• 2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the Treatment of Coccidioidomycosis

      Galgiani, John N.; Ampel, Neil M.; Blair, Janis E.; Catanzaro, Antonino; Geertsma, Francesca; Hoover, Susan E.; Johnson, Royce H.; Kusne, Shimon; Lisse, Jeffrey; MacDonald, Joel D.; et al. (OXFORD UNIV PRESS INC, 2016-09-15)
      It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. Infectious Diseases Society of America considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances. Coccidioidomycosis, also known as San Joaquin Valley fever, is a systemic infection endemic to parts of the southwestern United States and elsewhere in the Western Hemisphere. Residence in and recent travel to these areas are critical elements for the accurate recognition of patients who develop this infection. In this practice guideline, we have organized our recommendations to address actionable questions concerning the entire spectrum of clinical syndromes. These can range from initial pulmonary infection, which eventually resolves whether or not antifungal therapy is administered, to a variety of pulmonary and extrapulmonary complications. Additional recommendations address management of coccidioidomycosis occurring for special at-risk populations. Finally, preemptive management strategies are outlined in certain at-risk populations and after unintentional laboratory exposure.
    • The 2016 June Optical and Gamma-Ray Outburst and Optical Microvariability of the Blazar 3C 454.3

      Weaver, Zachary R.; Balonek, Thomas J.; Jorstad, Svetlana G.; Marscher, Alan P.; Larionov, Valeri M.; Smith, Paul S.; Boni, Samantha J.; Borman, George A.; Chapman, K. J.; Jenks, Leah G.; et al. (IOP PUBLISHING LTD, 2019-04-09)
      The quasar 3C 454.3 underwent a uniquely structured multifrequency outburst in 2016 June. The blazar was observed in the optical R-band by several ground-based telescopes in photometric and polarimetric modes, at gamma-ray frequencies by the Fermi Large Area Telescope, and at 43 GHz with the Very Long Baseline Array. The maximum flux density was observed on 2016 June 24 at both optical and gamma-ray frequencies, reaching S-opt(max) = 18.91 +/- 0.08 mJy and S-gamma(max) = 22.20 +/- 0.18 x 10(-6) ph cm(-2) s(-1), respectively. The 2016 June outburst possessed a precipitous decay at both gamma-ray and optical frequencies, with the source decreasing in flux density by a factor of 4 over a 24 hr period in the R-band. Intraday variability was observed throughout the outburst, with flux density changes between 1 and 5 mJy over the course of a night. The precipitous decay featured statistically significant quasiperiodic microvariability oscillations with an amplitude of similar to 2%-3% about the mean trend and a characteristic period of 36 minutes. The optical degree of polarization jumped from similar to 3% to nearly 20% during the outburst, while the position angle varied by similar to 120 degrees. A knot was ejected from the 43 GHz core on 2016 February 25, moving at an apparent speed nu(app) = 20.3c +/- 0.8c. From the observed minimum timescale of variability tau(min)(opt) approximate to 2 hr and derived Doppler factor delta = 22.6, we find the size of the emission region r less than or similar to 2.6 x 10(15) cm. If the quasiperiodic microvariability oscillations are caused by periodic variations of the Doppler factor of emission from a turbulent vortex, we derive the rotational speed of the vortex to be similar to 0.2c.
    • The 2016 Mw 7.8 Pedernales, Ecuador, Earthquake: Rapid Response Deployment

