Astrophysics and Astronomy Commons^™

Investigation Of The Asteroid - Neutron Star Collision Model For The Repeating Fast Radio Burst, Jeremy L. Smallwood, Rebecca G. Martin, Bing Zhang

Physics & Astronomy Faculty Research

The origin of fast radio bursts (FRBs) is still a mystery. One model proposed to interpret the only known repeating object, FRB 121102, is that the radio emission is generated from asteroids colliding with a highly magnetized neutron star (NS). With N-body simulations, we model a debris disc around a central star with an eccentric orbit intruding NS. As the NS approaches the first periastron passage, most of the comets are scattered away rather than being accreted by the NS. To match the observed FRB rate, the debris belt would have to be at least 3 orders of magnitude more …

Long-Term Spot Monitoring Of The Young Solar Analogue V889 Herculis, Teemu Willamo, Thomas Hackman, Jyri J. Lehtinen, Maarit J. Käpylä, Ilya Ilyin, Gregory W. Henry, Lauri Jetsu, Oleg Kochukhov, Nikolai Piskunov

Information Systems and Engineering Management Research Publications

Context. Starspots are important manifestations of stellar magnetic activity. By studying their behaviour in young solar analogues, we can unravel the properties of their magnetic cycles. This gives crucial information of the underlying dynamo process. Comparisons with the solar cycle enable us to infer knowledge about how the solar dynamo has evolved during the Sun’s lifetime.

Aims. Here we study the correlation between photometric brightness variations, spottedness, and mean temperature in V889 Her, a young solar analogue. Our data covers 18 years of spectroscopic and 25 years of photometric observations.

Methods. We use Doppler imaging to derive …

Misaligned Accretion Disc Formation Via Kozai-Lidov Oscillations, Alessia Franchini, Rebecca G. Martin, Stephen H. Lubow

Physics & Astronomy Faculty Research

We investigate the formation and evolution of misaligned accretion discs around the secondary component of a binary through mass transfer driven by Kozai–Lidov (KL) oscillations of the circumprimary disc’s eccentricity and inclination. We perform smoothed particle hydrodynamics simulations to study the amount of mass transferred to the secondary star as a function of both the disc and binary parameters. For the range of parameters we explore, we find that increasing the disc aspect ratio, viscosity parameter, and initial inclination as well as decreasing the binary mass ratio leads to larger amount of mass transfer, up to a maximum of about …

Infrared Spectroscopy Of Symbiotic Stars. Xii. The Neutron Star Syxb System 4u 1700+24 = V934 Herculis, Kenneth H. Hinkle, Francis C. Fekel, Richard Joyce, Joanna Mikołajewska, Cezary Gałan, Thomas Lebzelter

Information Systems and Engineering Management Research Publications

The X-ray symbiotic (SyXB) V934 Her = 4U 1700+24 is an M giant–neutron star (NS) binary system. Employing optical and infrared radial velocities spanning 29 yr combined with the extensive velocities in the literature, we compute the spectroscopic orbit of the M giant in that system. We determine an orbital period of 4391 days, or 12.0 yr, the longest for any SyXB and far longer than the 404 day orbit commonly cited for this system in the literature. In addition to the 12.0 yr orbital period, we find a shorter period of 420 days, similar to the one previously found. …

Giant Planet Effects On Terrestrial Planet Formation And System Architecture, Anna C. Childs, Elisa Quintana, Thomas Barclay, Jason H. Steffen

Physics & Astronomy Faculty Research

Using an updated collision model, we conduct a suite of high-resolution N-body integrations to probe the relationship between giant planet mass and terrestrial planet formation and system architecture. We vary the mass of the planets that reside at Jupiter’s and Saturn’s orbit and examine the effects on the interior terrestrial system. We find that massive giant planets are more likely to eject material from the outer edge of the terrestrial disc and produce terrestrial planets that are on smaller, more circular orbits. We do not find a strong correlation between exterior giant planet mass and the number of Earth analogues …

On The Broad-Band Synchrotron Spectra Of Pulsar Wind Nebulae, Siyao Xu, Noel Klinger, Oleg Kargaltsev, Bing Zhang

