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Articles 3031 - 3060 of 8856

Full-Text Articles in Astrophysics and Astronomy

The Taurus Boundary Of Stellar/Substellar (Tboss) Survey. Ii. Disk Masses From Alma Continuum Observations, Kimberly Ward-Duong, J. Patience, J. Bulger, G. Van Der Plas, F. Ménard, C. Pinte, A. P. Jackson, G. Bryden, N. J. Turner, P. Harvey, A. Hales, R. J. De Rosa Feb 2018

The Taurus Boundary Of Stellar/Substellar (Tboss) Survey. Ii. Disk Masses From Alma Continuum Observations, Kimberly Ward-Duong, J. Patience, J. Bulger, G. Van Der Plas, F. Ménard, C. Pinte, A. P. Jackson, G. Bryden, N. J. Turner, P. Harvey, A. Hales, R. J. De Rosa

Astronomy: Faculty Publications

We report 885 μm ALMA continuum flux densities for 24 Taurus members spanning the stellar/substellar boundary with spectral types from M4 to M7.75. Of the 24 systems, 22 are detected at levels ranging from 1.0 to 55.7 mJy. The two nondetections are transition disks, though other transition disks in the sample are detected. Converting ALMA continuum measurements to masses using standard scaling laws and radiative transfer modeling yields dust mass estimates ranging from ∼0.3 to 20 M ⊕. The dust mass shows a declining trend with central object mass when combined with results from submillimeter surveys of more massive Taurus …

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Thinking Out Loud On Primeval Atom, Big Bang & Biblical Account Of Creation, Florentin Smarandache, Victor Christianto Feb 2018

Thinking Out Loud On Primeval Atom, Big Bang & Biblical Account Of Creation, Florentin Smarandache, Victor Christianto

Branch Mathematics and Statistics Faculty and Staff Publications

In recent years, the Big Bang as described by the Lambda CDM-Standard Model Cosmology has become widely accepted by majority of physics and cosmology communities. Some people even have concluded that it has no serious alternative in horizon. Is that true? First, as we argued elsewhere, Big Bang relies on singularity, so, when we are able to describe the observed data without invoking singularity, then Big Bang model is no longer required. In this paper, we explore a few alternatives other than Big Bang which most cosmologists believe is the closest to biblical account of creation. We argue that re-reading …

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Grb 130427a Afterglow: A Test For Grb Models, Massimiliano De Pasquale, M. J. Page, D. A. Kann, S. R. Oates, S. Schulze, Bing Zhang, Z. Cano, B. Gendre, D. Malesani, A. Rossi, N. Gehrels, E. Troja, L. Piro, M. Boër, G. Stratta Feb 2018

Grb 130427a Afterglow: A Test For Grb Models, Massimiliano De Pasquale, M. J. Page, D. A. Kann, S. R. Oates, S. Schulze, Bing Zhang, Z. Cano, B. Gendre, D. Malesani, A. Rossi, N. Gehrels, E. Troja, L. Piro, M. Boër, G. Stratta

Physics & Astronomy Faculty Research

Gamma-ray Burst 130427A had the largest fluence for almost 30 years. With an isotropic energy output of 8.5×1053 erg and redshift of 0.34, it combined a very high energy release with a relative proximity to Earth in an unprecedented fashion. Sensitive X-ray facilities such as {\it XMM-Newton} and {\it Chandra} detected the afterglow of this event for a record-breaking baseline of 90 Ms. We show the X-ray light curve of GRB 130427A of this event over such an interval. The light curve shows an unbroken power law decay with a slope of α=1.31 over more than three decades in time. …

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A Young Solar Twin In The Rosette Cluster Ngc 2244 Line Of Sight, Jeremy M. Huber, John F. Kielkopf, Matthew Mengel, Bradley D. Carter, Gary J. Ferland, Frank O. Clark Jan 2018

A Young Solar Twin In The Rosette Cluster Ngc 2244 Line Of Sight, Jeremy M. Huber, John F. Kielkopf, Matthew Mengel, Bradley D. Carter, Gary J. Ferland, Frank O. Clark

Physics and Astronomy Faculty Publications

Based on prior precision photometry and cluster age analysis, the bright star GSC 00154−01819 is a possible young pre-main sequence member of the Rosette cluster, NGC 2244. As part of a comprehensive study of the large-scale structure of the Rosette and its excitation by the cluster stars, we noted this star as a potential backlight for a probe of the interstellar medium and extinction along the sight line towards a distinctive nebular feature projected on to the cluster centre. New high-resolution spectra of the star were taken with the University College London Echelle Spectrograph of the AAT. They reveal that …

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Nonreciprocal Localization Of Photons, Hamidreza Ramezani, Pankaj K. Jha, Yuan Wang, Xiang Zhang Jan 2018

