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Articles 31 - 60 of 967

Full-Text Articles in Physics

Empirical Models Of The Hβ Broad Emission Line Gas Density Field, Lizvette Villafaña, Tommaso Treu, Lourenzo Colleyn, Brendon J. Brewer, Aaron J. Barth, Matthew A. Malkan, Vivian U, Vardha N. Bennert Apr 2024

Empirical Models Of The Hβ Broad Emission Line Gas Density Field, Lizvette Villafaña, Tommaso Treu, Lourenzo Colleyn, Brendon J. Brewer, Aaron J. Barth, Matthew A. Malkan, Vivian U, Vardha N. Bennert

Physics

We present the second iteration of the caramel-gas code, an empirical model of the broad-line region (BLR) gas density field. Building on the initial development and testing of caramel-gas, we expand the meaning of the model parameter α, which initially represented only the power-law index of the dependency of emissivity on radial distance. In this work, we test a more generalized radial power-law index, α, that also includes a description of the effective emitting size(s) of the BLR structure as a function of radial distance. We select a sample of 10 active galactic nuclei (AGN) from three different …

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Exploration On Lysing Microalgae Using Pulsed Electric Fields, Fereshteh A. Bunk Apr 2024

Exploration On Lysing Microalgae Using Pulsed Electric Fields, Fereshteh A. Bunk

Physics

With a dangerously and rapidly changing climate [1], people globally are desperate to reduce CO2 emissions and protect our environment as evidenced by global initiatives such as the United Nations’ Paris Agreement [2]. Traditional fossil fuel extraction and combustion was responsible for 74% of U.S. greenhouse gas emissions in 2019, which contributes to climate change, ocean acidification, extreme weather events, sea level rise, pollution, and health issues which contributed to 350,000 premature deaths in the U.S. in 2018 [3]. This motivates the search for alternative, more sustainable fuel production. There have been many new, more sustainable solutions to traditional fossil …

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Non-Relativistic Limit Of Selected Terms From The Sme Dirac Lagrangian, Quinn Reece Mar 2024

Non-Relativistic Limit Of Selected Terms From The Sme Dirac Lagrangian, Quinn Reece

Physics

We examine a selection of individual CPT/Lorentz violating terms present in the relativistic lagrangian for a free spin- 1 2 Dirac fermion of mass m in the Standard Model Extension. Euler-Lagrange relations will be applied to give Dirac-like equations including these terms and a novel procedure will be used to generate non-relativistic limits of these equations which are Schr¨odinger-Pauli-like equations. These equations will be analyzed using classical quantum mechanics toy problems to gain physical intuition for the effects of the CPT violating terms, and the results will be discussed. We will conclude with discussion on future work will include the …

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Trapping And Scattering Of A Multiflagellated Bacterium By A Hard Surface, Alexander P. Petroff, Schuyler Mcdonough Mar 2024

Trapping And Scattering Of A Multiflagellated Bacterium By A Hard Surface, Alexander P. Petroff, Schuyler Mcdonough

Physics

Thiovulum majus, which is one of the fastest known bacteria, swims using hundreds of flagella. Unlike typical pusher cells, which swim in circular paths over hard surfaces, T. majus localize near hard boundaries by turning their flagella to exert a net force normal to the surface. To probe the torques that stabilize this hydrodynamically bound state, the trajectories of several thousand collisions between a T. majus cell and a wall of a quasi-two-dimensional microfluidic chamber are analyzed. Measuring the fraction of cells escaping the wall either to the left or to the right of the point of contact - and …

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Impacts Of Marine Heatwaves On Subsurface Temperatures And Dissolved Oxygen In The Chesapeake Bay, Nathan P. Shunk, Piero L. F. Mazzini, Ryan K. Walter Feb 2024

Impacts Of Marine Heatwaves On Subsurface Temperatures And Dissolved Oxygen In The Chesapeake Bay, Nathan P. Shunk, Piero L. F. Mazzini, Ryan K. Walter

Physics

Subsurface impacts associated with Marine Heatwaves (MHWs) in estuaries are not well understood, largely due to data scarcity. Using over three decades (1986–2021) of observations from several monitoring programs, this study investigates subsurface temperature and dissolved oxygen (DO) anomalies associated with surface MHWs in the Chesapeake Bay (CB). Seasonal variability in temperature anomalies followed a simple 1-D response to surface heating with downward heat transport and diffusion controlled by seasonally variable stratification and mixing. Two distinct temperature regimes were found: a thermally stratified spring-summer regime, when positive temperature anomalies were confined to the surface mixed layer (SML); and a homogeneous …

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Jwst Lensed Quasar Dark Matter Survey – I. Description And First Results, A. M. Nierenberg, R. E. Keeley, D. Sluse, D. Gilman, S. Birrer, T. Treu, K. N. Abazajian, T. Anguita, A. J. Benson, Vardha N. Bennert Feb 2024

