Planet Formation Imager (Pfi): Science Vision And Key Requirements,
2016
Swarthmore College
Planet Formation Imager (Pfi): Science Vision And Key Requirements, S. Kraus, J. D. Monnier, M. J. Ireland, G. Duchêne, C. Espaillat, S. Hönig, A. Juhasz, C. Mordasini, J. Olofsson, C. Paladini, K. Stassun, N. Turner, G. Vasisht, T. J. Harries, M. R. Bate, J.-F. Gonzalez, A. Matter, Z. Zhu, O. Panic, Z. Regaly, A. Morbidelli, F. Meru, S. Wolf, J. Ilee, J.-P. Berger, M. Zhao, Q. Kral, A. Morlok, A. Bonsor, D. Ciardi, S. R. Kane, K. Kratter, G. Laughlin, J. Pepper, S. Raymond, L. Labadie, R. P. Nelson, G. Weigelt, T. Ten Brummelaar, A. Pierens, R. Oudmaijer, W. Kley, B. Pope, Eric L.N. Jensen, A. Bayo, M. Smith, T. Boyajian, L. H. Quiroga-Nuñez, R. Millan-Gabet, A. Chiavassa, A. Gallenne, M. Reynolds, W.-J. De Wit, M. Wittkowski, F. Millour, P. Gandhi, C. Ramos Almeida, A. Alonso Herrero, C. Packham, M. Kishimoto, K. R. W. Tristram, J.-U. Pott, J. Surdej, D. Buscher, C. Haniff, S. Lacour, R. Petrov, S. Ridgway, P. Tuthill, G. Van Belle, P. Armitage, C. Baruteau, M. Benisty, B. Bitsch, S.-J. Paardekooper, C. Pinte, F. Masset, G. Rosotti
Physics & Astronomy Faculty Works
The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to ~100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the …
The Turning-Off Of Supernova Remnants: The Transition Into The Radiative Phase,
2016
Purdue University
The Turning-Off Of Supernova Remnants: The Transition Into The Radiative Phase, Ryan A. Lazur, Rodolfo Barniol Duran, Dimitrios Giannios
The Summer Undergraduate Research Fellowship (SURF) Symposium
Supernovae are amongst the most energetic events in the Universe. Understanding the different stages of the life of a supernova is currently one of the main objectives in astrophysics. During a supernova explosion, material with mass several times that of the Sun is ejected with a speed about 1/10 that of light. In current models, the transition from the Sedov-Taylor to the radiative phase is assumed to be almost instantaneous, which is not entirely accurate. Here the physics of the transition to the radiative phase will be revisited. Observations indicate that the supernova ejecta remains bright in the radio band …
Hst Hot-Jupiter Transmission Spectral Survey: Clear Skies For Cool Saturn Wasp-39b,
2016
California Institute of Technology
Hst Hot-Jupiter Transmission Spectral Survey: Clear Skies For Cool Saturn Wasp-39b, Patrick D. Fischer, Heather Knutson, David K. Sing, Gregory W. Henry, Michael H. Williamson, Jonathan J. Fortney, Adam S. Burrows, Tiffany Kataria, Nikolay Nikolov, Adam P. Showman, Gilda E. Ballester, Jean-Michel Désert, Suzanne Aigrain, Drake Deming, Alain Lecavelier Des Etangs, Alfred Vidal-Madjar
Information Systems and Engineering Management Research Publications
We present the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) optical transmission spectroscopy of the cool Saturn-mass exoplanet WASP-39b from 0.29-1.025 μm, along with complementary transit observations from Spitzer IRAC at 3.6 and 4.5 μm. The low density and large atmospheric pressure scale height of WASP-39b make it particularly amenable to atmospheric characterization using this technique. We detect a Rayleigh scattering slope as well as sodium and potassium absorption features; this is the first exoplanet in which both alkali features are clearly detected with the extended wings predicted by cloud-free atmosphere models. The full transmission spectrum is well …
Characterizing Exoplanet Host Star Atmospheres Using Spectroscopy,
2016
Rutgers University - New Brunswick/Piscataway
Characterizing Exoplanet Host Star Atmospheres Using Spectroscopy, Kristen Fahy
STAR Program Research Presentations
Exoplanet discovery is an exponentially growing field which is allowing scientists to discover new worlds beyond our own solar system. The aim for this research project was to specifically look at the stellar activity of host stars to determine if it is affecting the output data of target exoplanets. Previously, astronomers understood that stellar activity could influence the detection of new planets, but until now nobody has studied how it may specifically affect the planetary transit spectrum. By analyzing transit spectroscopy plots, I was able to match specific wavelengths corresponding to chemical signatures of the host star to determine if …
Development And Curation Of The Sample Data Library For The Astrobiogeochemistry Laboratory,