Physics & Astronomy Faculty Research

As shown by broad-band observations, pulsar wind nebulae (PWNe) are characterized by a broken power-law spectrum of synchrotron emission. Based on the modern magnetohydrodynamic (MHD) turbulence theories, we investigate the re-acceleration of electrons in the PWN through the adiabatic stochastic acceleration (ASA), which arises from fundamental dynamics of MHD turbulence. The ASA acts to flatten the injected energy spectrum of electrons at low energies, while synchrotron cooling results in a steep spectrum of electrons at high energies. Their dominance in different energy ranges leads to a flat radio spectrum (Fν ) and a steep X-ray spectrum. Our analytical spectral shapes …

Bright Opportunities For Atmospheric Characterization Of Small Planets: Masses And Radii Of K2-3 B, C, And D And Gj3470 B From Radial Velocity Measurements And Spitzer Transits, Molly Kosiarek, Ian J. M. Crossfield, Kevin K. Hardegree-Ullman, John H. Livingston, Björn Benneke, Gregory W. Henry, Ward S. Howard, David A. Berardo, Sarah C. Blunt, Benjamin J. Fulton, Lea A. Hirsch, Andrew W. Howard, Howard Isaacson, Erik A. Petigura, Evan Sinukoff, Lauren M. Weiss, Xavier Bonfils, Courtney D. Dressing, Heather Knutson, Joshua E. Schlieder, Michael Werner, Varoujan Gorjian, Jessica Krick, Farisa Y. Morales, Nicola Astudillo-Defru, J. M. Almenara, Xavier Delfosse, Thierry Forveille, Christophe Lovis, Michel Mayor, Felipe Murgas, Francesco Pepe, Nuno C. Santos, Stephane Udry, Henry T. Corbett, Octavi Fors, Nicholas M. Law, Jeffrey K. Ratzloff, Daniel Del Ser

Information Systems and Engineering Management Research Publications

We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer transit observations refined the transit ephemerides of K2-3 b, c, and d by over a factor of 10. We analyze ground-based photometry from the Evryscope and Fairborn Observatory to determine the characteristic stellar activity timescales for our Gaussian Process fit, including the stellar rotation period and activity region decay timescale. The stellar rotation signals for both stars are evident in the radial velocity data and …

Extreme Resonance Line Profile Variations In The Ultraviolet Spectra Of Ngc 1624-2: Probing The Giant Magnetosphere Of The Most Strongly Magnetized Known O-Type Star, A. David-Uraz, C. Erba, V. Petit, A. W. Fullerton, F. Martins, N. R. Walborn, R. Macinnis, R. H. Barbá, David H. Cohen, J. Maíz Apellániz, Y. Nazé, S. P. Owocki, J. O. Sundqvist, A Ud-Doula, G. A. Wade

Physics & Astronomy Faculty Works

In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the variability of its wind-sensitive resonance lines, comparing it to that of other known magnetic O stars. In particular, the observed variations in the profiles of the C  iv and Si  iv doublets between low state and high state are the largest observed in any magnetic O-type star, consistent with the expected properties of NGC 1624-2’s magnetosphere. We also observe a redshifted absorption component in the low state, a feature not seen …

Diagnosing The Clumpy Protoplanetary Disk Of The Uxor Type Young Star Gm Cephei, P. C. Huang, W. P. Chen, M. Mugrauer, R. Bischoff, J. Budaj, O. Burkhonov, S. Ehgamberdiev, R. Errmann, Z. Garai, H. Y. Hsiao, C. L. Hu, R. Janulis, Eric L.N. Jensen, S. Kiyota, K. Kuramoto, C. S. Lin, H. C. Lin, J. Z. Liu, O. Lux, H. Naito, R. Neuhäuser, J. Ohlert, E. Pakštienė, T. Pribulla, J. K. T. Qvam, S. Raetz, S. Sato, M. Schwartz, E. Semkov, S. Takagi, D. Wagner, M. Watanabe, Y. Zhang

Physics & Astronomy Faculty Works

UX Orionis stars (UXors) are Herbig Ae/Be or T Tauri stars exhibiting sporadic occultation of stellar light by circumstellar dust. GM Cephei is such a UXor in the young (∼4 Myr) open cluster Trumpler 37, showing prominent infrared excess, emission-line spectra, and flare activity. Our photometric monitoring (2008–2018) detects (1) an ∼3.43 day period, likely arising from rotational modulation by surface starspots, (2) sporadic brightening on timescales of days due to accretion, (3) irregular minor flux drops due to circumstellar dust extinction, and (4) major flux drops, each lasting for a couple of months with a recurrence time, though not …

