• Objective assessment of the effects of tumor motion in radiation therapy

      Ding, Yijun; Barrett, Harrison H; Kupinski, Matthew A; Vinogradskiy, Yevgeniy; Miften, Moyed; Jones, Bernard L; Univ Arizona, Coll Opt Sci; Univ Arizona, Dept Med Imaging (WILEY, 2019-07-01)
      Purpose Internal organ motion reduces the accuracy and efficacy of radiation therapy. However, there is a lack of tools to objectively (based on a medical or scientific task) assess the dosimetric consequences of motion, especially on an individual basis. We propose to use therapy operating characteristic (TOC) analysis to quantify the effects of motion on treatment efficacy for individual patients. We demonstrate the application of this tool with pancreatic stereotactic body radiation therapy (SBRT) clinical data and explore the origin of motion sensitivity. Methods The technique is described as follows. (a) Use tumor-motion data measured from patients to calculate the motion-convolved dose of the gross tumor volume (GTV) and the organs at risk (OARs). (b) Calculate tumor control probability (TCP) and normal tissue complication probability (NTCP) from the motion-convolved dose-volume histograms. (c) Construct TOC curves from TCP and NTCP models. (d) Calculate the area under the TOC curve (AUTOC) and use it as a figure of merit for treatment efficacy. We used tumor motion data measured from patients to calculate the relation between AUTOC and motion magnitude for 25 pancreatic SBRT treatment plans. Furthermore, to explore the driving factor of motion sensitivity of a given plan, we compared the dose distribution of motion-sensitive plans and motion-robust plans and studied the dependence of motion sensitivity to motion directions. Results Our technique is able to recognize treatment plans that are sensitive to motion. Under the presence of motion, the treatment efficacy of some plans changes from providing high tumor control and low risks of complications to providing no tumor control and high risks of side effects. Several treatment plans experience falloffs in AUTOC at a smaller magnitude of motion than other plans. In our dataset, a potential indicator of a motion-sensitive treatment plan is that the duodenum is in proximity to the tumor in the SI direction. Conclusions The TOC framework can serve as a tool to quantify the effects of internal organ motion in radiation therapy. With pancreatic SBRT clinical data, we applied this tool to study the change in treatment efficacy induced by motion for individual treatment plans. This framework could potentially be used clinically to understand the effects of motion in an individual patient and to design a patient-specific motion management plan. This framework could also be used in research to evaluate different components of the treatment process, such as motion-management techniques, treatment-planning algorithms, and treatment margins.
    • Objective Climatological Analysis of Extreme Weather Events in Arizona during the North American Monsoon

      Mazon, Jeremy J.; Castro, Christopher L.; Adams, David K.; Chang, Hsin-I; Carrillo, Carlos M.; Brost, John J.; Univ Arizona, Dept Hydrol & Atmospher Sci (AMER METEOROLOGICAL SOC, 2016-11)
      Almost one-half of the annual precipitation in the southwestern United States occurs during the North American monsoon (NAM). Given favorable synoptic-scale conditions, organized monsoon thunderstorms may affect relatively large geographic areas. Through an objective analysis of atmospheric reanalysis and observational data, the dominant synoptic patterns associated with NAM extreme events are determined for the period from 1993 to 2010. Thermodynamically favorable extreme-weather-event days are selected on the basis of atmospheric instability and precipitable water vapor from Tucson, Arizona, rawinsonde data. The atmospheric circulation patterns at 500 hPa associated with the extreme events are objectively characterized using principal component analysis. The first two dominant modes of 500-hPa geopotential-height anomalies of the severe-weather-event days correspond to type-I and type-II severe-weather-event patterns previously subjectively identified by Maddox et al. These patterns reflect a positioning of the monsoon ridge to the north and east or north and west, respectively, from its position in the "Four Corners" region during the period of the climatological maximum of monsoon precipitation from mid-July to mid-August. An hourly radar gauge precipitation product shows evidence of organized, westward-propagating convection in Arizona during the type-I and type-II severe weather events. This new methodological approach for objectively identifying severe weather events may be easily adapted to inform operational forecasting or analysis of gridded climate data.
    • Objective fall risk detection in stroke survivors using wearable sensor technology: a feasibility study

