstellar disk of dust and gas from their formation phase. The region of this disk closest to the star is entirely gaseous because dust evaporates at the high temperatures there, and this gaseous region is currently poorly understood. Using non-LTE circumstellar disk codes to model the optical and near-infrared spectra of five, early-type (B0Ve to B2Ve) Herbig Be stars obtained with the Canada-France-Hawaii telescope ESPaDOnS instrument, the density structure of each inner gaseous disks was determined and estimates of the disk masses and ...

2016 The University of Western Ontario

#### Insights From Unsupervised Clustering And Composite Spectral Analysis Into The Physical Properties Driving Emission And Absorption In Quasar Uv/Optical Spectra, Aycha Tammour

##### Electronic Thesis and Dissertation Repository

Although quasar spectra appear remarkably similar, subtle systematic differences are well- known and are linked to the physical conditions in the emitting regions. This thesis char- acterizes the properties of quasar optical and UV spectral features and reveals some of their underlying physical causes by analyzing large spectroscopic datasets from the Sloan Digital Sky Survey.

We first examine the narrow-line region using four optical emission lines with a range of ionization potentials (IPs) using a sample of 16,027 quasars with redshift z ≤ 0.75. We bin the sample using the continuum luminosity and the Hβ width to constrain the ...

Nucleosynthesis In Core-Collapse Supernovae, 2016 University of Tennessee, Knoxville

#### Nucleosynthesis In Core-Collapse Supernovae, Rachel E Mersch

##### EURēCA: Exhibition of Undergraduate Research and Creative Achievement

A Core-Collapse Supernova explosion occurs when nuclear fusion stops in the core of a massive star. Without a source of energy supplying enough pressure to balance gravity, the core becomes unstable and collapses to form a neutron star. Beyond the neutron star, a shockwave forms which moves outward through the star, causing heavier elements to be created through nuclear fusion. We have been studying the elements that are ejected from a Core-Collapse Supernova using a nuclear code network called XNet, which follows the thermonuclear kinetics. We use the results from a code called Chimera, which explores the mechanism of Core-Collapse ...

2016 DePaul University

#### Better Together

##### DePaul Magazine

Faculty have taken full advantage of the university's innovative intercollegiate grant program, and the resulting research is as interesting and diverse as the collaborators themselves. What is resulting is research on "Patient and Primary Care Provider Perspectives on Recreational and Therapeutic Cannabis Use Within a Changing Socioculltural and Political Context;" a new minor in climate change science and policy; a new class, Communication, Coding and Entrepreneurship; brain inflammation research; and the project "Cosmology Meets Continental Philosophy: Natural Laws and Why There Is Something Rather Than Nothing"

The Parallelization And Optimization Of The N-Body Problem Using Openmp And Openmpi, 2016 Gettysburg College

#### The Parallelization And Optimization Of The N-Body Problem Using Openmp And Openmpi, Nicholas J. Carugati

##### Student Publications

The focus of this research is exploring the efficient ways we can implement the NBody problem. The N-Body problem, in the field of physics, is a problem in which predicts or simulates the movements of planets and how they interact with each other gravitationally. For this research, we are viewing if the simulation can execute efficiently by delegating the heavy computational work through different cores of a CPU. The approach that is being used to figure this out is by integrating the parallelization API OpenMP and the message-passing library OpenMPI into the code. Rather than all the code executing on ...

Kelt-10b: The First Transiting Exoplanet From The Kelt-South Survey - A Hot Sub-Jupiter Transiting A V=10.7 Early G-Star, 2016 Swarthmore College

#### Kelt-10b: The First Transiting Exoplanet From The Kelt-South Survey - A Hot Sub-Jupiter Transiting A V=10.7 Early G-Star, R. B. Kuhn, J. E. Rodriguez, K. A. Collins, M. B. Lund, R. J. Siverd, K. D. Colón, J. Pepper, K. G. Stassun, P. A. Cargile, D. J. James, K. Penev, G. Zhou, D. Bayliss, T. G. Tan, I. A. Curtis, S. Udry, D. Segransan, D. Mawet, S. Dhital, J. Soutter, R. Hart, B. Carter, B. S. Gaudi, G. Myers, T. G. Beatty, J. D. Eastman, D. E. Reichart, J. B. Haislip, J. F. Kielkopf, A. Bieryla, D. W. Latham, Eric L.N. Jensen, T. E. Oberst, D. J. Stevens

