Now showing items 5601-5620 of 13755

    • Intestinal Microbiota Analyses of Litopenaeus vannamei During a Case of Atypical Massive Mortality in Northwestern Mexico

      López-Cortés, Alejandro; Latisnere-Barragán, Hever; García-Maldonado, José Q; Martínez, Miguel A; Munguía-Vega, Adrián; Univ Arizona, Conservat Genet Lab; Univ Arizona, Desert Lab Tumamoc Hill (SPRINGER, 2020-06-10)
      This study investigated the intestinal microbial community structure ofLitopenaeus vannameiat six different stages during shrimp farming. Our goal was to elucidate the bacterial profile and the changes in the relative abundance of taxa during an atypical massive mortality event in Sonora, Mexico. High-throughput sequencing of the 16S rRNA gene and denaturing gradient gel electrophoresis showed that Vibrionaceae was persistent with high relative abundances in the intestine from cultivated shrimp during all the studied stages. The massive mortality observed at day 63 could be related to an overabundance of different Operational Taxonomic Units (OTUs) ofVibrio,ShewanellaandClostridium. Principal coordinate analysis (PCoA) showed variations in microbial structure at different culture times. These findings suggest that OTUs of different taxa contributed to the community switch from healthy to diseased individuals, questioning the hypothesis that single bacterial species is the cause of disease outbreaks. This study provided data to improve the understanding of disease outbreaks during shrimp farming.
    • Intimate stimuli result in fronto-parietal activation changes in anorexia nervosa

      van Zutphen, L; Maier, S; Siep, N; Jacob, G A; Tüscher, O; van Elst, L Tebartz; Zeeck, A; Arntz, A; O'Connor, M-F; Stamm, H; et al. (SPRINGER, 2019-12-01)
      Background Intimacy is a key psychological problem in anorexia nervosa (AN). Empirical evidence, including neurobiological underpinnings, is however, scarce. Objective In this study, we evaluated various emotional stimuli including intimate stimuli experienced in patients with AN and non-patients, as well as their cerebral response. Methods Functional magnetic resonance imaging was conducted using stimuli with positive, neutral, negative and intimate content. Participants (14 AN patients and 14 non-patients) alternated between passive viewing and explicit emotion regulation. Results Intimate stimuli were experienced less positively in AN patients compared to non-patients. AN patients showed decreased cerebral responses in superior parietal cortices in response to positive and intimate stimuli. Intimate stimuli led to stronger activation of the orbitofrontal cortex, and lower activation of the bilateral precuneus in AN patients. Orbitofrontal responses decreased in AN patients during explicit emotion regulation. Conclusions These results show that intimate stimuli are of particular importance in AN patients, who show experiential differences compared to non-patients and altered activation of orbitofrontal and parietal brain structures. This supports that AN patients have difficulties with intimacy, attachment, self-referential processing and body perception.
    • Intra-assemblage variation in the macro-blade assemblage from the 1963 excavation at Shuidonggou locality 1, northern China, in the context of regional variation

      Li, Feng; Kuhn, Steven L; Chen, Fu-You; Gao, Xing; Univ Arizona, Sch Anthropol (PUBLIC LIBRARY SCIENCE, 2020-06-15)
      The emergence of the Upper Paleolithic and regional variability in early Upper Paleolithic industries are prominent topics in Paleolithic archaeology, with special relevance to the dispersal and differentiation of early modern human cultures across Eurasia. The so-called Initial Upper Paleolithic (IUP) has been considered a key element in the emergence of the Upper Paleolithic in northern Asia. Here, we examine the intra-assemblage variation in the collection from the 1963 excavation at Shuidonggou locality 1, a major IUP site in northern China. We combine technological and quantitative attribute analyses to investigate the variety of core reduction sequences and tool manufacture behaviors at the site. A range of core reduction sequences have been documented at Shuidonggou locality 1, including both simple core reduction and prepared core reduction yielding laminar (blade-like) products. The simple core reduction component may due to mixed non-IUP assemblages from different archaeological layers. Among the laminar core reduction sequences, the main strategy involves asymmetrical exploitation of the broad face of core blank, producing blades and elongate flakes, and resembling a recurrent Levallois blade methodsensu lato. We compare Shuidonggou laminar blank production with that of IUP assemblages in the Siberian Altai, northern Mongolia, and the Transbaikal region. The comparison demonstrates a general consistency to the basic blank production in IUP assemblages across northern Asia, with some regional variation. The results suggest a multi-directional model of diffusion of the IUP in northeast Asia.
    • Intracellular Iron Chelation Modulates the Macrophage Iron Phenotype with Consequences on Tumor Progression

