Open Access. Powered by Scholars. Published by Universities.®

Astrophysics and Astronomy Commons™

Open Access. Powered by Scholars. Published by Universities.®

2020

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 241 - 270 of 334

Full-Text Articles in Astrophysics and Astronomy

Sun-Like Stars Shed Light On Solar Climate Forcing, Philip G. Judge, Ricky Egeland, Gregory W. Henry Mar 2020

Sun-Like Stars Shed Light On Solar Climate Forcing, Philip G. Judge, Ricky Egeland, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Recently published precise stellar photometry of 72 Sun-like stars obtained at the Fairborn Observatory between 1993 and 2017 is used to set limits on the solar forcing of Earth's atmosphere of ±4.5 W m−2 since 1750. This compares with the +2.2 ± 1.1 W m−2 IPCC estimate for anthropogenic forcing. Three critical assumptions are made. In decreasing order of importance they are: (a) most of the brightness variations occur within the average time series length of ≈17 yr; (b) the Sun seen from the ecliptic behaves as an ensemble of middle-aged solar-like stars; and (c) narrowband photometry in the Strömgren …

Go to article

Discovery Of A Remarkably Powerful Broad Absorption-Line Quasar Outflow In Sdss J135246.37+423923.5, Hyunseop Choi, Karen M. Leighly, Donald M. Terndrup, Sarah C. Gallagher, Gordon T. Richards Mar 2020

Discovery Of A Remarkably Powerful Broad Absorption-Line Quasar Outflow In Sdss J135246.37+423923.5, Hyunseop Choi, Karen M. Leighly, Donald M. Terndrup, Sarah C. Gallagher, Gordon T. Richards

Physics and Astronomy Publications

Broad absorption-line (BAL) features in quasar spectra reveal an unambiguous signature of energetic outflows from central supermassive black holes, and thus, BAL quasars are prime targets for investigating the potential process of luminous quasar feedback on galaxies. We analyzed the rest-UV spectrum of an "overlapping trough" iron low-ionization broad absorption-line quasar (FeLoBAL) SDSS J135246.37+423923.5 using the novel spectral synthesis code SimBAL and discovered an extraordinarily fast and energetic BAL outflow. Our analysis revealed outflow velocities reaching ∼ -38,000 km s-1 with a velocity width of ∼ 10,000 km s-1, which is the largest FeLoBAL outflow velocity measured to date. The …

Go to article

The Solar Energetic Particle Event Of 2010 August 14: Connectivity With The Solar Source Inferred From Multiple Spacecraft Observations And Modeling, D. Lario, R.-Y. Kwon, I. G. Richardson, N. E. Raouafi, B. J. Thompson, T. T. Von Rosenvinge, M. L. Mays, P. A. Makela, H. Xie, H. M. Bain, M. Zhang, L. Zhao, H. V. Cane, A. Papaioannou, N. Thakur, P. Riley Mar 2020

The Solar Energetic Particle Event Of 2010 August 14: Connectivity With The Solar Source Inferred From Multiple Spacecraft Observations And Modeling, D. Lario, R.-Y. Kwon, I. G. Richardson, N. E. Raouafi, B. J. Thompson, T. T. Von Rosenvinge, M. L. Mays, P. A. Makela, H. Xie, H. M. Bain, M. Zhang, L. Zhao, H. V. Cane, A. Papaioannou, N. Thakur, P. Riley

Aerospace, Physics, and Space Science Faculty Publications

We analyze one of the first solar energetic particle (SEP) events of solar cycle 24 observed at widely separated spacecraft in order to assess the reliability of models currently used to determine the connectivity between the sources of SEPs at the Sun and spacecraft in the inner heliosphere. This SEP event was observed on 2010 August 14 by near-Earth spacecraft, STEREO-A (∼80° west of Earth) and STEREO-B (∼72° east of Earth). In contrast to near-Earth spacecraft, the footpoints of the nominal magnetic field lines connecting STEREO-A and STEREO-B with the Sun were separated from the region where the parent fast …

Go to article

Improving The Background Of Gravitational-Wave Searches For Core Collapse Supernovae: A Machine Learning Approach, M. Cavaglià, S. Gaudio, T. Hansen, K. Staats, M. Szczepanczyk, M. Zanolin Mar 2020