      Taylor-Piliae, Ruth E.; Mohler, M. Jane; Najafi, Bijan; Coull, Bruce M.; University of Arizona (TAYLOR & FRANCIS LTD, 2016-03-15)
      Background: Stroke survivors often have persistent neural deficits related to motor function and sensation, which increase their risk of falling, most of which occurs at home or in community settings. The use of wearable technology to monitor fall risk and gait in stroke survivors may prove useful in enhancing recovery and/or preventing injuries. Objective: Determine the feasibility of using wearable technology (PAMSys (TM)) to objectively monitor fall risk and gait in home and community settings in stroke survivors. Methods: In this feasibility study, we used the PAMSys to identify fall risk indicators (postural transitions: duration in seconds, and number of unsuccessful attempts), and gait (steps, speed, duration) for 48 hours during usual daily activities in stroke survivors (n=10) compared to age-matched controls (n=10). A questionnaire assessed device acceptability. Results: Stroke survivors mean age was 70 +/- 8 years old, were mainly Caucasian (60%) women (70%), and not significantly different than the age-matched controls (all P-values >0.20). Stroke survivors (100%) reported that the device was comfortable to wear, didn't interfere with everyday activities, and were willing to wear it for another 48 hours. None reported any difficulty with the device while sleeping, removing/putting back on for showering or changing clothes. When compared to controls, stroke survivors had significantly worse fall risk indicators and walked less (P<0.05). Conclusion: Stroke survivors reported high acceptability of 48 hours of continuous PAMSys monitoring. The use of in-home wearable technology may prove useful in monitoring fall risk and gait in stroke survivors, potentially enhancing recovery.
    • Objectively Measured Social Integration Is Associated With an Immune Risk Phenotype Following Marital Separation

      Hasselmo, Karen; Mehl, Matthias R; Tackman, Allison M; Carey, Angela L; Wertheimer, Anne M; Stowe, Raymond P; Sbarra, David A; Univ Arizona, Dept Psychol; Univ Arizona, Dept Med, Div Geriatr Gen Internal Med & Palliat Med (OXFORD UNIV PRESS INC, 2018-02)
      Background Close relationships play an integral role in human development, and robust evidence links marital separation and divorce to poor health outcomes. Social integration may play a key role in this association. In many ways, the study of marital separation and divorce provides an ideal model system for a more complete understanding of the association between life stress and physical health. Purpose The current study investigated associations among objectively measured social integration, psychological distress, and biomarkers of immune health in recently separated adults (N = 49). Methods We collected four measures of immune functioning-interleukin-6, C-reactive protein, and antibody titers to latent cytomegalovirus and Epstein-Barr virus-that were combined to yield a viral-Immune Risk Profile. To assess how variability in social integration is associated with immunological correlates following the end of a marriage, we incorporated observational ecological momentary assessment data using a novel methodology (the Electronically Activated Recorder). Results We found that objectively measured social behaviors are associated with concurrent viral-Immune Risk Profile scores over and above the effects of psychological distress and that psychological distress may be linked to biomarkers of immune health through social integration. Conclusions This research expands current knowledge of biomarkers of immune health after divorce and separation and includes a new methodology for objective measures of social engagement.
    • Les objets techniques au prisme du cycle hydrosocial : renouveaux théoriques et empiriques

      Germaine, Marie-Anne; Blanchon, David; Temple-Boyer, Élise; Fofack-Garcia, Rhoda; Univ Arizona (RESEAU DEVELOPPEMENT DURABLE & TERRITOIRES FRAGILES, 2019-12-20)
      This special issue entitled "Technical objects at the prism of hydrosocial cycle : new theoretical and empirical approaches" presents new insights concerning water-society relations in social sciences. It is characterized by interdisciplinary approaches and engages with two main theoretical frameworks : science and technology studies and political ecology. Both are indeed mobilized in order to deepen the analysis of the dialectical relation between technical objects and hydrosocial systems, by using the concept of hydrosocial cycle. Our aim is to explain how "infrastructure" and "apparatus" forge and transform water-society interrelations, reshape them and modify their functioning. But also how the hydrosocial cycle, in return, sets out particular forms of infrastructure and apparatus. This paper firstly introduces the theoretical and epistemological debates linked to this special issue. And then it presents the thirteen papers gathered in this special issue, which, based on empirical studies, offer different uses of hydrosocial cycle approach to investigate water/society dialectical relations.