Jwst Lensed Quasar Dark Matter Survey – I. Description And First Results, A. M. Nierenberg, R. E. Keeley, D. Sluse, D. Gilman, S. Birrer, T. Treu, K. N. Abazajian, T. Anguita, A. J. Benson, Vardha N. Bennert

Physics

The flux ratios of gravitationally lensed quasars provide a powerful probe of the nature of dark matter. Importantly, these ratios are sensitive to small-scale structure, irrespective of the presence of baryons. This sensitivity may allow us to study the halo mass function even below the scales where galaxies form observable stars. For accurate measurements, it is essential that the quasar’s light is emitted from a physical region of the quasar with an angular scale of milliarcseconds or larger; this minimizes microlensing effects by stars within the deflector. The warm dust region of quasars fits this criterion, as it has parsec-size …

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The Seoul National University Agn Monitoring Project. Iii. Hβ Lag Measurements Of 32 Luminous Active Galactic Nuclei And The High-Luminosity End Of The Size–Luminosity Relation, Jong-Hak Woo, Shu Wang, Suvendu Rakshit, Hojin Cho, Donghoon Son, Vardha N. Bennert, Elena Gallo, Edmund Hodges-Kluck, Tommaso Treu, Aaron J. Barth Feb 2024

The Seoul National University Agn Monitoring Project. Iii. Hβ Lag Measurements Of 32 Luminous Active Galactic Nuclei And The High-Luminosity End Of The Size–Luminosity Relation, Jong-Hak Woo, Shu Wang, Suvendu Rakshit, Hojin Cho, Donghoon Son, Vardha N. Bennert, Elena Gallo, Edmund Hodges-Kluck, Tommaso Treu, Aaron J. Barth

Physics

We present the main results from a long-term reverberation mapping campaign carried out for the Seoul National University AGN Monitoring Project (SAMP). High-quality data were obtained during 2015–2021 for 32 luminous active galactic nuclei (AGNs; i.e., continuum luminosity in the range of 1044–46 erg s−1) at a regular cadence, of 20–30 days for spectroscopy and 3–5 days for photometry. We obtain time lag measurements between the variability in the Hβ emission and the continuum for 32 AGNs; 25 of those have the best lag measurements based on our quality assessment, examining correlation strength and the posterior lag distribution. Our …

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Decades Of Eelgrass Meadow Dynamics Across The Northeast Pacific Support Seascape-Scale Conservation, S. H. Munsch, Ryan K. Walter, B. L. Sanderson, L. Reshitnyk, J. K. O'Leary, P. M. Kiffney, M. Hessing-Lewis, T. G. Gerwing, C. A. Endris, W. B. Chesney, K. M. Beheshti, F. L. Beaty Oct 2023

Decades Of Eelgrass Meadow Dynamics Across The Northeast Pacific Support Seascape-Scale Conservation, S. H. Munsch, Ryan K. Walter, B. L. Sanderson, L. Reshitnyk, J. K. O'Leary, P. M. Kiffney, M. Hessing-Lewis, T. G. Gerwing, C. A. Endris, W. B. Chesney, K. M. Beheshti, F. L. Beaty

Physics

Eelgrass meadows provide vital nearshore habitats and ecosystem services, but they have declined from human stressors and conservation efforts are now widespread. Dynamic ecosystems like eelgrass meadows naturally rearrange as disturbance and recruitment unfold across seascapes. However, some decisions that protect eelgrass only consider extant meadows, thus ignoring the potential for change. Here, we report decades of eelgrass dynamics observed across the northeast Pacific. Our observations support conservation expanded to the seascape scale, which includes potentially inhabitable areas along with extant meadows. We found that total seascape meadow area changed over time, and changes within seascapes were often asynchronous. Some …

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Signatures Of Feedback In The Spectacular Extended Emission Region Of Ngc 5972, Thomas Harvey, W. Peter Maksym, William Keel, Michael Koss, Vardha N. Bennert, S. Drew Chojnowski, Ezequiel Treister, Carolina Finlez, Chris J. Lintott, Alexei Moiseev, Brooke D. Simmons, Lia F. Sartori, Megan Urry Oct 2023

Signatures Of Feedback In The Spectacular Extended Emission Region Of Ngc 5972, Thomas Harvey, W. Peter Maksym, William Keel, Michael Koss, Vardha N. Bennert, S. Drew Chojnowski, Ezequiel Treister, Carolina Finlez, Chris J. Lintott, Alexei Moiseev, Brooke D. Simmons, Lia F. Sartori, Megan Urry

Physics

We present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 ‘Voorwerpjes’ galaxies. This galaxy contains an extended emission-line region (EELR) and an arcsecond scale nuclear bubble. NGC 5972 is a faded active galactic nucleus (AGN), with EELR luminosity suggesting a 2.1 dex decrease in Lbol in the last ∼5 ×104 yr. We investigate the role of AGN feedback in exciting the EELR and bubble given the long-term variability and potential accretion state changes. We detect broad-band (0.3–8 keV) X-ray emission in the near-nuclear regions, coincident with the [O III …

