Astrophysics and Astronomy Commons^™

A Catalog Of Visual-Like Morphologies In The 5 Candels Fields Using Deep Learning, M. Huertas-Company, R. Gravet, G. Cabrera-Vives, Pablo G. Pérez-González, J. Kartaltepe, Guillermo Barro, M. Bernardi, S. Mei, F. Shankar, P. Dimauro, E. F. Bell, Dale D. Kocevski, David C. Koo, Sandra M. Faber, Daniel H. Mcintosh

Physics and Astronomy Faculty Publications

We present a catalog of visual-like H-band morphologies of ~50.000 galaxies (H_f160w < 24.5) in the 5 CANDELS fields (GOODS-N, GOODS-S, UDS, EGS, and COSMOS). Morphologies are estimated using Convolutional Neural Networks (ConvNets). The median redshift of the sample is 〈z〉 ~ 1.25. The algorithm is trained on GOODS-S, for which visual classifications are publicly available, and then applied to the other 4 fields. Following the CANDELS main morphology classification scheme, our model retrieves for each galaxy the probabilities of having a spheroid or a disk, presenting an irregularity, being compact or a point source, and being unclassifiable. ConvNets are able to predict the fractions of votes given to a galaxy image with zero bias and ~10% scatter. The fraction of mis-classifications is …

X-Ray Emission From The Giant Magnetosphere Of The Magnetic O-Type Star Ngc 1624-2, V. Petit, D. H. Cohen, G. A. Wade, Y. Naze, S. P. Owocki, J. O. Sundqvist, A. Ud-Doula, A. Fullerton, M. Leutenegger, Marc Gagne

Earth & Space Sciences Faculty Publications

No abstract provided.

Searches For Continuous Gravitational Waves From Nine Young Supernova Remnants, J. Aasi, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

We describe directed searches for continuous gravitational waves (GWs) in data from the sixth Laser Interferometer Gravitational-wave Observatory (LIGO) science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of 10. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3-25.3 days using the matched-filtering -statistic. We found …

On The Disk Wind Mass Loss Rates In Qsos, Nicolas A. Pereyra

Physics & Astronomy Faculty Publications

We derive here a relatively simple expression for the total wind mass loss rates in QSOs within the accretion disk wind scenario. We show that the simple expression derived here for QSO disk wind mass loss rate is in a very good agreement with the more “exact” values obtained through significantly more complex and detailed numerically intensive 2.5D time-dependent simulations. Additionally we show that for typical QSO parameters, the disk itself will be emitting mostly in the UV/optical spectrum, in turn implying that the X-ray emission from QSOs likely is produced through some physical mechanism acting at radii smaller than …

Galaxy And Mass Assembly (Gama) : The Wavelength Dependence Of Galaxy Structure Versus Redshift And Luminosity., Rebecca Kennedy, Steven P. Bamford, Ivan K. Baldry, Boris Haußler, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Amanda J. Moffett, Cristina C. Popescu, Edward N. Taylor, Richard Tuffs, Marina Vika, Benedetta Vulcani

Faculty and Staff Scholarship

We study how the sizes and radial profiles of galaxies vary with wavelength, by fitting Sersic ´ functions simultaneously to imaging in nine optical and near-infrared bands. To quantify the wavelength dependence of effective radius we use the ratio, R, of measurements in two rest-frame bands. The dependence of Sersic index on wavelength, ´ N , is computed correspondingly. Vulcani et al. have demonstrated that different galaxy populations present sharply contrasting behaviour in terms of R and N . Here we study the luminosity dependence of this result. We find that at higher luminosities, early-type galaxies display a more substantial …

Galaxy And Mass Assembly (Gama) : The Bright Void Galaxy Population In The Optical And Mid-Ir., S. J. Penny, M. J. I. Brown, K. A. Pimbblet, M. E. Cluver, D. J. Croton, M. S. Owers, R. Lange, M. Alpaslan, I. K. Baldry, J. Bland-Hawthorn, S. Brough, S. P. Driver, Benne W. Holwerda, A. M. Hopkins, T. H. Jarrett, D. Heath Jones, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, M. Meyer, P. Norberg, A. S. G. Robotham, M. Rodrigues