      Meltzer, Anne; Beck, Susan; Ruiz, Mario; Hoskins, Mariah; Soto‐Cordero, Lillian; Stachnik, Joshua C.; Lynner, Colton; Porritt, Rob; Portner, Daniel; Alvarado, Alexandra; et al. (SEISMOLOGICAL SOC AMER, 2019-05)
      The April 2016 Pedernales earthquake ruptured a 100 km by 40 km segment of the subduction zone along the coast of Ecuador in an M-w 7.8 megathrust event east of the intersection of the Carnegie ridge with the trench. This portion of the subduction zone has ruptured on decadal time scales in similar size and larger earthquakes, and exhibits a range of slip behaviors, variations in segmentation, and degree of plate coupling along strike. Immediately after the earthquake, an international rapid response effort coordinated by the Instituto Geofisico at the Escuela Politecnica Nacional in Quito deployed 55 seismometers and 10 ocean-bottom seismometers above the rupture zone and adjacent areas to record aftershocks. In this article, we describe the details of the U.S. portion of the rapid response and present an earthquake cata-log from May 2016 to May 2017 produced using data recorded by these stations. Aftershocks focus in distinct clusters within and around the rupture area and match spatial patterns observed in long-term seismicity. For the first two and a half months, aftershocks exhibit a relatively sharp cutoff to the north of the mainshock rupture. In early July, an earthquake swarm occurred similar to 100 km to the northeast of the mainshock in the epicentral region of an M-w 7.8 earthquake in 1958. In December, an increase in seismicity occurred similar to 70 km to the northeast of the mainshock in the epicentral region of the 1906 earthquake. Data from the Pedernales earthquake and aftershock sequence recorded by permanent seismic and geodetic networks in Ecuador and the dense aftershock deployment provide an opportunity to examine the persistence of asperities for large to great earthquakes over multiple seismic cycles, the role of asperities and slow slip in subduction-zone megathrust rupture, and the relationship between locked and creeping parts of the subduction interface.
    • 20th century changes in carbon isotopes and water-use efficiency: tree-ring-based evaluation of the CLM4.5 and LPX-Bern models

      Keller, Kathrin M.; Lienert, Sebastian; Bozbiyik, Anil; Stocker, Thomas F.; Churakova (Sidorova), Olga V.; Frank, David C.; Klesse, Stefan; Koven, Charles D.; Leuenberger, Markus; Riley, William J.; et al. (COPERNICUS GESELLSCHAFT MBH, 2017-05-24)
      Measurements of the stable carbon isotope ratio (delta C-13) on annual tree rings offer new opportunities to evaluate mechanisms of variations in photosynthesis and stomatal conductance under changing CO2 and climate conditions, especially in conjunction with process-based biogeochemical model simulations. The isotopic discrimination is indicative of the ratio between the CO2 partial pressure in the intercellular cavities and the atmosphere (c(i)/c(a)) and of the ratio of assimilation to stomatal conductance, termed intrinsic water-use efficiency (iWUE). We performed isotope-enabled simulations over the industrial period with the land biosphere module (CLM4.5) of the Community Earth System Model and the Land Surface Processes and Exchanges (LPX-Bern) dynamic global vegetation model. Results for C3 tree species show good agreement with a global compilation of delta C-13 measurements on leaves, though modeled C-13 discrimination by C3 trees is smaller in arid regions than measured. A compilation of 76 tree-ring records, mainly from Europe, boreal Asia, and western North America, suggests on average small 20th century changes in isotopic discrimination and in c(i)/c(a) and an increase in iWUE of about 27% since 1900. LPX-Bern results match these century-scale reconstructions, supporting the idea that the physiology of stomata has evolved to optimize trade-offs between carbon gain by assimilation and water loss by transpiration. In contrast, CLM4.5 simulates an increase in discrimination and in turn a change in iWUE that is almost twice as large as that revealed by the tree-ring data. Factorial simulations show that these changes are mainly in response to rising atmospheric CO2. The results suggest that the downregulation of c(i)/c(a) and of photosynthesis by nitrogen limitation is possibly too strong in the standard setup of CLM4.5 or that there may be problems associated with the implementation of conductance, assimilation, and related adjustment processes on long-term environmental changes.
    • 21 years of research for the twenty-first century: revisiting the journal of environmental policy and planning

      Ellis, Geraint; Gerlak, Andrea K.; Daugbjerg, Carsten; Feindt, Peter H.; Metze, Tamara; Wu, Xun; Univ Arizona, Sch Geog Dev & Environm (Informa UK Limited, 2020-09-10)
    • 21st Century flood risk projections at select sites for the U.S. National Park Service