      Mertens, Christina; Akam, Eman Abureida; Rehwald, Claudia; Brüne, Bernhard; Tomat, Elisa; Jung, Michaela; Univ Arizona, Dept Chem & Biochem (PUBLIC LIBRARY SCIENCE, 2016-11-02)
      A growing body of evidence suggests that macrophage polarization dictates the expression of iron-regulated genes. Polarization towards iron sequestration depletes the microenvironment, whereby extracellular pathogen growth is limited and inflammation is fostered. In contrast, iron release contributes to cell proliferation, which is important for tissue regeneration. Moreover, macrophages constitute a major component of the infiltrates in most solid tumors. Considering the pivotal role of macrophages for iron homeostasis and their presence in association with poor clinical prognosis in tumors, we approached the possibility to target macrophages with intracellular iron chelators. Analyzing the expression of iron-regulated genes at mRNA and protein level in primary human macrophages, we found that the iron-release phenotype is a characteristic of polarized macrophages that, in turn, stimulate tumor cell growth and progression. The application of the intracellular iron chelator (TC3-S)(2) shifted the macrophage phenotype from iron release towards sequestration, as determined by the iron-gene profile and atomic absorption spectroscopy (AAS). Moreover, whereas the addition of macrophage supernatants to tumor cells induced tumor growth and metastatic behavior, the supernatant of chelator-treated macrophages reversed this effect. Iron chelators demonstrated potent anti-neoplastic properties in a number of cancers, both in cell culture and in clinical trials. Our results suggest that iron chelation could affect not only cancer cells but also the tumor microenvironment by altering the iron-release phenotype of tumor-associated macrophages (TAMs). The study of iron chelators in conjunction with the effect of TAMs on tumor growth could lead to an improved understanding of the role of iron in cancer biology and to novel therapeutic avenues for iron chelation approaches.
    • The Intracloud Lightning Fraction in the Contiguous United States

      Medici, Gina; Cummins, Kenneth L.; Cecil, Daniel J.; Koshak, William J.; Rudlosky, Scott D.; Univ Arizona, Dept Hydrol & Atmospher Sci; Department of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, Arizona; Department of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, Arizona; NASA George C. Marshall Space Flight Center/NSSTC, Huntsville, Alabama; NASA George C. Marshall Space Flight Center/NSSTC, Huntsville, Alabama; et al. (AMER METEOROLOGICAL SOC, 2017-11)
      This work addresses the long-term relative occurrence of cloud-to-ground (CG) and intracloud (IC; no attachment to ground) flashes for the contiguous United States (CONUS). It expands upon an earlier analysis by Boccippio et al. who employed 4-yr datasets provided by the U.S. National Lightning Detection Network (NLDN) and the Optical Transient Detector (OTD). Today, the duration of the NLDN historical dataset has more than tripled, and OTD data can be supplemented with data from the Lightning Imaging Sensor (LIS). This work is timely, given the launch of GOES-16, which includes the world's first geostationary lightning mapper that will observe total lightning (IC and CG) over the Americas and adjacent ocean regions. Findings support earlier results indicating factor-of-10 variations in the IC:CG ratio throughout CONUS, with climatological IC fraction varying between 0.3 and greater than 0.9. The largest values are seen in the Pacific Northwest, central California, and where Colorado borders Kansas and Nebraska. An uncertainty analysis indicates that the large values in the northwest and central California are likely not due to measurement uncertainty. The high IC:CG ratio (. 4) throughout much of Texas reported by Boccippio et al. is not supported by this longer-term climatology. There is no clear evidence of differences in IC fraction between land and coastal ocean. Lightning characteristics in six selected large regions show a consistent positive relationship between IC fraction and the percent of positive CG flashes, irrespective of lightning incidence (flash density), dominant season, or diurnal maximum period.
    • Intracontinental subduction beneath the Pamir Mountains: Constraints from thermokinematic modeling of shortening in the Tajik fold-and-thrust belt