Nonreciprocal Localization Of Photons, Hamidreza Ramezani, Pankaj K. Jha, Yuan Wang, Xiang Zhang

Physics & Astronomy Faculty Publications

We demonstrate that it is possible to localize photons nonreciprocally in a moving photonic lattice made by spatiotemporally modulating the atomic response, where the dispersion acquires a spectral Doppler shift with respect to the probe direction. A static defect placed in such a moving lattice produces a spatial localization of light in the band gap with a shifting frequency that depends on the direction of incident field with respect to the moving lattice. This phenomenon has an impact not only in photonics but also in broader areas such as condensed matter and acoustics, opening the doors for designing new devices …

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Transfer Entropy And Cumulant Based Cost As Measures Of Nonlinear Causal Relationships In Space Plasmas: Applications To D St., Jay R. Johnson, Simon Wing, Enrico Camporeale Jan 2018

Transfer Entropy And Cumulant Based Cost As Measures Of Nonlinear Causal Relationships In Space Plasmas: Applications To D St., Jay R. Johnson, Simon Wing, Enrico Camporeale

Faculty Publications

It is well known that the magnetospheric response to the solar wind is nonlinear. Information theoretical tools such as mutual information, transfer entropy, and cumulant based analysis are able to characterize the nonlinearities in the system. Using cumulant based cost, we show that nonlinear significance of D st peaks at 3–12 hours lags that can be attributed to VBs which also exhibit similar behavior. However, the nonlinear significance that peaks at lags 25, 50, and 90 hours can be attributed to internal dynamics, which may be related to the relaxation of the ring current. These peaks are absent in the …

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The First Post-Kepler Brightness Dips Of Kic 8462852, Tabetha S. Boyajian, Roi Alonso, Alex Ammerman, David Armstrong Jan 2018

The First Post-Kepler Brightness Dips Of Kic 8462852, Tabetha S. Boyajian, Roi Alonso, Alex Ammerman, David Armstrong

University Faculty Publications and Creative Works

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in 2015 October, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1%-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor," which persist on timescales from several days to weeks. Our main results so far are as follows: (i) there are no apparent changes of the stellar …