2016
University of Southern California
Development And Curation Of The Sample Data Library For The Astrobiogeochemistry Laboratory, Meika R. Nwaomah, Lorenia Jimenez, Michael Tuite
STAR Program Research Presentations
In 2011, the National Science Foundation (NSF) initiated EarthCube, an integrated cyber infrastructure initiative, to tackle challenges within geoscience research. EarthCube’s goal is to improve public access and collaboration within the geoscience community. During the summer of 2015, the Astrobiogeochemistry Laboratory (abcLab) joined the collective efforts of EarthCube by developing the Sample Data Library (SDL) for the Jet Propulsion Laboratory (JPL). The main focus of the SDL concentrates on effectively curating the samples collected by researchers within the Planetary Chemistry and Astrobiology section at JPL. The goal of this summer internship was to assimilate field notes, images, and from data …
Flickering Analysis Of Ch Cygni Using Kepler Data,
2016
East Tennessee State University
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 …
Cytoplasmic Dynein Binding, Run Length, And Velocity Are Guided By Long-Range Electrostatic Interactions,
2016
Clemson University
Cytoplasmic Dynein Binding, Run Length, And Velocity Are Guided By Long-Range Electrostatic Interactions, Lin Li, Joshua Alper, Emil Alexov
Publications
Dyneins are important molecular motors involved in many essential biological processes, including cargo transport along microtubules, mitosis, and in cilia. Dynein motility involves the coupling of microtubule binding and unbinding to a change in the configuration of the linker domain induced by ATP hydrolysis, which occur some 25 nm apart. This leaves the accuracy of dynein stepping relatively inaccurate and susceptible to thermal noise. Using multi-scale modeling with a computational focusing technique, we demonstrate that the microtubule forms an electrostatic funnel that guides the dynein’s microtubule binding domain (MTBD) as it finally docks to the precise, keyed binding location on …
Experimental Simulations Of Recurring Slope Lineae And Other Flow Formation Features On Mars,
2016
University of Arkansas, Fayetteville
Experimental Simulations Of Recurring Slope Lineae And Other Flow Formation Features On Mars, Julia Ann Heydenreich
Graduate Theses and Dissertations
Various flow formation features from gullies to recurring slope lineae (RSL) have been identified across the martian surface. The formation of these geologic features are still being determined. Recently, several aspects of these flow features indicate that salt water flows in the subsurface during the warmer months when the ice melts. This paper explores the formation of these processes using laboratory experimental simulations. Experiments were conducted in a wooden flume under varying martian conditions of temperature, slope angle, regolith simulant and a liquid subsurface flow. By adjusting the flume at specific heights, several slopes were obtained to mimic the slopes …
The Sluggs Survey: The Mass Distribution In Early-Type Galaxies Within Five Effective Radii And Beyond,
2016
Swinburne University of Technology
The Sluggs Survey: The Mass Distribution In Early-Type Galaxies Within Five Effective Radii And Beyond, Adebusola Alabi, Duncan Forbes, Aaron Romanowsky, Jean Brodie, Jay Strader, Joachim Janz, Vincenzo Pota, Nicola Pastorello, Christopher Usher, Lee Spitler, Caroline Foster, Zachary Jennings, Alexa Villaume, Sreeja Kartha
Faculty Publications
We study mass distributions within and beyond 5 effective radii (Re) in 23 early-type galaxies from the SAGES Legacy Unifying Globulars and Galaxies Survey, using their globular cluster (GC) kinematic data. The data are obtained with Keck/DEep Imaging Multi-Object Spectrograph, and consist of line-of-sight velocities for ∼3500 GCs, measured with a high precision of ∼15 km s−1 per GC and extending out to ∼13 Re. We obtain the mass distribution in each galaxy using the tracer mass estimator of Watkins et al. and account for kinematic substructures, rotation of the GC systems and galaxy flattening in our mass estimates. The …
Current Sheet Flapping Motions In The Tailwind Flow Of Magnetic Reconnection,
2016
University of Science and Technology of China
Current Sheet Flapping Motions In The Tailwind Flow Of Magnetic Reconnection, Mingyu Wu, Quanming Lu, Martin Volwerk, Zoltán Vörös, Xuanye Ma, Shui Wang