      Chapman, James B.; Carrapa, Barbara; Ballato, Paolo; DeCelles, Peter G.; Worthington, James; Oimahmadov, Ilhomjon; Gadoev, Mustafo; Ketcham, Richard; Univ Arizona, Dept Geosci (GEOLOGICAL SOC AMER, INC, 2017)
      A regional, balanced cross section is presented for the thin-skinned Tajik fold-and-thrust belt, constrained by new structural and stratigraphic data, industrial well-log data, flexural modeling, and existing geologic and geophysical mapping. A sequential restoration of the section was calibrated with 15 new apatite (U-Th)/He ages and 7 new apatite fission-track ages from samples of the major thrust sheets within the Tajik fold-and-thrust belt. Thermokinematic modeling indicates that deformation in the Tajik fold-and-thrust belt began during the Miocene (prior to or ca. 17 Ma) and continues to near present, with long-term shortening rates of similar to 4-6 mm/yr and Pliocene to present rates of similar to 6-8 mm/yr. The Tajik fold-and-thrust belt can be characterized as two distinct, oppositely verging thrust belts. Deformation initiated at opposite margins of the Tajik foreland basin, adjacent the southwest Tian Shan and northwest Pamir Mountains, and propagated toward the center of the basin, eventually incorporating the foreland basin entirely into a composite fold-and-thrust belt. The western Tajik fold-and-thrust belt records at least 35-40 km of total shortening and is part of the greater Tian Shan orogenic system. The eastern Tajik fold-and-thrust belt records similar to 30 km of shortening linked to the Pamir Mountains. The amount of shortening in the Tajik fold-and-thrust belt is significantly less than predicted by models of intracontinental subduction, which call for subduction of an similar to 300-km-long slab of continental Tajik-Tarim lithosphere beneath the Pamir. Field observations and structural relationships suggest that the Mesozoic and younger sedimentary rocks of the Tajik Basin were deposited on and across the Northern Pamir terrane and then subsequently uplifted and eroded during orogenic growth, rather than undergoing subduction beneath the Pamir. The Paleozoic-Proterozoic(?) metasedimentary and igneous rocks exposed in the Northern Pamir terrane are equivalent to the middle-lower crust of the Tajik Basin, which has become incorporated into the Pamir orogen. We propose that the southdipping zone of deep seismicity beneath the Pamir, which is the basis for the intra-continental subduction model, is related to gravitational foundering (by delamination or large-scale dripping) of Pamir lower crust and mantle lithosphere. This contrasts with previous models that related the Pamir seismic zone to subduction with or without roll-back of Asian lithosphere. Delamination may explain the initiation of extension in the Pamir gneiss domes and does not require a change in plate boundary forces to switch between compressional and extensional regimes. Because the Pamir is the archetype for active subduction of continental lithosphere in the interior of continental plates (intracontinental subduction), the viability of this particular tectonic process may need to be reassessed.
    • Intracranial source activity (eLORETA) related to scalp-level asymmetry scores and depression status

      Smith, Ezra E.; Cavanagh, James F.; Allen, John J. B.; Univ Arizona, Dept Psychol (WILEY, 2018-01)
      Frontal EEG alpha asymmetry provides a promising index of depression risk, yet very little is known about the neural sources of alpha asymmetry. To identify these sources, this study examined alpha asymmetry using a distributed inverse solution: exact low resolution brain electromagnetic tomography (eLORETA). Findings implicated a generator in lateral midfrontal regions that contributed to both surface asymmetry and depression risk. Participants with any lifetime history of depressive episodes were characterized by less left than right activity in the precentral gyrus and midfrontal gyrus. Anhedonia accounted for a significant portion of the relationship between alpha asymmetry and lifetime major depressive disorder. Results are suggestive of convergence between motivational and capability models of asymmetry and replicate results from experimental studies in a large resting-state data set. The capability model of frontal alpha asymmetry is contextualized in terms of motor preparedness following emotional mobilization.
    • Intraindividual Behavioral Variability Predicts Foraging Outcome in a Beach-dwelling Jumping Spider