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The First Post-Kepler Brightness Dips Of Kic 8462852, Tabetha S. Boyajian, Roi Alonso, Alex Ammerman, David Armstrong, Andrés Asensio Ramos, K. Barkaoui, Thomas G. Beatty, Zouhair Benkhaldoun, Paul Benni, Rory O. Bentley, Andrei Berdyugin, Svetlana Berdyugina, Serge Bergeron, Allyson Bieryla, Michaela G. Blain, Alicia Capetillo Blanco, Eva H. L. Bodman, Anne Boucher, Mark Bradley, Stephen M. Brincat, Thomas G. Brink, John Briol, David J. A. Brown, Jan Budaj, Artem Burdanov, Bryson Cale, Miguel Aznar Carbo, R. Castillo García, Wendy J. Clark, Geoffrey C. Clayton, James L. Clem, Phillip H. Coker, Evan M. Cook, Chris M. Copperwheat, Jason L. Curtis, Roc M. Cutri, Borbála Cseh, C. H. Cynamon, Alex J. Daniels, James R. A. Davenport, Hans J. Deeg, Roberto De Lorenzo, Thomas De Jaeger, Jean-Bruno Desrosiers, John Dolan, D. J. Dowhos, Franky Dubois, Russell Durkee, Shawn Dvorak, Lynn Easley, Nick Edwards, Tyler G. Ellis, Emery Erdelyi, Steve Ertel, Rafael G. Farfán, Jay Farihi, Alexei V. Filippenko, Emma Foxell, Davide Gandolfi, Faustino Garcia, Frank Giddens, Michaël Gillon, Juan-Luis González-Carballo, Carlos González-Fernández, Jonay I. González Hernández, Keith A. Graham, Kenton A. Greene, Joao Gregorio, Na'ama Hallakoun, Ottó Hanyecz, Gerry R. Harp, Gregory W. Henry, E. Herrero, Caleb F. Hildbold, D. Hinzel, Gonzalo Holgado, Bernadett Ignácz, Ilya Ilyin, Valentin D. Ivanov, ‪Emmanuel Jehin, Helen E. Jermak, Steve Johnston, Stella Kafka, Csilla Kalup, Emmanuel Kardasis, Shai Kaspi, Grant M. Kennedy, F. Kiefer, Collin L. Kielty, Dennis Kessler, Harri Kiiskinen, Thomas L. Killestein, Ronald A. King, Vladimír Kollar, Heidi Korhonen, C. Kotnik, Réka Könyves-Tóth, Levente Kriskovics, Nathan Krumm, Vadim Krushinsky, E. Kundra, Francois-Rene Lachapelle, Daryll Lacourse, P. Lake, Kristine Lam, Gavin P. Lamb, Dave Lane, Marie Wingyee Lau, Pablo Lewin, Chris Lintott, Carey Lisse, Ludwig Logie, Nicolas Longeard, M. Lopez Villanueva, E. Whit Ludington, Amy Mainzer, Lison Malo, Chris Maloney, Andrew Mann, A. Mantero, Massimo Marengo, Jon Marchant, María Jesús Martínez González, Joseph R. Masiero, Jon C. Mauerhan, James Mccormac, Aaron Mcneely, Huan Y. A. Meng, Mike Miller, Lawrence A. Molnar, Juan Carlos Morales, Brett M. Morris, Matthew W. Muterspaugh, David Nespra, Carrie R. Nugent, Katherine M. Nugent, A. Odasso, Derek O'Keeffe, Arto Oksanen, John M. O'Meara, András Ordasi, Hugh Osborn, John J. Ott, J. R. Parks, Diego Rodriguez Perez, Vance Petriew, Roger Pickard, András Pál, Peter Plavchan, Don Pollacco, Francisco Pozo-Nuñez, Francisco J. Pozuelos, Steve Rau, Seth Redfield, Howard Relles, Ignasi Ribas, Jon Richards, Joonas L. O. Saario, Emily J. Safron, J. Martin Sallai, Krisztián Sárneczky, Bradley E. Schaefer, Clea F. Schumer, Madison Schwartzendruber, Michael H. Siegel, Andrew P. V. Siemion, Brooke D. Simmons, Joshua D. Simon, Sergio Simón-Díaz, Michael L. Sitko, Hector Socas-Navarro, Ádám Sódor, Donn Starkey, Iain A. Steele, Geoff Stone, Klaus G. Strassmeier, Rachel A. Street, Tricia Sullivan, Jari Suomela, Jon J. Swift, Gyula M. Szabó, Róbert Szabó, Róbert Szakáts, Tamás Szalai, Angelle M. Tanner, Borja Toledo-Padrón, Tamás Tordai, Amaury H. M. J. Triaud, Jake D. Turner, Joseph H. Ulowetz, Marian Urbanik, Siegfried Vanaverbeke, Andrew Vanderburg, Krisztián Vida, Brad P. Vietje, József Vinkó, Kaspar Von Braun, Elizabeth O. Waagen, Dan Walsh, Christopher A. Watson, R. C. Weir, Klaus Wenzel, Carlos Westendorp, Michael W. Williamson, Jason T. Wright, Mark C. Wyatt, Weikang Zheng, Gabriella Zsidi Jan 2018