Improving The Background Of Gravitational-Wave Searches For Core Collapse Supernovae: A Machine Learning Approach, M. Cavaglià, S. Gaudio, T. Hansen, K. Staats, M. Szczepanczyk, M. Zanolin

Physics Faculty Research & Creative Works

Based on the priorO1-O2observing runs, about30%of the data collected by Advanced LIGO and Virgo Internext observing runs are expected tobe single-interferometer data, i.e. they will be collected at times when only one detector in the network is operating in observing mode. Searches for gravitational-wave signals from supernova events do not rely on matched filtering techniques because of the stochastic nature of the signals. If a Galactic supernova occurs during single-interferometer times, separation of its unmodelled gravitational-wave signal from noise will be even more difficult due to lack of coherence between detectors. We present a novel machine learning method to perform …

Go to article

Host-Galaxy Morphology Of 14 Local Active Galaxies As Imaged By The Hubble Space Telescope, Tomas Henry Snyder Mar 2020

Host-Galaxy Morphology Of 14 Local Active Galaxies As Imaged By The Hubble Space Telescope, Tomas Henry Snyder

Physics

Active galactic nuclei (AGNs) are galaxies with super-massive black holes, that are undergoing accretion, at their centers. The study of these objects provides us with a deeper understanding of how the black holes evolved along with their host galaxies since black hole mass is highly correlated with bulge mass. A sample of 66 AGNs were imaged using the Hubble Space Telescope (HST) and 14 of those are analyzed in this paper to determine their structure, bulge luminosity, and bulge type. The program GALFIT is implemented to determine these parameters, that will be used in further research in the future. These …

Go to article

Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv Mar 2020

Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv

Theses and Dissertations

In the future, a hazardous asteroid will find itself on a collision course with Earth. It is an inevitability; the question is not if, but when. For asteroids of moderate size or larger, a nuclear device is one of humanity's only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how changing the output neutron energy from a nuclear device detonation affects asteroid deflection. The notional asteroid target was 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. To calculate the …

Go to article

Lack Of Debye And Meissner Screening In Strongly Magnetized Quark Matter At Intermediate Densities, Bo Feng, Efrain J. Ferrer, Israel Portillo Mar 2020

Lack Of Debye And Meissner Screening In Strongly Magnetized Quark Matter At Intermediate Densities, Bo Feng, Efrain J. Ferrer, Israel Portillo

Physics & Astronomy Faculty Publications

We study the static responses of cold quark matter in the intermediate baryonic density region (characterized by a chemical potential μ) in the presence of a strong-magnetic field. We consider in particular, the so-called magnetic dual Chiral Density Wave (MDCDW) phase, which is materialized by an inhomogeneous condensate formed by a particle-hole pair. It is shown, that the MDCDW phase is more stable in the weak-coupling regime than the one considered in the magnetic catalysis of chiral symmetry braking phenomenon and even than the chiral symmetric phase that was expected to be realized at sufficiently high baryonic chemical potential. The …

Go to article

A Writing Intensive Upper Division Astrophysics/Planetary Science Course, Laura M. Woodney Feb 2020

A Writing Intensive Upper Division Astrophysics/Planetary Science Course, Laura M. Woodney

Q2S Enhancing Pedagogy

This poster describes the major writing components of an upper division Astronomy or Planetary Science course. These components are intended to be integrated throughout the semester along with the content of the course. The papers the instructor chooses for the scaffolded assignments should compliment/enhance the content the students are learning in the course. This project used the "Backwards Design" method from Bean (2011, citation in poster): where the instructor first identifies the final project, determines what challenges the students will encounter attempting to do that project, and then builds scaffolded assignments intended to address each of these challenges. This presentation …

Go to article

Fast Radio Bursts From Interacting Binary Neutron Star Systems, Bing Zhang Feb 2020

Fast Radio Bursts From Interacting Binary Neutron Star Systems, Bing Zhang

Physics & Astronomy Faculty Research

Recent observations of repeating fast radio bursts (FRBs) suggest that some FRBs reside in an environment consistent with that of binary neutron star (BNS) mergers. The bursting rate for repeaters could be very high and the emission site is likely from a magnetosphere. We discuss a hypothesis of producing abundant repeating FRBs in BNS systems. Decades to centuries before a BNS system coalesces, the magnetospheres of the two neutron stars start to interact relentlessly. Abrupt magnetic reconnection accelerates particles, which emit coherent radio waves in bunches via curvature radiation. FRBs are detected as these bright radiation beams point toward Earth. …