      Lichtenstein, James L. L.; Chism, Gregory T.; Kamath, Ambika; Pruitt, Jonathan N.; Univ Arizona, Grad Interdisciplinary Program Entomol & Insect (NATURE PUBLISHING GROUP, 2017-12-22)
      Animal personality, defined as consistent differences between individuals in behavior, has been the subject of hundreds if not thousands of papers. However, little work explores the fitness consequences of variation in behavior within individuals, or intraindividual variability (IIV). We probe the effects of behavioral IIV on predator-prey interaction outcomes in beach-dwelling jumping spiders (Terralonus californicus). Prior studies have found that spiders with higher body condition (body mass relative to size) behave more variably. Thus, we hypothesized that jumping spider activity level IIV would relate positively to foraging performance. To address this, we tested for associations between activity IIV, average activity level, and two measures of foraging success in laboratory mesocosms: change in spider mass and the number of prey killed. Activity IIV positively correlated with the mass that spiders gained from prey, but not with the number of prey killed. This suggests that spiders with high IIV consumed a greater proportion of their prey or used less energy. Interestingly, average activity level (personality) predicted neither metric of foraging success, indicating that behavioral IIV can predict metrics of success that personality does not. Therefore, our findings suggest that IIV should be considered alongside personality in studies of predator-prey interactions.
    • Intraoperative visualization of plasmon resonant liposomes using augmented microscopy

      Watson, Jeffrey R.; Garland, Summer; Romanowski, Marek; Univ Arizona, Dept Biomed Engn; The Univ. of Arizona (United States); The Univ. of Arizona (United States); The Univ. of Arizona (United States) (SPIE-INT SOC OPTICAL ENGINEERING, 2017-02-08)
      Plasmon resonance associated with nanoparticles of gold can enable photothermal ablation of tissues or controlled drug release with exquisite temporal and spatial control. These technologies may support many applications of precision medicine. However, clinical implementations of these technologies will require new methods of intraoperative imaging and guidance. Near-infrared laser surgery is a prime example that relies on improved image guidance. Here we set forth applications of augmented microscopy in guiding surgical procedures employing plasmon resonant gold-coated liposomes. Absorption of near-infrared laser light is the first step in activation of various diagnostic and therapeutic functions of these novel functional nanoparticles. Therefore, we demonstrate examples of near-infrared visualization of the laser beam and gold-coated liposomes. The augmented microscope proves to be a promisingimage guidance platform for a range of image-guided medical procedures.
    • Intraperitoneal injections as an alternative method for micro-CT contrast enhanced detection of murine liver tumors

      Sweeney, Nathan; Marchant, Stephen; Martinez, Jesse D; Univ Arizona, Canc Ctr; Univ Arizona, Canc Biol Grad Interdisciplinary Program; Univ Arizona, Cell & Mol Med (FUTURE SCI LTD, 2019-05-03)
      Micro-computed tomography (micro-CT) coupled with tissue, or vascular, specific contrast agent has emerged as a powerful tool for detecting and monitoring tumor growth in the liver of murine animals. Intravenous injections of contrast agents can be technically challenging and lead to errors that can considerably influence the outcome of a preclinical study, prompting an alternative method. Here we assessed the effectiveness of intraperitoneal injections of polyiodinated triglycerides emulsions (FenestraLC) in micro-CT imaging of young SCID (8 weeks) and old BALB/c (48 weeks) mice with xenograft or carcinogen-induced liver tumors, respectively, and determined an optimal acquisition time. Utilizing an intraperitoneal injection is a viable alternative administration route for using Fenestrain detection and quantification of murine liver tumor burden. METHOD SUMMARY We report that intraperitoneal injections of polyiodinated triglycerides emulsions are a suitable alternative to the intravenous administration route in detecting and quantifying murine liver tumor burden.
    • The Intraseasonal and Interannual Variability of Arctic Temperature and Specific Humidity Inversions

      Yu, Lejiang; Yang, Qinghua; Zhou, Mingyu; Zeng, Xubin; Lenschow, Donald H.; Wang, Xianqiao; Han, Bo; Univ Arizona, Dept Atmospher Sci (MDPI, 2019-04-22)
      Temperature and humidity inversions are common in the Arctic's lower troposphere, and are a crucial component of the Arctic's climate system. In this study, we quantify the intraseasonal oscillation of Arctic temperature and specific humidity inversions and investigate its interannual variability using data from the Surface Heat Balance of the Arctic (SHEBA) experiment from October 1997 to September 1998 and the European Centre for Medium-Range Forecasts (ECMWF) Reanalysis (ERA)-interim for the 1979-2017 period. In January 1998, there were two noticeable elevated inversions and one surface inversion. The transitions between elevated and surface-based inversions were associated with the intraseasonal variability of the temperature and humidity differences between 850 and 950 hPa. The self-organizing map (SOM) technique is utilized to obtain the main modes of surface and elevated temperature and humidity inversions on intraseasonal time scales. Low (high) pressure and more (less) cloud cover are related to elevated (surface) temperature and humidity inversions. The frequency of strong (weak) elevated inversions over the eastern hemisphere has decreased (increased) in the past three decades. The wintertime Arctic Oscillation (AO) and Arctic Dipole (AD) during their positive phases have a significant effect on the occurrence of surface and elevated inversions for two Nodes only.
    • Intravenous Immunoglobulin for Congenital Parvovirus Myocarditis

