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2018

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Articles 31 - 60 of 440

Full-Text Articles in Astrophysics and Astronomy

A Plausible Resolution To Hilbert’S Failed Attempt To Unify Gravitation & Electromagnetism, Florentin Smarandache, Victor Christianto, Robert Neil Boyd Dec 2018

A Plausible Resolution To Hilbert’S Failed Attempt To Unify Gravitation & Electromagnetism, Florentin Smarandache, Victor Christianto, Robert Neil Boyd

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we explore the reasons why Hilbert’s axiomatic program to unify gravitation theory and electromagnetism failed and outline a plausible resolution of this problem. The latter is based on Gödel’s incompleteness theorem and Newton’s aether stream model.

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Book Review: Life On Mars: What To Know Before We Go, T. D. Oswalt Dec 2018

Book Review: Life On Mars: What To Know Before We Go, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Life on Mars: what to know before we go. Princeton, 2018. 302p index ISBN 9780691180533, $29.95; ISBN 9781400889945 ebook, contact publisher for price.

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Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern Dec 2018

Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern

Biological Sciences Undergraduate Honors Theses

Methanogens, some of Earth’s most primitive prokaryotic organisms, are candidates for possible life forms capable of inhabiting Mars. Specifically, four different species (Methanobacterium formicicum, Methanococcus maripaludis, Methanosarcina barkeri, Methanothermobacter wolfeii) were analyzed for their tolerance to the presence of illite clay. Illite is a crystalline mineral that has been identified from regions of Mars’s surface. Results indicated that all four species grew with some success in the illite at different concentrations. This experimentation with methanogens’ abilities to survive and reproduce in the presence of illite allows for a more accurate understanding of the potential capability of microbial …

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Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories, Benne W. Holwerda, J. S. Bridge, R. Ryan, M. A. Kenworthy, N. Pirzkal, M. Andersen, S. Wilkins, R. Smit, S. R. Bernard, T. Meshkat, R. Steele, R. C. Bouwens Dec 2018

Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories, Benne W. Holwerda, J. S. Bridge, R. Ryan, M. A. Kenworthy, N. Pirzkal, M. Andersen, S. Wilkins, R. Smit, S. R. Bernard, T. Meshkat, R. Steele, R. C. Bouwens

Faculty and Staff Scholarship

Aims. We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. Methods. We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color-color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and …

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Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, B. Wang Dec 2018

Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, B. Wang

Physics Faculty Publications

We survey the current phenomenological status of semi-inclusive deeply inelastic scattering at moderate hard scales and in the limit of very large transverse momentum. As the transverse momentum becomes comparable to or larger than the overall hard scale, the differential cross sections should be calculable with fixed order perturbative QCD (pQCD) methods, while small transverse momentum (transverse-momentum-dependent factorization) approximations should eventually break down. We find large disagreement between HERMES and COMPASS data and fixed order calculations done with modern parton densities, even in regions of kinematics where such calculations should be expected to be very accurate. Possible interpretations are suggested.

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Cm-Wavelength Obserations Of Mwc 758: Resolved Dust Trapping In A Vortex, Simon Casassus, Sebastián Marino, Wladimir Lyra, Clément Baruteau, Matías Vidal, Alwyn Wootten, Sebastián Pérez, Felipe Alarcon, Marcelo Barraza, Miguel Cárcamo, Ruobing Dong, Anibal Sierra, Zhaohuan Zhu, Luca Ricci, Valentin Christiaens, Lucas Cieza Nov 2018

Cm-Wavelength Obserations Of Mwc 758: Resolved Dust Trapping In A Vortex, Simon Casassus, Sebastián Marino, Wladimir Lyra, Clément Baruteau, Matías Vidal, Alwyn Wootten, Sebastián Pérez, Felipe Alarcon, Marcelo Barraza, Miguel Cárcamo, Ruobing Dong, Anibal Sierra, Zhaohuan Zhu, Luca Ricci, Valentin Christiaens, Lucas Cieza

Physics & Astronomy Faculty Research

The large crescents imaged by ALMA in transition discs suggest that azimuthal dust trapping concentrates the larger grains, but centimetre–wavelengths continuum observations are required to map the distribution of the largest observable grains. A previous detection at ∼1 cm of an unresolved clump along the outer ring of MWC 758 (Clump 1), and buried inside more extended sub-mm continuum, motivates followup VLA observations. Deep multiconfiguration integrations reveal the morphology of Clump 1 and additional cm-wave components that we characterize via comparison with a deconvolution of recent 342 GHz data (∼1 mm). ... See full text for complete abstract.