Go to article

Secondary Gravity Waves Generated By Breaking Mountain Waves Over Europe, Christopher J. Heale, Jonathan B. Snively, Katrina Bossert, S. L. Vadas, Lars Hoffmann, A. Dörnbrack, G. Stober, C. Jacobi Feb 2020

Secondary Gravity Waves Generated By Breaking Mountain Waves Over Europe, Christopher J. Heale, Jonathan B. Snively, Katrina Bossert, S. L. Vadas, Lars Hoffmann, A. Dörnbrack, G. Stober, C. Jacobi

Publications

A strong mountain wave, observed over Central Europe on 12 January 2016, is simulated in 2D under two fixed background wind conditions representing opposite tidal phases. The aim of the simulation is to investigate the breaking of the mountain wave and subsequent generation of nonprimary waves in the upper atmosphere. The model results show that the mountain wave first breaks as it approaches a mesospheric critical level creating turbulence on horizontal scales of 8–30 km. These turbulence scales couple directly to horizontal secondary waves scales, but those scales are prevented from reaching the thermosphere by the tidal winds, which act …

Go to article

Group Vibrational Mode Assignments As A Broadly Applicable Tool For Characterizing Ionomer Membrane Structure As A Function Of Degree Of Hydration, Neili Loupe, Khaldoon Abu-Hakmeh, Shuitao Gao, Luis Gonzalez, Matthew Ingargiola, Kayla Mathiowetz, Ryan Cruse, Jonathan Doan, Isaiah Salas, Nicholas Dimakis Feb 2020

Group Vibrational Mode Assignments As A Broadly Applicable Tool For Characterizing Ionomer Membrane Structure As A Function Of Degree Of Hydration, Neili Loupe, Khaldoon Abu-Hakmeh, Shuitao Gao, Luis Gonzalez, Matthew Ingargiola, Kayla Mathiowetz, Ryan Cruse, Jonathan Doan, Isaiah Salas, Nicholas Dimakis

Physics & Astronomy Faculty Publications

Infrared spectra of Nafion, Aquivion, and the 3 M membrane were acquired during total dehydration of fully hydrated samples. Fully hydrated exchange sites are in a sulfonate form with a C3V local symmetry. The mechanical coupling of the exchange site to a side chain ether link gives rise to vibrational group modes that are classified as C3V modes. These mode intensities diminish concertedly with dehydration. When totally dehydrated, the sulfonic acid form of the exchange site is mechanically coupled to an ether link with no local symmetry. This gives rise to C1 group modes that …

Go to article

Asteroid Belt Survival Through Stellar Evolution: Dependence On The Stellar Mass, Rebecca G. Martin, Mario Livio, Jeremy L. Smallwood, Cheng Chen Feb 2020

Asteroid Belt Survival Through Stellar Evolution: Dependence On The Stellar Mass, Rebecca G. Martin, Mario Livio, Jeremy L. Smallwood, Cheng Chen

Physics & Astronomy Faculty Research

Polluted white dwarfs are generally accreting terrestrial-like material that may originate from a debris belt like the asteroid belt in the Solar system. ... See full text for complete abstract.

Go to article

The Effects Of Disc Self-Gravity And Radiative Cooling On The Formation Of Gaps And Spirals By Young Planets, Shangjia Zhang, Zhaohuan Zhu Feb 2020

The Effects Of Disc Self-Gravity And Radiative Cooling On The Formation Of Gaps And Spirals By Young Planets, Shangjia Zhang, Zhaohuan Zhu

Physics & Astronomy Faculty Research

We have carried out 2D hydrodynamical simulations to study the effects of disc self-gravity and radiative cooling on the formation of gaps and spirals. (1) With disc self-gravity included, we find stronger, more tightly wound spirals and deeper gaps in more massive discs. The deeper gaps are due to the larger Angular Momentum Flux (AMF) of the waves excited in more massive discs, as expected from the linear theory. The position of the secondary gap does not change, provided that the disc is not extremely massive (Q ≳ 2). (2) With radiative cooling included, the excited spirals become monotonically more …

