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Articles 31 - 60 of 669
Full-Text Articles in Physics
Developing Process Variables Necessary To Operate Simulacrum: The Lcls Accelerator Simulator, Mirian G. Juan Estrella
Developing Process Variables Necessary To Operate Simulacrum: The Lcls Accelerator Simulator, Mirian G. Juan Estrella
STAR Program Research Presentations
The Linac Coherent Light Source (LCLS) is a free electron laser that is located at SLAC National Accelerator Laboratory. It fires 120 pulses per second, creating x-ray snapshots of materials at the atomic and molecular level as it undergoes any changes or processes. This resulted in many scientific discoveries in chemistry, biology, energy science, and technology. Now, there is a new vision at SLAC regarding LCLS: to develop Simulacrum. Simulacrum is a system that simulates LCLS and its control system. Within Simulacrum there exits services that contain process variables that measure specific parts of a device on LCLS, which communicate …
Measuring Length Of Electron Bunches With Optics In Lcls-Ii, Nathan Ahn, Alan Fisher
Measuring Length Of Electron Bunches With Optics In Lcls-Ii, Nathan Ahn, Alan Fisher
STAR Program Research Presentations
Since the launch of the LINAC Coherent Light Source (LCLS) in 2009, there have been over 1,000 publications enabling pioneering research across multiple fields. Advances include: harnessing the sun’s light, revealing life’s secrets and aiding drug development, developing future electronics, designing new materials and exploring fusion, customizing chemical reactions, and many more. These discoveries gathered worldwide attention, and now work has begun on a new revolutionary tool, LCLS-II. The LCLS-II will pulse at a million times a second, compared to the 120 pulses from the LCLS. Within the LCLS-II, there are two chicanes, serpentine curves. As the electron beam passes …
Space Telescope And Optical Reverberation Mapping Project. Viii. Time Variability Of Emission And Absorption In Ngc5548 Based On Modeling The Ultraviolet Spectrum, G. A. Kriss, G. De Rosa, J. Ely, B. M. Peterson, Vardha Nicola Bennert, Y. Zu
Space Telescope And Optical Reverberation Mapping Project. Viii. Time Variability Of Emission And Absorption In Ngc5548 Based On Modeling The Ultraviolet Spectrum, G. A. Kriss, G. De Rosa, J. Ely, B. M. Peterson, Vardha Nicola Bennert, Y. Zu
Physics
We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Lyα and C iv, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original …
A Single Fast Radio Burst Localized To A Massive Galaxy At Cosmological Distance, K. W. Bannister, A. T. Deller, C. Phillips, J.-P. Macquart, Vardha Nicola Bennert, C. D. Wilson
A Single Fast Radio Burst Localized To A Massive Galaxy At Cosmological Distance, K. W. Bannister, A. T. Deller, C. Phillips, J.-P. Macquart, Vardha Nicola Bennert, C. D. Wilson
Physics
Fast radio bursts (FRBs) are brief radio emissions from distant astronomical sources. Some are known to repeat, but most are single bursts. Nonrepeating FRB observations have had insufficient positional accuracy to localize them to an individual host galaxy. We report the interferometric localization of the single-pulse FRB 180924 to a position 4 kiloparsecs from the center of a luminous galaxy at redshift 0.3214. The burst has not been observed to repeat. The properties of the burst and its host are markedly different from those of the only other accurately localized FRB source. The integrated electron column density along the line …
Proteomic Changes Across A Natural Temperature Gradient In A Marine Gastropod, M Christina Vasquez, Marilla R. Lippert, Crow White, Ryan K. Walter, Lars Tomanek
Proteomic Changes Across A Natural Temperature Gradient In A Marine Gastropod, M Christina Vasquez, Marilla R. Lippert, Crow White, Ryan K. Walter, Lars Tomanek
Physics