Publications
The feature and origin of current sheet flapping motions are one of most interesting issues of magnetospheric dynamics. In this paper we report the flapping motion of the current sheet detected in the tailward flow of a magnetic reconnection event on 7 February 2009. This flapping motion with frequency about 12 mHz was accompanied by magnetic turbulence. The observations by the tail‐elongated fleet of five Time History of Events and Macroscale Interactions during Substorms probes indicate that these flapping oscillations were rather confined within the tailward flow than were due to a global process. This flapping motion could be due …
Galaxy And Mass Assembly (Gama) : Understanding The Wavelength Dependence Of Galaxy Structure With Bulge-Disc Decompositions.,
2016
University of Nottingham
Galaxy And Mass Assembly (Gama) : Understanding The Wavelength Dependence Of Galaxy Structure With Bulge-Disc Decompositions., Rebecca Kennedy, Steven P. Bamford, Boris Haußler, Ivan K. Baldry, Malcolm Bremer, Sarah Brough, Michael J. I. Brown, Simon P. Driver, Kenneth Duncan, Alister W. Graham, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Steven Phillipps, Marina Vika, Benedetta Vulcani
Faculty and Staff Scholarship
With a large sample of bright, low-redshift galaxies with optical–near-IR imaging from the GAMA survey we use bulge-disc decompositions to understand the wavelength-dependent behaviour of single-Sérsic structural measurements. We denote the variation in single-Sérsic index with wavelength as N N , likewise for effective radius we use R R . We find that most galaxies with a substantial disc, even those with no discernable bulge, display a high value of N N . The increase in Sérsic index to longer wavelengths is therefore intrinsic to discs, apparently resulting from radial variations in stellar population and/or dust reddening. Similarly, low values …
Variability Of Mars' Seasonal North Polar Cap,
2016
Gordon State College
Variability Of Mars' Seasonal North Polar Cap, Richard W. Schmude Jr.
Georgia Journal of Science
Mars’ seasonal north polar cap (hereafter sNPC) underwent year-to-year changes between 2008 and 2015 or Mars years 29–33. The writer monitored changes in the sNPC using images made with the MARCI camera onboard the Mars Reconnaissance Orbiter (MRO). Nine isolated bright spots corresponding to Korolev, Lomonosov, and Louth Craters, the albedo features Ierne, Olympia (or Lemuria), and Cecropia, and three unnamed features were examined. The following was concluded: 1) the sNPC underwent small year-to-year changes between 2008 and 2015 [MY = 29–33], 2) there are no years where all temporary frost features lasted longer than their mean lifespan, and 3) …
Constraining The Age And Distance Of The Galactic Supernova Remnant G156.2+5.7 By H A Expansion Measurements,
2016
Chuo University
Constraining The Age And Distance Of The Galactic Supernova Remnant G156.2+5.7 By H A Expansion Measurements, Satoru Katsuda, Masaomi Tanaka, Tomoki Morokuma, Robert Fesen, Dan Milisavljevic
Dartmouth Scholarship
We present deep Hα images of portions of the X-ray bright, but optically faint, Galactic supernova remnant G156.2+5.7, revealing numerous and delicately thin non-radiative filaments, which mark the location of the remnant's forward shock. These new images show that these filaments have a complex structure not visible on previous lower resolution optical images. By comparing Hα images taken in 2004 at the McDonald Observatory and in 2015–2016 at the Kiso Observatory, we set a stringent 1σ upper limit of expansion to be 0.06 arcsec/yr. This proper motion, combined with a shock speed of 500 km s−1 …
The Supermassive Black Hole And Double Nucleus Of The Core Elliptical Ngc 5419,
2016
Max Planck Institute for Extraterrestrial Physics
The Supermassive Black Hole And Double Nucleus Of The Core Elliptical Ngc 5419, Ximena Mazzalay, Jens Thomas, Roberto P. Saglia, Gary A. Wegner
Dartmouth Scholarship
We obtained adaptive-optics assisted SINFONI observations of the central regions of the giant elliptical galaxy NGC5419 with a spatial resolution of 0.2 arcsec (≈55 pc). NGC5419 has a large depleted stellar core with a radius of 1.58 arcsec (430 pc). HST and SINFONI images show a point source located at the galaxy's photocentre, which is likely associated with the low-luminosity AGN previously detected in NGC5419. Both the HST and SINFONI images also show a second nucleus, off-centred by 0.25 arcsec (≈70 pc). Outside of the central double nucleus, we measure an almost constant velocity dispersion of σ∼350 km/s. In the …