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Detection Of Helium In The Atmosphere Of The Exo-Neptune Hat-P-11b, Megan Mansfield, Jacob L. Bean, Antonija Oklopčić, Laura Kreidberg, Jean-Michel Désert, Eliza M. R. Kempton, Michael R. Line, Jonathan J. Fortney, Gregory W. Henry, Matthias Mallonn, Kevin B. Stevenson, Diana Dragomir, Romain Allart, Vincent Bourrier Nov 2018

Detection Of Helium In The Atmosphere Of The Exo-Neptune Hat-P-11b, Megan Mansfield, Jacob L. Bean, Antonija Oklopčić, Laura Kreidberg, Jean-Michel Désert, Eliza M. R. Kempton, Michael R. Line, Jonathan J. Fortney, Gregory W. Henry, Matthias Mallonn, Kevin B. Stevenson, Diana Dragomir, Romain Allart, Vincent Bourrier

Information Systems and Engineering Management Research Publications

The helium absorption triplet at a wavelength of 10833 Å has been proposed as a way to probe the escaping atmospheres of exoplanets. Recently this feature was detected for the first time using Hubble Space Telescope (HST) WFC3 observations of the hot Jupiter WASP-107b. We use similar HST/WFC3 observations to detect helium in the atmosphere of the hot Neptune HAT-P-11b at the 4σ confidence level. We compare our observations to a grid of 1D models of hydrodynamic escape to constrain the thermospheric temperatures and mass loss rate. We find that our data are best fit by models with high mass …

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An Optical Transmission Spectrum For The Ultra-Hot Jupiter Wasp-121b Measured With The Hubble Space Telescope, Thomas M. Evans, David K. Sing, Jayesh M. Goyal, Nikolay Nikolov, Mark S. Marley, Kevin Zahnle, Gregory W. Henry, Joanna K. Barstow, Munazza K. Alam, Jorge Sanz-Forcada, Tiffany Kataria, Nikole K. Lewis, Panayotis Lavvas, Gilda E. Ballester, Lotfi Ben-Jaffel, Sarah D. Blumenthal, Vincent Bourrier, Benjamin Drummond, Antonio García Muñoz, Mercedes López-Morales, Pascal Tremblin, David Ehrenreich, Hannah R. Wakeford, Lars A. Buchhave, Alain Lecavelier Des Etangs, Éric Hébrard, Michael H. Williamson Nov 2018

An Optical Transmission Spectrum For The Ultra-Hot Jupiter Wasp-121b Measured With The Hubble Space Telescope, Thomas M. Evans, David K. Sing, Jayesh M. Goyal, Nikolay Nikolov, Mark S. Marley, Kevin Zahnle, Gregory W. Henry, Joanna K. Barstow, Munazza K. Alam, Jorge Sanz-Forcada, Tiffany Kataria, Nikole K. Lewis, Panayotis Lavvas, Gilda E. Ballester, Lotfi Ben-Jaffel, Sarah D. Blumenthal, Vincent Bourrier, Benjamin Drummond, Antonio García Muñoz, Mercedes López-Morales, Pascal Tremblin, David Ehrenreich, Hannah R. Wakeford, Lars A. Buchhave, Alain Lecavelier Des Etangs, Éric Hébrard, Michael H. Williamson

Information Systems and Engineering Management Research Publications

We present an atmospheric transmission spectrum for the ultra-hot Jupiter WASP-121b, measured using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. Across the 0.47–1 wavelength range, the data imply an atmospheric opacity comparable to—and in some spectroscopic channels exceeding—that previously measured at near-infrared wavelengths (1.15–1.65 ). Wavelength-dependent variations in the opacity rule out a gray cloud deck at a confidence level of 3.7σ and may instead be explained by VO spectral bands. We find a cloud-free model assuming chemical equilibrium for a temperature of 1500 K and a metal enrichment of 10–30× solar matches …