Responses of marine ectotherms to variable environmental temperature often entails maintenance of cellular homeostasis and physiological function through temperature compensation and physiological changes. We investigated the physiological response to thermal stress by examining proteomic changes in the marine kelp forest gastropod and emerging fisheries species Kellet's whelk (Kelletia kelletii) across a naturally-existing thermal gradient that ranges from a warmer-water site inside the species' native range and extends to the northern, cold-water edge of the range. We hypothesized that abundance of cellular stress response and energy metabolism proteins would increase with decreasing temperature in support of cold-compensation. Our exploratory …
Pnnl Dark Matter Bubble Chamber Simulation, Carl M. Krutz
Pnnl Dark Matter Bubble Chamber Simulation, Carl M. Krutz
STAR Program Research Presentations
Based on observations of interactions between objects on a cosmic scale, scientists have determined that a large percentage (85%) of the universe’s mass is not visible. Weakly Interacting Massive Particles (WIMPs) are one of the primary candidates for this dark matter. Many current projects seek to find WIMPs through various search methods. The PICO dark matter experiment involves observing an underground chamber at SNOLAB for bubbles created when energy in the form of radiation is deposited in a superheated liquid. The group at Pacific Northwest National Lab (PNNL) working on the PICO project seeks to develop improvements to the project’s …
Jet-Driven Galaxy-Scale Gas Outflows In The Hyperluminous Quasar 3c 273, Bernd Husemann, Vardha Nicola Bennert, Knud Jahnke, Timothy A. Davis, Jong-Hak Woo, Julia Scharwächter, Andreas Schulze, Massimo Gaspari, Martin A. Zwaan
Jet-Driven Galaxy-Scale Gas Outflows In The Hyperluminous Quasar 3c 273, Bernd Husemann, Vardha Nicola Bennert, Knud Jahnke, Timothy A. Davis, Jong-Hak Woo, Julia Scharwächter, Andreas Schulze, Massimo Gaspari, Martin A. Zwaan
Physics
We present an unprecedented view of the morphology and kinematics of the extended narrow-line region (ENLR) and molecular gas around the prototypical hyperluminous quasar 3C 273 (L bol ~ 1047 erg s−1 at z = 0.158) based on VLT-MUSE optical 3D spectroscopy and ALMA observations. We find the following: (1) the ENLR size of 12.1 ± 0.2 kpc implies a smooth continuation of the size–luminosity relation out to large radii or a much larger break radius as previously proposed. (2) The kinematically disturbed ionized gas with line splits reaching 1000 km s−1 out to 6.1 ± …
Feature Identification In Time Series Data Sets, Justin Shaw, Marek Stastna, Aaron Coutino, Ryan K. Walter, Eduard Reinhardt
Feature Identification In Time Series Data Sets, Justin Shaw, Marek Stastna, Aaron Coutino, Ryan K. Walter, Eduard Reinhardt
Physics
We present a computationally inexpensive, flexible feature identification method which uses a comparison of time series to identify a rank-ordered set of features in geophysically-sourced data sets. Many physical phenomena perturb multiple physical variables nearly simultaneously, and so features are identified as time periods in which there are local maxima of absolute deviation in all time series. Unlike other available methods, this method allows the analyst to tune the method using their knowledge of the physical context. The method is applied to a data set from a moored array of instruments deployed in the coastal environment of Monterey Bay, California, …
Agn Photoionization Of Gas In Companion Galaxies As A Probe Of Agn Radiation In Time And Direction, William C. Keel, Vardha Nicola Bennert, Anna Pancoast, Chelsea E. Harris, Anna Nierenberg, S. Drew Chojnowski, Alexei V. Moiseev, Dmitry V. Oparin, Chris J. Lintott, Kevin Schawinski, Graham Mitchell, Claude Cornen
Agn Photoionization Of Gas In Companion Galaxies As A Probe Of Agn Radiation In Time And Direction, William C. Keel, Vardha Nicola Bennert, Anna Pancoast, Chelsea E. Harris, Anna Nierenberg, S. Drew Chojnowski, Alexei V. Moiseev, Dmitry V. Oparin, Chris J. Lintott, Kevin Schawinski, Graham Mitchell, Claude Cornen
Physics