##### Physics & Astronomy Faculty Works

We report the discovery of KELT-10b, the first transiting exoplanet discovered using the KELT-South telescope. KELT-10b is a highly inflated sub-Jupiter mass planet transiting a relatively bright V = 10.7 star (TYC 8378-64-1), with Teff = 5948 ± 74 K, log g = 4.319_{-0.030}^{+0.020} and [Fe/H] = 0.09_{-0.10}^{+0.11}, an inferred mass M = 1.112_{-0.061}^{+0.055} M and radius R = 1.209_{-0.035}^{+0.047} R. The planet has a radius Rp = 1.399_{-0.049}^{+0.069} RJ and mass Mp = 0.679_{-0.038 ...

The Biomolecule Sequencer Project: Nanopore Sequencing As A Dual-Use Technology For Crew Health And Astrobiology Investigations, 2016 NASA Johnson Space Center

#### The Biomolecule Sequencer Project: Nanopore Sequencing As A Dual-Use Technology For Crew Health And Astrobiology Investigations, K. K. John, D. S. Botkin, A. S. Burton, S. L. Castro-Wallace, J. D. Chaput, J. P. Dworkin, Niles Lehman, M. L. Lupisella, C. E. Mason, D. J. Smith, S. Stahl, C. Switzer

##### Chemistry Faculty Publications and Presentations

Human missions to Mars will fundamentally transform how the planet is explored, enabling new scientific discoveries through more sophisticated sample acquisition and processing than can currently be implemented in robotic exploration. The presence of humans also poses new challenges, including ensuring astronaut safety and health and monitoring contamination. Because the capability to transfer materials to Earth will be extremely limited, there is a strong need for in situ diagnostic capabilities. Nucleotide sequencing is a particularly powerful tool because it can be used to: (1) mitigate microbial risks to crew by allowing identification of microbes in water, in air, and on ...

2016 Dublin Institute of Technology

#### Hawking Radiation Screening And Penrose Process Shielding In The Kerr Black Hole, Eamon Mc Caughey

##### Articles

The radial motion of massive particles in the equatorial plane of aKerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle’s angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined.

Stellar Activity And Exclusion Of The Outer Planet In The Hd 99492 System, 2016 Swarthmore College

#### Stellar Activity And Exclusion Of The Outer Planet In The Hd 99492 System, Eric L. N. Jensen, S. R. Kane, B. Thirumalachari, G. W. Henry, N. R. Hinkel, T. S. Boyajian, D. A. Fischer, A. W. Howard, H. T. Isaacson, J. T. Wright

##### Physics & Astronomy Faculty Works

A historical problem for indirect exoplanet detection has been contending with the intrinsic variability of the host star. If the variability is periodic, it can easily mimic various exoplanet signatures, such as radial velocity (RV) variations that originate with the stellar surface rather than the presence of a planet. Here we present an update for the HD 99492 planetary system, using new RV and photometric measurements from the Transit Ephemeris Refinement and Monitoring Survey. Our extended time series and subsequent analyses of the Ca ii H&K emission lines show that the host star has an activity cycle of ~13 ...

Session F-3: “It Is Rocket Science”, 2016 Illinois Mathematics and Science Academy

#### Session F-3: “It Is Rocket Science”, Carmela Jones, Christine L. Moskalik

##### Professional Learning Day

All current NASA rocket launchers are no longer useable because all of the available rocket-fuel sources on Earth have been depleted. Participants will serve as NASA engineers tasked with developing non-fuel-based rocket launcher prototypes in an effort to maintain current and future NASA space programs and missions. Model how you will get your students to take off with Rocket Science.