The First Post-Kepler Brightness Dips Of Kic 8462852, Tabetha S. Boyajian, Roi Alonso, Alex Ammerman, David Armstrong, Andrés Asensio Ramos, K. Barkaoui, Thomas G. Beatty, Zouhair Benkhaldoun, Paul Benni, Rory O. Bentley, Andrei Berdyugin, Svetlana Berdyugina, Serge Bergeron, Allyson Bieryla, Michaela G. Blain, Alicia Capetillo Blanco, Eva H. L. Bodman, Anne Boucher, Mark Bradley, Stephen M. Brincat, Thomas G. Brink, John Briol, David J. A. Brown, Jan Budaj, Artem Burdanov, Bryson Cale, Miguel Aznar Carbo, R. Castillo García, Wendy J. Clark, Geoffrey C. Clayton, James L. Clem, Phillip H. Coker, Evan M. Cook, Chris M. Copperwheat, Jason L. Curtis, Roc M. Cutri, Borbála Cseh, C. H. Cynamon, Alex J. Daniels, James R. A. Davenport, Hans J. Deeg, Roberto De Lorenzo, Thomas De Jaeger, Jean-Bruno Desrosiers, John Dolan, D. J. Dowhos, Franky Dubois, Russell Durkee, Shawn Dvorak, Lynn Easley, Nick Edwards, Tyler G. Ellis, Emery Erdelyi, Steve Ertel, Rafael G. Farfán, Jay Farihi, Alexei V. Filippenko, Emma Foxell, Davide Gandolfi, Faustino Garcia, Frank Giddens, Michaël Gillon, Juan-Luis González-Carballo, Carlos González-Fernández, Jonay I. González Hernández, Keith A. Graham, Kenton A. Greene, Joao Gregorio, Na'ama Hallakoun, Ottó Hanyecz, Gerry R. Harp, Gregory W. Henry, E. Herrero, Caleb F. Hildbold, D. Hinzel, Gonzalo Holgado, Bernadett Ignácz, Ilya Ilyin, Valentin D. Ivanov, ‪Emmanuel Jehin, Helen E. Jermak, Steve Johnston, Stella Kafka, Csilla Kalup, Emmanuel Kardasis, Shai Kaspi, Grant M. Kennedy, F. Kiefer, Collin L. Kielty, Dennis Kessler, Harri Kiiskinen, Thomas L. Killestein, Ronald A. King, Vladimír Kollar, Heidi Korhonen, C. Kotnik, Réka Könyves-Tóth, Levente Kriskovics, Nathan Krumm, Vadim Krushinsky, E. Kundra, Francois-Rene Lachapelle, Daryll Lacourse, P. Lake, Kristine Lam, Gavin P. Lamb, Dave Lane, Marie Wingyee Lau, Pablo Lewin, Chris Lintott, Carey Lisse, Ludwig Logie, Nicolas Longeard, M. Lopez Villanueva, E. Whit Ludington, Amy Mainzer, Lison Malo, Chris Maloney, Andrew Mann, A. Mantero, Massimo Marengo, Jon Marchant, María Jesús Martínez González, Joseph R. Masiero, Jon C. Mauerhan, James Mccormac, Aaron Mcneely, Huan Y. A. Meng, Mike Miller, Lawrence A. Molnar, Juan Carlos Morales, Brett M. Morris, Matthew W. Muterspaugh, David Nespra, Carrie R. Nugent, Katherine M. Nugent, A. Odasso, Derek O'Keeffe, Arto Oksanen, John M. O'Meara, András Ordasi, Hugh Osborn, John J. Ott, J. R. Parks, Diego Rodriguez Perez, Vance Petriew, Roger Pickard, András Pál, Peter Plavchan, Don Pollacco, Francisco Pozo-Nuñez, Francisco J. Pozuelos, Steve Rau, Seth Redfield, Howard Relles, Ignasi Ribas, Jon Richards, Joonas L. O. Saario, Emily J. Safron, J. Martin Sallai, Krisztián Sárneczky, Bradley E. Schaefer, Clea F. Schumer, Madison Schwartzendruber, Michael H. Siegel, Andrew P. V. Siemion, Brooke D. Simmons, Joshua D. Simon, Sergio Simón-Díaz, Michael L. Sitko, Hector Socas-Navarro, Ádám Sódor, Donn Starkey, Iain A. Steele, Geoff Stone, Klaus G. Strassmeier, Rachel A. Street, Tricia Sullivan, Jari Suomela, Jon J. Swift, Gyula M. Szabó, Róbert Szabó, Róbert Szakáts, Tamás Szalai, Angelle M. Tanner, Borja Toledo-Padrón, Tamás Tordai, Amaury H. M. J. Triaud, Jake D. Turner, Joseph H. Ulowetz, Marian Urbanik, Siegfried Vanaverbeke, Andrew Vanderburg, Krisztián Vida, Brad P. Vietje, József Vinkó, Kaspar Von Braun, Elizabeth O. Waagen, Dan Walsh, Christopher A. Watson, R. C. Weir, Klaus Wenzel, Carlos Westendorp, Michael W. Williamson, Jason T. Wright, Mark C. Wyatt, Weikang Zheng, Gabriella Zsidi

Information Systems and Engineering Management Research Publications

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in 2015 October, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1%–2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor," which persist on timescales from several days to weeks. Our main results so far are as follows: (i) there are no apparent changes of the stellar …

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First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al. Jan 2018

First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper …

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First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, Teviet Creighton, Mario C. Diaz, S. R. Morriss, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Robert Stone, Darkhan Tuyenbayev, Guillermo Valdes Jan 2018

First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, Teviet Creighton, Mario C. Diaz, S. R. Morriss, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Robert Stone, Darkhan Tuyenbayev, Guillermo Valdes

Physics & Astronomy Faculty Publications

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper …

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An Hst/Stis Optical Transmission Spectrum Of Warm Neptune Gj 436b, Joshua D. Lothringer, Björn Benneke, Ian J. M. Crossfield, Gregory W. Henry, Caroline Morley, Diana Dragomir, Travis Barman, Heather Knutson, Eliza Kempton, Jonathan J. Fortney, Peter Mccullough, Andrew W. Howard Jan 2018

An Hst/Stis Optical Transmission Spectrum Of Warm Neptune Gj 436b, Joshua D. Lothringer, Björn Benneke, Ian J. M. Crossfield, Gregory W. Henry, Caroline Morley, Diana Dragomir, Travis Barman, Heather Knutson, Eliza Kempton, Jonathan J. Fortney, Peter Mccullough, Andrew W. Howard