We consider active galactic nucleus (AGN) photoionization of gas in companion galaxies (cross-ionization) as a way to sample the intensity of AGN radiation in both direction and time, independent of the gas properties of the AGN host galaxies. From an initial set of 212 AGN+companion systems, identified with the help of Galaxy Zoo participants, we obtained long-slit optical spectra of 32 pairs that were a priori likely to show cross-ionization based on projected separation or angular extent of the companion. From emission-line ratios, 10 of these systems are candidates for cross-ionization, roughly the fraction expected if most AGNs have ionization …
Low Cost Timing System For High Precision Particle Detection, Eric Madrigal, Sasha Dolgashev, Vi Tran
Low Cost Timing System For High Precision Particle Detection, Eric Madrigal, Sasha Dolgashev, Vi Tran
STAR Program Research Presentations
The project goal was to find a way to make a low-cost high precision timing system. High precision timing systems are already on the market, however, at a high cost. Various particle research projects need a large number of timers, so a substantial budget is required. In order to bypass the need for a large enough budget, commercially available parts were used and tested. The timing system consisted of multiple parts with different low-cost microchips and counters. In order for the project to meet its goal, the timers need to work under 50 picoseconds. Although some tests showed the timers …
Ultra-Fast X-Ray Diffraction Of Metastable Structures During Hydrogen Crystallization, Andrew Pham
Ultra-Fast X-Ray Diffraction Of Metastable Structures During Hydrogen Crystallization, Andrew Pham
STAR Program Research Presentations
Big discoveries can come from small element, and hydrogen is the simplest element in the universe, but its property has been intensely studied in recent years. Hydrogen has a notably complex phase diagram, and its application is important to many scientific fields, such as fundamental physics, inertial confinement fusion, planetary sciences, etc. While sophisticated static observations have probed its structure at extremely high pressures, the higher-temperature studies applying dynamic compression is confined to optical measurement methods. In this project over the summer, I will present spectrally resolved x-ray scattering assessment from plasmons in dynamic compressed deuterium. Collaborating Compton scattering and …
The Lick Agn Monitoring Project 2011: Photometric Light Curves, Anna Pancoast, Andreas Skielboe, Liuyi Pei, Vardha Nicola Bennert, Jong-Hak Woo
The Lick Agn Monitoring Project 2011: Photometric Light Curves, Anna Pancoast, Andreas Skielboe, Liuyi Pei, Vardha Nicola Bennert, Jong-Hak Woo
Physics
In Spring 2011, the Lick AGN Monitoring Project observed a sample of 15 bright, nearby Seyfert 1 galaxies in the V band as part of a reverberation mapping campaign. The observations were taken at six ground-based telescopes, including the West Mountain Observatory 0.91 m telescope, the 0.76 m Katzman Automatic Imaging Telescope, 0.6 m Super-LOTIS at Kitt Peak, the Palomar 60 inch telescope, and the 2 m Faulkes telescopes North and South. The V-band light curves measure the continuum variability of our sample of Seyferts on an almost daily cadence for 2–3 months. We use image-subtraction software to isolate …
Memory In A Contact Line, Charity Lizardo, Esmeralda Orozco, Audrey Profeta, Nathan C. Keim
Memory In A Contact Line, Charity Lizardo, Esmeralda Orozco, Audrey Profeta, Nathan C. Keim
STAR Program Research Presentations
We study the behavior of the liquid-solid-vapor contact line of water held in a narrow gap between two plates. A syringe pump injects and withdraws a constant, small volume of the water, driving the contact line back and forth repeatedly and changing its shape. We take photos of the contact line after each cycle. Comparing subsequent images to each other, we find that after several cycles the contact line reaches one of two steady states: a reversible steady state, where the shape is not changing, or a fluctuating steady state, where the shape continues to change slightly. Experiments on acrylic …