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The Dragonfly Nearby Galaxies Survey. V. Hst/Acs Observations Of 23 Low Surface Brightness Objects In The Fields Of Ngc 1052, Ngc 1084, M96, And Ngc 4258, Yotam Cohen, Pieter Van Dokkum, Shany Danieli, Aaron Romanowsky, Roberto Abraham, Allison Merritt, Jielai Zhang, Lamiya Mowla, J. Diederik Kruijssen, Charlie Conroy, Asher Wasserman Nov 2018

The Dragonfly Nearby Galaxies Survey. V. Hst/Acs Observations Of 23 Low Surface Brightness Objects In The Fields Of Ngc 1052, Ngc 1084, M96, And Ngc 4258, Yotam Cohen, Pieter Van Dokkum, Shany Danieli, Aaron Romanowsky, Roberto Abraham, Allison Merritt, Jielai Zhang, Lamiya Mowla, J. Diederik Kruijssen, Charlie Conroy, Asher Wasserman

Faculty Publications

We present Hubble Space Telescope/Advanced Camera for Surveys (ACS) imaging of 23 very low surface brightness (μ e,V  ~ 25–27.5) galaxies detected in the fields of four nearby galaxy groups. These objects were selected from deep optical imaging obtained with the Dragonfly Telephoto Array. Seven are newly identified, while most of the others had been seen previously in visual surveys of deep photographic plates and more recent surveys. Few have previously been studied in detail. From the ACS images, we measure distances to the galaxies using both the tip of the red giant branch method and the surface brightness fluctuations …

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The Dark Energy Survey: Data Release 1, T. M. C. Abott, F. B. Abdalla, S. Allam, A. Amara, J. Annis, J. Asorey, S. Avila, O. Ballester, M. Banerji, Wayne A. Barkhouse Nov 2018

The Dark Energy Survey: Data Release 1, T. M. C. Abott, F. B. Abdalla, S. Allam, A. Amara, J. Annis, J. Asorey, S. Avila, O. Ballester, M. Banerji, Wayne A. Barkhouse

Physics Faculty Publications

We describe the first public data release of the Dark Energy Survey, DES DR1, consisting of reduced single-epoch images, co-added images, co-added source catalogs, and associated products and services assembled over the first 3 yr of DES science operations. DES DR1 is based on optical/near-infrared imaging from 345 distinct nights (2013 August to 2016 February) by the Dark Energy Camera mounted on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. We release data from the DES wide-area survey covering ~5000 deg2 of the southern Galactic cap in five broad photometric bands, grizY. DES DR1 …

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Magic, Matrimony, And The Moon: Medieval Lunar Symbolism In J.R.R. Tolkien’S “The Lay Of Aotrou And Itroun” And “The Fall Of Arthur”, Kristine Larsen Nov 2018

Magic, Matrimony, And The Moon: Medieval Lunar Symbolism In J.R.R. Tolkien’S “The Lay Of Aotrou And Itroun” And “The Fall Of Arthur”, Kristine Larsen

Journal of Tolkien Research

This paper (originally delivered at the 2017 International Medieval Congress at the University of Leeds, UK) explores common lunar symbolism in "The Lay of Aotrou and Itroun" and "The Fall of Arthur."

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Photospheric Radius Evolution Of Homologous Explosions, Liang-Duan Liu, Bing Zhang, Ling-Jun Wang, Zi-Gao Dai Nov 2018

Photospheric Radius Evolution Of Homologous Explosions, Liang-Duan Liu, Bing Zhang, Ling-Jun Wang, Zi-Gao Dai

Physics & Astronomy Faculty Research

Recent wide-field surveys discovered new types of peculiar optical transients that showed diverse behaviors of the evolution of photospheric properties. We develop a general theory of homologous explosions with constant opacity, paying special attention to the evolution of the photospheric radius R ph. We find that regardless of the density distribution profile, R ph always increases early on and decreases at late times. This result does not depend on the radiation and cooling processes inside the ejecta. The general rising/falling behavior of R ph can be used to quickly diagnose whether the source originates from a supernova-like explosion. The shape …