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Temperature Evolution Of Domains And Intradomain Chirality In 1t- Tas2, Boning Yu, Ghilles Ainouche, Manoj Singh, Bishnu Sharma, James Huber, Michael Boyer Sep 2023

Temperature Evolution Of Domains And Intradomain Chirality In 1t- Tas2, Boning Yu, Ghilles Ainouche, Manoj Singh, Bishnu Sharma, James Huber, Michael Boyer

Physics

We use scanning tunneling microscopy to study the temperature evolution of the atomic-scale properties of the nearly commensurate charge density wave (NC-CDW) state of the low-dimensional material 1T-TaS2. Our measurements at 203, 300, and 354 K, roughly spanning the temperature range of the NC-CDW state, show that while the average CDW periodicity is temperature independent, domaining and the local evolution of the CDW lattice within a domain are temperature dependent. Further, we characterize the temperature evolution of the displacement field associated with the recently discovered intradomain chirality of the NC-CDW state by calculating the local rotation vector. Intradomain chirality throughout …

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Dynamics Of Magnetoelastic Robots In Water-Saturated Granular Beds, Animesh Biswas, Trinh Huynh, Balaram Desai, Max Moss, Arshad Kudrolli Sep 2023

Dynamics Of Magnetoelastic Robots In Water-Saturated Granular Beds, Animesh Biswas, Trinh Huynh, Balaram Desai, Max Moss, Arshad Kudrolli

Physics

We investigate the dynamics of a magnetoelastic robot with a dipolar magnetic head and a slender elastic body as it performs undulatory strokes and burrows through water-saturated granular beds. The robot is actuated by an oscillating magnetic field and moves forward when the stroke amplitude increases above a critical threshold. By visualizing the medium, we show that the undulating body fluidizes the bed, resulting in the appearance of a dynamic burrow, which rapidly closes in behind the moving robot as the medium loses energy. We investigate the applicability of Lighthill's elongated body theory of fish locomotion, and estimate the contribution …

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Cluster Scaling And Critical Points: A Cautionary Tale, W. Klein, Harvey Gould, Sakib Matin Sep 2023

Cluster Scaling And Critical Points: A Cautionary Tale, W. Klein, Harvey Gould, Sakib Matin

Physics

Many systems in nature are conjectured to exist at a critical point, including the brain and earthquake faults. The primary reason for this conjecture is that the distribution of clusters (avalanches of firing neurons in the brain or regions of slip in earthquake faults) can be described by a power law. Because there are other mechanisms such as 1/f noise that can produce power laws, other criteria that the cluster critical exponents must satisfy can be used to conclude whether or not the observed power-law behavior indicates an underlying critical point rather than an alternate mechanism. We show how a …

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First Measurement Of The Nuclear-Recoil Ionization Yield In Silicon At 100 Ev, M. F. Albakry, I. Alkhatib, D. Alonso, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, S. Das, F. De Brienne, M. Rios, S. Dharani, M. L. Di Vacri, M. D. Diamond, M. Elwan, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germound, M. Ghaith, S. R. Golwala, J. Hall, S. A.S. Harms, N. Hassan, B. A. Hines, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, M. Lee, M. Litke, J. Liu, Y. Lui, B. Loer, E. Lopez Asamar, P. Lukens, D. B. Macfarlane, R. Mahapatra, N. Mast, A. J. Mayer, H. Meyer Zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, B. Nebolsky, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, L. Pandey, S. Pandey, R. Partridge, D. S. Pedreros, L. Perna, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, E. Tanner, A. Roberts, A. E. Robinson, T. Saab, D. Sadek, B. Sadoulet, S. P. Sahoo, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, P. Sinervo, Z. Speaks, J. Street, H. Sun, G. D. Terry, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. Von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, K. Wykoff, S. Yellin, Betty A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, A. Zeolla, E. Zhang, L. Zheng, Y. Zheng, A. Zuniga, P. An, P. S. Barbeau, S. C. Hedges, L. Li, J. Runge Aug 2023

First Measurement Of The Nuclear-Recoil Ionization Yield In Silicon At 100 Ev, M. F. Albakry, I. Alkhatib, D. Alonso, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, S. Das, F. De Brienne, M. Rios, S. Dharani, M. L. Di Vacri, M. D. Diamond, M. Elwan, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germound, M. Ghaith, S. R. Golwala, J. Hall, S. A.S. Harms, N. Hassan, B. A. Hines, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, M. Lee, M. Litke, J. Liu, Y. Lui, B. Loer, E. Lopez Asamar, P. Lukens, D. B. Macfarlane, R. Mahapatra, N. Mast, A. J. Mayer, H. Meyer Zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, B. Nebolsky, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, L. Pandey, S. Pandey, R. Partridge, D. S. Pedreros, L. Perna, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, E. Tanner, A. Roberts, A. E. Robinson, T. Saab, D. Sadek, B. Sadoulet, S. P. Sahoo, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, P. Sinervo, Z. Speaks, J. Street, H. Sun, G. D. Terry, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. Von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, K. Wykoff, S. Yellin, Betty A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, A. Zeolla, E. Zhang, L. Zheng, Y. Zheng, A. Zuniga, P. An, P. S. Barbeau, S. C. Hedges, L. Li, J. Runge

Physics

We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a monoenergetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4 keV down to 100 eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100 eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.