Simulations Of Microscopic Propulsion Of Soft Elastic Bodies, David Urbanik, Shikhar Man Dwivedi, Colin Denniston

Physics and Astronomy Publications

Using simulations that realistically model both hydrodynamic and elastic behavior, we study the motion of a microscopic, driven elastic sphere immersed in water. We first confirm the “jittery” relaxation recently predicted theoretically for an externally driven elastic sphere. The sphere is then divided in two and each section is driven internally with the two sections 180° out of phase. With periodic and perfectly symmetric driving, the elastic sphere spontaneously breaks symmetry and can attain macroscopic average swimming velocities to the right or left, the direction depending only on the initial state. With asymmetric driving the elastic sphere swims in one …

Tess Discovery Of An Ultra-Short-Period Planet Around The Nearby M Dwarf Lhs 3844, R. Vanderspek, C. X. Huang, A. Vanderburg, G. R. Ricker, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, J. Burt, J. Dittmann, E. Newton, S. N. Quinn, A. Shporer, D. Charbonneau, J. Irwin, K. Ment, J. G. Winters, K. A. Collins, P. Evans, T. Gan, R. Hart, Eric L.N. Jensen, J. Kielkopf, S. Mao, W. Waalkes, F. Bouchy, M. Marmier, L. D. Nielsen, G. Ottoni, F. Pepe, D. Ségransan, S. Udry, T. Henry, L. A. Paredes, H.-S. James, R. H. Hinojosa, M. L. Silverstein, E. Palle, Z. Berta-Thompson, I. Crossfield, M. D. Davies, D. Dragomir, M. Fausnaugh, A. Glidden, J. Pepper, E. H. Morgan, M. Rose, J. D. Twicken, J. N. S. Villaseñor, L. Yu, G. Bakos, J. Bean, L. A. Buchhave, J. Christensen-Dalsgaard, J. L. Christiansen, D. R. Ciardi, M. Clampin, N. De Lee, D. Deming, J. Doty, J. G. Jernigan, L. Kaltenegger, J. J. Lissauer, P. R. Mccullough, N. Narita, M. Paegert, A. Pal, S. Rinehart, D. Sasselov, B. Sato, A. Sozzetti, K. G. Stassun, G. Torres

Physics & Astronomy Faculty Works

Data from the newly commissioned Transiting Exoplanet Survey Satellite has revealed a "hot Earth" around LHS 3844, an M dwarf located 15 pc away. The planet has a radius of 1.303 ± 0.022 R_⊕ and orbits the star every 11 hr. Although the existence of an atmosphere around such a strongly irradiated planet is questionable, the star is bright enough (I = 11.9, K = 9.1) for this possibility to be investigated with transit and occultation spectroscopy. The star's brightness and the planet's short period will also facilitate the measurement of the planet's mass through Doppler spectroscopy.

Multileptonic Signals Of Co-Annihilating Left-Right Supersymmetric Dark Matter, Arindam Chatterjee, Mariana Frank, Benjamin Fuks, Katri Huitu, Subhadeep Mondal, Santosh Kumar Rai, Harri Waltari

Journal Articles

We perform a comprehensive dark matter analysis of left-right supersymmetric scenarios that includes constraints from dark matter direct and indirect detection experiments and that presents distinctive features from those available in minimal supersymmetry. We concentrate on dark matter candidates which, while satisfying all constraints, are different from those of the minimal supersymmetric standard model. We consider in our analysis all possible co-annihilation channels relevant for setups in which several states are light and nearly degenerate, and devise a set of representative benchmark points, requiring co-annihilations, which satisfy all restrictions. We then study their consequent LHC signals, which exhibit promising new …

The Dependence Of Intrinsic Alignment Of Galaxies On Wavelength Using Kids And Gama, Christos Georgiou, Harry Johnston, Henk Hoekstra, Massimo Viola, Konrad Kuijken, Benjamin Joachimi, Nora Elisa Chisari, Daniel J. Farrow, Hendrik Hildebrandt, Benne W. Holwerda, Arun Kannawadi