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Graphene Used As A Lateral Force Microscopy Calibration Material In The Low-Load Non-Linear Regime, Mathias J. Boland, Jacob L. Hempel, Armin Ansary, Mohsen Nasseri, Douglas R. Strachan Nov 2018

Graphene Used As A Lateral Force Microscopy Calibration Material In The Low-Load Non-Linear Regime, Mathias J. Boland, Jacob L. Hempel, Armin Ansary, Mohsen Nasseri, Douglas R. Strachan

Physics and Astronomy Faculty Publications

A lateral force microscopy (LFM) calibration technique utilizing a random low-profile surface is proposed that is successfully employed in the low-load non-linear frictional regime using a single layer of graphene on a supporting oxide substrate. This calibration at low loads and on low friction surfaces like graphene has the benefit of helping to limit the wear of the LFM tip during the calibration procedure. Moreover, the low-profiles of the calibration surface characteristic of these layered 2D materials, on standard polished oxide substrates, result in a nearly constant frictional, adhesive, and elastic response as the tip slides over the surface, making …

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The Causes Of The Red Sequence, The Blue Cloud, The Green Valley, And The Green Mountain, Stephen A. Eales, Maarten Baes, Nathan Bourne, Malcolm Bremer, Michael J.I. Brown, Christopher Clark, David Clements, Pieter De Vis, Simon Driver, Loretta Dunne, Simon Dye, Cristina Furlanetto, Benne W. Holwerda, R. J. Ivison, L. S. Kelvin, Maritza Lara-Lopez, Lerothodi Leeuw, Jon Loveday, Steve Maddox, Michal J. Michalowski, Steven Phillipps, Aaron Robotham, Dan Smith, Matthew Smith, Elisabetta Valiante, Paul Van Der Werf, Angus Wright Nov 2018

The Causes Of The Red Sequence, The Blue Cloud, The Green Valley, And The Green Mountain, Stephen A. Eales, Maarten Baes, Nathan Bourne, Malcolm Bremer, Michael J.I. Brown, Christopher Clark, David Clements, Pieter De Vis, Simon Driver, Loretta Dunne, Simon Dye, Cristina Furlanetto, Benne W. Holwerda, R. J. Ivison, L. S. Kelvin, Maritza Lara-Lopez, Lerothodi Leeuw, Jon Loveday, Steve Maddox, Michal J. Michalowski, Steven Phillipps, Aaron Robotham, Dan Smith, Matthew Smith, Elisabetta Valiante, Paul Van Der Werf, Angus Wright

Faculty and Staff Scholarship

The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a 'green mountain'. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause …

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Biosignature Anisotropy Modeled On Temperate Tidally Locked M-Dwarf Planets, Howard Chen, Eric T. Wolf, Ravi Kopparapu, Shawn Domagal-Goldman, Daniel E. Horton Nov 2018

Biosignature Anisotropy Modeled On Temperate Tidally Locked M-Dwarf Planets, Howard Chen, Eric T. Wolf, Ravi Kopparapu, Shawn Domagal-Goldman, Daniel E. Horton

Aerospace, Physics, and Space Science Faculty Publications

A planet’s atmospheric constituents (e.g., O2, O3, H2Ov, CO2, CH4, and N2O) can provide clues to its surface habitability, and may offer biosignature targets for remote life detection efforts. The plethora of rocky exoplanets found by recent transit surveys (e.g., the Kepler mission) indicates that potentially habitable systems orbiting K- and M-dwarf stars may have very different orbital and atmospheric characteristics than Earth. To assess the physical distribution and observational prospects of various biosignatures and habitability indicators, it is important to understand how they may change under different astrophysical and geophysical configurations, and to simulate these changes with …

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Diffusion And Concentration Of Solids In The Dead Zone Of A Protoplanetary Disk, Chao-Chin Yang, Mordecai-Mark Mac Low, Anders Johansen Nov 2018

Diffusion And Concentration Of Solids In The Dead Zone Of A Protoplanetary Disk, Chao-Chin Yang, Mordecai-Mark Mac Low, Anders Johansen