      Van Dusen, Peter; Rajagopalan, Balaji; Lawrence, David J.; Condon, Laura E.; Smillie, Gary; Gangopadhyay, Subhrendu; Pruitt, Tom; Univ Arizona, Dept Hydrol & Atmospher Sci (ELSEVIER, 2020-02-04)
      Assessing flood risk using stationary flood frequency analysis techniques is commonplace. Flood risk However, it is increasingly evident that the stationarity assumption of these analyses does not hold as anthropogenic climate change could shift a site's hydroclimate beyond the range of historical behaviors. We employ nonstationary flood frequency models using the generalized extreme value (GEV) distribution to model changing flood risk for select seasons at twelve National Parks across the U.S. In this GEV model, the location and/or scale parameters of the distribution are allowed to change as a function of time-variable covariates. We use historical precipitation and modeled flows from the Variable Infiltration Capacity model (VIC), a land-surface model that simulates land-atmosphere fluxes using water and energy balance equations, as covariates to fit a best nonstationary GEV model to each site. We apply climate model projections of precipitation and VIC flows to these models to obtain future flood probability estimates. Our model results project a decrease in flood risk for sites in the southwestern U.S. region and an increase in flood risk for sites in northern and eastern regions of the U.S. for the selected seasons. The methods and results presented will enable the NPS to develop strategies to ensure public safety and efficient infrastructure management and planning in a nonstationary climate.
    • The 25 parsec local white dwarf population

      Holberg, J. B.; Oswalt, T. D.; Sion, E. M.; McCook, G. P.; Univ Arizona, Lunar & Planetary Lab (OXFORD UNIV PRESS, 2016-11-01)
      We have extended our detailed survey of the local white dwarf population from 20 to 25 pc, effectively doubling the sample volume, which now includes 232 stars. In the process, newstars within 20 pc have been added, a more uniform set of distance estimates as well as improved spectral and binary classifications are available. The present 25 pc sample is estimated to be about 68 per cent complete (the corresponding 20 pc sample is now 86 per cent complete). The space density of white dwarfs is unchanged at 4.8 +/- 0.5 x 10(-3) pc(-3). This new study includes a white dwarf mass distribution and luminosity function based on the 232 stars in the 25 pc sample. We find a significant excess of single stars over systems containing one or more companions (74 per cent versus 26 per cent). This suggests mechanisms that result in the loss of companions during binary system evolution. In addition, this updated sample exhibits a pronounced deficiency of nearby 'Sirius-like' systems. 11 such systems were found within the 20 pc volume versus only one additional system found in the volume between 20 and 25 pc. An estimate of white dwarf birth rates during the last similar to 8 Gyr is derived from individual remnant cooling ages. A discussion of likely ways new members of the local sample may be found is provided.
    • A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

      Omori, Y.; Chown, R.; Simard, G.; Story, K. T.; Aylor, K.; Baxter, E. J.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; et al. (IOP PUBLISHING LTD, 2017-11-07)
      We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and Planck temperature data. The 150 GHz temperature data from the 2500 deg(2) SPT-SZ survey is combined with the Planck 143 GHz data in harmonic space to obtain a temperature map that has a broader l coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential C-L(phi phi), and compare it to the theoretical prediction for a.CDM cosmology consistent with the Planck 2015 data set, finding a best-fit amplitude of 0.95(-0.06)(+0.06) (stat.)(-0.01)(+0.01)+ (sys.). The null hypothesis of no lensing is rejected at a significance of 24 sigma. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, C-L(phi) G, between the SPT+ Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit C-L(phi G) to a power law of the form p(L) = a(L/L-0)(-b) with a, L-0, and b fixed, and find eta(phi G) = C-L(phi G)/p(L) = 0.94(-0.04)(+0.04), which is marginally lower, but in good agreement with eta(phi G) = 1.00-(+0.02)(0.01), the best-fit amplitude for the cross-correlation of Planck-2015 CMB lensing and WISE galaxies over similar to 67% of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey, whose footprint nearly completely covers the SPT 2500 deg(2) field.
    • 29P/Schwassmann–Wachmann 1, A Centaur in the Gateway to the Jupiter-family Comets

