Toward Cold Radical Chemistry With Cryogenic Buffer Gas Beams, 2017 University of Colorado at Boulder
Toward Cold Radical Chemistry With Cryogenic Buffer Gas Beams, Maya Ilyinichna Fabrikant
Physics Graduate Theses & Dissertations
Creating cold molecular samples allows us to study chemical reactions that happen at temperatures characteristic of the interstellar medium. Additionally, cold environments can stabilize very reactive molecules like radicals, which can allow us to study difficult-to-observe reactions or intermediate states in the reaction process. Cryogenic buffer-gas beams (CBGB) have gained popularity as bright, low temperature molecular sources for spectroscopy and reaction studies. We have determined a method for efficiently loading a signicant fraction of these new sources into a traveling-wave Stark decelerator, which uses time-varying inhomogeneous electric fields to decelerate polar molecules. We have also combined a CBGB with the ...
Disk Heating, Galactoseismology, And The Formation Of Stellar Halos, 2017 Columbia University
Disk Heating, Galactoseismology, And The Formation Of Stellar Halos, Kathryn V. Johnston, Adrian M. Price-Whelan, Maria Bergemann, Chervin F. P. Laporte, Ting S. Li, Allyson A. Sheffield, Steven R. Majewski, Rachael S. Beaton, Branimir Sesar, Sanjib Sharma
Publications and Research
Deep photometric surveys of the MilkyWay have revealed diffuse structures encircling our Galaxy far beyond the “classical” limits of the stellar disk. This paper reviews results from our own and other observational programs, which together suggest that, despite their extreme positions, the stars in these structures were formed in our Galactic disk. Mounting evidence from recent observations and simulations implies kinematic connections between several of these distinct structures. This suggests the existence of collective disk oscillations that can plausibly be traced all the way to asymmetries seen in the stellar velocity distribution around the Sun. There are multiple interesting implications ...
Maximum Mass Restraint Of Neutron Stars: Quarks, Pion, Kaons, And Hyperons, 2017 Claremont McKenna College
Maximum Mass Restraint Of Neutron Stars: Quarks, Pion, Kaons, And Hyperons, Garrett Ryan
CMC Senior Theses
This thesis explores the topic of maximum mass stability of neutron stars. The outer structure is detailed and explores nuclear pasta phases, the neutron drip line, and density transitions of matter in the crust and atmosphere layers. Other discussion points include superfluids in the crust and core, vortex roles in neutron stars, and magnetic field effects on the EOS in neutron stars. The inner core is studied in much more detail due to its significant role in EOS. The variety of stars include pion condensate stars, kaon condensate stars, npeu stars, npeu stars with the inclusion of hyperons, quark-hybrid stars ...
Gemini: The Twins Of Leda, 2017 Parkland College
Gemini: The Twins Of Leda, Derek Schneider
Natural Sciences Poster Sessions
This poster for the Natural Sciences Poster Session at Parkland College features the constellation Gemini, identifying prominent stars in the constellation and objects within the region (nebulae, clusters, galaxies), calculating the lifespans of the stars in the constellation, calculating average rise time change, and briefly touching on the associated mythology.
Canis Major, 2017 Parkland College
Canis Major, Sage A. Russell
Natural Sciences Poster Sessions
This poster for the Natural Sciences Poster Session features the constellation Canis Major. Features of the poster include a calculation of the change in rise time to calculate the passage of a year, determining the life span of the major stars in the constellation, and identifying Messier objects within the region.
Utilizing The O-C Method To Determine Third-Body Existence In Eclipsing Binary Systems, 2017 Embry-Riddle Aeronautical University
Utilizing The O-C Method To Determine Third-Body Existence In Eclipsing Binary Systems, Patrice Majewski, Tomomi Otani, Terry D. Oswalt
Previous studies on the subject of eclipsing binaries (EBs) within the Kepler field have been adequately determined the period, distance, and other stellar parameters of these systems (Borkovits, et al. 2015). Additionally, with the use of Observed-minus-Calculated (O-C) plots, variation in the timing of timing of eclipses can be easily detected. The eclipse timing shifts may be caused by dynamical effects or by light-travel time effects (LTTE) caused by the existence of a third body. The following research was conducted on ten binaries within the Kepler “K2” Campaign 5 field whose light curves (LCs) showed evidence of eclipses with periods ...
First Performance Results Of A New Field-Widened Spatial Heterodyne Spectrometer For Geocoronal Hα Research, 2017 University of Wisconsin - Madison
First Performance Results Of A New Field-Widened Spatial Heterodyne Spectrometer For Geocoronal Hα Research, D. D. Gardner, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig, S. M. Nossal, L. M. Haffner
A new, high-resolution ﬁeld-widened spatial heterodyne spectrometer (FW-SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry-Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW-SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts.Coincident Hα observations by FW-SHS and PBO FPI were obtained over similar integration ...