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The Seoul National University Agn Monitoring Project. Iv. Hα Reverberation Mapping Of Six Agns And The Hα Size–Luminosity Relation, Hojin Cho, Jong-Hak Woo, Shu Wang, Donghoon Son, Jaejin Shin, Suvendu Rakshit, Aaron J. Barth, Vardha N. Bennert, Elena Gallo, Edmund Hodges-Kluck, Tommaso Treu, Hyun-Ji Bae, Wanjin Cho, Adi Foord, Jaehyuk Geum, Yashashree Jadhav, Yiseul Jeon, Kyle M. Kabasares, Daeun Kang, Wonseok Kang, Changseok Kim, Donghwa Kim, Minjin Kim, Taewoo Kim, Huynh Anh N. Lee, Matthew A. Malkan, Amit Kumar Mandal, Daeseong Park, Hyun-Il Sung, Vivian U, Peter R. Williams Aug 2023

The Seoul National University Agn Monitoring Project. Iv. Hα Reverberation Mapping Of Six Agns And The Hα Size–Luminosity Relation, Hojin Cho, Jong-Hak Woo, Shu Wang, Donghoon Son, Jaejin Shin, Suvendu Rakshit, Aaron J. Barth, Vardha N. Bennert, Elena Gallo, Edmund Hodges-Kluck, Tommaso Treu, Hyun-Ji Bae, Wanjin Cho, Adi Foord, Jaehyuk Geum, Yashashree Jadhav, Yiseul Jeon, Kyle M. Kabasares, Daeun Kang, Wonseok Kang, Changseok Kim, Donghwa Kim, Minjin Kim, Taewoo Kim, Huynh Anh N. Lee, Matthew A. Malkan, Amit Kumar Mandal, Daeseong Park, Hyun-Il Sung, Vivian U, Peter R. Williams

Physics

The broad-line region (BLR) size–luminosity relation has paramount importance for estimating the mass of black holes in active galactic nuclei (AGNs). Traditionally, the size of the Hβ BLR is often estimated from the optical continuum luminosity at 5100 Å, while the size of the Hα BLR and its correlation with the luminosity is much less constrained. As a part of the Seoul National University AGN Monitoring Project, which provides 6 yr photometric and spectroscopic monitoring data, we present our measurements of the Hα lags of high-luminosity AGNs. Combined with the measurements for 42 AGNs from the literature, …

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Effects Of Basin-Scale Climate Modes And Upwelling On Nearshore Marine Heatwaves And Cold Spells In The California Current, Michael Dalsin, Ryan K. Walter, Piero L. F. Mazzini Jul 2023

Effects Of Basin-Scale Climate Modes And Upwelling On Nearshore Marine Heatwaves And Cold Spells In The California Current, Michael Dalsin, Ryan K. Walter, Piero L. F. Mazzini

Physics

Marine heatwaves and cold spells (MHWs/MCSs) have been observed to be increasing globally in frequency and intensity based on satellite remote sensing and continue to pose a major threat to marine ecosystems worldwide. Despite this, there are limited in-situ based observational studies in the very shallow nearshore region, particularly in Eastern Boundary Current Upwelling Systems (EBUS). We analyzed a unique dataset collected in shallow waters along central California spanning more than four decades (1978–2020) and assessed links with basin-scale climate modes [Pacific Decadal Oscillation (PDO) and El Niño (MEI)] and regional-scale wind-driven upwelling. We found no significant increase/decrease in MHW/MCS …

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Computational Model Of Twisted Elastic Ribbons, Madelyn Leembruggen, Jovana Andrejevic, Arshad Kudrolli, Chris H. Rycroft Jul 2023

Computational Model Of Twisted Elastic Ribbons, Madelyn Leembruggen, Jovana Andrejevic, Arshad Kudrolli, Chris H. Rycroft

Physics

We develop an irregular lattice mass-spring model to simulate and study the deformation modes of a thin elastic ribbon as a function of applied end-to-end twist and tension. Our simulations reproduce all reported experimentally observed modes, including transitions from helicoids to longitudinal wrinkles, creased helicoids and loops with self-contact, and transverse wrinkles to accordion self-folds. Our simulations also show that the twist angles at which the primary longitudinal and transverse wrinkles appear are well described by various analyses of the Föppl-von Kármán equations, but the characteristic wavelength of the longitudinal wrinkles has a more complex relationship to applied tension than …

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Density-Mediated Spin Correlations Drive Edge-To-Bulk Flow Transition In Active Chiral Matter, Alexander P. Petroff, Christopher Whittington, Arshad Kudrolli Jul 2023