Information Systems and Engineering Management Research Publications

GJ 436b is a prime target for understanding warm Neptune exoplanet atmospheres and a target for multiple James Webb Space Telescope (JWST) Guaranteed Time Observation programs. Here, we report the first space-based optical transmission spectrum of the planet using two Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) transit observations from 0.53 to 1.03 μm. We find no evidence for alkali absorption features, nor evidence of a scattering slope longward of 0.53 μm. The spectrum is indicative of moderate to high metallicity (∼100–1000× solar), while moderate-metallicity scenarios (∼100× solar) require aerosol opacity. The optical spectrum also rules out some …

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Asymmetric Kelvin-Helmholtz Instability At Jupiter's Magnetopause Boundary: Implications For Corotation-Dominated Systems, B. Zhang, P. A. Delamere, X. Ma, B. Burkholder, M. Wiltberger, J. G. Lyon, V. G. Merkin, K. A. Sorathia Jan 2018

Asymmetric Kelvin-Helmholtz Instability At Jupiter's Magnetopause Boundary: Implications For Corotation-Dominated Systems, B. Zhang, P. A. Delamere, X. Ma, B. Burkholder, M. Wiltberger, J. G. Lyon, V. G. Merkin, K. A. Sorathia

Publications

The multifluid Lyon‐Fedder‐Mobarry (MFLFM) global magnetosphere model is used to study the interactions between solar wind and rapidly rotating, internally driven Jupiter magnetosphere. The MFLFM model is the first global simulation of Jupiter magnetosphere that captures the Kelvin‐Helmholtz instability (KHI) in the critically important subsolar region. Observations indicate that Kelvin‐Helmholtz vortices are found predominantly in the dusk sector. Our simulations explain that this distribution is driven by the growth of KHI modes in the prenoon and subsolar region (e.g., >10 local time) that are advected by magnetospheric flows to the dusk sector. The period of density fluctuations at the dusk …

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Luminous And Obscured Quasars And Their Host Galaxies, Agnese Del Moro, David M. Alexander, Franz E. Bauer, Emanuele Daddi, Dale D. Kocevski, Flora Stanley, Daniel H. Mcintosh Jan 2018

Luminous And Obscured Quasars And Their Host Galaxies, Agnese Del Moro, David M. Alexander, Franz E. Bauer, Emanuele Daddi, Dale D. Kocevski, Flora Stanley, Daniel H. Mcintosh

Physics and Astronomy Faculty Publications

The most heavily-obscured, luminous quasars might represent a specific phase of the evolution of the actively accreting supermassive black holes and their host galaxies, possibly related to mergers. We investigated a sample of the most luminous quasars at z ≈ 1 − 3 in the GOODS fields, selected in the mid-infrared band through detailed spectral energy distribution (SED) decomposition. The vast majority of these quasars (~80%) are obscured in the X-ray band and ~30% of them to such an extent, that they are undetected in some of the deepest (2 and 4 Ms) Chandra X-ray data. Although no clear relation …

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On The Formation Mechanisms Of Compact Elliptical Galaxies, Anna Ferré-Mateu, Duncan Forbes, Aaron Romanowsky, Joachim Janz, Christopher Dixon Jan 2018

On The Formation Mechanisms Of Compact Elliptical Galaxies, Anna Ferré-Mateu, Duncan Forbes, Aaron Romanowsky, Joachim Janz, Christopher Dixon

Faculty Publications

In order to investigate the formation mechanisms of the rare compact elliptical (cE) galaxies, we have compiled a sample of 25 cEs with good SDSS spectra, covering a range of stellar masses, sizes and environments. They have been visually classified according to the interaction with their host, representing different evolutionary stages. We have included clearly disrupted galaxies, galaxies that despite not showing signs of interaction are located close to a massive neighbour (thus are good candidates for a stripping process), and cEs with no host nearby. For the latter, tidal stripping is less likely to have happened and instead they …

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Rotation In [C Ii]-Emitting Gas In Two Galaxies At A Redshift Of 6.8, Renske Smit, Rychard J. Bouwens, Stefano Carniani, Pascal A. Oesch, Ivo Labbé, Garth D. Illingworth, Paul Van Der Werf, Larry D. Bradley, Valentino Gonzalez, Jacqueline A. Hodge, Benne W. Holwerda, Roberto Maiolino, Wei Zheng Jan 2018

Rotation In [C Ii]-Emitting Gas In Two Galaxies At A Redshift Of 6.8, Renske Smit, Rychard J. Bouwens, Stefano Carniani, Pascal A. Oesch, Ivo Labbé, Garth D. Illingworth, Paul Van Der Werf, Larry D. Bradley, Valentino Gonzalez, Jacqueline A. Hodge, Benne W. Holwerda, Roberto Maiolino, Wei Zheng