      Kurland, Yonatan; Kylat, Ranjit I.; Johnson, Drew C.; Barber, Brent J.; Bedrick, Alan D.; Bader, Mohammad Y.; Univ Arizona, Arizona Hlth Sci Ctr, Dept Pediat; Univ Arizona, Arizona Hlth Sci Ctr, Sect Neonatal Perinatal Med & Dev Biol; Univ Arizona, Arizona Hlth Sci Ctr, Sect Pediat Cardiol (GEORG THIEME VERLAG KG, 2018-01-18)
      Congenital parvovirus infection has a diverse presentation ranging from asymptomatic infants to intrauterine demise secondary to red cell aplasia or myocarditis. Treatment is aimed at correcting anemia with intrauterine and postnatal transfusions. We report a case of fetal hydrops with severe atrioventricular regurgitation and myocardial dysfunction secondary to parvovirus infection in a preterm infant. Myocarditis and myocardial dysfunction responded to immunoglobulin administration.
    • Intravenous Immunoglobulin-Induced Pulmonary Embolism: It Is Time to Act!

      Bilal, Jawad; Riaz, Irbaz B; Hill, Jennifer L; Zangeneh, Tirdad T; Univ Arizona, Dept Internal Med (LIPPINCOTT WILLIAMS & WILKINS, 2016-08)
      Pulmonary embolism (PE) is a common clinical problem affecting 600,000 patients per year in the United States. Although the diagnosis can be easily confirmed by imaging techniques, such as computed tomographic angiography of the chest, the identification of underlying mechanism leading to PE is important for appropriate duration of anticoagulation, and prevention of subsequent episodes. The differential diagnosis of underlying mechanism is broad and must include careful review of medication history. Drug-related thromboembolic disease can be easily missed and may have catastrophic consequences. The identification of the culprit drug is important for prevention of subsequent episodes and choosing appropriate duration of anticoagulation. We report a case of a middle-aged man who developed PE after administration of intravenous immunoglobulin.
    • Intravenous peramivir vs oral oseltamivir in high-risk emergency department patients with influenza: Results from a pilot randomized controlled study

      Hsieh, Yu-Hsiang; Dugas, Andrea F; LoVecchio, Frank; McBryde, Breana; Ricketts, Erin P; Saliba-Shaw, Kathryn; Rothman, Richard E; Univ Arizona, Coll Med, Dept Emergency Med (WILEY, 2020-10-02)
      Background Peramivir offers a single-dose intravenous (IV) treatment option for influenza (vs 5-day oral dosing for oseltamivir). We sought to compare outcomes of emergency department (ED) patients at high risk for influenza complications treated with IV peramivir vs oral oseltamivir. Methods During the 2015-16 and 2016-17 influenza seasons, adult patients in two US EDs were randomized to either oral oseltamivir or IV peramivir treatment group. Eligibility included positive molecular influenza test; met CDC criteria for antiviral treatment; able to provide informed consent and agree to follow-up assessment. Outcomes were measured by clinical end-point indicators, including FLU-PRO Score, Ordinal Scale, Patient Global Impression on Severity Score, and Karnofsky Performance Scale for 14 days. Non-inferiorttest was performed to assess comparative outcomes between the two groups. Results Five hundred and seventy-five (68%) of 847 influenza-positive patients were approached. Two hundred and eighty-four met enrollment criteria and 179 were enrolled; of these 95 (53%) were randomized to peramivir, and 84 to oseltamivir. Average FLU-PRO score at baseline was similar (peramivir: 2.67 vs oseltamivir: 2.52); the score decreased over time for both groups (day 5: peramivir: 1.71 vs oseltamivir: 1.62; day 10: peramivir: 1.48 vs oseltamivir: 1.37; day 14: peramivir: 1.40 vs oseltamivir: 1.33; allP < .05 for significantly non-inferior). Influenza-related complications were similar between two groups (All: peramivir: 31% vs oseltamivir: 21%,P > .05; pneumonia: peramivir: 11% vs oseltamivir: 14%,P > .05). Conclusions Clinical outcomes of influenza-infected patients treated with single-dose IV peramivir were comparable to those treated with oral oseltamivir, suggesting potential utility of peramivir for influenza-infected patients in the ED.
    • Intra‐Annual Climate Anomalies in Northwestern North America Following the 1783–1784 CE Laki Eruption