      Satyapal, S.; Secrest, Nathan J.; Rothberg, B.; O’Connor, J. A.; Ellison, Sara L.; Hickox, Ryan C.; Constantin, A.; Gliozzi, M.; Rosenberg, and J. L.; Univ Arizona, LBT Observ (IOP PUBLISHING LTD, 2016-08-08)
      There is mounting evidence that supermassive black holes (SMBHs) form and grow in bulgeless galaxies. However, a robust determination of the fraction of active galactic nuclei (AGNs) in bulgeless galaxies, an important constraint to models of SMBH seed formation and merger-free models of AGN fueling, is unknown, since optical studies have been shown to be incomplete for AGNs in low-mass galaxies. In a recent study using the Wide-field Infrared Survey Explorer, we discovered hundreds of bulgeless galaxies that display mid-infrared signatures of extremely hot dust suggestive of powerful accreting massive black holes, despite having no signatures of black hole activity at optical wavelengths. Here we report X-ray follow-up observations of J122434.66+555522.3, a nearby (z = 0.052) isolated bulgeless galaxy that contains an unresolved X-ray source detected at the 3 sigma level by XMM-Newton with an observed luminosity uncorrected for intrinsic absorption of L2-10 (keV) = (1.1 +/- 0.4) x 10(40) erg s(-1). Ground-based near-infrared spectroscopy with the Large Binocular Telescope and multiwavelength observations from ultraviolet to millimeter wavelengths together suggest that J1224+5555 harbors a highly absorbed AGN with an intrinsic absorption of N-H > 10(24) cm(-2). The hard X-ray luminosity of the putative AGN corrected for absorption is L2-10 keV similar to 3 x 10(42) erg s(-1), which, depending on the bolometric correction factor, corresponds to a bolometric luminosity of the AGN of L-bol 6 x 10(43)-3 x 10(44) erg s(-1). and a lower mass limit for the black hole of M-BH similar or equal to 2 x 10(6) M-circle dot, based on the Eddington limit. While enhanced X-ray emission and hot dust can be produced by star formation in extremely low metallicity environments typical in dwarf galaxies, J1224+5555 has a stellar mass of similar to 2.0 x 10(10) M-circle dot and an above solar metallicity (12 + logO/H = 9.11), typical of our WISE-selected bulgeless galaxy. sample. While collectively. these observations suggest the presence of an AGN, we caution that identifying obscured AGNs in the low-luminosity regime is challenging. and often requires multiwavelength observations. These observations suggest that low-luminosity AGNs can be heavily obscured and reside in optically quiescent galaxies, adding to the growing body of evidence that the fraction of bulgeless galaxies with accreting black holes may be significantly underestimated based on optical studies.
    • Observable predictions for massive-neutrino cosmologies with model-independent dark energy

      Diaz Rivero, Ana; Miranda, V.; Dvorkin, Cora; Univ Arizona, Steward Observ, Dept Astron (AMER PHYSICAL SOC, 2019-09-04)
      We investigate the bounds on the sum of neutrino masses in a cosmic-acceleration scenario where the equation of state w(z) of dark energy (DE) is constructed in a model-independent way, using a basis of principal components (PCs) that are allowed to cross the phantom barrier w(z)=−1. We find that the additional freedom provided to w(z) means the DE can undo changes in the background expansion induced by massive neutrinos at low redshifts. This has two significant consequences: (1) it leads to a substantial increase in the upper bound for the sum of the neutrino masses (Mν<0.33–0.55 eV at the 95% C.L. depending on the data sets and number of PCs included) compared to studies that choose a specific parametrization for w(z); and (2) it causes ∼1σ deviations from ΛCDM in the luminosity distance and the Hubble expansion rate at higher redshifts (z≳2), where the contribution of DE is subdominant and there is little constraining data. The second point consequently means that there are also observable deviations in the shear power spectrum and in the matter power spectrum at low redshift, since the clustering of matter throughout cosmic time depends on the expansion rate. This provides a compelling case to pursue high-z BAO and SN measurements as a way of disentangling the effects of neutrinos and dark energy. Finally, we find that the additional freedom given to the dark energy component has the effect of lowering S8 with respect to ΛCDM.
    • Observable shape of black hole photon rings