Faculty and Staff Scholarship

The earliest galaxies are thought to have emerged during the first billion years of cosmic history, initiating the ionization of the neutral hydrogen that pervaded the Universe at this time. Studying this 'epoch of reionization' involves looking for the spectral signatures of ancient galaxies that are, owing to the expansion of the Universe, now very distant from Earth and therefore exhibit large redshifts. However, finding these spectral fingerprints is challenging. One spectral characteristic of ancient and distant galaxies is strong hydrogen-emission lines (known as Lyman-α lines), but the neutral intergalactic medium that was present early in the epoch of reionization …

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Unexpected Occurrence Of Mesospheric Frontal Gravity Wave Events Over The South Pole (90 Degrees S), P.-D. Pautet, M. J. Taylor, J. B. Snively, C. Solorio Jan 2018

Unexpected Occurrence Of Mesospheric Frontal Gravity Wave Events Over The South Pole (90 Degrees S), P.-D. Pautet, M. J. Taylor, J. B. Snively, C. Solorio

Publications

Since 2010, Utah State University has operated an infrared Advanced Mesospheric Temperature Mapper at the Amundsen–Scott South Pole station to investigate the upper atmosphere dynamics and temperature deep within the vortex. A surprising number of “frontal” gravity wave events (86) were recorded in the mesospheric OH(3,1) band intensity and rotational temperature images (typical altitude of ~87 km) during four austral winters (2012–2015). These events are gravity waves (GWs) characterized by a sharp leading wave front followed by a quasi-monochromatic wave train that grows with time. A particular subset of frontal gravity wave events has been identified in the past (Dewan …

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Electrical Control Of Structural And Physical Properties Via Strong Spin-Orbit Interactions In Sr2Iro4, Gang Cao, Jasminka Terzic, H. D. Zhao, H. Zheng, Lance E. De Long, Peter S. Riseborough Jan 2018

Electrical Control Of Structural And Physical Properties Via Strong Spin-Orbit Interactions In Sr2Iro4, Gang Cao, Jasminka Terzic, H. D. Zhao, H. Zheng, Lance E. De Long, Peter S. Riseborough

Physics and Astronomy Faculty Publications

Electrical control of structural and physical properties is a long-sought, but elusive goal of contemporary science and technology. We demonstrate that a combination of strong spin-orbit interactions (SOI) and a canted antiferromagnetic Mott state is sufficient to attain that goal. The antiferromagnetic insulator Sr2IrO4 provides a model system in which strong SOI lock canted Ir magnetic moments to IrO6 octahedra, causing them to rigidly rotate together. A novel coupling between an applied electrical current and the canting angle reduces the Néel temperature and drives a large, nonlinear lattice expansion that closely tracks the magnetization, increases the …

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Sdss-Iv Manga: Uncovering The Angular Momentum Content Of Central And Satellite Early-Type Galaxies, J. E. Greene, A. Leauthaud, E. Emsellem, J. Ge, A. Aragón-Salamanca, J. Greco, Y. -T. Lin, S. Mao, K. Masters, M. Merrifield, S. More, N. Okabe, D. P. Schneider, D. Thomas, D. A. Wake, K. Pan, D. Bizyaev, D. Oravetz, A. Simmons, Renbin Yan, F. Van Den Bosch Jan 2018

Sdss-Iv Manga: Uncovering The Angular Momentum Content Of Central And Satellite Early-Type Galaxies, J. E. Greene, A. Leauthaud, E. Emsellem, J. Ge, A. Aragón-Salamanca, J. Greco, Y. -T. Lin, S. Mao, K. Masters, M. Merrifield, S. More, N. Okabe, D. P. Schneider, D. Thomas, D. A. Wake, K. Pan, D. Bizyaev, D. Oravetz, A. Simmons, Renbin Yan, F. Van Den Bosch

Physics and Astronomy Faculty Publications

We study 379 central and 159 satellite early-type galaxies with two-dimensional kinematics from the integral-field survey Mapping Nearby Galaxies at APO (MaNGA) to determine how their angular momentum content depends on stellar and halo mass. Using the Yang et al. group catalog, we identify central and satellite galaxies in groups with halo masses in the range 1012.5 h-1 M⊙ < M200b < 1015 h-1 M⊙. As in previous work, we see a sharp dependence on stellar mass, in the sense that ~70% of galaxies with stellar mass M* > 1011 h-2 M …

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Thinking Out Loud On Early Creation Through The Lens Of Hermeneutics Of Sherlock Holmes (Towards A Model Of Universe Based On Turbulence-Generated Sound Theory), Victor Christianto, Florentin Smarandache Jan 2018

Thinking Out Loud On Early Creation Through The Lens Of Hermeneutics Of Sherlock Holmes (Towards A Model Of Universe Based On Turbulence-Generated Sound Theory), Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In recent years, apparently the Big Bang as described by the Lambda CDM-Standard Model Cosmology has become widely accepted by majority of physics and cosmology communities. Even some people have concluded that it has no serious alternative in horizon. Is that true? First, as we argued elsewhere, Big Bang story relies on singularity. In other words, when we are able to describe the observed data without invoking singularity, then Big Bang model is no longer required. Therefore, here we explore a few alternative stories other than Big Bang story, which most cosmologists believe it is the nearest to Biblical account …