Faculty and Staff Scholarship

We examine the properties of galaxies in the Galaxies and Mass Assembly (GAMA) survey located in voids with radii >10 h−1 Mpc. Utilizing the GAMA equatorial survey, 592 void galaxies are identified out to z ≈ 0.1 brighter than Mr = −18.4, our magnitude completeness limit. Using the WHα versus [N ii]/Hα (WHAN) line strength diagnostic diagram, we classify their spectra as star forming, AGN, or dominated by old stellar populations. For objects more massive than 5 × 109 M⊙, we identify a sample of 26 void galaxies with old stellar populations classed as passive and retired …

Excess Mid-Infrared Flux: An Indicator Of Mass Loss In Cepheids?, Edward G. Schmidt

Edward Schmidt Publications

Spectral energy distributions for 132 classical and type II Cepheids were searched for evidence of excess flux above the photospheric level in the mid-infrared. Eight of them were found to have unambiguously strong excess emission while a further 13 showed evidence of weak emission. The presence of emission appears to be unrelated to either the pulsational amplitude or the effective temperature while strong emission is limited to stars with periods longer than 11 days, with a single exception. For the stars with strong emission we attempted to fit the energy distribution with a stellar wind model. No acceptable fit could …

The Impact Of Solar Wind Ulf Bz Fluctuations On Geomagnetic Activity For Viscous Timescales During Strongly Northward And Southward Imf, A. Osmane, A. P. Dimmock, R. Naderpour, T. I. Pulkkinen, K. Nykyri

Publications

We analyze more than 17 years of OMNI data to statistically quantify the impact of IMF Bz fluctuations on AL by using higher-order moments in the AL-distribution as a proxy. For strongly southward interplanetary magnetic field (IMF), the AL distribution function is characterized by a decrease of the skewness, a shift of its peak from −30 nT to −200 nT, and a broadening of the distribution core. During northward IMF, the distribution of AL is characterized by a significant reduction of the standard deviation and weight in the tail. Following this characterization of AL for southward and northward IMF, we …

Sunspot Proxy To Predict The Number Of Spes Per Year Based On Yearly Sunspot Number, Zachary Robinson

Von Braun Symposium Student Posters

No abstract provided.

Study Solar Activity In The Backside Of The Sun, Catherine A. Gibbs

Von Braun Symposium Student Posters

No abstract provided.

What Do Shocks Tell Us About Galaxy Clusters?, Sarthak Dasadia

Von Braun Symposium Student Posters

No abstract provided.

Verifying The Associations Of Fermi Source3fgl 2015.6+3709, Qiana Hunt

Von Braun Symposium Student Posters

No abstract provided.

Searching For Terrestrial Gamma-Ray Flashes Via Lightning And The Fermi Space Telescope, Kareem Omar

Von Braun Symposium Student Posters

No abstract provided.

University Scholar Series: Michael Kaufman, Michael Kaufman

University Scholar Series

H2O in Interstellar Space: How the Universe Conspires to Make Water Everywhere

On October 28, 2015, Dr. Michael Kaufman spoke in the University Scholar Series hosted by Provost Andy Feinstein at the Dr. Martin Luther King, Jr. Library. His talk was titled “H₂O in Interstellar Space: How the Universe Conspires to Make Water, Water Everywhere.” Dr. Kaufman's astrophysics research focuses on the interactions and feedback between newly formed stars and the interstellar medium—the raw material from which stars form. He constructs computational models of the radiative transfer, dynamics and chemistry that occur in regions of active star formation, …

On The Formation And Evolution Of The First Be Star In A Black Hole Binary Mwc 656, M. Grudzinska, K. Belczynski, J. Casares, S. E. De Mink, J. Ziolkowski, I. Negueruela, M. Ribó, I. Ribas, J. M. Paredes, A. Herrero, M. Benacquista

Physics & Astronomy Faculty Publications

We find that the formation of MWC 656 (the first Be binary containing a black hole) involves a common envelope phase and a supernova explosion. This result supports the idea that a rapidly rotating Be star can emerge out of a common envelope phase, which is very intriguing because this evolutionary stage is thought to be too fast to lead to significant accretion and spin up of the B star.We predict ~10-100 of B-BH binaries to currently reside in the Galactic disc, among which around 1/3 contain a Be star, but there is only a small chance to observe a …