Density-Mediated Spin Correlations Drive Edge-To-Bulk Flow Transition In Active Chiral Matter, Alexander P. Petroff, Christopher Whittington, Arshad Kudrolli

Physics

We demonstrate that edge currents develop in active chiral matter due to boundary shielding over a wide range of densities corresponding to a gas, fluid, and crystal. The system is composed of spinning disk-shaped grains with chirally arranged tilted legs confined in a circular vibrating chamber. The edge currents are shown to increasingly drive circulating bulk flows with area fraction as percolating clusters develop due to increasing spin-coupling between neighbors mediated by frictional contacts. Edge currents are observed even in the dilute limit. While, at low area fraction, the average flux vanishes except within a distance that is of the …

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Search For Low-Mass Dark Matter Via Bremsstrahlung Radiation And The Migdal Effect In Supercdms, M. F. Albakry, I. Alkhatib, D. Alonso-González, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, S. Das, F. De Brienne, M. Rios, S. Dharani, M. L. Di Vacri, M. D. Diamond, M. Elwan, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, J. Hall, N. Hassan, B. A. Hines, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, M. Lee, A. Li, M. Litke, J. Liu, Y. Liu, B. Loer, E. Lopez Asamar, P. Lukens, D. B. Macfarlane, R. Mahapatra, J. S. Mammo, N. Mast, A. J. Mayer, H. Meyer Zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, L. Pandey, S. Pandey, R. Partridge, D. S. Pedreros, L. Perna, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, T. Saab, D. Sadek, B. Sadoulet, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, P. Sinervo, J. Street, H. Sun, G. D. Terry, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. Von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, C. -P. Wu, K. Wykoff, S. Yellin, Betty A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, A. Zuniga Jun 2023

Search For Low-Mass Dark Matter Via Bremsstrahlung Radiation And The Migdal Effect In Supercdms, M. F. Albakry, I. Alkhatib, D. Alonso-González, D. W. P. Amaral, T. Aralis, T. Aramaki, I. J. Arnquist, I. Ataee Langroudy, E. Azadbakht, S. Banik, C. Bathurst, R. Bhattacharyya, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y. -Y. Chang, M. Chaudhuri, R. Chen, N. Chott, J. Cooley, H. Coombes, J. Corbett, P. Cushman, S. Das, F. De Brienne, M. Rios, S. Dharani, M. L. Di Vacri, M. D. Diamond, M. Elwan, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, K. Fouts, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, J. Hall, N. Hassan, B. A. Hines, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, V. K. S. Kashyap, M. H. Kelsey, A. Kubik, N. A. Kurinsky, M. Lee, A. Li, M. Litke, J. Liu, Y. Liu, B. Loer, E. Lopez Asamar, P. Lukens, D. B. Macfarlane, R. Mahapatra, J. S. Mammo, N. Mast, A. J. Mayer, H. Meyer Zu Theenhausen, É. Michaud, E. Michielin, N. Mirabolfathi, B. Mohanty, J. Nelson, H. Neog, V. Novati, J. L. Orrell, M. D. Osborne, S. M. Oser, W. A. Page, L. Pandey, S. Pandey, R. Partridge, D. S. Pedreros, L. Perna, R. Podviianiuk, F. Ponce, S. Poudel, A. Pradeep, M. Pyle, W. Rau, E. Reid, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, T. Saab, D. Sadek, B. Sadoulet, I. Saikia, J. Sander, A. Sattari, B. Schmidt, R. W. Schnee, S. Scorza, B. Serfass, S. S. Poudel, D. J. Sincavage, P. Sinervo, J. Street, H. Sun, G. D. Terry, F. K. Thasrawala, D. Toback, R. Underwood, S. Verma, A. N. Villano, B. Von Krosigk, S. L. Watkins, O. Wen, Z. Williams, M. J. Wilson, J. Winchell, C. -P. Wu, K. Wykoff, S. Yellin, Betty A. Young, T. C. Yu, B. Zatschler, S. Zatschler, A. Zaytsev, E. Zhang, L. Zheng, A. Zuniga

Physics

We present a new analysis of previously published SuperCDMS data using a profile likelihood framework to search for sub-GeV dark matter (DM) particles through two inelastic scattering channels: bremsstrahlung radiation and the Migdal effect. By considering these possible inelastic scattering channels, experimental sensitivity can be extended to DM masses that are undetectable through the DM-nucleon elastic scattering channel, given the energy threshold of current experiments. We exclude DM masses down to 220  MeV/𝑐2 at 2.7×10−30  cm2 via the bremsstrahlung channel. The Migdal channel search provides overall considerably more stringent limits and excludes DM masses down to 30  MeV/𝑐 …

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Optimization Of Flagellar Locomotion In The Low Reynolds Number Regime, Aidan M. Trodden, Aidan M. Trodden Jun 2023

Optimization Of Flagellar Locomotion In The Low Reynolds Number Regime, Aidan M. Trodden, Aidan M. Trodden

