Physical Sciences and Mathematics Commons^™

Identifying The O’Connell Effect In Eclipsing Binary Stars, Nicholas Paolella

Computer Science and Information Technology Faculty

Data science techniques have wide-ranging applications throughout scientific explorations. One, is filtering astronomical data to better understand specific populations, such as binary stars. Specifically, binary stars that exhibit the O’Connell effect are worthy of study as this phenomenon is still not well understood. The O’Connell effect can be defined as the asymmetry of maxima in the light curves, as captured by the instrument, while observing the eclipsing binary system in question. There is significant data captured by NASA and curated by Villanova University, which enabled the investigation of eclipsing binary stars and the attributes of which may help identify the …

A Multi-Wavelength Determination Of The Total Luminosity And Star Formation Rate Of The Milky Way, Joshua L. Mascoop

Graduate Theses, Dissertations, and Problem Reports

The star formation rate (SFR) of the Milky Way is poorly understood in comparison to the SFR of other galaxies. In order to better find the Galaxy's place in the universe, it is imperative to understand the star formation activity occurring within it. We characterize the Galactic \hii\ region luminosity function (LF) at multiple infrared and radio wavelengths using a sample of 797 first Galactic quadrant \hii regions compiled from the WISE Catalog of Galactic \hii Regions. This sample is statistically complete for all regions powered by single stars of type O9.5V and earlier.

We find that neither a single …

Connecting The Optical Regime To The X-Ray In Neutron Star Low Mass X-Ray Binaries, Alexander B. Igl

LSU Doctoral Dissertations

Using Rossi X-Ray Timing Explorer and Otto Struve Telescope data of low mass X-ray binaries (LMXBs) Cyg X-2 and Sco X-1, the optical regime’s relationship to the X-ray was investigated through several angles. Discrete cross correlations using the optical and X-ray data revealed evidence of reprocessing in both datasets. These were more consistently present in Sco X-1, where both small and obvious features were seen at less than 4 s of optical lag. The size of these lags makes it likely that most of the reprocessing is taking place on the accretion disk. Parameterization of the Z tracks led to …

Mapping Galactic Acceleration With Pulsar Timing, Abigail Moran

University Scholar Projects

We have conducted a cross match of objects in Gaia Early Data Release 3 and millisecond pulsars (MSPs) in the International Pulsar Timing Array’s Data Release 2 (IPTA DR2) to identify binary systems. Gaia has parallax measurements for these optical companions, which we combine with pulsar timing based parallax measurements to calculate new combined MSP distances. Through this crossmatch with IPTA DR2 we improved five distance measurements and found the first parallax measurement for one MSP.

Using this Gaia crossmatch method now with a well-timed subset of the Australia Telescope National Facility’s database, we found three new pulsar distances. We …

Identifying And Analyzing Multi-Star Systems Among Tess Planetary Candidates Using Gaia, Katie E. Bailey

Electronic Theses and Dissertations

Exoplanets represent a young, rapidly advancing subfield of astrophysics where much is still unknown. It is therefore important to analyze trends among their parameters to learn more about these systems. More complexity is added to these systems with the presence of additional stellar companions. To study these complex systems, one can employ programming languages such as Python to parse databases such as those constructed by TESS and Gaia to bridge the gap between exoplanets and stellar companions. Data can then be analyzed for trends in these multi-star exoplanet systems and in juxtaposition to their single-star counterparts. This research was able …

Where Are The Habitable Planets In Our Local Group Of Galaxies?, William C. Windsor

Undergraduate Student Research Internships Conference

No abstract provided.

Using Nasa's Tess Mission To Search For Extremely Low Mass White Dwarf Stars, Corinna Peña

Undergraduate Honors Thesis Collection

Extremely low-mass white dwarf stars (ELM) are white dwarf stars with a mass lower than 0.45 solar masses that could not have evolved through normal processes within the lifetime of our universe. Therefore, these objects can only be created through a common envelope phase or a stable Roche lobe overflow while in a binary. These objects have periods between a few minutes to a few hours, so they are very short lived which makes them very rare. My goal for this project was to find these ELM stars by using NASA's Transiting Exoplanet Survey Satellite (TESS) data. I analyzed this …

Dr. Jennifer Hoffman, Anit Tyagi

DU Undergraduate Research Journal Archive

An interview with Dr. Jennifer Hoffman.