Physics & Astronomy Faculty Research

The streaming instability is a promising mechanism to drive the formation of planetesimals in protoplanetary disks. To trigger this process, it has been argued that sedimentation of solids onto the mid-plane needs to be efficient, and therefore that a quiescent gaseous environment is required. It is often suggested that dead-zone or disk-wind structure created by non-ideal magnetohydrodynamical (MHD) effects meets this requirement. However, simulations have shown that the mid-plane of a dead zone is not completely quiescent. In order to examine the concentration of solids in such an environment, we use the local-shearing-box approximation to simulate a particlegas system with …

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A New Look At T Tauri Star Forbidden Lines: Mhd-Driven Winds From The Inner Disk, Min Fang, Ilaria Pascucci, Suzan Edwards, Uma Gorti, Andrea Banzatti, Mario Flock, Patrick Hartigan, Gregory J. Herczeg, Andrea K. Dupree Nov 2018

A New Look At T Tauri Star Forbidden Lines: Mhd-Driven Winds From The Inner Disk, Min Fang, Ilaria Pascucci, Suzan Edwards, Uma Gorti, Andrea Banzatti, Mario Flock, Patrick Hartigan, Gregory J. Herczeg, Andrea K. Dupree

Astronomy: Faculty Publications

Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. We report the first high-resolution (∆v ∼ 6 km s−1 ) analysis of [S II] λ4068, [O I] λ5577, and [O I] λ6300 lines from a sample of 48 T Tauri stars. Following Simon et al. (2016), we decompose them into three kinematic components: a high-velocity component (HVC) associated with jets, and a low-velocity narrow (LVC-NC) and broad (LVC-BC) components. We confirm previous findings that many LVCs are blueshifted by more than 1.5 km s−1 thus most likely trace a …

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Bunching Coherent Curvature Radiation In Three-Dimensional Magnetic Field Geometry: Application To Pulsars And Fast Radio Bursts, Yuan-Pei Yang, Bing Zhang Nov 2018

Bunching Coherent Curvature Radiation In Three-Dimensional Magnetic Field Geometry: Application To Pulsars And Fast Radio Bursts, Yuan-Pei Yang, Bing Zhang

Physics & Astronomy Faculty Research

The extremely high brightness temperatures of pulsars and fast radio bursts (FRBs) require their radiation mechanisms to be coherent. Coherent curvature radiation from bunches has been long discussed as the mechanism for radio pulsars and recently for FRBs. Assuming that bunches are already generated in pulsar magnetospheres, we calculate the spectrum of coherent curvature radiation under a three-dimensional magnetic field geometry. Different from previous works assuming parallel trajectories and a monoenergetic energy distribution of electrons, we consider a bunch characterized by its length, curvature radius of the trajectory family, bunch opening angle, and electron energy distribution. We find that the …

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A Long-Lived Neutron Star Merger Remnant In Gw170817: Constraints And Clues From X-Ray Observations, L Piro, E Troja, Bing Zhang, G Ryan, H Van Eerten, R Ricci, M H. Wieringa, A Tiengo, N R. Butler, S B. Cenko, O D. Fox, H G. Khandrika, G Novara, A Rossi, T Sakamoto Nov 2018

A Long-Lived Neutron Star Merger Remnant In Gw170817: Constraints And Clues From X-Ray Observations, L Piro, E Troja, Bing Zhang, G Ryan, H Van Eerten, R Ricci, M H. Wieringa, A Tiengo, N R. Butler, S B. Cenko, O D. Fox, H G. Khandrika, G Novara, A Rossi, T Sakamoto

Physics & Astronomy Faculty Research

Multimessenger observations of GW170817 have not conclusively established whether the merger remnant is a black hole (BH) or a neutron star (NS). We show that a long-lived magnetized NS with a poloidal field B ≈ 1012 G is fully consistent with the electromagnetic dataset, when spin-down losses are dominated by gravitational wave (GW) emission. ... See full text for complete abstract.