      Gralla, Samuel E.; Lupsasca, Alexandru; Univ Arizona, Dept Phys (AMER PHYSICAL SOC, 2020-12-01)
      Motivated by the prospect of measuring a black hole photon ring, in previous work we explored the interferometric signature produced by a bright, narrow curve in the sky. interferometric observations of such a curve measure its "projected position function" r . (n) over cap, where r parametrizes the curve and (n) over cap denotes its unit normal vector. In this paper, we show by explicit construction that a curve can be fully reconstructed from its projected position, completing the argument that space interferometry can in principle determine the detailed photon ring shape. In practice, near-term observations may be limited to the visibility amplitude alone, which contains incomplete shape information: for convex curves, the amplitude only encodes the set of projected diameters (or "widths") of the shape. We explore the freedom in reconstructing a convex curve from its widths, giving insight into the shape information probed by technically plausible future astronomical measurements. Finally, we consider the Kerr "critical curve" in this framework and present some new results on its shape. We analytically show that the critical curve is an ellipse at small spin or inclination, while at extremal spin it becomes the convex hull of a Cartesian oval. We find a simple oval shape, the "phoval," which reproduces the critical curve with high fidelity over the whole parameter range.
    • Observation and confirmation of nine strong-lensing systems in Dark Energy Survey Year 1 data

      Nord, B; Buckley-Geer, E; Lin, H; Kuropatkin, N; Collett, T; Tucker, D L; Diehl, H T; Agnello, A; Amara, A; Abbott, T M C; et al. (OXFORD UNIV PRESS, 2020-01-28)
      We describe the observation and confirmation of nine new strong gravitational lenses discovered in Year 1 data from the Dark Energy Survey (DES). We created candidate lists based on (i) galaxy group and cluster samples, and (ii) photometrically selected galaxy samples. We selected 46 candidates through visual inspection and then used the Gemini Multi-Object Spectrograph (GMOS) at the Gemini South telescope to acquire a spectroscopic follow-up of 21 of these candidates. Through an analysis of these spectroscopic follow-up data, we confirmed nine new lensing systems and rejected two candidates, and the analysis was inconclusive on 10 candidates. For each of the confirmed systems, our report measured spectroscopic properties, estimated source image-lens separations, and estimated enclosed masses as well. The sources that we targeted have an i-band surface brightness range of i(SB) similar to 22-24 mag arcsec(-2) and a spectroscopic redshift range of z(spec) similar to 0.8-2.6. The lens galaxies have a photometric redshift range of z(lens) similar to 0.3-0.7. The lensing systems range in source image-lens separation from 2 to 9 arcsec and in enclosed mass from 10(12) to 10(13) M-circle dot.

      Nord, B.; Buckley-Geer, E.; Lin, H.; Diehl, H. T.; Helsby, J.; Kuropatkin, N.; Amara, A.; Collett, T.; Allam, S.; Caminha, G. B.; et al. (IOP PUBLISHING LTD, 2016-08-05)
      We report the observation and confirmation of the first group-and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either were not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z similar to 0.80-3.2 and in i-band surface brightness i(SB) similar to 23-25 mag arcsec(-2) (2 '' aperture). For each of the six systems, we estimate the Einstein radius theta(E) and the enclosed mass M-enc, which have ranges theta(E) similar to 5 ''-9 '' and M-enc similar to 8 x 10(12) to 6 x 10(13)M(circle dot), respectively.
    • Observation of Electroweak Production of a Same-Sign W Boson Pair in Association with Two Jets in pp Collisions root s=13 TeV with the ATLAS Detector

      Berlendis, S; Cheu, E; Delitzsch, C M; Johns, K A; Jones, S; Lampl, W; LeBlanc, M; Leone, R; Loch, P; Nayyar, R; et al. (AMER PHYSICAL SOC, 2019-10-15)
      This Letter presents the observation and measurement of electroweak production of a same-sign W boson pair in association with two jets using 36.1 fb(-1) of proton-proton collision data recorded at a center-of-mass energy root s = 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed in the detector fiducial phase-space region, defined by the presence of two same-sign leptons, electron or muon, and at least two jets with a large invariant mass and rapidity difference. A total of 122 candidate events are observed for a background expectation of 69 +/- 7 events, corresponding to an observed signal significance of 6.5 standard deviations. The measured fiducial signal cross section is sigma(f)(id) = 2.89(-0.48)(+0.51)(stat)(-0.28)(+0.29)(syst) fb.
    • Observation of electroweak W(+/-)Z boson pair production in association with two jets in pp collisions at root s=13 TeV with the ATLAS detector