      Sarid, G.; Volk, K.; Steckloff, J. K.; Harris, W.; Womack, M.; Woodney, L. M.; Univ Arizona, Lunar & Planetary Lab (IOP PUBLISHING LTD, 2019-09-23)
      Jupiter-family comets (JFCs) are the evolutionary products of trans-Neptunian objects (TNOs) that evolve through the giant planet region as Centaurs and into the inner solar system. Through numerical orbital evolution calculations following a large number of TNO test particles that enter the Centaur population, we have identified a short-lived dynamical Gateway, a temporary low-eccentricity region exterior to Jupiter through which the majority of JFCs pass. We apply an observationally based size distribution function to the known Centaur population and obtain an estimated Gateway region population. We then apply an empirical fading law to the rate of incoming JFCs implied by the the Gateway region residence times. Our derived estimates are consistent with observed population numbers for the JFC and Gateway populations. Currently, the most notable occupant of the Gateway region is 29P/Schwassmann–Wachmann 1 (SW1), a highly active, regularly outbursting Centaur. SW1's present-day, very-low-eccentricity orbit was established after a 1975 Jupiter conjunction and will persist until a 2038 Jupiter conjunction doubles its eccentricity and pushes its semimajor axis out to its current aphelion. Subsequent evolution will likely drive SW1's orbit out of the Gateway region, perhaps becoming one of the largest JFCs in recorded history. The JFC Gateway region coincides with a heliocentric distance range where the activity of observed cometary bodies increases significantly. SW1's activity may be typical of the early evolutionary processing experienced by most JFCs. Thus, the Gateway region, and its most notable occupant SW1, are critical to both the dynamical and physical transition between Centaurs and JFCs.
    • 2D broadband beamsteering with large-scale MEMS optical phased array

      Wang, Youmin; Zhou, Guangya; Zhang, Xiaosheng; Kwon, Kyungmok; Blanche, Pierre-A.; Triesault, Nicholas; Yu, Kyoung-sik; Wu, Ming C.; Univ Arizona, Coll Opt Sci (OPTICAL SOC AMER, 2019-04-29)
      Optical-phased arrays (OPAs) enable complex beamforming, random-access beam pointing, and simultaneous scan and tracking of multiple targets by controlling the phases of two-dimensional (2D) coherent emitters. So far, no OPA can achieve all desirable features including large 2D arrays, high optical efficiency, wideband operation in wavelengths, fast response time, and large steering angles at the same time. Here, we report on a large-scale 2D OPA with novel microelectro-mechanical-system (MEMS)-actuated phase shifters. Wavelength-independent phase shifts are realized by physically moving a grating element in the lateral direction. The OPA has 160 x 160 independent phase shifters across an aperture of 3.1 mm x 3.2 mm. It has a measured beam divergence of 0.042 degrees x 0.031 degrees, a field of view (FOV) of 6.6 degrees x 4.4 degrees, and a response time of 5.7 mu s. It is capable of providing about 25,600 rapidly steerable spots within its FOV. The grating phase shifters are optimized for the near-infrared telecom wavelength bands from 1200 to 1700 nm with 85% optical efficiency. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
    • 2D semiconductor nonlinear plasmonic modulators

      Klein, Matthew; Badada, Bekele H; Binder, Rolf; Alfrey, Adam; McKie, Max; Koehler, Michael R; Mandrus, David G; Taniguchi, Takashi; Watanabe, Kenji; LeRoy, Brian J; et al. (NATURE PUBLISHING GROUP, 2019-07-22)
      A plasmonic modulator is a device that controls the amplitude or phase of propagating plasmons. In a pure plasmonic modulator, the presence or absence of a plasmonic pump wave controls the amplitude of a plasmonic probe wave through a channel. This control has to be mediated by an interaction between disparate plasmonic waves, typically requiring the integration of a nonlinear material. In this work, we demonstrate a 2D semiconductor nonlinear plasmonic modulator based on a WSe2 monolayer integrated on top of a lithographically defined metallic waveguide. We utilize the strong interaction between the surface plasmon polaritons (SPPs) and excitons in the WSe2 to give a 73 % change in transmission through the device. We demonstrate control of the propagating SPPs using both optical and SPP pumps, realizing a 2D semiconductor nonlinear plasmonic modulator, with an ultrafast response time of 290 fs.
    • 2D zonal integration with unordered data