Faculty and Staff Scholarship

The outer regions of galaxies are more susceptible to the tidal interactions that lead to intrinsic alignments of galaxies. The resulting alignment signal may therefore depend on the passband if the colours of galaxies vary spatially. To quantify this, we measured the shapes of galaxies with spectroscopic redshifts from the GAMA survey using deep gri imaging data from the KiloDegree Survey. The performance of the moment-based shape measurement algorithm DEIMOS was assessed using dedicated image simulations, which showed that the ellipticities could be determined with an accuracy better than 1% in all bands. Additional tests for potential systematic errors did …

Applications Of Information Theory In Solar And Space Physics, Jay R. Johnson, Simon Wing

Faculty Publications

Characterizing and modeling processes at the sun and space plasma in our solar system are difficult because the underlying physics is often complex, nonlinear, and not well understood. The drivers of a system are often nonlinearly correlated with one another, which makes it a challenge to understand the relative effects caused by each driver. However, entropy-based information theory can be a valuable tool that can be used to determine the information flow among various parameters, causalities, untangle the drivers, and provide observational constraints that can help guide the development of the theories and physics-based models. We review two examples of …

A Concept Of Biopharmaceutical Nanosatellite, Jakub Mielczarek, Adam Zadrozny

Physics & Astronomy Faculty Publications

The article is a short overview of a proposal of a CubeSat type nanosatellite designed to conduct biopharmaceutical tests on the low earth orbit. Motivations behind the emerging demand for such solution nowadays and in the close future are emphasized. The possible objectives and challenges to be addressed in the planned biopharmaceutical CubeSat missions are discussed. In particular, it is hard to imagine progress of the space tourism and colonization of Mars without a wide-ranging development of pharmaceutics dedicated to be used in space. Finally, an exemplary layout of a 3U type CubeSat is presented. We stress that, thanks to …

Cosmology, Craig W. Steele

Journal of Humanistic Mathematics

No abstract provided.

Astronomy For Educators, Daniel E. Barth

Open Educational Resources

Astronomy for Educators provides new and accomplished K-12 instructors with concepts and projects for low-cost, high-impact STEM classroom instruction that is built around the National Academies National Research Council's K-12 Framework for Science Education.

Late Delivery Of Nitrogen To The Earth, Cheng Chen, Jeremy L. Smallwood, Rebecca G. Martin, Mario Livio

Physics & Astronomy Faculty Research

Atmospheric nitrogen may be a necessary ingredient for the habitability of a planet as its presence helps to prevent water loss from a planet. The present-day nitrogen isotopic ratio, N-15/N-14, in the Earth's atmosphere is a combination of the primitive Earth's ratio and the ratio that might have been delivered in comets and asteroids. Asteroids have a nitrogen isotopic ratio that is close to the Earth's. This indicates either a similar formation environment to the Earth or that the main source of nitrogen was delivery by asteroids. However, according to geological records, the Earth's atmosphere could have been enriched in …

A Fermi Gamma-Ray Burst Monitor Search For Electromagnetic Signals Coincident With Gravitational-Wave Candidates In Advanced Ligo's First Observing Run, E. Burns, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Robert Stone, Darkhan Tuyenbayev, Wenhui Wang

Physics & Astronomy Faculty Publications

We present a search for prompt gamma-ray counterparts to compact binary coalescence gravitational wave (GW) candidates from Advanced LIGO's first observing run (O1). As demonstrated by the multimessenger observations of GW170817/GRB 170817A, electromagnetic and GW observations provide complementary information about the astrophysical source, and in the case of weaker candidates, may strengthen the case for an astrophysical origin. Here we investigate low-significance GW candidates from the O1 compact binary coalescence searches using the Fermi Gamma-Ray Burst Monitor (GBM), leveraging its all sky and broad energy coverage. Candidates are ranked and compared to background to measure the significance. Those with false …

A Complete Analytic Gravitational Wave Model For Undergraduates, Dillon Buskirk, Maria Babiuc-Hamilton

Physics Faculty Research

Gravitational waves are produced by orbiting massive binary objects, such as black holes and neutron stars, and propagate as ripples in the very fabric of space-time. As the waves carry off orbital energy, the two bodies spiral into each other and eventually merge. They are described by Einstein's equations of general relativity. For the early phase of the orbit, called the inspiral, Einstein equations can be linearised and solved through analytical approximations, while for the late phase, near the merger, we need to solve the fully nonlinear Einstein's equations on supercomputers. In order to recover the gravitational wave for the …