      Edwards, Julie; Anchukaitis, Kevin J.; Zambri, Brian; Andreu‐Hayles, Laia; Oelkers, Rose; D'Arrigo, Rosanne; von Arx, Georg; School of Geography, Development, and Environment, University of Arizona; Laboratory of Tree-Ring Research, University of Arizona (Blackwell Publishing Ltd, 2020-12-14)
      The 1783–1784 CE Laki eruption in Iceland was one of the largest, in terms of the mass of SO2 emitted, high-latitude eruptions in the last millennium, but the seasonal and regional climate response was heterogeneous in space and time. Although the eruption did not begin until early June, tree-ring maximum latewood density (MXD) reconstructions from Alaska suggest that the entire 1783 summer was extraordinarily cold. We use high-resolution quantitative wood anatomy, climate model simulations, and proxy systems modeling to resolve the intra-annual climate effects of the Laki eruption on temperatures over northwestern North America. We measured wood anatomical characteristics of white spruce (Picea glauca) trees from two northern Alaska sites. Earlywood cell characteristics of the 1783 ring are normal, while latewood cell wall thickness is significantly and anomalously reduced compared to non-eruption years. Combined with complementary evidence from climate model experiments and proxy systems modeling, these features indicate an abrupt and premature cessation of cell wall thickening due to a rapid temperature decrease toward the end of the growing season. Reconstructions using conventional annual resolution MXD likely over-estimate total growing season cooling in this year, while ring width fails to capture this abrupt late-summer volcanic signal. Our study has implications not only for the interpretation of the climatic impacts of the Laki eruption in North America, but more broadly demonstrates the importance of timing and internal variability when comparing proxy temperature reconstructions and climate model simulations. It further demonstrates the value of developing cellular-scale tree-ring proxy measurements for paleoclimatology. © 2020. American Geophysical Union. All Rights Reserved.
    • The Intricate Structure of HH 508, the Brightest Microjet in the Orion Nebula

      Wu, Ya-Lin; Close, Laird M.; Kim, Jinyoung Serena; Males, Jared R.; Morzinski, Katie M.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2018-02-21)
      We present Magellan adaptive optics Ha imaging of HH 508, which has the highest surface brightness among protostellar jets in the Orion Nebula. We find that HH 508 actually has a shorter component to the west, and a longer and knotty component to the east. The east component has a kink at 0.'' 3 from the jet-driving star theta(1) Ori B-2, so it may have been deflected by the wind/radiation from the nearby theta(1) Ori B1B5. The origin of both components is unclear, but if each of them is a separate jet, then theta(1) Ori B-2 may be a tight binary. Alternatively, HH 508 may be a slow-moving outflow, and each component represents an illuminated cavity wall. The ionization front surrounding theta(1) Ori B2B3 does not directly face theta(1) Ori B1B5, suggesting that the EUV radiation from theta(1) Ori C plays a dominant role in affecting the morphology of proplyds even in the vicinity of theta(1) Ori B1B5. Finally, we report an Ha blob that might be ejected by the binary proplyd LV 1.
    • Intrinsic alignment in redMaPPer clusters – II. Radial alignment of satellites towards cluster centres