Go to article

Gj 1252 B: A 1.2 R⊕ Planet Transiting An M3 Dwarf At 20.4 Pc, A. Shporer, K. A. Collins, N. Astudillo-Defru, J. Irwin, X. Bonfils, K. I. Collins, E. Matthews, J. G. Winters, D. R. Anderson, J. D. Armstrong, D. Charbonneau, R. Cloutier, T. Daylan, T. Gan, M. N. Günther, C. Hellier, K. Horne, C. X. Huang, Eric L.N. Jensen, J. Kielkopf, E. Palle, R. Sefako, K. G. Stassun, T.-G. Tan, A. Vanderburg, G. R. Ricker, D. W. Latham, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, K. Colon, C. D. Dressing, S. Léepine, P. S. Muirhead, M. E. Rose, J. D. Twicken, J. N. Villasenor Feb 2020

Gj 1252 B: A 1.2 R⊕ Planet Transiting An M3 Dwarf At 20.4 Pc, A. Shporer, K. A. Collins, N. Astudillo-Defru, J. Irwin, X. Bonfils, K. I. Collins, E. Matthews, J. G. Winters, D. R. Anderson, J. D. Armstrong, D. Charbonneau, R. Cloutier, T. Daylan, T. Gan, M. N. Günther, C. Hellier, K. Horne, C. X. Huang, Eric L.N. Jensen, J. Kielkopf, E. Palle, R. Sefako, K. G. Stassun, T.-G. Tan, A. Vanderburg, G. R. Ricker, D. W. Latham, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, K. Colon, C. D. Dressing, S. Léepine, P. S. Muirhead, M. E. Rose, J. D. Twicken, J. N. Villasenor

Physics & Astronomy Faculty Works

We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 R⊕ and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 M⊕, 0.391 ± 0.020 R⊕) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Gaia astrometry, and high angular resolution imaging to show that the transit signal seen in the TESS data must originate from a transiting planet. We do so by ruling out all false-positive scenarios that attempt to explain the transit signal …

Go to article

A Guide To Ligo-Virgo Detector Noise And Extraction Of Transient Gravitational-Wave Signals, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, T. Alford, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, Tiffany Summerscales Feb 2020

A Guide To Ligo-Virgo Detector Noise And Extraction Of Transient Gravitational-Wave Signals, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, T. Alford, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, Tiffany Summerscales

Faculty Publications

© 2020 IOP Publishing Ltd. The LIGO Scientific Collaboration and the Virgo Collaboration have cataloged eleven confidently detected gravitational-wave events during the first two observing runs of the advanced detector era. All eleven events were consistent with being from well-modeled mergers between compact stellar-mass objects: black holes or neutron stars. The data around the time of each of these events have been made publicly available through the gravitational-wave open science center. The entirety of the gravitational-wave strain data from the first and second observing runs have also now been made publicly available. There is considerable interest among the broad scientific …

Go to article

Expectation Values Of Coherent States For Su(2) Lattice Gauge Theories, Klaus Liegener, Ernst-Albrecht Zwicknagel Feb 2020

Expectation Values Of Coherent States For Su(2) Lattice Gauge Theories, Klaus Liegener, Ernst-Albrecht Zwicknagel

Faculty Publications

This article investigates properties of semiclassical Gauge Field Theory Coherent States for general quantum gauge theories. Useful, e.g., for the canonical formulation of Lattice Gauge Theories these states are labelled by a point in the classical phase space and constructed such that the expectation values of the canonical operators are sharply peaked on said phase space point. For the case of the non-abelian gauge group SU(2), we will explicitly compute the expectation value of general polynomials including the first order quantum corrections. This allows asking more precise questions about the quantum fluctuations of any given semiclassical system.