Physics

This report investigates the computational and theoretical techniques - modeled by E. Lauga and C. Eloy - used to optimize the shape of an activated flagellum for enhanced cell motility. Cell motility is ubiquitous and has a large affect on biological systems such as marine life ecosystems, reproduction, and infection. The physical principles governing flagellar propulsion are explored using computational fluid dynamics simulations, mathematical modeling, and the sequential quadratic programming (SQP) optimization algorithm. Through iterative refinement, we can identify optimized flagellar shapes that would minimize the energetic cost dependent on a single dimensionless sperm numbers (Sp). The computation of the …

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Optimizing Solid Thermal Storage In Insulated Solar Electric Cookers, Stefan Avramov Jun 2023

Optimizing Solid Thermal Storage In Insulated Solar Electric Cookers, Stefan Avramov

Physics

Insulated Solar Electric Cookers, more commonly known by their acronym ISECookers, are an alternative to biomass cooking. The ISECooker in its simplest form is a solar panel connected to a heating element, in contact with a cooking pot in an insulated chamber. An aluminum puck can be heated as solid thermal storage (STS) for increased power and night time cooking. Power was limited to about 500 W by the interface between the STS and cookpot. Powdered graphite and silver were separately applied to increase thermal flow. However, the powdered graphite decreased the thermal flow, while powdered silver decreased the temperature …

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Diffusion-Driven Aggregation Of Particles In Quasi-2d Membranes, Oscar Gullickson Rausis Jun 2023

Diffusion-Driven Aggregation Of Particles In Quasi-2d Membranes, Oscar Gullickson Rausis

Physics

Many biological membranes can be modeled as two-dimensional (2D) viscous fluid sheets surrounded by three-dimensional (3D) fluids of different viscosity. Such membranes are dubbed quasi-2D as they exhibit properties of both 2D and 3D fluids. The Saffman length is a parameter that describes the energy exchange between the membrane and bulk fluids and controls the cross-over from 2D to 3D hydrodynamics. We aim to model diffusion-driven aggregation of particles embedded in a quasi-2D membrane. It is known that hydrodynamic interactions between solute particles significantly reduce their aggregation rate in 3D fluids. It is expected that in quasi-2D membranes the reduction …

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A Monte-Carlo Simulation Of Gamma Rays In A Sodium Iodide Detector, Ben Kessler Jun 2023

A Monte-Carlo Simulation Of Gamma Rays In A Sodium Iodide Detector, Ben Kessler

Physics

Gamma rays principally interact with matter through Compton scattering, photoelectric effect, pair production, and triplet production. The focus of this simulation is to study the theoretical energy spectrum created by gamma rays from a Cesium-137 source, which produces gamma photons with an energy of 0.662 MeV. At this energy level, most interactions are results of Compton scatters and the photoelectric effect. Therefore, this simulation only models those two effects on gamma rays. Using Monte Carlo methods and the Metropolis algorithm to sample the probability distributions of the two effects allowed for the simulation of gamma rays in a Sodium Iodide …

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Flushing Time Variability In A Short, Low-Inflow Estuary, Mohsen Taherkhani, Sean Vitousek, Ryan K. Walter, Jennifer O'Leary, Amid P. Khodadoust May 2023

Flushing Time Variability In A Short, Low-Inflow Estuary, Mohsen Taherkhani, Sean Vitousek, Ryan K. Walter, Jennifer O'Leary, Amid P. Khodadoust

Physics

Flushing time, the time scale for exchange and mixing between embayed and oceanic waters in an estuary, plays an integral role in determining water quality and aquatic ecosystem health. Here, we investigated the spatiotemporal variability of flushing times throughout Morro Bay, a short, low-inflow estuary (LIE) on the California coast, using a calibrated and validated hydrodynamic model (Delft3D). Morro Bay has historically supported an extensive eelgrass (Zostera marina) habitat, which declined substantially from 139 to 5.4 ha during 2007–2017. Eelgrass decline motivated the current research into the role of changing bed roughness and oceanic drivers (i.e., tide and …

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Quantum Phases Of Lattice Dipolar Bosons Coupled To A High-Finesse Cavity, Yaghmorassene Hebib, Chao Zhang, Jin Yang, Barbara Capogrosso-Sansone May 2023

Quantum Phases Of Lattice Dipolar Bosons Coupled To A High-Finesse Cavity, Yaghmorassene Hebib, Chao Zhang, Jin Yang, Barbara Capogrosso-Sansone

Physics

Two types of long-range interactions, dipolar interaction and cavity-mediated interaction, lead to exotic quantum phases. Both interactions were realized and observed in optical lattice setups. Here, we study quantum phases of dipolar bosons trapped in optical lattices and coupled to a high-finesse cavity where both dipolar interaction and cavity-mediated interaction coexist. We perform quantum Monte Carlo simulations and find that the checkerboard solid is enhanced and the checkerboard supersolid phase can exist in a wide range of densities (e.g., 0.27≲n≲0.73). Our unbiased numerical results suggest that both solid and supersolid phases can be achieved experimentally with magnetic atoms coupled to …