Black Holes And Einstein: A Commentary Of The Types Of Black Holes That Produce Gravitational Waves, Sage A. Russell
A with Honors Projects
Perhaps the most the notorious player in the astronomical field, objects known as black holes captivate the imaginations of scientists and average folk the world over, but as much as we adore hypothesizing about what black holes are like, there is so much that we’re only just finding out about. From 1909 until 1918, famed physicist Albert Einstein predicted many characteristics of spacetime and the effect of massive objects on it, including the notion of an energy-carrying wave moving at the speed of light that causes ripples through the fabric of spacetime, otherwise known as gravitational waves. A relatively ...
Search For Binaries In The Kepler K2 Fields Using Pulsation Timing Method, 2017 Embry-Riddle Aeronautical University
Search For Binaries In The Kepler K2 Fields Using Pulsation Timing Method, Tomomi Otani, Terry Oswalt
Finding orbital solutions of binaries which have small mass ratios (50 days) is challenging using traditional techniques. The radial velocity method is a good way to detect such binary stars, however it requires large telescopes. Therefore, the search for binaries in those regions is still incomplete. For binaries in this regime with at least one component that pulsates, pulsation timing is a better approach. Orbital solutions for such systems can be obtained from the periodic change in pulse arrival times as the star’s reflex motion is manifested by the changing distance along the line of sight. We present a ...
O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, 2017 Embry-Riddle Aeronautical University
O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, Tomomi Otani, Terry Oswalt, Alexander Stone-Martinez, Dana Singh, Kenneth Sampson, Aliyah Khan, Austin Seepersad, Caila Deabreu, Adam Moss, Claudia Morello
PG 1219 + 534 (KY Uma) is a subdwarf B pulsating star with multiple periodicities between 120 – 175 s. PG 1219 + 534 was monitored for 90 hours during 2010-1 and 2016 using the 0.9 m SARA-KP telescope at Kitt Peak National Observatory (KPNO) in Arizona and the 0.8m Ortega telescope at Florida Institute of Technology in Melbourne, Florida. So far, the most promising theory for the origin of subdwarf B (sdB) stars is that they result from binary mass transfer near the Helium Flash stage of evolution. The observations of PG 1219 + 534 reported here are part of our ...
Environmentally Driven Galaxy Evolution And Quenching: Insights From The Low-Redshift Circumgalactic Medium, 2017 University of Massachusetts Amherst
Environmentally Driven Galaxy Evolution And Quenching: Insights From The Low-Redshift Circumgalactic Medium, Joseph Burchett
The gaseous halos of galaxies -- the circumgalactic medium (CGM) -- serve as interfaces playing host to the fueling and feedback processes that sustain and regulate star formation. Furthermore, interactions between galaxies one with another and with larger scale structure, such as galaxy cluster halos, must necessarily act through the CGM. This dissertation examines the CGM as traced by H I, C IV, and O VI absorption lines across wide range of halo environments, from isolated dwarf galaxies with M* < 108 Msun to galaxy clusters with Mhalo > 1014 Msun. By first conducting a blind survey of C IV ...
Astrophysical Accretion And Feedback: The Bayesian Linchpin Of Theory And Observation, 2017 University of Massachusetts - Amherst
Astrophysical Accretion And Feedback: The Bayesian Linchpin Of Theory And Observation, Shawn Roberts
Despite being a major pillar of galaxy evolution, galactic feedback from stars and supermassive black holes (SMBHs) is subject to very little observational constraint. This is particularly true of the hot component, as viewed in X-rays. Yet, the hot component is directly linked to much of the energetic feedback released from these compact objects. X-ray observations suffer from several challenges that make placing this constraint a difficult task. In the face of considerable model uncertainty, these challenges underscore the need for novel X-ray data analysis techniques. In this dissertation, I seek to lend a unique perspective to X-ray data analysis ...
Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, 2017 Embry-Riddle Aeronautical University
Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, Terry D. Oswalt, Derek Buzasi, Tomomi Otani
We are determining rotation periods for an ensemble of over 100 wide non-interacting binary stars in the K2 Campaign 5 field that contain two main sequence dwarfs, as well as a smaller sample containing at least one white dwarf component. Observations of such coeval pairs provide the basis for our new investigation of rotation-based age determinations. Such “gyrochronology” ages can achieve a precision that exceeds most other current method of stellar age determination. Here we present a status report on our analysis of the light curves extracted from the K2 Campaign 5 field.
Gyrochronology Of Wide Binaries In The Kepler K2 Fields, 2017 Embry-Riddle Aeronautical University
Gyrochronology Of Wide Binaries In The Kepler K2 Fields, Alexander Stone-Martinez, Gustavo Villarroel, Patrice Majewski, Tomomi Otani, Terry Oswalt, Andrew Mcnaughton
Gyrochronology is the method of determining a stars age based on its rotation period and mass. A cool main sequence star loses it's angular momentum as it ages, so the rotation rate slows down. Gyrochronology has been tested on star clusters in previous studies and now we are applying the theory to binary stars. Components of a binary should be the same age, so Gyrochronology should return the same age for both stars in binary systems. We examined the rotation periods for 290 wide binary main sequence stars in the Kepler K2 fields. These observations are part of a ...