Go to article

Effects Of Opacity Temperature Dependence On Radiatively Accelerated Clouds, Sergei Dyda, Daniel Proga, Christopher S. Reynolds Feb 2020

Effects Of Opacity Temperature Dependence On Radiatively Accelerated Clouds, Sergei Dyda, Daniel Proga, Christopher S. Reynolds

Physics & Astronomy Faculty Research

We study how different opacity–temperature scalings affect the dynamical evolution of irradiated gas clouds using time-dependent radiation-hydrodynamics simulations. When clouds are optically thick, the bright side heats up and expands, accelerating the cloud via the rocket effect. Clouds that become more optically thick as they heat accelerate ∼35 per cent faster than clouds that become optically thin. An enhancement of ∼85 per cent in the acceleration can be achieved by having a broken power-law opacity profile, which allows the evaporating gas driving the cloud to become optically thin and not attenuate the driving radiation flux. We find that up to …

Go to article

Imaging The 44 Au Kuiper Belt Analog Debris Ring Around Hd 141569a With Gpi Polarimetry, Juan Sebastián Bruzzone, Stanimir Metchev, Gaspard Duchene, Maxwell A. Millar-Blanchaer, Ruobing Dong, Thomas M. Esposito, Jason J. Wang, James R. Graham, Johan Mazoyer, Schuyler Wolff, S. Mark Ammons, Adam C. Schneider, Alexandra Z. Greenbaum, Brenda C. Matthews, Pauline Arriaga, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Robert J. De Rosa, Rene Doyon, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, Pascale Hibon, Justin Hom, Li Wei Hung, Patrick Ingraham, Paul Kalas, Quinn Konopacky, Kimberly Ward-Duong, Et Al Feb 2020

Imaging The 44 Au Kuiper Belt Analog Debris Ring Around Hd 141569a With Gpi Polarimetry, Juan Sebastián Bruzzone, Stanimir Metchev, Gaspard Duchene, Maxwell A. Millar-Blanchaer, Ruobing Dong, Thomas M. Esposito, Jason J. Wang, James R. Graham, Johan Mazoyer, Schuyler Wolff, S. Mark Ammons, Adam C. Schneider, Alexandra Z. Greenbaum, Brenda C. Matthews, Pauline Arriaga, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Robert J. De Rosa, Rene Doyon, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, Pascale Hibon, Justin Hom, Li Wei Hung, Patrick Ingraham, Paul Kalas, Quinn Konopacky, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

We present the first polarimetric detection of the inner disk component around the pre-main-sequence B9.5 star HD 141569A. Gemini Planet Imager H-band (1.65 μm) polarimetric differential imaging reveals the highest signal-to-noise ratio detection of this ring yet attained and traces structure inward to 0.″25 (28 au at a distance of 111 pc). The radial polarized intensity image shows the east side of the disk, peaking in intensity at 0.″40 (44 au) and extending out to 0.″9 (100 au). There is a spiral arm-like enhancement to the south, reminiscent of the known spiral structures on the outer rings of the disk. …

Go to article

The Gemini Planet Imager Exoplanet Survey: Dynamical Mass Of The Exoplanet Β Pictoris B From Combined Direct Imaging And Astrometry, Eric L. Nielsen, Robert J. De Rosa, Jason J. Wang, Johannes Sahlmann, Paul Kalas, Gaspard Duchêne, Julien Rameau, Mark S. Marley, Didier Saumon, Bruce Macintosh, Maxwell A. Millar-Blanchaer, Meiji M. Nguyen, S. Mark Ammons, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Thomas M. Esposito, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, James R. Graham, Alexandra Z. Greenbaum, Pascale Hibon, Li Wei Hung, Patrick Ingraham, Quinn Konopacky, James E. Larkin, Jérôme Maire, Kimberly Ward-Duong, Et Al Feb 2020

The Gemini Planet Imager Exoplanet Survey: Dynamical Mass Of The Exoplanet Β Pictoris B From Combined Direct Imaging And Astrometry, Eric L. Nielsen, Robert J. De Rosa, Jason J. Wang, Johannes Sahlmann, Paul Kalas, Gaspard Duchêne, Julien Rameau, Mark S. Marley, Didier Saumon, Bruce Macintosh, Maxwell A. Millar-Blanchaer, Meiji M. Nguyen, S. Mark Ammons, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Thomas M. Esposito, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, James R. Graham, Alexandra Z. Greenbaum, Pascale Hibon, Li Wei Hung, Patrick Ingraham, Quinn Konopacky, James E. Larkin, Jérôme Maire, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

We present new observations of the planet β Pictoris b from 2018 with the Gemini Planet Imager (GPI), the first GPI observations following conjunction. Based on these new measurements, we perform a joint orbit fit to the available relative astrometry from ground-based imaging, the Hipparcos Intermediate Astrometric Data (IAD), and the Gaia DR2 position, and demonstrate how to incorporate the IAD into direct imaging orbit fits. We find a mass consistent with predictions of hot-start evolutionary models and previous works following similar methods, though with larger uncertainties: 12.8+5.3-3.2 M Jup. Our eccentricity determination of disfavors circular orbits. We consider orbit …