      Berlendis, S.; Cheu, E.; Delitzsch, C.M.; Johns, K.A.; Jones, S.; Lampl, W.; LeBlanc, M.; Leone, R.; Loch, P.; Nayyar, R.; et al. (ELSEVIER SCIENCE BV, 2019-06-10)
      An observation of electroweak W(+/-)Z production in association with two jets in proton-proton collisions is presented. The data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016 at a centre-of-mass energy of root s = 13 TeV are used, corresponding to an integrated luminosity of 36.1 fb(-1). Events containing three identified leptons, either electrons or muons, and two jets are selected. The electroweak production of W(+/-)Z bosons in association with two jets is measured with an observed significance of 5.3 standard deviations. A fiducial cross-section for electroweak production including interference effects and for a single leptonic decay mode is measured to be sigma(WZjj-EW) = 0.57(-0.13)(+0.14) (stat.) (+0.07)(-0.06) (syst.) fb. Total and differential fiducial cross-sections of the sum of W(+/-)Zjj electroweak and strong productions for several kinematic observables are also measured. (C) 2019 The Author(s). Published by Elsevier B.V.
    • Observation of elliptically polarized light from total internal reflection in bubbles

      Miller, Sawyer; Ding, Yitian; Jiang, Linan; Tu, Xingzhou; Pau, Stanley; Univ Arizona, James C Wyant Coll Opt Sci (NATURE PUBLISHING GROUP, 2020-05-26)
      Bubbles are ubiquitous in the natural environment, where different substances and phases of the same substance forms globules due to differences in pressure and surface tension. Total internal reflection occurs at the interface of a bubble, where light travels from the higher refractive index material outside a bubble to the lower index material inside a bubble at appropriate angles of incidence, which can lead to a phase shift in the reflected light. Linearly polarized skylight can be converted to elliptically polarized light with efficiency up to 53% by single scattering from the water-air interface. Total internal reflection from air bubble in water is one of the few sources of elliptical polarization in the natural world. Stationary and dynamic scenes of air bubbles in water in both indoor and outdoor settings are studied using an imaging polarimeter. Our results are important for studies in fluid dynamics, remote sensing, and polarimetry.
    • Observation of Light-by-Light Scattering in Ultraperipheral Pb plus Pb Collisions with the ATLAS Detector

      Berlendis, S.; Cheu, E.; Delitzsch, C. M.; Johns, K. A.; Jones, S.; Lampl, W.; LeBlanc, M.; Leone, R.; Loch, P.; Rutherfoord, J. P.; et al. (AMER PHYSICAL SOC, 2019-07-31)
      This Letter describes the observation of the light-by-light scattering process, gamma gamma -> gamma gamma, in Pb + Pb collisions at root S-NN = 5.02 TeV. The analysis is conducted using a data sample corresponding to an integrated luminosity of 1.73 nb(-1), collected in November 2018 by the ATLAS experiment at the LHC. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy E-T(gamma) > 3 GeV and pseudorapidity vertical bar eta(gamma)vertical bar < 2.4, diphoton invariant mass above 6 GeV, and small diphoton transverse momentum and acoplanarity. After applying all selection criteria, 59 candidate events are observed for a background expectation of 12 +/- 3 events. The observed excess of events over the expected background has a significance of 8.2 standard deviations. The measured fiducial cross section is 78 +/- 13(stat) +/- 7(syst) +/- 3(lumi) nb.
    • An Observation of Racial and Gender Disparities in Congestive Heart Failure Admissions Using the National Inpatient Sample