      Smith, Greg A.; University of Arizona, James C. Wyant College of Optical Sciences (The Optical Society, 2021-05-25)
      Numerical integration of two-dimensional gradient data is an important step for many slope-measuring optical instruments. However, existing methods are limited by low accuracy or data location restrictions. The zonal integration algorithm in this paper is a generalized process that works with unordered data viaTaylor series approximations of finite difference calculations. This method does not require iteration, and all significant steps rely on matrix calculations for a least-squares solution. Simultaneous integration and interpolation is achieved with high accuracy and arbitrary data locations. © 2021 Optical Society of America.
    • 2D-FFTLog: efficient computation of real-space covariance matrices for galaxy clustering and weak lensing

      Fang (方啸), Xiao; Eifler, Tim; Krause, Elisabeth; Univ Arizona, Dept Astron; Univ Arizona, Steward Observ; Univ Arizona, Dept Phys (OXFORD UNIV PRESS, 2020-06-17)
      Accurate covariance matrices for two-point functions are critical for inferring cosmological parameters in likelihood analyses of large-scale structure surveys. Among various approaches to obtaining the covariance, analytic computation is much faster and less noisy than estimation from data or simulations. However, the transform of covariances from Fourier space to real space involves integrals with two Bessel integrals, which are numerically slow and easily affected by numerical uncertainties. Inaccurate covariances may lead to significant errors in the inference of the cosmological parameters. In this paper, we introduce a 2D-FFTLog algorithm for efficient, accurate, and numerically stable computation of non-Gaussian real-space covariances for both 3D and projected statistics. The 2D-FFTLog algorithm is easily extended to perform real-space bin-averaging. We apply the algorithm to the covariances for galaxy clustering and weak lensing for a Dark Energy Survey Year 3-like and a Rubin Observatory's Legacy Survey of Space and Time Year 1-like survey, and demonstrate that for both surveys, our algorithm can produce numerically stable angular bin-averaged covariances with the flat sky approximation, which are sufficiently accurate for inferring cosmological parameters. The code COSMOCOV for computing the real-space covariances with or without the flat-sky approximation is released along with this paper.
    • 2HDM neutral scalars under the LHC

      Kling, Felix; Su, Shufang; Su, Wei; Univ Arizona, Dept Phys (SPRINGER, 2020-06-26)
      Two Higgs Doublet Models (2HDM) provide a simple framework for new physics models with an extended Higgs sector. The current LHC results, including both direct searches for additional non-Standard Model (SM) Higgs bosons, as well as precision measurements of the SM-like Higgs couplings, already provide strong constraints on the 2HDM parameter spaces. In this paper, we examine those constraints for the neutral scalars in the Type-I and Type-II 2HDM. In addition to the direct search channels with SM final states: H/A → ff¯¯¯, VV, Vh, hh, we study in particular the exotic decay channels of H/A → AZ/HZ once there is a mass hierarchy between the non-SM Higgses. We found that H/A → AZ/H Z channel has unique sensitivity to the alignment limit region which remains unconstrained by conventional searches and Higgs precision measurements. This mode also extends the reach at intermediate tβ for heavy mA that are not covered by the other direct searches.
    • 3 mJ All-Fiber MOPA With a Short-Length Highly Er3+-Doped Phosphate Fiber

      Olson, Joshua; Zhu, Xiushan; Baker, R. Dawson; Wiersma, Kort; Li, Michael; Zong, Jie; Chavez-Pirson, Arturo; Peyghambarian, N.; The College of Optical Sciences, The University of Arizona (Institute of Electrical and Electronics Engineers (IEEE), 2020-12-01)
      A very large mode-area 2 wt% erbium-doped double-clad phosphate fiber with a core diameter of 60 mu m and core numerical aperture of 0.03 was fabricated and used for the last stage amplifier of an all-fiber pulsed laser master-oscillator power amplifier (MOPA) at 1550 nm. The Er3+ double-clad phosphate fiber has a cladding-core ratio of 2.17 and a V number of 3.6 at 1550 nm. 3 mJ pulses with 21.5 ns duration were obtained with Gaussian-like spatial beam profile with only a 75 cm long phosphate gain fiber.
    • 3-D Printed Parts for a Multilayer Phased Array Antenna System