Go to article

Galaxy And Mass Assembly (Gama): Defining Passive Galaxy Samples And Searching For The Uv Upturn, S. Phillipps, S. S. Ali, M. N. Bremer, R. De Propris, A. E. Sansom, M. E. Cluver, M. Alpaslan, S. Brough, M. J.I. Brown, L. J.M. Davies, S. P. Driver, M. W. Grootes, Benne W. Holwerda, A. M. Hopkins, P. A. James, K. Pimbblet, A. S.G. Robotham, E. N. Taylor, L. Wang Feb 2020

Galaxy And Mass Assembly (Gama): Defining Passive Galaxy Samples And Searching For The Uv Upturn, S. Phillipps, S. S. Ali, M. N. Bremer, R. De Propris, A. E. Sansom, M. E. Cluver, M. Alpaslan, S. Brough, M. J.I. Brown, L. J.M. Davies, S. P. Driver, M. W. Grootes, Benne W. Holwerda, A. M. Hopkins, P. A. James, K. Pimbblet, A. S.G. Robotham, E. N. Taylor, L. Wang

Faculty and Staff Scholarship

We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to individual galaxies with no measurable influence from the galaxies' larger environment. We first define a clean sample of passive galaxies without a significant contribution to their UV flux from low-level star formation. We confirm that galaxies with the optical colours of red sequence galaxies often have signs of residual star formation, which, without other information, would prevent a convincing demonstration of …

Go to article

Radiometric Stability Of The Saber Instrument, Martin G. Mlynczak, Taumi Daniels, Linda A. Hunt, Jia Yue, B. Thomas Marshall, James M. Russell Iii, Ellis E. Remsburg, Joseph Tansock, Roy Esplin, Mark Jensen, Andrew Shumway, Larry Gordley, J. -H. Yee Jan 2020

Radiometric Stability Of The Saber Instrument, Martin G. Mlynczak, Taumi Daniels, Linda A. Hunt, Jia Yue, B. Thomas Marshall, James M. Russell Iii, Ellis E. Remsburg, Joseph Tansock, Roy Esplin, Mark Jensen, Andrew Shumway, Larry Gordley, J. -H. Yee

Space Dynamics Laboratory Publications

The SABER instrument on the National Aeronautics and Space Administration Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics satellite continues to provide a long‐term record of Earth's stratosphere, mesosphere, and lower thermosphere. The SABER data are being used to examine long‐term changes and trends in temperature, water vapor, and carbon dioxide. A tacit, central assumption of these analyses is that the SABER instrument radiometric calibration is not changing with time; that is, the instrument is stable. SABER stratospheric temperatures and those derived from Global Positioning System Radio Occultation measurements are compared to examine SABER's stability. Global Positioning System Radio Occultation measurements are inherently stable …

Go to article

Fenderson, Julia Katharine (Squires), 1905-1989 (Sc 3500), Manuscripts & Folklife Archives Jan 2020

Fenderson, Julia Katharine (Squires), 1905-1989 (Sc 3500), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "Additional Files" below) for Manuscripts Small Collection 3500. “The Viewing of Halley’s Comet: 1910-1986, A Personal Remembrance by Julia Squires Fenderson as told to Charles Arterburn,” a reminiscence by Mrs. Fenderson, of Culver City, California, of her viewings of Halley’s Comet: first with her father in 1910 at a Catholic mission in Albuquerque, New Mexico; and again in 1986, at the Santa Monica (California) College Planetarium. Includes an explanatory e-mail from Charles Arterburn.