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Quantum Algorithms, Architecture, And Error Correction, Ciarán Ryan-Anderson Nov 2018

Quantum Algorithms, Architecture, And Error Correction, Ciarán Ryan-Anderson

Physics & Astronomy ETDs

Quantum algorithms have the potential to provide exponential speedups over some of the best known classical algorithms. These speedups may enable quantum devices to solve currently intractable problems such as those in the fields of optimization, material science, chemistry, and biology. Thus, the realization of large-scale, reliable quantum-computers will likely have a significant impact on the world. For this reason, the focus of this dissertation is on the development of quantum-computing applications and robust, scalable quantum-architectures. I begin by presenting an overview of the language of quantum computation. I then, in joint work with Ojas Parekh, analyze the performance of …

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J/Ψ Production Cross Section And Its Dependence On Charged-Particle Multiplicity In P + P Collisions At √S=200 Gev, J. Adam, L. Adamczyk, J. R. Adams, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, F. Atetalla, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, K. Barish, A. J. Bassill, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, Renee H. Fatemi, Suvarna Ramachandran Nov 2018

J/Ψ Production Cross Section And Its Dependence On Charged-Particle Multiplicity In P + P Collisions At √S=200 Gev, J. Adam, L. Adamczyk, J. R. Adams, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, F. Atetalla, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, K. Barish, A. J. Bassill, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We present a measurement of inclusive J/ψ production at mid-rapidity (|y| < 1) in p+p collisions at a center-of-mass energy of √s=200 GeV with the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The differential production cross section for J/ψ as a function of transverse momentum (pT) for 0 < pT < 14 GeV/c and the total cross section are reported and compared to calculations from the color evaporation model and the non-relativistic Quantum Chromodynamics model. The dependence of J/ψ relative yields in three pT intervals on charged-particle multiplicity at mid-rapidity is measured for …

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The Bright-End Galaxy Candidates At Z ∼ 9 From 79 Independent Hst Fields, T. Morishita, M. Trenti, M. Stiavelli, L. D. Bradley, D. Coe, P. A. Oesch, C. A. Mason, J. S. Bridge, Benne W. Holwerda, R. C. Livermore, B. Salmon, K. B. Schmidt, J. M. Shull, T. Treu Nov 2018

The Bright-End Galaxy Candidates At Z ∼ 9 From 79 Independent Hst Fields, T. Morishita, M. Trenti, M. Stiavelli, L. D. Bradley, D. Coe, P. A. Oesch, C. A. Mason, J. S. Bridge, Benne W. Holwerda, R. C. Livermore, B. Salmon, K. B. Schmidt, J. M. Shull, T. Treu

Faculty and Staff Scholarship

We present a full data analysis of the pure-parallel Hubble Space Telescope (HST) imaging observations in the Brightest of Reionizing Galaxies Survey (BoRG[z9]) in Cycle 22. The medium-deep exposures with five HST/WFC3IR+UVIS filter bands from 79 independent sightlines (∼370 arcmin2) provide the least biased determination of number density for z 9 bright galaxies against cosmic variance. After a strict two-step selection for candidate galaxies, including dropout color and photometric redshift analyses, and revision of previous BoRG candidates, we identify one source at z ∼ 10 and two sources at z ∼ 9. The z ∼ 10 candidate shows evidence of …

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Reason In Motion, Luke Francis Nov 2018

Reason In Motion, Luke Francis

Student Works

This essay will explain the historical models of the solar system, which was the known universe for most of human history. There is far more to each model than simply positioning different celestial bodies at the center of the system, and the stories of the astronomers who derived the controversial theories are not discussed often enough. The creation of these theories is part of a much broader revolution in scientific thought and marked the start of a series of observational discoveries that would change the the philosophy of science for centuries to come.

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Bayesian Analysis Of Two Stellar Populations In Galactic Globular Clusters Ii: Ngc 5024, Ngc 5272, And Ngc 6352, Rachel Wagner-Kaiser, Ted Von Hippel, David Stenning, Elliot Robinson, Ata Sarajedini, David Van Dyk, Nathan Stein, William H. Jefferys Nov 2018

Bayesian Analysis Of Two Stellar Populations In Galactic Globular Clusters Ii: Ngc 5024, Ngc 5272, And Ngc 6352, Rachel Wagner-Kaiser, Ted Von Hippel, David Stenning, Elliot Robinson, Ata Sarajedini, David Van Dyk, Nathan Stein, William H. Jefferys

Publications

We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival ACS Treasury observations of Galactic Globular Clusters to find and characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC 6352. For these three clusters, both single and double-population analyses are used to determine a best fit isochrone(s). We employ a sophisticated Bayesian analysis technique to simultaneously fit the cluster parameters (age, distance, absorption, and metallicity) that characterize each cluster. For the two-population analysis, unique population level helium values are also fit to each distinct population of the cluster and the relative proportions of the …