Validation Of The Nonhydrostatic General Curvilinear Coastal Ocean Mode (Gccom) For Stratified Flows, Mariangel Garcia, Paul Choboter, Ryan K. Walter, Jose E. Castillo
Validation Of The Nonhydrostatic General Curvilinear Coastal Ocean Mode (Gccom) For Stratified Flows, Mariangel Garcia, Paul Choboter, Ryan K. Walter, Jose E. Castillo
Physics
While global-and basin-scale processes can be captured quite well with computationally-inexpensive hydrostatic models, smaller-scale features such as shoaling nonlinear internal waves and bores, coastal fronts, and other convective processes require the use of a nonhydrostatic model to accurately capture dynamics. Here the nonhydrostatic capabilities of the General Curvilinear Coastal Ocean Model (GCCOM) in a stratified environment are introduced. GCCOM is a three-dimensional, nonhydrostatic Large Eddy Simulation (LES), rigid lid model that has the ability to run in a fully three-dimensional general curvilinear coordinate system. This model was previously validated for unstratified flows with curvilinear coordinates. Here, recent advances of the …
Detrital Zircon Geochronology And Evolution Of The Nacimiento Block Late Mesozoic Forearc Basin, Central California Coast, Scott Johnston, Andrew R.C. Kylander-Clark, Alan D. Chapman
Detrital Zircon Geochronology And Evolution Of The Nacimiento Block Late Mesozoic Forearc Basin, Central California Coast, Scott Johnston, Andrew R.C. Kylander-Clark, Alan D. Chapman
Physics
Forearc basins are first-order products of convergent-margin tectonics, and their sedimentary deposits offer unique perspectives on coeval evolution of adjacent arcs and subduction complexes. New detrital zircon U-Pb geochronologic data from 23 sandstones and 11 individual conglomerate clasts sampled from forearc basin strata of the Nacimiento block, an enigmatic stretch of the Cordilleran forearc exposed along the central California coast, place constraints on models for forearc deformation during evolution of the archetypical Cordilleran Mesozoic margin. Deposition and provenance of the Nacimiento forearc developed in three stages: (1) Late Jurassic– Valanginian deposition of lower Nacimiento forearc strata with zircon derived from …
Geologic Map And Structural Development Of The Noerthernmost Sur-Nacimiento Fault Zone, Central California Coast, Scott M. Johnston, John S. Singleton, Alan D. Chapman, Gabriella Murray
Geologic Map And Structural Development Of The Noerthernmost Sur-Nacimiento Fault Zone, Central California Coast, Scott M. Johnston, John S. Singleton, Alan D. Chapman, Gabriella Murray
Physics
The Sur-Nacimiento fault exposed along the central California coast (United States) juxtaposes the Salinian block arc against the Nacimiento block accretionary complex, cuts out the majority of the forearc basin and western arc, and requires a minimum of 150 km of orogen-normal crustal excision within the Mesozoic California convergent margin. Despite this significant strain, the kinematic evolution of the Sur-Nacimiento fault remains poorly understood, with diverse hypotheses suggesting sinistral, dextral, thrust, or normal displacement along the fault. This Late Cretaceous–Paleogene strain history is complicated by the location of the fault within a belt of subparallel faults that have accommodated significant …
Revealing The Broad Line Region Of Ngc 1275: The Relationship To Jet Power, Brian Punsly, Paola Marziani, Vardha Nicola Bennert, Hiroshi Nagai, Mark A. Gurwell
Revealing The Broad Line Region Of Ngc 1275: The Relationship To Jet Power, Brian Punsly, Paola Marziani, Vardha Nicola Bennert, Hiroshi Nagai, Mark A. Gurwell
Physics
NGC 1275 is one of the most conspicuous active galactic nuclei (AGN) in the local universe. The radio jet currently emits a flux density of ~10 Jy at ~1 mm wavelengths, down from the historic high of ~65 Jy in 1980. Yet, the nature of the AGN in NGC 1275 is still controversial. It has been debated whether this is a broad emission line (BEL) Seyfert galaxy, an obscured Seyfert galaxy, a narrow line radio galaxy, or a BL Lac object. We clearly demonstrate a persistent Hβ BEL over the last 35 yr with a full width at half …