Measurement Of The Target-Normal Single-Spin Asymmetry In Quasielastic Scattering From The Reaction 3He↑(E,E′ ), Chiranjib Dutta, Wolfgang Korsch, Y.-W. Zhang, E. Long, M. Mihovilovič, G. Jin, K. Allada, B. Anderson, J. R. M. Annand, T. Averett, C. Ayerbe-Gayoso, W. Boeglin

Physics and Astronomy Faculty Publications

We report the first measurement of the target single-spin asymmetry, A_y, in quasielastic scattering from the inclusive reaction ³He^↑(e,e′ ) on a ³He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A_y can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q²=0.13, 0.46, and …

Absolute Dimensions Of The Metallic-Line Eclipsing Binary V501 Monocerotis, Guillermo Torres, Claud H. Sandberg Lacy, Krešimir Pavlovski, Francis C. Fekel, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We report extensive high-resolution spectroscopic observations and V-band differential photometry of the slightly eccentric 7.02 day detached eclipsing binary V501 Mon (A6m+F0), which we use to determine its absolute dimensions to high precision (0.3% for the masses and 1.8% for the radii, or better). The absolute masses, radii, and temperatures are MA = 1.6455 ± 0.0043 M⊙, RA = 1.888 ± 0.029 R⊙, and ${T}_{{\rm{eff}}}^{{\rm{A}}}$ = 7510 ± 100 K for the primary and MB = 1.4588 ± 0.0025 M⊙, RB = 1.592 ± 0.028 R⊙, and TeffB = 7000 ± 90 K for the secondary. Apsidal motion has been …

Pulsar J0453+1559: A Double Neutron Star System With A Large Mass Asymmetry, J. G. Martinez, K. Stovall, P. C.C. Freire, J. S. Deneva, F. A. Jenet, M. A. Mclaughlin, M. Bagchi, S. D. Bates, A. Ridolfi

Physics & Astronomy Faculty Publications

To understand the nature of supernovae and neutron star (NS) formation, as well as binary stellar evolution and their interactions, it is important to probe the distribution of NS masses. Until now, all double NS (DNS) systems have been measured as having a mass ratio close to unity (q ≥ 0.91). Here, we report the measurement of the individual masses of the 4.07-day binary pulsar J0453+1559 from measurements of the rate of advance of periastron and Shapiro delay: the mass of the pulsar is Mp = 1.559 � 0.005 Mo and that of its companion is Mo; q = 0.75. …

Stochastic Acceleration Of Galactic Cosmic Rays By Compressible Plasma Fluctuations In Supernova Shells, Ming Zhang

Aerospace, Physics, and Space Science Faculty Publications

A theory of 2-stage acceleration of Galactic cosmic rays in supernova remnants is proposed. The first stage is accomplished by the supernova shock front, where a power-law spectrum is established up to a certain cutoff energy. It is followed by stochastic acceleration with compressible waves/turbulence in the downstream medium. With a broad ∝k^(-2) spectrum for the compressible plasma fluctuations, the rate of stochastic acceleration is constant over a wide range of particle momentum. In this case, the stochastic acceleration process extends the power-law spectrum cutoff energy of Galactic cosmic rays to the knee without changing the spectral slope. This situation …

Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, P. Pilleri, Daniel B. Reisenfeld, T. H. Zurbuchen, S. T. Lepri, P. Shearer, J. A. Gilbert, R. Von Steiger, R. C. Wiens

Physics and Astronomy Faculty Publications

We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009), and the period in which the Genesis spacecraft was collecting SW (late 2001-early 2004). We differentiate our analysis in terms in SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative …

Arecibo Pulsar Survey Using Alfa. Iv. Mock Spectrometer Data Analysis, Survey Sensitivity, And The Discovery Of 40 Pulsars, P. Lazarus, A. Brazier, J. W.T. Hessels, C. Karako-Argaman, V. M. Kaspi, R. Lynch, E. Madsen, C. Patel, S. M. Ransom, Fredrick Jenet

Physics & Astronomy Faculty Publications

The on-going Arecibo Pulsar-ALFA (PALFA) survey began in 2004 and is searching for radio pulsars in the Galactic plane at 1.4 GHz. Here we present a comprehensive description of one of its main data reduction pipelines that is based on the PRESTO software and includes new interference-excision algorithms and candidate selection heuristics. This pipeline has been used to discover 40 pulsars, bringing the surveys discovery total to 144 pulsars. Of the new discoveries, eight are millisecond pulsars (MSPs; P 10 ms) and one is a Fast Radio Burst (FRB). This pipeline has also re-detected 188 previously known pulsars, 60 of …