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Solar Eclipse, 2017 (Sc 3152), Manuscripts & Folklife Archives Jan 2018

Solar Eclipse, 2017 (Sc 3152), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid only for Manuscripts Small Collection 3152. Materials relating to the 2017 solar eclipse as experienced primarily in Bowling Green and Hopkinsville, Kentucky and vicinity. Includes viewing glasses, first day stamped covers, stickers, art work, photographs (in digital format), promotional materials, and impressions of the eclipse contributed as part of WKU’s Department of Library Special Collections’ “Tell Us About Your Eclipse Day” project. Also includes wristbands, handouts and volunteer information relating to an eclipse viewing event for schoolchildren held at WKU’s Smith-Houchens Stadium. Digital photographs are stored in the Photo Archives.

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Integrated Multi-Terminal Devices Consisting Of Carbon Nanotube, Few-Layer Graphene Nanogaps And Few-Layer Graphene Nanoribbons Having Crystallographically Controlled Interfaces, Douglas R. Strachan, David P. Hunley Jan 2018

Integrated Multi-Terminal Devices Consisting Of Carbon Nanotube, Few-Layer Graphene Nanogaps And Few-Layer Graphene Nanoribbons Having Crystallographically Controlled Interfaces, Douglas R. Strachan, David P. Hunley

Physics and Astronomy Faculty Patents

The present invention relates to atomically-thin channel materials with crystallographically uniform interfaces to atomically-thin commensurate graphene electrodes and/or nanoribbons separated by nanogaps that allow for nanoelectronics based on quantum transport effects and having significantly improved contact resistances.

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Differential Rotation In Magnetic Chemically Peculiar Stars, Zdeněk Mikulášek, Jiří Krtička, Ernst Paunzen, Michal Švanda, Stefan Hummerich, Klaus Bernhard, Miroslav Jagelka, Jan Janík, Gregory W. Henry, Matthew E. Shultz Jan 2018

Differential Rotation In Magnetic Chemically Peculiar Stars, Zdeněk Mikulášek, Jiří Krtička, Ernst Paunzen, Michal Švanda, Stefan Hummerich, Klaus Bernhard, Miroslav Jagelka, Jan Janík, Gregory W. Henry, Matthew E. Shultz

Information Systems and Engineering Management Research Publications

Magnetic chemically peculiar (mCP) stars constitute about 10% of upper-main-sequence stars and are characterized by strong magnetic fields and abnormal photospheric abundances of some chemical elements. Most of them exhibit strictly periodic light, magnetic, radio, and spectral variations that can be fully explained by a rigidly rotating main-sequence star with persistent surface structures and a stable global magnetic field. Long-term observations of the phase curves of these variations enable us to investigate possible surface differential rotation with unprecedented accuracy and reliability. The analysis of the phase curves in the best-observed mCP stars indicates that the location and the contrast of …

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Resistance Temperature Detectors In A Cryostat Refrigeration System, Kirsten Marie Manahan, Alice Callen Jan 2018

Resistance Temperature Detectors In A Cryostat Refrigeration System, Kirsten Marie Manahan, Alice Callen

STAR Program Research Presentations

The Large Synoptic Survey Telescope (LSST) is a ground-based telescope that will survey the Southern sky every few nights. Located in the telescope will be a 3.2 gigapixel digital camera. To ensure proper instrumentation of the camera, there must be a monitored stable temperature. As part of my research, I assembled resistance temperature detectors and tested them to verify their reliability in measuring temperature in the camera’s cryostat refrigeration cooling system. Resistance temperature detectors function by the principle of thermal resistivity, in which their electrical resistances vary as temperature varies. Through testing, I was able to determine whether these particular …

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Symmetry Of Energy Divergence Anomalies Associated With The El Niño-Southern Oscillation, Evan Kutta, Jason A. Hubbart, Timothy P. Eichler, Anthony R. Lupo Jan 2018

Symmetry Of Energy Divergence Anomalies Associated With The El Niño-Southern Oscillation, Evan Kutta, Jason A. Hubbart, Timothy P. Eichler, Anthony R. Lupo

Faculty & Staff Scholarship

The El Niño-Southern Oscillation (ENSO) is a dominant source of global climate variability. The effects of this phenomenon alter the flow of heat from tropical to polar latitudes, resulting in weather and climate anomalies that are difficult to forecast. The current work quantified two components of the vertically integrated equation for the total energy content of an atmospheric column, to show the anomalous horizontal redistribution of surface heat flux anomalies. Symmetric and asymmetric components of the vertically integrated latent and sensible heat flux divergence were quantified using ERA-Interim atmospheric reanalysis output on 30 model layers between 1979 and 2016. Results …