Validation Of The Nonhydrostatic General Curvilinear Coastal Ocean Model (Gccom) For Stratified Flows, Mariangel Garcia, Paul Choboter, Ryan K. Walter, Jose E. Castillo
Validation Of The Nonhydrostatic General Curvilinear Coastal Ocean Model (Gccom) For Stratified Flows, Mariangel Garcia, Paul Choboter, Ryan K. Walter, Jose E. Castillo
Physics
While global- and basin-scale processes can be captured quite well with computationally-inexpensive hydrostatic models, smaller-scale features such as shoaling nonlinear internal waves and bores, coastal fronts, and other convective processes require the use of a nonhydrostatic model to accurately capture dynamics. Here the nonhydrostatic capabilities of the General Curvilinear Coastal Ocean Model (GCCOM) in a stratified environment are introduced. GCCOM is a three-dimensional, nonhydrostatic Large Eddy Simulation (LES), rigid lid model that has the ability to run in a fully three-dimensional general curvilinear coordinate system. This model was previously validated for unstratified flows with curvilinear coordinates. Here, recent advances of …
Studying The [O Iii]Λ5007 Å Emission-Line Width In A Sample Of ∼ 80 Local Active Galaxies: A Surrogate For Σ⋆?, Vardha Nicola Bennert, Donald Loveland, Edward Donohue, Maren Cosens, Sean Lewis, S. Komossa, Tommaso Treu, Matthew A. Malkan, Nathan Milgram, Kelsi Flatland, Matthew W. Auger, Daesong Park, Mariana S. Lazarova
Studying The [O Iii]Λ5007 Å Emission-Line Width In A Sample Of ∼ 80 Local Active Galaxies: A Surrogate For Σ⋆?, Vardha Nicola Bennert, Donald Loveland, Edward Donohue, Maren Cosens, Sean Lewis, S. Komossa, Tommaso Treu, Matthew A. Malkan, Nathan Milgram, Kelsi Flatland, Matthew W. Auger, Daesong Park, Mariana S. Lazarova
Physics
For a sample of ∼ 80 local (0.02 ≤ z" role="presentation">z ≤ 0.1) Seyfert-1 galaxies with high-quality long-slit Keck spectra and spatially resolved stellar-velocity dispersion (σ⋆) measurements, we study the profile of the [O iii]λ5007 Å emission line to test the validity of using its width as a surrogate for σ⋆. Such an approach has often been used in the literature, since it is difficult to measure σ⋆ for type-1 active galactic nuclei (AGNs) due to the AGN continuum outshining the stellar-absorption lines. Fitting the [O iii] line with a single Gaussian or Gauss–Hermite …
Assessment Of Surface Wind Datasets For Estimating Offshore Wind Energy Along The Central California Coast, Yi-Hui Wang, Ryan K. Walter, Crow White, Hayley Farr, Benjamin I. Ruttenberg
Assessment Of Surface Wind Datasets For Estimating Offshore Wind Energy Along The Central California Coast, Yi-Hui Wang, Ryan K. Walter, Crow White, Hayley Farr, Benjamin I. Ruttenberg
Physics
In the United States, Central California has gained significant interest in offshore wind energy due to its strong winds and proximity to existing grid connections. This study provides a comprehensive evaluation of near-surface wind datasets in this region, including satellite-based observations (QuikSCAT, ASCAT, and CCMP V2.0), reanalysis (NARR and MERRA), and regional atmospheric models (WRF and WIND Toolkit). This work highlights spatiotemporal variations in the performance of the respective datasets in relation to in-situ buoy measurements using error metrics over both seasonal and diurnal time scales. The two scatterometers(QuikSCAT and ASCAT) showed the best overall performance, albeit with significantly …
The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region, Peter R. Williams, Anna Pancoast, Tommaso Treu, Brendon J. Brewer, Vardha N. Bennert, Jong-Hak Woo
The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region, Peter R. Williams, Anna Pancoast, Tommaso Treu, Brendon J. Brewer, Vardha N. Bennert, Jong-Hak Woo
Physics