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What Does The Geometry Of The Hβblr Depend On?, Lizvette Villafaña, Peter R. Williams, Tommaso Treu, Brendon J. Brewer, Aaron J. Barth, Vivian U, Vardha N. Bennert, Hengxiao Guo, Misty C. Bentz, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Michael D. Joner, Matthew A. Malkan, Jong-Hak Woo, Bela Abolfathi, Thomas Bohn, K. Azalee Bostroem, Goni Halevi, Carol E. Hood, J. Chuck Horst, Maxime De Kouchkovsky, Benjamin Kuhn, Douglas C. Leonard, Raúl Michel, Melanie Kae B. Olaes, Daeseong Park, Jordan N. Runco, Remington O. Sexton, Isaac Shivvers, Chance L. Spencer, Benjamin E. Stahl, Samantha Stegman, Jonelle L. Walsh, Weikang Zheng May 2023

What Does The Geometry Of The Hβblr Depend On?, Lizvette Villafaña, Peter R. Williams, Tommaso Treu, Brendon J. Brewer, Aaron J. Barth, Vivian U, Vardha N. Bennert, Hengxiao Guo, Misty C. Bentz, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Michael D. Joner, Matthew A. Malkan, Jong-Hak Woo, Bela Abolfathi, Thomas Bohn, K. Azalee Bostroem, Goni Halevi, Carol E. Hood, J. Chuck Horst, Maxime De Kouchkovsky, Benjamin Kuhn, Douglas C. Leonard, Raúl Michel, Melanie Kae B. Olaes, Daeseong Park, Jordan N. Runco, Remington O. Sexton, Isaac Shivvers, Chance L. Spencer, Benjamin E. Stahl, Samantha Stegman, Jonelle L. Walsh, Weikang Zheng

Physics

We combine our dynamical modeling black-hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover individual scale factors, f, used in traditional reverberation-mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (CARAMEL) studies that have utilized our methods. Aiming to improve the precision of black-hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations between f and other AGN/BLR parameters. We find (i) evidence for a …

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Tdcosmo - Xii. Improved Hubble Constant Measurement From Lensing Time Delays Using Spatially Resolved Stellar Kinematics Of The Lens Galaxy, Anowar J. Shajib, Pritom Mozumdar, Geoff C.-F. Chen, Tommaso Treu, Michele Cappellari, Shawn Knabel, Sherry H. Suyu, Vardha N. Bennert, Joshua A. Frieman, Dominique Sluse, Simon Birrer, Frederic Courbin, Christopher D. Fassnacht, Lizvette Villafaña, Peter R. Williams May 2023

Tdcosmo - Xii. Improved Hubble Constant Measurement From Lensing Time Delays Using Spatially Resolved Stellar Kinematics Of The Lens Galaxy, Anowar J. Shajib, Pritom Mozumdar, Geoff C.-F. Chen, Tommaso Treu, Michele Cappellari, Shawn Knabel, Sherry H. Suyu, Vardha N. Bennert, Joshua A. Frieman, Dominique Sluse, Simon Birrer, Frederic Courbin, Christopher D. Fassnacht, Lizvette Villafaña, Peter R. Williams

Physics

Strong-lensing time delays enable the measurement of the Hubble constant (H0) independently of other traditional methods. The main limitation to the precision of time-delay cosmography is mass-sheet degeneracy (MSD). Some of the previous TDCOSMO analyses broke the MSD by making standard assumptions about the mass density profile of the lens galaxy, reaching 2% precision from seven lenses. However, this approach could potentially bias the H0 measurement or underestimate the errors. For this work, we broke the MSD for the first time using spatially resolved kinematics of the lens galaxy in RXJ1131−1231 obtained from the Keck Cosmic …

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The Nature Of Lobal Qsos. Ii. Hst/Wfc3 Observations Reveal Host Galaxies Dominated By Mergers, Mariana S. Lazarova, Gabriela Canalizo, Mark Lacy, Wyatt Behn, Kaitlyn Raub, Vardha N. Bennert, Duncan Farrah May 2023

The Nature Of Lobal Qsos. Ii. Hst/Wfc3 Observations Reveal Host Galaxies Dominated By Mergers, Mariana S. Lazarova, Gabriela Canalizo, Mark Lacy, Wyatt Behn, Kaitlyn Raub, Vardha N. Bennert, Duncan Farrah