      Huang, Hung-Jin; Mandelbaum, Rachel; Freeman, Peter E; Chen, Yen-Chi; Rozo, Eduardo; Rykoff, Eli; Univ Arizona, Dept Phys (OXFORD UNIV PRESS, 2018-03)
      We study the orientations of satellite galaxies in redMaPPer clusters constructed from the Sloan Digital Sky Survey at 0.1 < z < 0.35 to determine whether there is any preferential tendency for satellites to point radially towards cluster centres. We analyse the satellite alignment (SA) signal based on three shape measurement methods (re-Gaussianization, de Vaucouleurs, and isophotal shapes), which trace galaxy light profiles at different radii. The measured SA signal depends on these shape measurement methods. We detect the strongest SA signal in isophotal shapes, followed by de Vaucouleurs shapes. While no net SA signal is detected using re-Gaussianization shapes across the entire sample, the observed SA signal reaches a statistically significant level when limiting to a subsample of higher luminosity satellites. We further investigate the impact of noise, systematics, and real physical isophotal twisting effects in the comparison between the SA signal detected via different shape measurement methods. Unlike previous studies, which only consider the dependence of SA on a few parameters, here we explore a total of 17 galaxy and cluster properties, using a statistical model averaging technique to naturally account for parameter correlations and identify significant SA predictors. We find that the measured SA signal is strongest for satellites with the following characteristics: higher luminosity, smaller distance to the cluster centre, rounder in shape, higher bulge fraction, and distributed preferentially along the major axis directions of their centrals. Finally, we provide physical explanations for the identified dependences and discuss the connection to theories of SA.
    • Intrinsic alignments in redMaPPer clusters – I. Central galaxy alignments and angular segregation of satellites

      Huang, Hung-Jin; Mandelbaum, Rachel; Freeman, Peter E.; Chen, Yen-Chi; Rozo, Eduardo; Rykoff, Eli; Baxter, Eric J.; Univ Arizona, Dept Phys (OXFORD UNIV PRESS, 2016-11-21)
      The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94 817 members within 0.1 < z < 0.35, based on the red-sequence Matched-filter Probabilistic Percolation cluster catalogue constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes and the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centring probability, and redder colour. Satellites with redder colour, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation towards their central galaxy major axes. Finally, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.
    • The Intrinsic Characteristics of Galaxies on the SFR–M ∗ Plane at 1.2 < z < 4: I. The Correlation between Stellar Age, Central Density, and Position Relative to the Main Sequence

      Lee, Bomee; Giavalisco, Mauro; Whitaker, Katherine E.; Williams, Christina C.; Ferguson, Henry C.; Acquaviva, Viviana; Koekemoer, A.; Straughn, Amber N.; Guo, Yicheng; Kartaltepe, Jeyhan S.; et al. (IOP PUBLISHING LTD, 2018-01-31)
      We use the deep CANDELS observations in the GOODS North and South fields to revisit the correlations between stellar mass (M-*), star formation rate (SFR) and morphology, and to introduce a fourth dimension, the mass-weighted stellar age, in galaxies at 1.2 < z < 4. We do this by making new measures of M-*, SFR, and stellar age thanks to an improved SED fitting procedure that allows various star formation history for each galaxy. Like others, we find that the slope of the main sequence (MS) of star formation in the (M-*; SFR) plane bends at high mass. We observe clear morphological differences among galaxies across the MS, which also correlate with stellar age. At all redshifts, galaxies that are quenching or quenched, and thus old, have high Sigma(1) (the projected density within the central 1 kpc), while younger, star-forming galaxies span a much broader range of Sigma(1), which includes the high values observed for quenched galaxies, but also extends to much lower values. As galaxies age and quench, the stellar age and the dispersion of Sigma(1) for fixed values of M* shows two different regimes: one at the low-mass end, where quenching might be driven by causes external to the galaxies; the other at the high-mass end, where quenching is driven by internal causes, very likely the mass given the low scatter of Sigma(1) (mass quenching). We suggest that the monotonic increase of central density as galaxies grow is one manifestation of a more general phenomenon of structural transformation that galaxies undergo as they evolve.

      Jones, Mackenzie L.; Hickox, Ryan C.; Black, Christine S.; Hainline, Kevin N.; DiPompeo, Michael A.; Goulding, Andy D.; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2016-07-14)
      An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGNs). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test whether or not an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous work suggesting that young galaxies in optical surveys have an observed lognormal Eddington ratio distribution. We simulate the optical emission line properties of a population of galaxies and AGNs using a broad, instantaneous luminosity distribution described by a Schechter function near the Eddington limit. This simulated AGN population is then compared to observed galaxies via their positions on an emission line excitation diagram and Eddington ratio distributions. We present an improved method for extracting the AGN distribution using BPT diagnostics that allows us to probe over one order of magnitude lower in Eddington ratio, counteracting the effects of dilution by star formation. We conclude that for optically selected AGNs in young galaxies, the intrinsic Eddington ratio distribution is consistent with a possibly universal, broad power law with an exponential cutoff, as this distribution is observed in old, optically selected galaxies and X-rays.