Brightening Of The Bridge: Reflections Of A Past Sgr A* Outburst In Galactic Center Molecular Clouds, Nathalie Kanoelani Takiko Jones

Senior Projects Spring 2021

The center of our Milky Way galaxy is located more than 200,000 trillion km from Earth in the constellation Sagittarius. At the very center of our galaxy is a super-massive black hole called Sagittarius A$^{*}$. The black hole is surrounded by many interesting objects, including molecular clouds. Molecular clouds are large, cold clouds of gas in which stars are formed. Telescopes like NuSTAR have observed X-rays (radiation 10,000 times higher in energy than visible light) coming from these molecular clouds. Since cold gas cannot create such high energy emission by itself, there must be some external source of radiation interacting …

Axial Symmetry Tests Of Milky Way Disk Stars Probe The Galaxy's Matter Distribution, Austin Hinkel

Theses and Dissertations--Physics and Astronomy

In Galactic dynamics, various assumptions have been employed for mathematical ease. These assumptions are approximately valid, but departures reveal perturbations on our Galaxy. In this dissertation, we select a complete, Gaia DR2 data set, and using this data, we find evidence for axial symmetry breaking in the Galaxy, away from the spiral arms and the Galactic bar. This asymmetry is compatible with a prolate dark matter halo tilted with respect to the disk, with a long axis pointing in the direction of the Magellanic Clouds, and this matches an inventory of nearby torques. These asymmetries vary North and South of …

Automated Spectroscopic Detection And Mapping Using Alma And Machine Learningtechniques, Steven Cocke, Andrew Wilkins, Josephine Mcdaniel, John Santerre, Conor Nixon

SMU Data Science Review

In this paper we present a methodology for automating theclassification of spectrally resolved observations of multiple emissionlines with the Atacama Large Millimeter/submillimeter Array (ALMA).Molecules in planetary atmospheres emit or absorb different wavelengthsof light thereby providing a unique signature for each species. ALMAdata were taken from interferometric observations of Titan made be-tween UT 2012 July 03 23:22:14 and 2012 July 04 01:06:18 as part ofALMA project 2011.0.00319.S. We first employed a greedy set cover algorithm to identify the most probable molecules that would reproducethe set of frequencies with respective flux greater than 3σaway from themean. We then selected a subset of …

Perfect Circles: A Study Of The Scattering Regions Of Wolf Rayet Binary Stars, Stella Yoos, Jennifer Hoffman, Andrew Fullard

DU Undergraduate Research Journal Archive

Although we have been able to develop an understanding of many aspects of stellar evolution and formation, a few key gaps remain. One is the fate of massive binary star systems composed of Wolf-Rayet (WR) and O-type stars. In these WR + O binaries, the stellar winds surrounding these stars collide, creating a complex interaction region in which light from the stars scatters and becomes polarized. To study these scattering regions, I employ a technique that allows me to map the polarization of the light emitted from these stars and track its variation over the binary orbit. I found that …

Milky Way Morphology, Laurence A. Marschall

Physics and Astronomy Faculty Publications

From our limited perspective—living on a planet that orbits one of several hundred billion stars inside the Milky Way—the detailed structure of our home galaxy is difficult to determine. It has long been recognized by astronomers as a typical spiral galaxy, one of countless flattened pinwheels of stars seen throughout the universe. By mapping the distances to more than 2,400 stars, scientists have now created, with unprecedented precision, a three-dimensional map that shows the Milky Way has a twisted shape. [excerpt]

Statistical Analysis Of Stellar Evolution, David A. Van Dyk, Ted Von Hippel, Steven Degenarro, Nathan Stein, William Jefferys

Ted von Hippel

Color-Magnitude Diagrams (CMDs) are plots that compare the magnitudes (luminosities) of stars in different wavelengths of light (colors). High nonlinear correlations among the mass, color, and surface temperature of newly formed stars induce a long narrow curved point cloud in a CMD known as the main sequence. Aging stars form new CMD groups of red giants and white dwarfs. The physical processes that govern this evolution can be described with mathematical models and explored using complex computer models. These calculations are designed to predict the plotted magnitudes as a function of parameters of scientific interest, such as stellar age, mass, …