Multispectral Observations And Analysis Of The Rosette Nebula, 2017 University of Kentucky
Multispectral Observations And Analysis Of The Rosette Nebula, Jeremy Huber
Theses and Dissertations--Physics and Astronomy
The Rosette nebula is a large, ring-shaped emission nebula with a distinctive central cavity excavated by its central cluster of OB stars. Toward understanding the three dimensional structure and fundamental physical processes of this object, we have acquired flux-calibrated, 4-degree field, deep exposures of the Rosette region through 3 nm bandwidth H-alpha (656.3 nm) as well as H-beta (486.1nm), [OIII] (500.7 nm) and [SII] (671.6 nm) filters with 4.5 nm bandwidth. The 4 arcsec/pixel images are supplemented with 4 degree field slit spectra and combined with archival data from the Galactic Evolution Explorer satellite ...
Using Student Characteristics, Student Spatial-Content Knowledge, And Teacher Spatial-Content Knowledge To Predict Student Spatial-Content Knowledge Of Lunar Phases, Kyle A. Curry
Theses and Dissertations--Science, Technology, Engineering, and Mathematics (STEM) Education
Student demographic characteristics of gender and race/ethnicity, students’ spatial-content knowledge as measured by pre-instructional performance on the Lunar Phases Concept Inventory (LPCI) (Lindell & Olsen), and post-instructional performance on the Purdue Visualization of Rotations Test (PSVT) (Bodner & Guay, 1997), and teachers’ spatial-content knowledge as measured by the two assessments were considered to predict students’ overall understanding of lunar phases as measured by post-instructional results on the LPCI. A mixed modeling approach was used in a hierarchal manner to evaluate the student learning outcomes. Results showed that student gender was not a significant predictor of post-instructional student performance, but students who ...
Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, 2017 Embry-Riddle Aeronautical University
Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, T. D. Oswalt, T. Otani, A. Stone-Martinez, P. Majewski, D. Buzasi
Essential to understanding the history of the Galaxy’s stellar populations, ages are among the most difficult to measure properties of stars. Accurate stellar ages would provide key leverage on problems ranging from the habitability of exoplanets to the Galaxy’s chemical evolution and age. Gyrochronology, the empirical relation between rotation and age, is believed to be among the best current methods of stellar age determination. Using several hundred wide non-interacting binaries identified in the Kepler mission “K2” extended mission fields we are testing this paradigm. Such wide pairs afford a unique opportunity to unravel and calibrate the effects of ...
The Sluggs Survey: A Catalog Of Over 4000 Globular Cluster Radial Velocities In 27 Nearby Early-Type Galaxies, 2016 Swinburne University of Technology
The Sluggs Survey: A Catalog Of Over 4000 Globular Cluster Radial Velocities In 27 Nearby Early-Type Galaxies, Duncan A. Forbes, Adebusola B. Alabi, Jean P. Brodie, Aaron J. Romanowsky, Jay Strader, Caroline Foster, Christopher Usher, Lee R. Spitler, Sabine Bellstedt, Nicola Pastorello, Alexa Villaume, Asher Wasserman, Vincenzo Pota
Aaron J. Romanowsky
Sdss-Iv Manga: Spatially Resolved Star Formation Histories In Galaxies As A Function Of Galaxy Mass And Type, 2016 University of Portsmouth, UK
Sdss-Iv Manga: Spatially Resolved Star Formation Histories In Galaxies As A Function Of Galaxy Mass And Type, D. Goddard, D. Thomas, C. Maraston, K. Westfall, J. Etherington, R. Riffel, M. D. Mallmann, Z. Zheng, M. Argudo-Fernández, J. Lian, M. 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, D. P. Schneider
Physics and Astronomy Faculty Publications
We study the internal gradients of stellar population properties within 1.5 Re for a representative sample of 721 galaxies, with stellar masses ranging between 109 M⊙ and 1011.5 M⊙ from the SDSS-IV MaNGA Integral-Field-Unit survey. Through the use of our full spectral fitting code firefly, we derive light- and mass-weighted stellar population properties and their radial gradients, as well as full star formation and metal enrichment histories. We also quantify the impact that different stellar population models and full spectral fitting routines have on the derived stellar population properties and the radial gradient measurements. In ...
Sdss-Iv Manga: The Impact Of Diffuse Ionized Gas On Emission-Line Ratios, Interpretation Of Diagnostic Diagrams And Gas Metallicity Measurements, Kai Zhang, Renbin Yan, Kevin Bundy, Matthew Bershady, L. Matthew Haffner, René Walterbos, Roberto Maiolino, Christy Tremonti, Daniel Thomas, Niv Drory, Amy Jones, Francesco Belfiore, Sebastian F. Sánchez, Aleksandar M. Diamond-Stanic, Dmitry Bizyaev, Christian Nitschelm, Brett Andrews, Jon Brinkmann, Joel R. Brownstein, Edmond Cheung, Cheng Li, David R. Law, Alexandre Roman Lopes, Daniel Oravetz, Kaike Pan, Thaisa Storchi Bergmann, Audrey Simmons
Physics and Astronomy Faculty Publications
Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed by Mapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low ΣHα regions display enhanced [S II]/Hα, [N II]/Hα, [O II]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and ΣHα. In line ratio diagnostic diagrams, contamination by DIG moves H II ...