We present models of the Hβ-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from the Lick AGN Monitoring Project 2011 sample, drawing inferences on the BLR structure and dynamics as well as the mass of the central supermassive black hole. We find that the BLR is generally a thick disk, viewed close to face-on, with preferential emission back toward the ionizing source. The dynamics in our sample range from near-circular elliptical orbits to inflowing or outflowing trajectories. We measure black hole masses of for PG 1310−108, for Mrk 50, for Mrk 141, for Mrk 279, for Mrk …
Reversible Motion In A Contact Line, Audrey Profeta, Esmeralda Orozco, Juan A. Ortiz Salazar, Dani Medina, Nathan C. Keim
Reversible Motion In A Contact Line, Audrey Profeta, Esmeralda Orozco, Juan A. Ortiz Salazar, Dani Medina, Nathan C. Keim
STAR Program Research Presentations
When a body of liquid sits on a surface, an irregular border between the wet and dry regions of the surface exists, called the contact line. Driving this contact line back and forth repeatedly can change its shape.We use a syringe pump to cyclically infuse and withdraw a predetermined volume of water, and take photos of the contact line after each cycle. Comparing these images to each other determines if the contact line is returning to the same shape. We find that below a critical value of infused volume, after many cycles the contact line reaches a steady state in …
Hydrodynamics In A Shallow Seasonally Low-Inflow Estuary Following Eelgrass Collapse, Ryan K. Walter, Edwin J. Rainville, Jennifer K. O'Leary
Hydrodynamics In A Shallow Seasonally Low-Inflow Estuary Following Eelgrass Collapse, Ryan K. Walter, Edwin J. Rainville, Jennifer K. O'Leary
Physics
Hydrodynamics play a critical role in mediating biological and ecological processes and can have major impacts on the distribution of habitat-forming species. Low-inflow estuaries are widespread in arid regions and during the dry season in Mediterranean climates. There is a growing need to evaluate dynamics and exchange processes in these systems and the resultant ecological linkages. We investigate the role that hydrodynamics play in shaping environmental gradients in a short and seasonally low-inflow estuary located along the central California coast. Since 2007, eelgrass meadows in Morro Bay have declined by more than 90%, representing the collapse of the major …
Anisotropic Conductive Adhesives For Interdigitated Back Contact (Ibc) Silicon Solar Cells, Katherine M. Lohmuste, Manuel Schnabel, Maikel F.A.M. Van Hest
Anisotropic Conductive Adhesives For Interdigitated Back Contact (Ibc) Silicon Solar Cells, Katherine M. Lohmuste, Manuel Schnabel, Maikel F.A.M. Van Hest
STAR Program Research Presentations
The current manufacturing process for solar panels using interdigitated back contact (IBC) silicon solar cells involves a multi-step metallization and interconnection process in which a substantial amount of silver is used. This work focuses on a new process using conductive adhesives (CA) which would increase efficiency and lower cost through a one-step metallization and interconnection process that combines with encapsulation using little silver and only requiring metal patterning on the back sheet or back glass. It would also not require direct metallization of the silicon, which would result in fewer defects, while increasing voltage and therefore efficiency. Silver-coated Poly(Methyl Methacrylate) …
Calibration And Limitations Of The Mg Ii Line-Based Black Hole Masses, Jong-Hak Woo, Huynh Anh N. Le, Marios Karouzos, Dawoo Park, Daesong Park, Matthew A. Malkan, Tommaso Treu, Vardha Nicola Bennert
Calibration And Limitations Of The Mg Ii Line-Based Black Hole Masses, Jong-Hak Woo, Huynh Anh N. Le, Marios Karouzos, Dawoo Park, Daesong Park, Matthew A. Malkan, Tommaso Treu, Vardha Nicola Bennert
Physics
We present single-epoch black hole mass () calibrations based on the rest-frame ultraviolet (UV) and optical measurements of Mg ii 2798 Å and Hβ 4861 Å lines and the active galactic nucleus (AGN) continuum, using a sample of 52 moderate-luminosity AGNs at z ~ 0.4 and z ~ 0.6 with high-quality Keck spectra. We combine this sample with a large number of luminous AGNs from the Sloan Digital Sky Survey to increase the dynamic range for a better comparison of UV and optical velocity and luminosity measurements. With respect to the reference based on the line dispersion of H …