2016 IMSA

#### Session B-1: Model Building In Planetary Science And The Ngss, Eric Hawker

##### Professional Learning Day

In this session I will guide teachers through the steps my students take in Planetary Science to develop a conceptual model of how planetary interiors work. Teachers will then create concept maps from their conceptual models, and then use their models and maps to understand planetary systems other than Earth.

Probing The Fitting Accuracy Of Active Galaxy Spectra, 2016 California Polytechnic State University, San Luis Obispo

#### Probing The Fitting Accuracy Of Active Galaxy Spectra, Aaron T. Line

##### Physics

Prior to this study, Dr. Vardha N. Bennert and collaborators selected a sample of ~100 local active galaxies to study the relationships between black hole mass and host galaxy properties. The broad Hβ width is necessary to determine black hole mass. This value is determined using a spectral decomposition code was scripted in IDL by Dr. Daeseong Park. The script fit spectral features and collected data for properties such as width of emission lines and continuum contribution percentages. The results were logged for further analysis.

To probe the accuracy of the fitting process, artificial spectra were created and fitted to ...

2016 Brigham Young University - Provo

#### Improvements To The Two-Point In Situ Method For Measurement Of The Room Constant And Sound Power In Semi-Reverberant Rooms, Zachary R. Jensen

##### All Theses and Dissertations

The two-point in situ method is a technique for measuring the room constant of a semi-reverberant room and the sound power of a source in that room simultaneously using two measurement positions. Using a reference directivity source, where the directivity factor along any given axis of the source has been measured, one is able to use the Hopkins-Stryker equation to measure both the room constant and the sound power level of another source rather simply. Using both numerical and experimental data, it was found that by using generalized energy density (GED) as a measurement quantity, the results were more accurate ...

2016 Brigham Young University - Provo

#### Development, Evaluation, And Validation Of A High-Resolution Directivity Measurement System For Played Musical Instruments, K Joshua Bodon

##### All Theses and Dissertations

A high-resolution directivity measurement system at Brigham Young University has been renovated and upgraded. Acoustical treatments have been installed on the microphone array, professional-grade audio hardware and cabling have been utilized, and user-friendly MATLAB processing and plotting codes have been developed. The directivities of 16 played musical instruments and several loudspeakers have been measured by the system, processed, and plotted. Using loudspeakers as simulated musicians, a comprehensive analysis was completed to validate the system and understand its error bounds. A comparison and evaluation of repeated-capture to single-capture spherical systems was made to demonstrate the high level of detail provided by ...

X-Ray, Uv And Optical Analysis Of Supergiants: Ε Ori, 2016 Swarthmore College

#### X-Ray, Uv And Optical Analysis Of Supergiants: Ε Ori, David H. Cohen, R. E. Puebla, D. J. Hillier, J. Zsargó, M. A. Leutenegger

##### Physics & Astronomy Faculty Works

We present a multi-wavelength (X-ray to optical) analysis, based on non-local thermodynamic equilibrium photospheric+wind models, of the B0 Ia-supergiant: ϵ Ori. The aim is to test the consistency of physical parameters, such as the mass-loss rate and CNO abundances, derived from different spectral bands. The derived mass-loss rate is M˙/f∞−−−√∼ 1.6 × 10−6 M⊙ yr−1 where f∞ is the volume filling factor. However, the S iv λλ1062,1073 profiles are too strong in the models; to fit the observed profiles it is necessary to use f∞ <0.01. This value is a factor of 5 to 10 lower than inferred from other diagnostics, and implies M˙≲1×10−7 M⊙ yr−1. The discrepancy could be related to porosity–vorosity effects or a problem with the ionization of sulphur in the wind. To fit the UV profiles of N v and O vi it was necessary to include emission from an interclump medium with a density contrast (ρcl/ρICM) of ∼100. X-ray emission in H/He like and Fe L lines was modelled using four plasma components located within the wind. We derive plasma temperatures from 1 × 106 to 7 × 106 K, with lower temperatures starting in the outer regions (R0 ∼ 3–6 R*), and a hot component starting closer to the star (R0 ≲ 2.9 R*). From X-ray line profiles we infer M˙<4.9 × 10−7 M⊙ yr−1. The X-ray spectrum (≥0.1 kev) yields an X-ray luminosity LX ∼ 2.0 × 10−7Lbol, consistent with the superion line profiles. X-ray abundances are in agreement with those derived from the UV and optical analysis: ϵ Ori is slightly enhanced in nitrogen and depleted in carbon and oxygen, evidence for CNO processed material.