The Impact Of Hii Regions On The Interstellar Medium Of Our Galaxy, Matteo Luisi

Graduate Theses, Dissertations, and Problem Reports

The interstellar medium (ISM) of our Galaxy contains low-density diffuse ionized gas known as the warm ionized medium (WIM). O- and B-type stars emit large amounts of ionizing radiation and it is believed that a fraction of this radiation escapes from their fully ionized HII regions and into the ISM where it is responsible for maintaining the ionization of the WIM. Here we aim to better understand how the radiation produced by OB stars is able to leak from the HII regions, how the radiation field changes during this process, and how the radiation affects the ambient ISM. Using Green …

Unh Observatory Exoplanet Transit Depth Limit, Nicholas R. Larose

Honors Theses and Capstones

Using the University of New Hampshire Observatory, we performed multiple exoplanet transits observations on a variety of systems. Of these transits, those performed with ideal weather conditions were chosen to do extensive analysis on. The transit chosen for initial analysis was HAT-P-56b. We then used Z-Score values, along with the average mean and standard deviation collected from multiple transits to determine a minimum possible transit depth of 7.4 +/- 0.6 mmag. This value will allow UNH to access exoplanet transit observation and / or confirm potential exoplanets, thus making the UNH Observatory more research capable. A follow up threshold transit …

Book Review: Spectral Atlas For Amateur Astronomers: A Guide To The Spectra Of Astronomical Objects And Terrestrial Light Sources, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Spectral Atlas for Amateur Astronomers: A Guide to the Spectra of Astronomical Objects and Terrestrial Light Sources by Richard Walker. Cambridge 2017, 277 p bibl index, 9781107165908 $89.99, 9781316731048 $72.00

Cataclysmic Variable Stars In The Sloan Digital Sky Survey, Sinead Humphrey, Samantha Smiley, Andres Munoz, Brian Saboriendo

DePaul Discoveries

The purpose of this study is to identify Cataclysmic Variables (CVs) using spectroscopic and photometric data. CVs are useful for studying plasma physics in extreme conditions such as the high temperature and strong magnetic fields seen in CV accretion disks. They are also critical for understanding the evolution of binary stars, both in the field and in globular clusters. This project used photometric and spectroscopic data from the Sloan Digital Sky Survey (SDSS) to identify and classify CVs. 6,000 objects were selected based on multi-color criteria and analyzed using spectral data. Approximately 1% of these objects in the sample were …

Unseen Science: Modern Discoveries Too Far Away Or Tiny For Human Eyes, Lucy Huang

Capstones

As science has progressed, scientists have realized that evidence goes beyond the realms of physical sight. Whether it is too small or difficult to find, scientists have developed different ways to get around this problem. We see this in cancer genomics and in extrasolar planetary research. Scientists use what they know and what they measure to validate their work.

https://lucy-huang-9tge.squarespace.com/

Book Review: Chandra's Cosmos: Dark Matter, Black Holes, And Other Wonders Revealed By Nasa's Premier X-Ray Observatory, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Chandra's cosmos: dark matter, black holes, and other wonders revealed by NASA's premier X-ray observatory by Wallace H. Tucker. Smithsonian Books, 2017. 266p bibl index ISBN 9781588345875, $29.95; ISBN 9781588345882 ebook, contact publiser for price.

Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of From the Realm of the Nebulae to Populations of Galaxies : Dialogues on a Century of Research, Astrophysics and Space Science Library, 435. by Mauro D'Onofrio, Roberto Rampazzo, and Simone Zaggia Springer, 2016 785p bibl index afp, 9783319310046 $279.00, 9783319310060 $219.00

Mayo Dark Skies Park: A Virtual Experience, Mayo Dark Skies Community Group, Frank Prendergast

Datasets

The Mayo Dark Skies Community Group, in collaboration with the Dublin Institution of Technology, is pleased to launch a digital virtual experience of the Mayo Dark Sky Park. Following its designation as an International Dark Sky Park (Gold Tier), it is now possible to experience a part of this magnificent and pristine skyscape on your computer. This has been made possible using open source software (Stellarium http://www.stellarium.org/) and a specially commissioned digital panorama of the horizon surrounding the Ballycroy National Park Visitor Centre.