Go to article

Resolving The Fu Orionis System With Alma: Interacting Twin Disks?, Sebastian Perez, Antonio Hales, Hauyu Baobab Liu, Zhaohuan Zhu, Simon Casassus, Jonathan Williams, Alice Zurlo, Nicolas Cuello, Lucas Cieza, David Principe Jan 2020

Resolving The Fu Orionis System With Alma: Interacting Twin Disks?, Sebastian Perez, Antonio Hales, Hauyu Baobab Liu, Zhaohuan Zhu, Simon Casassus, Jonathan Williams, Alice Zurlo, Nicolas Cuello, Lucas Cieza, David Principe

Physics & Astronomy Faculty Research

FU Orionis objects are low-mass pre-main sequence stars characterized by dramatic outbursts several magnitudes in brightness. These outbursts are linked to episodic accretion events in which stars gain a significant portion of their mass. The physical processes behind these accretion events are not yet well understood. The archetypal FU Ori system, FU Orionis, is composed of two young stars with detected gas and dust emission. The continuum emitting regions have not been resolved until now. Here, we present 1.3 mm observations of the FU Ori binary system using the Atacama Large Millimeter/submillimeter Array. The disks are resolved at 40 mas …

Go to article

Calibration Transients In Ligo Detectors, Thomas Daniel Abbott Jan 2020

Calibration Transients In Ligo Detectors, Thomas Daniel Abbott

LSU Doctoral Dissertations

This dissertation describes a novel method of analyzing fluctuations in the time-dependent calibration models of the LIGO interferometers to estimate their effect on strain reconstruction for gravitational-wave detections. The time-dependence of the calibration model of each detector is tracked with a set of parameters which are continuously measured while the interferometers are operating. These parameters track slow variations in the sensing function of the detectors as well as the actuators that hold the detectors in an operational state. The time-dependent parameter data during the second observation run (O2 [November 30, 2016 16:00 UTC to August 25, 2017 22:00:00 UTC]) and …

Go to article

Mass Determinations Of The Three Mini-Neptunes Transiting Toi-125, Louise D. Nielsen, D. Gandolfi, D. J. Armstrong, J. S. Jenkins, M. Fridlund, N. C. Santos, F. Dai, V. Adibekyan, R. Luque, Jason H. Steffen, M. Esposito, F. Meru, S. Sabotta, E. Bolmont, D. Kossakowski, J. F. Otegi, F. Murgas, M. Stalport, F. Rodler, M. R. Diaz, N. T. Kurtovic, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, R. Allart, J. M. Almenara, D. Barrado, S. C.C. Barros Jan 2020

Mass Determinations Of The Three Mini-Neptunes Transiting Toi-125, Louise D. Nielsen, D. Gandolfi, D. J. Armstrong, J. S. Jenkins, M. Fridlund, N. C. Santos, F. Dai, V. Adibekyan, R. Luque, Jason H. Steffen, M. Esposito, F. Meru, S. Sabotta, E. Bolmont, D. Kossakowski, J. F. Otegi, F. Murgas, M. Stalport, F. Rodler, M. R. Diaz, N. T. Kurtovic, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, R. Allart, J. M. Almenara, D. Barrado, S. C.C. Barros

Physics & Astronomy Faculty Research

The Transiting Exoplanet Survey Satellite, TESS, is currently carrying out an all-sky search for small planets transiting bright stars. In the first year of the TESS survey, a steady progress was made in achieving the mission’s primary science goal of establishing bulk densities for 50 planets smaller than Neptune. During that year, the TESS’s observations were focused on the southern ecliptic hemisphere, resulting in the discovery of three mini-Neptunes orbiting the star TOI-125, a V = 11.0 K0 dwarf. We present intensive HARPS radial velocity observations, yielding precise mass measurements for TOI-125b, TOI-125c, and TOI-125d. TOI-125b has an orbital period …

Go to article

Tracing The Dynamical Mass In Galaxy Disks Using H I Velocity Dispersion And Its Implications For The Dark Matter Distribution In Galaxies, Stacy S. Mcgaugh Jan 2020

Tracing The Dynamical Mass In Galaxy Disks Using H I Velocity Dispersion And Its Implications For The Dark Matter Distribution In Galaxies, Stacy S. Mcgaugh

Faculty Scholarship

We present a method to derive the dynamical mass of face-on galaxy disks using their neutral hydrogen (H i) velocity dispersion (σ H i). We have applied the method to nearby, gas-rich galaxies that have extended H i gas disks and have low inclinations. The galaxy sample includes four large disk galaxies, NGC 628, NGC 6496, NGC 3184, and NGC 4214, and three dwarf galaxies, DDO 46, DDO 63, and DDO 187. We have used archival H i data from The H i Nearby Galaxy Survey (THINGS) and the LITTLE THINGS survey to derive the H i gas distributions and …