Physics

Low-ionization broad absorption line QSOs (LoBALs) are suspected to be merging systems in which extreme, active galactic nucleus-driven outflows have been triggered. Whether or not LoBALs are uniquely associated with mergers, however, has yet to be established. To characterize the morphologies of LoBALs, we present the first high-resolution morphological analysis of a volume-limited sample of 22 Sloan Digital Sky Survey (SDSS)-selected LoBALs at 0.5 < z < 0.6 from Hubble Space Telescope Wide Field Camera 3 observations. Host galaxies are resolved in 86% of the systems in F125W, which is sensitive to old stellar populations, while only 18% are detected in F475W, which traces young, unobscured stellar populations. Signs of recent or ongoing tidal interaction are present in 45%–64% of the hosts, including double nuclei, tidal tails, bridges, plumes, shells, and extended debris. Ongoing interaction with a companion is apparent in 27%−41% of the LoBALs, with as much as 1/3 of the sample representing late-stage mergers at projected nuclear separations <10 kpc. Detailed surface brightness modeling indicates that 41% of the hosts are bulge dominated while only 18% are disks. We discuss trends in various properties as a function of merger stage and parametric morphology. Notably, mergers are associated with slower, dustier winds than those seen in undisturbed/unresolved hosts. Our results favor an evolutionary scenario in which quasar-level accretion during various merger stages is associated with the observed outflows in low-z LoBALs. We discuss differences between LoBALs and FeLoBALs and show that selection via the traditional balnicity index would have excluded all but one of the mergers.

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Application Of Deep Learning For Classification Of Intertidal Eelgrass From Drone-Acquired Imagery, Krti Tallam, Nam Nguyen, Jonathan Ventura, Andrew G. Fricker, Sadie Calhoun, Jennifer O’Leary, Mauriça Fitzgibbons, Ian C. Robbins, Ryan K. Walter Apr 2023

Application Of Deep Learning For Classification Of Intertidal Eelgrass From Drone-Acquired Imagery, Krti Tallam, Nam Nguyen, Jonathan Ventura, Andrew G. Fricker, Sadie Calhoun, Jennifer O’Leary, Mauriça Fitzgibbons, Ian C. Robbins, Ryan K. Walter

Physics

Shallow estuarine habitats are globally undergoing rapid changes due to climate change and anthropogenic influences, resulting in spatiotemporal shifts in distribution and habitat extent. Yet, scientists and managers do not always have rapidly available data to track habitat changes in real-time. In this study, we apply a novel and a state-of-the-art image segmentation machine learning technique (DeepLab) to two years of high-resolution drone-based imagery of a marine flowering plant species (eelgrass, a temperate seagrass). We apply the model to eelgrass (Zostera marina) meadows in the Morro Bay estuary, California, an estuary that has undergone large eelgrass declines and the subsequent …

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Superconductivity And Fermi Surface Studies Of Β″-(Bedt-Ttf)2[(H2o)(Nh4)2cr(C2o4)3]·18-Crown-6, Brett Laramee, Raju Ghimire, David Graf, Lee Martin, Toby J. Blundell, Charles Agosta Mar 2023

Superconductivity And Fermi Surface Studies Of Β″-(Bedt-Ttf)2[(H2o)(Nh4)2cr(C2o4)3]·18-Crown-6, Brett Laramee, Raju Ghimire, David Graf, Lee Martin, Toby J. Blundell, Charles Agosta

Physics

We report rf-penetration depth measurements of the quasi-2D organic superconductor (Formula presented.) -(BEDT-TTF) (Formula presented.) [(H (Formula presented.) O)(NH (Formula presented.)) (Formula presented.) Cr(C (Formula presented.) O (Formula presented.)) (Formula presented.)]·18-crown-6, which has the largest separation between consecutive conduction layers of any 2D organic metal with a single packing motif. Using a contactless tunnel diode oscillator measurement technique, we show the zero-field cooling dependence and field sweeps up to 28 T oriented at various angles with respect to the crystal conduction planes. When oriented parallel to the layers, the upper critical field, (Formula presented.) T, which is the calculated paramagnetic …

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Northeast Pacific Eelgrass Dynamics: Interannual Expansion Distances And Meadow Area Variation Over Time, Stuart H. Munsch, Fiona L. Beaty, Kathryn M. Beheshti, W. Bryant Chesney, Charlie A. Endris, Travis G. Gerwing, Margot Hessing-Lewis, Peter M. Kiffney, Jennifer K. O’Leary, Luba Reshitnyk, Beth L. Sanderson, Ryan K. Walter Feb 2023

Northeast Pacific Eelgrass Dynamics: Interannual Expansion Distances And Meadow Area Variation Over Time, Stuart H. Munsch, Fiona L. Beaty, Kathryn M. Beheshti, W. Bryant Chesney, Charlie A. Endris, Travis G. Gerwing, Margot Hessing-Lewis, Peter M. Kiffney, Jennifer K. O’Leary, Luba Reshitnyk, Beth L. Sanderson, Ryan K. Walter

Physics

Ecosystems constantly change, yet managers often lack information to move beyond static habitat assumptions. As human impacts and geographic information systems advance, it is important and feasible to quantify past habitat boundary shifts to inform management decisions (e.g. protective perimeters) robust to near-term habitat changes. This is the case in eelgrass (Zostera spp.), an ecosystem engineer that forms dynamic, often protected meadows. Practitioners protect areas to avoid human stress to eelgrass, but they can lack quantitative descriptions of the near-term potential for eelgrass meadows to shift into unprotected areas. Here, we quantified interannual eelgrass meadow boundary shifts within 23 sites …

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