Stellarium is an open source planetarium for your computer and shows a fully realistic …

Flickering Analysis Of Ch Cygni Using Kepler Data, Thomas Holden Dingus

Undergraduate Honors Theses

Utilizing data from the Kepler Mission, we analyze a flickering phenomenon in the symbiotic variable star CH Cygni. We perform a spline interpolation of an averaged lightcurve and subtract the spline to acquire residual data. This allows us to analyze the deviations that are not caused by the Red Giant’s semi-regular periodic variations. We then histogram the residuals and perform moment calculations for variance, skewness, and kurtosis for the purpose of determining the nature of the flickering. Our analysis has shown that we see a much smaller scale flickering than observed in the previous literature. Our flickering scale is on …

Back Half Of The Year, Ian R. Clarke

Physics and Astronomy Faculty Publications

Here we are in the back half of 2016, and the days are getting shorter. We have, as of today, lost 18 minutes since the solstice on June 20, and the speed of that change is quickening. You may wonder why it is that we have our hottest weather after our longest day is behind us. The simple answer is that it takes time for land and water masses to warm up. That’s the reason that Sept. 21 is likely to be a lot warmer than March 21, even though they have the same amount of daylight. [excerpt]

Living In The Milky Way, Ian R. Clarke

Physics and Astronomy Faculty Publications

It’s finally here. Today, June 20 at 6:34 p.m., is the the summer solstice, also known as the first day of summer and, confusingly enough, midsummer’s eve. From a scientific perspective, it marks the moment the sun reaches its northernmost point in our sky. As a result of that position, it’s the shortest night and longest day if you live north of the equator. [excerpt]

Peering Through The Dust: Nustar Observations Of Two First-2mass Red Quasars, Stephanie M. Lamassa, Angelo Ricarte, Eilat Glikman, C. Megan Urry, Daniel Stern, Tahir Yaqoob, George B. Lansbury, Francesca Civano

Dartmouth Scholarship

Some reddened quasars appear to be transitional objects in the merger-induced black hole growth/galaxy evolution paradigm, where a heavily obscured nucleus starts to be unveiled by powerful quasar winds evacuating the surrounding cocoon of dust and gas. Hard X-ray observations are able to peer through this gas and dust, revealing the properties of circumnuclear obscuration. Here, we present NuSTAR and XMM-Newton/Chandra observations of FIRST-2MASS selected red quasars F2M 0830+3759 and F2M 1227+3214. We find that though F2M 0830+3759 is moderately obscured (N_H,Z=2.1±0.2×10²² cm⁻²) and F2M 1227+3214 is mildly absorbed (N_H,Z=3.4+0.8−0.7×10²¹ cm^{−2 …}

Building A Scalable Global Data Processing Pipeline For Large Astronomical Photometric Datasets, Paul Doyle

Other

Astronomical photometry is the science of measuring the flux of a celestial object. Since its introduction, the CCD has been the principle method of measuring flux to calculate the apparent magnitude of an object. Each CCD image taken must go through a process of cleaning and calibration prior to its use. As the number of research telescopes increases the overall computing resources required for image processing also increases. Existing processing techniques are primarily sequential in nature, requiring increasingly powerful servers, faster disks and faster networks to process data. Existing High Performance Computing solutions involving high capacity data centres are complex …

Maximizing Precision Of Variable Star Photometry With Digital Cameras In Suburban Environments, David Hergesheimer

STAR Program Research Presentations

Photometry is the measure of the brightness of an object. When making such measurements on stars, it is done is units of magnitude, which is on a logarithmic scale with a base of ~2.512. Variable star photometry using a commercially available digital camera is not going to be as accurate and precise as equipment used by astronomers, and because of the logarithmic scale of magnitude used, determining how much of an effect different error reduction strategies have is not straightforward, and is best done experimentally.

My research is conducting photometry on variable stars (changing brightness) with a digital camera, and …

1207-3900_Opt_Mage, Jonathan Gagné

Publications and Research

No abstract provided.

1207-3900_Nir_Spex, Jonathan Gagné

Publications and Research

No abstract provided.