      Tandon, Varun; Stringer, Bryan; Conner, Chad; Gabriel, Andre; Tripathi, Byomesh; Balakumaran, Kathir; Chen, Kai; Univ Arizona, Cardiol, Coll Med (CUREUS INC, 2020-10-12)
      Background Congestive heart failure (CHF) is a frequent cause of inpatient admissions in the United States. The purpose of this study was to analyze the racial and gender disparities that occur in CHF admissions and determine the impact of these disparities on medical expenditure. Methods We analyzed the National Inpatient Sample (NIS) database from 2009 to 2014 for patients with a primary discharge diagnosis of CHF, and further stratified the cohort on the basis of race and sex. Multivariate analysis was performed to identify the association between CHF and total charges along with other variables such as mortality, length of stay (LOS), and number of procedures. Results There were a total of 5,491,050 admissions with a primary diagnosis of CHF from 977,850 in 2009 to 901,425 in 2014. Females accounted for 49.7%. Total charges for CHF admission were highest in Asians at an average cost of $59,668. African Americans had the lowest mortality rate at 1.75%, however, they also had an average age of admission of 63.47 years, compared to Caucasian at 76.76 (p<0.05). Total charges for males were $42,920 and $36,744 for females (p<0.05). Males also had more procedures at 1.16 vs 0.98 for females (p<0.05). Elixhauser mortality score was higher in males than females at 5.95 vs 5.42 (p<0.05). Conclusion Healthcare disparities exist in CHF admissions in both contexts of race and gender. Further studies are required to pinpoint the source of these differences not only to address mortality but also expenditure costs.
    • Observation of the associated production of a top quark and a Z boson in pp collisions at root s=13 TeV with the ATLAS detector

      Aad, G.; Abbott, B.; Abbott, D. C.; Abud, A. Abed; Abeling, K.; Abhayasinghe, D. K.; Abidi, S. H.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; et al. (SPRINGER, 2020-07)
      Single top-quark production in association with a Z boson, where the Z boson decays to a pair of charged leptons, is measured in the trilepton channel. The proton-proton collision data collected by the ATLAS experiment from 2015 to 2018 at a centre-of-mass energy of 13 TeV are used, corresponding to an integrated luminosity of 139 fb(-1). Events containing three isolated charged leptons (electrons or muons) and two or three jets, one of which is identified as containing a b-hadron, are selected. The main backgrounds are from t (t) over barZ and diboson production. Neural networks are used to improve the background rejection and extract the signal. The measured cross-section for tl(+)l(-) q production, including non-resonant dilepton pairs with m(l+l-) > 30 GeV, is 97 +/- 13 (stat.) +/- 7 (syst.) fb, consistent with the Standard Model prediction.
    • An Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres

      Kempton, Eliza M.-R.; Bean, Jacob L.; Parmentier, Vivien; Univ Arizona, Dept Planetary Sci; Univ Arizona, Lunar & Planetary Lab (IOP PUBLISHING LTD, 2017-08-18)
      The nature of aerosols in hot exoplanet atmospheres is one of the primary vexing questions facing the exoplanet field. The complex chemistry, multiple formation pathways, and lack of easily identifiable spectral features associated with aerosols make it especially challenging to constrain their key properties. We propose a transmission spectroscopy technique to identify the primary aerosol formation mechanism for the most highly irradiated hot Jupiters (HIHJs). The technique is based on the expectation that the two key types of aerosols-photochemically generated hazes and equilibrium condensate clouds-are expected to form and persist in different regions of a highly irradiated planet's atmosphere. Haze can only be produced on the permanent daysides of tidally locked hot Jupiters, and will be carried downwind by atmospheric dynamics to the evening terminator (seen as the trailing limb during transit). Clouds can only form in cooler regions on the nightside and morning terminator of HIHJs (seen as the leading limb during transit). Because opposite limbs are expected to be impacted by different types of aerosols, ingress and egress spectra, which primarily probe opposing sides of the planet, will reveal the dominant aerosol formation mechanism. We show that the benchmark HIHJ, WASP-121b, has a transmission spectrum consistent with partial aerosol coverage and that ingress-egress spectroscopy would constrain the location and formation mechanism of those aerosols. In general, using this diagnostic we find that observations with the James Webb Space Telescope and potentially with the Hubble Space Telescope should be able to distinguish between clouds and haze for currently known HIHJs.
    • Observational diagnostics of elongated planet-induced vortices with realistic planet formation time-scales