      Yu, Xiaoju; Liang, Min; Shemelya, Corey; Roberson, David A.; Wicker, Ryan; MacDonald, Eric; Xin, Hao; Univ Arizona; Univ Arizona, Dept Elect & Comp Engn (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018-10-01)
      In this work, a three-dimensional printable multilayer phased array system was designed to demonstrate the applicability of additive manufacturing for radio frequency (RF) systems. A hybrid process incorporating a thermal wire-mesh embedding method for conductors and thermoplastic material extrusion for dielectrics is employed. The designed phased array, operating at 3.5 GHz, consists of three functional layers: a 1-to-4 Wilkinson divider at the bottom, embedded voltage-controlled phase shifters at the center, and patch antennas on the top. Standalone parts of the proposed multilayer phased array were printed to verify the integrated dielectric-conductor printing process as well as the incorporation of active semiconductor devices at room temperature.
    • 3.6 AND 4.5 μm SPITZER PHASE CURVES OF THE HIGHLY IRRADIATED HOT JUPITERS WASP-19b AND HAT-P-7b

      Wong, Ian; Knutson, Heather A.; Kataria, Tiffany; Lewis, Nikole K.; Burrows, Adam; Fortney, Jonathan J.; Schwartz, Joel C.; Shporer, Avi; Agol, Eric; Cowan, Nicolas B.; et al. (IOP PUBLISHING LTD, 2016-05-27)
      We analyze full-orbit phase curve observations of the transiting hot Jupiters WASP-19b and HAT-P-7b at 3.6 and 4.5 mu m, obtained using the Spitzer Space Telescope. For WASP-19b, we measure secondary eclipse depths of 0.485% +/- 0.024% and 0.584% +/- 0.029% at 3.6 and 4.5 mu m, which are consistent with a single blackbody with effective temperature 2372 +/- 60 K. The measured 3.6 and 4.5 mu m secondary eclipse depths for HAT-P-7b are 0.156% +/- 0.009% and 0.190% +/- 0.006%, which are well described by a single blackbody with effective temperature 2667 +/- 57 K. Comparing the phase curves to the predictions of one-dimensional and three-dimensional atmospheric models, we find that WASP-19b's dayside emission is consistent with a model atmosphere with no dayside thermal inversion and moderately efficient day-night circulation. We also detect an eastward-shifted hotspot, which suggests the presence of a superrotating equatorial jet. In contrast, HAT-P-7b's dayside emission suggests a dayside thermal inversion and relatively inefficient day-night circulation; no hotspot shift is detected. For both planets, these same models do not agree with the measured nightside emission. The discrepancies in the model-data comparisons for WASP-19b might be explained by high-altitude silicate clouds on the nightside and/or high atmospheric metallicity, while the very low 3.6 mu m nightside planetary brightness for HAT-P-7b may be indicative of an enhanced global C/O ratio. We compute Bond albedos of 0.38 +/- 0.06 and 0 (<0.08 at 1 sigma) for WASP-19b and HAT-P-7b, respectively. In the context of other planets with thermal phase curve measurements, we show that WASP-19b and HAT-P-7b fit the general trend of decreasing day-night heat recirculation with increasing irradiation.
    • 3.8 μm Imaging of 400–600 K Brown Dwarfs and Orbital Constraints for WISEP J045853.90+643452.6AB