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Dance Of Two Supermassive Binary Black Holes, Karishma Bansal Nov 2018

Dance Of Two Supermassive Binary Black Holes, Karishma Bansal

Shared Knowledge Conference

Black holes exist in a various range of masses ranging from stellar mass (~ 10 Solar Mass) to Supermassive black holes (SMBHs, million to billion Solar Mass). It is expected that as the separation between the black holes decreases, emission of gravitational waves will grow stronger, which makes binary black holes one of the most promising sources for gravitational radiation detection. Gravitational waves from merging stellar-mass black holes have recently been discovered by LIGO; however, we are yet to detect them from binary SMBHs. These massive black holes reside at the heart of most of the galaxies and when two …

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Nonthermal Dark Matter From Early Matter Domination, Jacek Ksawery Osinski Nov 2018

Nonthermal Dark Matter From Early Matter Domination, Jacek Ksawery Osinski

Shared Knowledge Conference

Dark matter (DM) production in the early universe traditionally assumes a standard thermal history where the universe is in a radiation-dominated phase after the end of inflation until matter-radiation equality. However, the presence of additional scalar fields (which is a generic prediction of explicit string constructions) can lead to an epoch of early matter domination (EMD) that ends before the onset of big bang nucleosynthesis. Such an EMD phase has important cosmological consequences and renders thermal production of DM irrelevant. We present three scenarios for DM production involving an era of EMD: evaporation of primordial black holes into DM, DM …

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The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat Nov 2018

The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat

Posters-at-the-Capitol

Lunar swirls are complex patterns on the Moon with distinct brightness signatures and magnetic characteristics. Current research has suggested that the formation of lunar swirls relies on local magnetic fields to shield impinging solar wind, based on a shift in electromagnetic wavelength peaks related to solar radiation and space weathering. Our research combined recent models and methods to characterize these anomalies at the surface of the Moon, exploring the effects of field strength and position. We have produced a high resolution map of a famous swirl named Reiner Gamma using magnetic dipole modeling. These maps and models are considered when …

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The Shape Of The Orbit In Flrw Spacetimes, David Garfinkle, Lawrence R. Mead, H.I. Ringermacher Nov 2018

The Shape Of The Orbit In Flrw Spacetimes, David Garfinkle, Lawrence R. Mead, H.I. Ringermacher

Faculty Publications

The shape of the orbit of a free particle is examined in Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies. The spatial projection of the orbit is time-independent and has a simple geometric description. We relate this description to the expression in terms of standard FLRW coordinates.

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Fast Radio Burst Energetics And Detectability From High Redshifts, Bing Zhang Nov 2018

Fast Radio Burst Energetics And Detectability From High Redshifts, Bing Zhang

Physics & Astronomy Faculty Research

We estimate the upper limit redshifts of known fast radio bursts (FRBs) using the dispersion measure (DM)-redshift (z) relation and derive the upper limit peak luminosity L p and energy E of FRBs within the observational band. The average z upper limits range from 0.17 to 3.10, the average L p upper limits range from 1.24 × 1042 erg s−1 to 7.80 × 1044 erg s−1, and the average E upper limits range from 6.91 × 1039 erg to 1.94 × 1042 erg. FRB 160102 with DM = 2596.1 ± 0.3 pc cm−3 likely has a redshift greater than 3. …

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Interaction Between Gravitational Radiation And Electromagnetic Radiation, Preston Jones, Douglas Singleton Nov 2018

Interaction Between Gravitational Radiation And Electromagnetic Radiation, Preston Jones, Douglas Singleton

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In this review paper we investigate the connection between gravity and electromagnetism from Faraday to the present day. The particular focus is on the connection between gravitational and electromagnetic radiation. We discuss electromagnetic radiation produced when a gravitational wave passes through a magnetic field. We then discuss the interaction of electromagnetic radiation with gravitational waves via Feynman diagrams of the process graviton + graviton → photon + photon. Finally we review recent work on the vacuum production of counterpart electromagnetic radiation by gravitational waves.

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