Vanadium Pentoxide Nanobelt-Reduced Graphene Oxide Nanosheet Composites As High-Performance Pseudocapacitive Electrodes: Ac Impedanc Spectroscopy Data Modeling And Theoretical Calculations,
2016
The University of Texas Rio Grande Valley
Vanadium Pentoxide Nanobelt-Reduced Graphene Oxide Nanosheet Composites As High-Performance Pseudocapacitive Electrodes: Ac Impedanc Spectroscopy Data Modeling And Theoretical Calculations, Sanju Gupta, Bryce Aberg, Sara B. Carrizosa, Nicholas Dimakis
Physics & Astronomy Faculty Publications
Graphene nanosheets and graphene nanoribbons, G combined with vanadium pentoxide (VO) nanobelts (VNBs) and VNBs forming GVNB composites with varying compositions were synthesized via a one-step low temperature facile hydrothermal decomposition method as high-performance electrochemical pseudocapacitive electrodes. VNBs from vanadium pentoxides (VO) are formed in the presence of graphene oxide (GO), a mild oxidant, which transforms into reduced GO (rGOHT), assisting in enhancing the electronic conductivity coupled with the mechanical robustness of VNBs. From electron microscopy, surface sensitive spectroscopy and other complementary structural characterization, hydrothermally-produced rGO nanosheets/nanoribbons are decorated with and inserted within the VNBs' layered crystal structure, which further …
Completeness Of The Nearby White Dwarf Sample: Let Us Count The Ways,
2016
Embry-Riddle Aeronautical University
Completeness Of The Nearby White Dwarf Sample: Let Us Count The Ways, Terry D. Oswalt, Jay Holberg, Edward M. Sion
Publications
We have recently extended our ongoing survey of the local white dwarf population, effectively doubling the sample volume. Based upon the latest distance determinations, Holberg et al. (2016) estimated the present 20 pc and 25 pc samples were about 86 and 68 percent complete, respectively. Here we examine how the completeness of the 25 pc sample depends upon other observables such as apparent magnitude, proper motion, photometric color index, etc. The results may provide additional clues to why “Sirius-Like systems” are underrepresented in the extended 25 pc sample and how additional nearby single white dwarf stars may be found.
Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914,
2016
The University of Texas Rio Grande Valley
Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov
Physics & Astronomy Faculty Publications
A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the …
Back Half Of The Year,
2016
Gettysburg College
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]
The Intrinsic Eddington Ratio Distribution Of Active Galactic Nuclei In Star-Forming Galaxies From The Sloan Digital Sky Survey,
2016
Dartmouth College
The Intrinsic Eddington Ratio Distribution Of Active Galactic Nuclei In Star-Forming Galaxies From The Sloan Digital Sky Survey, Mackenzie L. Jones, Ryan C. Hickox, Christine S. Black, Kevin N. Hainline, Michael A. Dipompeo, Andy D. Goulding
Dartmouth Scholarship
An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGNs). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test whether or not an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous …
Binary Central Stars Of Planetary Nebulae Discovered Through Photometric Variability. Iv. The Central Stars Of Hatr 4 And Hf 2-2,
2016
Valparaiso University
Binary Central Stars Of Planetary Nebulae Discovered Through Photometric Variability. Iv. The Central Stars Of Hatr 4 And Hf 2-2, Todd C. Hillwig, Howard E. Bond, David J. Frew, S C. Schaub, Eva Hl Bodman
Physics and Astronomy Faculty Publications
We explore the photometrically variable central stars of the planetary nebulae HaTr 4 and Hf 2-2. Both have been classified as close binary star systems previously based on their light curves alone. Here, we present additional arguments and data confirming the identification of both as close binaries with an irradiated cool companion to the hot central star. We include updated light curves, orbital periods, and preliminary binary modeling for both systems. We also identify for the first time the central star of HaTr 4 as an eclipsing binary. Neither system has been well studied in the past, but we utilize …