      Hammer, Michael; Pinilla, Paola; Kratter, Kaitlin M; Lin, Min-Kai; Univ Arizona, Steward Observ (OXFORD UNIV PRESS, 2019-01)
      Gap-opening planets can generate dust-trapping vortices that may explain some of the latest discoveries of high-contrast crescent-shaped dust asymmetries in transition discs. While planet-induced vortices were previously thought to have concentrated shapes, recent computational work has shown that these features naturally become much more elongated in the gas when simulations account for the relatively long time-scale over which planets accrete their mass. In this work, we conduct two-fluid hydrodynamical simulations of vortices induced by slowly growing Jupiter-mass planets in discs with very low viscosity (alpha = 3 x 10(-5)). We simulate the dust dynamics for four particle sizes spanning 0.3 mm to 1 cm in order to produce synthetic ALMA images. In our simulations, we find that an elongated vortex still traps dust, but not directly at its centre. With a flatter pressure bump and disruptions from the planet's overlapping spiral density waves, the dust instead circulates around the vortex. This motion (1) typically carries the peak off-centre, (2) spreads the dust out over a wider azimuthal extent >= 180 degrees, (3) skews the azimuthal profile towards the front of the vortex, and (4) can also create double peaks in newly formed vortices. In particular, we expect that the most defining observational signature, a peak offset of more than 30 degrees, should be detectable > 30 per cent of the time in observations with a beam diameter of at most the planet's separation from its star.
    • Observational Evidence for Summer Rainfall at Titan's North Pole

      Dhingra, Rajani D.; Barnes, Jason W.; Brown, Robert H.; Burrati, Bonnie J.; Sotin, Christophe; Nicholson, Phillip D.; Baines, Kevin H.; Clark, Roger N.; Soderblom, Jason M.; Jauman, Ralf; et al. (AMER GEOPHYSICAL UNION, 2019-02-07)
      Methane rain on Saturn's moon Titan makes it the only place, other than Earth, where rain interacts with the surface. When and where that rain wets the surface changes seasonally in ways that remain poorly understood. Here we report the discovery of a bright ephemeral feature covering an area of 120,000 km(2) near Titan's north pole in observations from Cassini's near-infrared instrument, Visual and Infrared Mapping Spectrometer on 7 June 2016. Based on the overall brightness, spectral characteristics, and geologic context, we attribute this new feature to specular reflections from a rain-wetted solid surface like those off of a sunlit wet sidewalk. The reported observation is the first documented rainfall event at Titan's north pole and heralds the arrival of the northern summer (through climatic evidence), which has been delayed relative to model predictions. This detection helps constrain Titan's seasonal change and shows that the "wet-sidewalk effect can be used to identify other rain events."
    • Observational Signature of Circumstellar Interaction and 56Ni-mixing in the Type II Supernova 2016gfy

      Singh, Avinash; Kumar, Brajesh; Moriya, Takashi J.; Anupama, G. C.; Sahu, D. K.; Brown, Peter J.; Andrews, Jennifer E.; SMITH, NATHAN; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2019-09-04)
      The optical and ultraviolet broadband photometric and spectroscopic observations of the Type II supernova (SN) 2016gfy are presented. The V-band light curve (LC) shows a distinct plateau phase with a slope of s(2) similar to 0.12 mag (100 day)(-1) and a duration of 90 +/- 5 days. Detailed analysis of SN 2016gfy provided a mean Ni-56 mass of 0.033 +/- 0.003 M-circle dot, a progenitor radius of similar to 350-700 R-circle dot, a progenitor mass of similar to 12-15 M-circle dot, and an explosion energy of (0.9-1.4) x 10(51) erg s(-1). The P-Cygni profile of H alpha in the early-phase spectra (similar to 11-21 days) shows a boxy emission. Assuming that this profile arises from the interaction of the SN ejecta with the pre-existing circumstellar material (CSM), it is inferred that the progenitor underwent a recent episode (30-80 yr prior to the explosion) of enhanced mass loss. Numerical modeling suggests that the early LC peak is reproduced better with an existing CSM of 0.15 M-circle dot spread out to similar to 70 au. A late-plateau bump is seen in the VRI LCs during similar to 50-95 days. This bump is explained as a result of the CSM interaction and/or partial mixing of radioactive Ni-56 in the SN ejecta. Using strong-line diagnostics, a subsolar oxygen abundance is estimated for the supernova H II region (12 + log(O/H) = 8.50 +/- 0.11), indicating an average metallicity for the host of an SN II. A star formation rate of similar to 8.5 M-circle dot yr(-1) is estimated for NGC 2276 using the archival GALEX FUV data.