First Nustar Observations Of Mrk 501 Within A Radio To Tev Multi-Instrument Campaign, P. T. Reynolds, Nustar, Magic, Veritas, F-Gamma

Physical Sciences Publications

We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsähovi, and the F-Gamma consortium. Some of the MAGIC observations were affected …

Spin Nematics, Valence-Bond Solids, And Spin Liquids In So(N) Quantum Spin Models On The Triangular Lattice, Ribhu K. Kaul

Physics and Astronomy Faculty Publications

We introduce a simple model of SO(N) spins with two-site interactions which is amenable to quantum Monte Carlo studies without a sign problem on nonbipartite lattices. We present numerical results for this model on the two-dimensional triangular lattice where we find evidence for a spin nematic at small N, a valence-bond solid at large N, and a quantum spin liquid at intermediate N. By the introduction of a sign-free four-site interaction, we uncover a rich phase diagram with evidence for both first-order and exotic continuous phase transitions.

Redicting The Α Comae Berenices Time Of Eclipse: How 3 Ambiguous Measurements Out Of 609 Caused A 26 Year Binary's Eclipse To Be Missed, Matthew W. Muterspaugh, Marcella J. P. Wijngaarden, Hubertus F. Henrichs, Benjamin F. Lane, William I. Hartkopf, Gregory W. Henry, Gail H. Schaefer, Chris D. Farrington, Christian A. Hummel, Robert T. Zavala

Information Systems and Engineering Management Research Publications

The dwarf stars in the 26 year period binary α Com were predicted to eclipse each other in early 2015. That prediction was based on an orbit model made with over 600 astrometric observations using micrometers, speckle interferometry, and long baseline optical interferometry. Unfortunately, it has been realized recently that the position angle measurements for three of the observations from ∼100 years ago were in error by 180°, which warped the orbital fit. The eclipse was likely 2 months earlier than predicted (MJD 56979, 2014 November 18 UT, 7 days before the first photometric observations of this system for the …

Discovery Of An Apparent High Latitude Galactic Supernova Remnant, Robert A. Fesen, Jack M. M. Neustadt, Christine S. Black, Ari H. D. Koeppel

Dartmouth Scholarship

Deep Hα images of a faint emission complex 4.0 x 5.5 degrees in angular extent and located far off the Galactic plane at l = 70.0 degrees, b=-21.5 degrees reveal numerous thin filaments suggestive of a supernova remnant's shock emission. Low dispersion optical spectra covering the wavelength range 4500 - 7500 A show only Balmer line emissions for one filament while three others show a Balmer dominated spectrum along with weak [N I] 5198, 5200 A, [O I] 6300, 6364 A, [N II] 6583 A, [S II] 6716, 6731 A and in one case [O III] 5007 A line emission. …

Sun-Like Magnetic Cycles In The Rapidly Rotating Young Solar Analog Hd 30495, Ricky Egeland, Travis S. Metcalfe, Jeffrey C. Hall, Gregory W. Henry

Information Systems and Engineering Management Research Publications

A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial (∼2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has …

Research And Development Of A Smart Module Integrated Converter For The Future Of Renewable Energy, Phong Tran

University Grant Program Reports

This research focused on developing of a Smart Module Integrated Converter for grid-connected solar photovoltaic (PV) system. This technology enhances the commercial micro-inverters with novel network-supported, grid-adapted functionalities. The micro-inverter utilizes open source and reference design from Microchip to keep design and production at low cost.

Astr 103: Descriptive Astronomy Syllabus, Michael Sibbernsen

Department of Physics and Astronomy: Syllabi

Syllabus for ASTR 103 Descriptive Astronomy for Fall 2015 semester.

Astr 224: Astronomy And Astrophysics Laboratory, Zachary Smith

Department of Physics and Astronomy: Syllabi

Syllabus for ASTR 224 Astronomy and Astrophysics Laboratory for Fall 2015.

Astr 204: Introduction To Astronomy And Astrophysics, Shawn Langan

Department of Physics and Astronomy: Syllabi

Syllabus for ASTR 204 Introduction to Astronomy and Astrophysics for Fall 2015 semester.