Go to article

Evaluating Climate Variability Of The Canonical Hot-Jupiters Hd 189733b And Hd 209458b Through Multi-Epoch Eclipse Observations, Brian M. Kilpatrick, Tiffany Kataria, Nikole K. Lewis, Robert T. Zellem, Gregory W. Henry, Nicolas B. Cowan, Julien De Wit, Jonathan J. Fortney, Heather Knutson, Sara Seager, Adam P. Showman, Gregory S. Tucker Jan 2020

Evaluating Climate Variability Of The Canonical Hot-Jupiters Hd 189733b And Hd 209458b Through Multi-Epoch Eclipse Observations, Brian M. Kilpatrick, Tiffany Kataria, Nikole K. Lewis, Robert T. Zellem, Gregory W. Henry, Nicolas B. Cowan, Julien De Wit, Jonathan J. Fortney, Heather Knutson, Sara Seager, Adam P. Showman, Gregory S. Tucker

Information Systems and Engineering Management Research Publications

Here we present the analysis of multi-epoch secondary eclipse observations of HD 189733b and HD 209458b as a probe of temporal variability in the planetary climate using both Spitzer channels 1 and 2 (3.6 and 4.5 μm). We expect hot-Jupiter atmospheres to be dynamic environments exhibiting time varying weather. However, it is uncertain to what extent temporal variability will be observable when considering disk integrated observations. We do not detect statistically significant variability and are able to place useful upper limits on the infrared variability amplitudes in these atmospheres. There are very few planets with multi-epoch observations at the required …

Go to article

Model Comparison From Ligo-Virgo Data On Gw170817'S Binary Components And Consequences For The Merger Remnant, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, S. Anand, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, Tiffany Summerscales Jan 2020

Model Comparison From Ligo-Virgo Data On Gw170817'S Binary Components And Consequences For The Merger Remnant, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, S. Anand, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, Tiffany Summerscales

Faculty Publications

© 2020 IOP Publishing Ltd. GW170817 is the very first observation of gravitational waves originating from the coalescence of two compact objects in the mass range of neutron stars, accompanied by electromagnetic counterparts, and offers an opportunity to directly probe the internal structure of neutron stars. We perform Bayesian model selection on a wide range of theoretical predictions for the neutron star equation of state. For the binary neutron star hypothesis, we find that we cannot rule out the majority of theoretical models considered. In addition, the gravitational-wave data alone does not rule out the possibility that one or both …

Go to article

On Possibility Of Binary Companion Of The Sun: A Serendipity Finding And Comparison With Uvs Model Of Solar System, Victor Christianto, Florentin Smarandache Jan 2020

On Possibility Of Binary Companion Of The Sun: A Serendipity Finding And Comparison With Uvs Model Of Solar System, Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

While we completely understood that a binary dwarf companion of the Sun has not been accepted by majority of astronomers, allow us to present some new arguments, along with our own serendipitous encounter with such a binary companion of the Sun. We hope that the present note will be found useful for further investigations, in relation to Planet Nine and such a dwarf star companion of the Sun (sometimes dubbed as Nemesis). Nonetheless, this article is not an exhaustive review of such dwarf companion star theories.

Go to article

The Large Scale Behaviour In The Disk Of Δ Scorpii From 2000-2018, Mark W. Suffak, Carol E. Jones, Christopher Tycner, Gregory W. Henry, Alex Cavaliéri Carciofi, Bruno C. Mota, A. C. Rubio Jan 2020

The Large Scale Behaviour In The Disk Of Δ Scorpii From 2000-2018, Mark W. Suffak, Carol E. Jones, Christopher Tycner, Gregory W. Henry, Alex Cavaliéri Carciofi, Bruno C. Mota, A. C. Rubio

Information Systems and Engineering Management Research Publications

We model the circumstellar disk of δ Sco using the 3-dimensional Monte Carlo radiative transfer code HDUST in order to quantify the large scale changes in the disk through the years 2000 to 2018, and to see if these changes can be attributed to the secondary star affecting the disk throughout its orbit. We determine our best-fitting models through matching simulated observations to actual Hα spectroscopy and V-band photometric observations. Our modelling results confirm previous findings that the disk of δ Sco was forming early in the century. We also find a period of disk dissipation when the companion is …

Go to article

First Prev Next Last