The Mimes Survey Of Magnetism In Massive Stars: Introduction And Overview, 2016 Swarthmore College

#### The Mimes Survey Of Magnetism In Massive Stars: Introduction And Overview, David H. Cohen, G. A. Wade, C. Neiner, E. Alecian, J. H. Grunhut, V. Petit, B. De Batz, D. A. Bohlender, H. F. Heinrichs, O. Kochukhov, J. D. Landstreet, N. Manset, F. Martins, S. Mathis, M. E. Oksala, S. P. Owocki, T. Rivinius, M. E. Shultz, J. O. Sundqvist, R. H. D. Townsend, A. Ud-Doula, J.-C. Bouret, J. Braithwaite, M. Briquet, A. C. Carciofi, A. David-Uraz, C. P. Folsom, A. W. Fullerton, B. Leroy, W. L. F. Marcolino, A. F. J. Moffat, Y. Nazé, N. St Louis, M. Aurière, S. Bagnulo, J. D. Bailey, R. H. Barbá, A. Blazère, T. Böhm, C. Catala, J.-F. Donati, L. Ferrario, D. Harrington, I. D. Howarth, R. Ignace, L. Kaper, T. Lüftinger, R. Prinja, J. S. Vink, W. W. Weiss, I. Yakunin

##### Physics & Astronomy Faculty Works

The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O- and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada–France–Hawaii Telescope, Narval at the Télescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla ...

Kelt-4ab: An Inflated Hot Jupiter Transiting The Bright (V~10) Component Of A Hierarchical Triple, 2016 Swarthmore College

#### Kelt-4ab: An Inflated Hot Jupiter Transiting The Bright (V~10) Component Of A Hierarchical Triple, Eric L. N. Jensen, J. D. Eastman, T. G. Beatty, R. J. Siverd, J. M. O. Antognini, M. T. Penny, E. J. Gonzales, J. R. Crepp, A. W. Howard, R. L. Avril, A. Bieryla, K. Collins, B. J. Fulton, J. Ge, J. Gregorio, B. Ma, S. N. Mellon, T. E. Oberst, J. Wang, B. S. Gaudi, J. Pepper, K. G. Stassun, L. A. Buchhave, D. W. Latham, P. Berlind, M. L. Calkins, P. A. Cargile, K. D. Colón, S. Dhital, G. A. Esquerdo, J. A. Johnson, J. F. Kielkopf, M. Manner, Q. Mao, K. K. Mcleod, K. Penev, R. P. Stefanik, R. Street, R. Zambelli, D. L. Depoy, A. Gould, J. L. Marshall, R. W. Pogge, M. Trueblood, P. Trueblood

##### Physics & Astronomy Faculty Works

We report the discovery of KELT-4Ab, an inflated, transiting Hot Jupiter orbiting the brightest component of a hierarchical triple stellar system. The host star is an F star with ${T}_{{\rm{eff}}}$ = $6206\pm 75$ K, $\mathrm{log}g$ = $4.108\pm 0.014$, $[{\rm{Fe}}/{\rm{H}}]$ = $-{0.116}_{-0.069}^{+0.065}$, ${M}_{*}$ = ${1.201}_{-0.061}^{+0.067}$ $\;{M}_{\odot }$, and ${R}_{*}$ = ${1.603}_{-0.038}^{+0.039}$ $\;{R}_{\odot }$. The best-fit linear ephemeris is ${\mathrm{BJD}}_{\mathrm{TDB}}$ $\;=\;2456193.29157\pm 0.00021$ \$\quad +\quad E(2 ...