Influence Of Internal Bores On Larval Fish Abundance And Community Composition, Patrick J. Phelan, John Steinbeck, Ryan K. Walter
Influence Of Internal Bores On Larval Fish Abundance And Community Composition, Patrick J. Phelan, John Steinbeck, Ryan K. Walter
Physics
A persistent semidiurnal internal tidal bore feature occurs at the head of the Monterey Bay Submarine Canyon and drives regular intrusions of cold, subthermocline waters onto the adjacent shelf. In this study, we examine the influence of this internal tidal bore feature on the larval fish community using over a year of periodic larval fish samples collected coincidently with physical measurements. Larval samples were categorized into one of two water mass periods: a “warm period” representative of shallow coastal shelf waters and a “cold period” characteristics of colder waters present during internal bore forcing. Using multivariate statistical methods, we show …
Stability Of The Broad-Line Region Geometry And Dynamics In Arp 151 Over Seven Years, A. Pancoast, A. J. Barth, K. Horne, T. Treu, Vardha N. Bennert, H. Winkler
Stability Of The Broad-Line Region Geometry And Dynamics In Arp 151 Over Seven Years, A. Pancoast, A. J. Barth, K. Horne, T. Treu, Vardha N. Bennert, H. Winkler
Physics
The Seyfert 1 galaxy Arp 151 was monitored as part of three reverberation mapping campaigns spanning 2008–2015. We present modeling of these velocity-resolved reverberation mapping data sets using a geometric and dynamical model for the broad-line region (BLR). By modeling each of the three data sets independently, we infer the evolution of the BLR structure in Arp 151 over a total of 7 yr and constrain the systematic uncertainties in nonvarying parameters such as the black hole mass. We find that the BLR geometry of a thick disk viewed close to face-on is stable over this time, although the size …
Coastal Upwelling Seasonality And Variability Of Temperature And Chlorophyll In A Small Coastal Embayment, Ryan K. Walter, Kevin Armenta, Brandon Shearer, Ian C. Robbins, John Steinbeck
Coastal Upwelling Seasonality And Variability Of Temperature And Chlorophyll In A Small Coastal Embayment, Ryan K. Walter, Kevin Armenta, Brandon Shearer, Ian C. Robbins, John Steinbeck
Physics
While the seasonality of wind-driven coastal upwelling in eastern boundary upwelling systems has long been established, many studies describe two distinct seasons (upwelling and non-upwelling), a generalized framework that does not capture details relevant to marine ecosystems. In this contribution, we present a more detailed description of the annual cycle and upwelling seasonality for an understudied location along the central California coast. Using both the mean monthly upwelling favorable wind stress and the monthly standard deviation, we define the following seasons (contiguous months) and a transitional period (non-contiguous months): “Winter Storms” season (Dec-Jan-Feb), “Upwelling Transition” period (Mar and Jun), …
X-Ray Spectroscopy Of Nio And Nanodiamond At Ssrl, Jackson Earl
X-Ray Spectroscopy Of Nio And Nanodiamond At Ssrl, Jackson Earl
STAR Program Research Presentations
The first aspect of this research project focuses on investigating the surface chemistry of high pressure high temperature (HPHT) nanodiamond by using X-ray spectroscopy techniques at the Stanford Synchrotron Radiation Lightsource (SSRL). HPHT nanodiamond is being examined as a biosensing tool for electric field detection based on the fluorescent nitrogen vacancy center hosted within diamond. With use of the transition edge spectrometer (TES), a state-of-the-art X-ray fluorescence detector, we are able to probe the surface and bulk properties of diamond. Preliminary work using density functional theory (DFT) has been done, offering insight into ground state energies and electronic structure. DFT …
Resistance Temperature Detectors In A Cryostat Refrigeration System, Kirsten Marie Manahan, Alice Callen
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 …