      Leggett, S. K.; Dupuy, Trent J.; Morley, Caroline V.; Marley, Mark S.; Best, William M. J.; Liu, Michael C.; Apai, D.; Casewell, S. L.; Geballe, T. R.; Gizis, John E.; et al. (IOP PUBLISHING LTD, 2019-09-09)
      Half of the energy emitted by late-T- and Y-type brown dwarfs emerges at 3.5 <= lambda mu m <= 5.5. We present new L' (3.43 <= lambda mu m <= 4.11) photometry obtained at the Gemini North telescope for nine late-T and Y dwarfs, and synthesize L' from spectra for an additional two dwarfs. The targets include two binary systems that were imaged at a resolution of 0.'' 25. One of these, WISEP J045853.90+643452.6AB, shows significant motion, and we present an astrometric analysis of the binary using Hubble Space Telescope, Keck Adaptive Optics, and Gemini images. We compare lambda similar to 4 mu m observations to models, and find that the model fluxes are too low for brown dwarfs cooler than similar to 700 K. The discrepancy increases with decreasing temperature, and is a factor of similar to 2 at T-eff = 500 K and similar to 4 at T-eff = 400 K. Warming the upper layers of a model atmosphere generates a spectrum closer to what is observed. The thermal structure of cool brown dwarf atmospheres above the radiative-convective boundary may not be adequately modeled using pure radiative equilibrium; instead heat may be introduced by thermochemical instabilities (previously suggested for the L- to T-type transition) or by breaking gravity waves (previously suggested for the solar system giant planets). One-dimensional models may not capture these atmospheres, which likely have both horizontal and vertical pressure/temperature variations.
    • 360° Switched Beam SIW Horn Arrays at 60 GHz, Phase Centers, and Friis Equation

      Baniya, Prabhat; Melde, Kathleen L.; Department of Electrical and Computer Engineering, University of Arizona (Institute of Electrical and Electronics Engineers Inc., 2021-02-03)
      The link model of switched beam horn arrays at 60 GHz based on the substrate integrated waveguide (SIW) technology with 360° angular coverage is presented. Each array has eight identical printed horn elements. The elements are oriented 45° relative to one another and can be individually excited to produce eight endfire beams in the horizontal plane. The over-the-air (OTA) transmission coefficients are measured and simulated between two arrays, in the line-of-sight (LoS) and non-LoS (NLoS) directions. The phase centers (PCs) of the excited elements are determined from post-processing optimization of simulated far-fields and incorporated in the Friis equation to accurately model the transmission. © 2021 The authors; USNC-URSI and IEEE will have full rights to publish, market, put on Xplore, etc.
    • 3C 294 revisited: Deep Large Binocular Telescope AO NIR images and optical spectroscopy

      Heidt, J.; Quirrenbach, A.; Hoyer, N.; Thompson, D.; Pramskiy, A.; Agapito, G.; Esposito, S.; Gredel, R.; Miller, D.; Pinna, E.; et al. (EDP SCIENCES S A, 2019-07-31)
      Context. High redshift radio galaxies are among the most massive galaxies at their redshift, are often found at the center of protoclusters of galaxies, and are expected to evolve into the present day massive central cluster galaxies. Thus they are a useful tool to explore structure formation in the young Universe. Aims. 3C 294 is a powerful FR II type radio galaxy at z = 1.786. Past studies have identified a clumpy structure, possibly indicative of a merging system, as well as tentative evidence that 3C 294 hosts a dual active galactic nucleus (AGN). Due to its proximity to a bright star, it has been subject to various adaptive optics imaging studies. Methods. In order to distinguish between the various scenarios for 3C 294, we performed deep, high-resolution adaptive optics near-infrared imaging and optical spectroscopy of 3C 294 with the Large Binocular Telescope. Results. We resolve the 3C 294 system into three distinct components separated by a few tenths of an arcsecond on our images. One is compact, the other two are extended, and all appear to be non-stellar. The nature of each component is unclear. The two extended components could be a galaxy with an internal absorption feature, a galaxy merger, or two galaxies at different redshifts. We can now uniquely associate the radio source of 3C 294 with one of the extended components. Based on our spectroscopy, we determined a redshift of z = 1.784 +/- 0.001, which is similar to the one previously cited. In addition we found a previously unreported emission line at lambda 6749.4 angstrom in our spectra. It is not clear that it originates from 3C 294. It could be the Ne [IV] doublet lambda 2424/2426 angstrom at z = 1.783, or belong to the compact component at a redshift of z similar to 4.56. We thus cannot unambiguously determine whether 3C 294 hosts a dual AGN or a projected pair of AGNs.