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Insights Into The Magnetic Dead Layer In La0.7sr0.3mno3 Thin Films From Temperature, Magnetic Field And Thickness Dependence Of Their Magnetization, N. Mottaghi, M.S. Seehra, R. Trappen, S. Kumari, Chih-Yeh Huang, S. Yousefi, G.B. Cabrera, A.H. Romero, M.B. Holcomb Jan 2018

Insights Into The Magnetic Dead Layer In La0.7sr0.3mno3 Thin Films From Temperature, Magnetic Field And Thickness Dependence Of Their Magnetization, N. Mottaghi, M.S. Seehra, R. Trappen, S. Kumari, Chih-Yeh Huang, S. Yousefi, G.B. Cabrera, A.H. Romero, M.B. Holcomb

Faculty & Staff Scholarship

Experimental investigations of the magnetic dead layer in 7.6 nm thick film of La0.7Sr0.3MnO3 (LSMO) are reported. The dc magnetization (M) measurements for a sample cooled to T = 5 K in applied field H = 0 reveal the presence of negative remanent magnetization (NRM) in the M vs. H (magnetic field) measurements as well as in the M vs. T measurements in H = 50 Oe and 100 Oe. The M vs. T data in ZFC (zero-field-cooled) and FC (field-cooled) protocols are used to determine the blocking temperature TB in different H. Isothermal hysteresis loops at differ- ent T …

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Examples Of The Birkhoff Theorem And Its Generalizations, Charles G. Torre Jan 2018

Examples Of The Birkhoff Theorem And Its Generalizations, Charles G. Torre

Tutorials on... in 1 hour or less

In this worksheet I demonstrate three versions of Birkhoff's theorem, which is a characterization of spherically symmetric solutions of the Einstein equations. The three versions considered here correspond to taking the "Einstein equations" to be: (1) the vacuum Einstein equations; (2) the Einstein equations with a cosmological constant (3) the Einstein-Maxwell equations. I will restrict my attention to 4-dimensional spacetimes.

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How To Make Tetrads, Charles G. Torre Jan 2018

How To Make Tetrads, Charles G. Torre

How to... in 10 minutes or less

This is a worksheet which demonstrates tools for creating orthonormal and null tetrads for a given spacetime.

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Investigating The Opal Cubesat’S Ability To Measure Thermospheric Gravity Waves, Kenneth Zia, Michael J. Taylor, Ludger Scherliess Jan 2018

Investigating The Opal Cubesat’S Ability To Measure Thermospheric Gravity Waves, Kenneth Zia, Michael J. Taylor, Ludger Scherliess

Posters

Understanding the Earth’s lower thermosphere is of high interest to the space science community because of competing forcing due to solar heating above and episodic wave forcing from below. The NSF sponsored OPAL cubesat is designed to measure the temperature profile in this region by observing day-time O2 A time O2 A-band (~760nm) emission on the limb and is expected to be launched from the ISS (International Space Station). To band (~760nm) emission on the limb and is expected to be launched from the ISS (International Space Station). To investigate the instrument’s ability to detect space weather signatures (i.e. solar …

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Approximate Approaches For Nuclear Weak Interaction Rates In Astrophysics, Benjamin M. Anderson Jan 2018

Approximate Approaches For Nuclear Weak Interaction Rates In Astrophysics, Benjamin M. Anderson

Bridges: A Journal of Student Research

Nuclear weak interactions, like beta decay, are important inputs for modeling astrophysical explosions. In the allowed approximation, these processes proceed as Fermi or Gamow Teller (GT) processes where the spins of the electron and neutrino are anti-parallel or parallel, respectively. In the GT case, transition probability is spread over many final states in the daughter nucleus, with each probability determination requiring numerical integration of the available phase space. Developing a fast and accurate method for calculating each contribution to the total decay rate would provide reliable weak rate libraries for astrophysical modelers. The phase space integrand includes the classical statistical …

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Symmetric Criticality In General Relativity, Charles G. Torre Jan 2018

Symmetric Criticality In General Relativity, Charles G. Torre

Research Vignettes

In this worksheet I explore the local Lagrangian version of the Principle of Symmetric Criticality (PSC) due to Anderson, Fels, and Torre], which asserts the commutativity of the processes (i) of symmetry reduction (for finding group-invariant fields) and (ii) forming Euler-Lagrange equations. There are two obstructions to PSC, which I will call the Lie algebra obstruction and the isotropy obstruction. In this worksheet I will illustrate these obstructions in the General Theory of Relativity.

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