44 research outputs found

    CHARIS Science: Performance Simulations for the Subaru Telescope's Third-Generation of Exoplanet Imaging Instrumentation

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    We describe the expected scientific capabilities of CHARIS, a high-contrast integral-field spectrograph (IFS) currently under construction for the Subaru telescope. CHARIS is part of a new generation of instruments, enabled by extreme adaptive optics (AO) systems (including SCExAO at Subaru), that promise greatly improved contrasts at small angular separation thanks to their ability to use spectral information to distinguish planets from quasistatic speckles in the stellar point-spread function (PSF). CHARIS is similar in concept to GPI and SPHERE, on Gemini South and the Very Large Telescope, respectively, but will be unique in its ability to simultaneously cover the entire near-infrared JJ, HH, and KK bands with a low-resolution mode. This extraordinarily broad wavelength coverage will enable spectral differential imaging down to angular separations of a few λ/D\lambda/D, corresponding to ∼\sim0.\!\!''1. SCExAO will also offer contrast approaching 10−510^{-5} at similar separations, ∼\sim0.\!\!''1--0.\!\!''2. The discovery yield of a CHARIS survey will depend on the exoplanet distribution function at around 10 AU. If the distribution of planets discovered by radial velocity surveys extends unchanged to ∼\sim20 AU, observations of ∼\sim200 mostly young, nearby stars targeted by existing high-contrast instruments might find ∼\sim1--3 planets. Carefully optimizing the target sample could improve this yield by a factor of a few, while an upturn in frequency at a few AU could also increase the number of detections. CHARIS, with a higher spectral resolution mode of R∼75R \sim 75, will also be among the best instruments to characterize planets and brown dwarfs like HR 8799 cde and κ\kappa And b.Comment: 13 pages, 7 figures, proceedings from SPIE Montrea

    A Chromaticity Analysis and PSF Subtraction Techniques for SCExAO/CHARIS Data

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    We present an analysis of instrument performance using new observations taken with the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) instrument and the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. In a correlation analysis of our data sets (which use the broadband mode covering the J band through the K band in a single spectrum), we find that chromaticity in the SCExAO/CHARIS system is generally worse than temporal stability. We also develop a point-spread function (PSF) subtraction pipeline optimized for the CHARIS broadband mode, including a forward modeling-based exoplanet algorithmic throughput correction scheme. We then present contrast curves using this newly developed pipeline. An analogous subtraction of the same data sets using only the H-band slices yields the same final contrasts as the full JHK sequences; this result is consistent with our chromaticity analysis, illustrating that PSF subtraction using spectral differential imaging (SDI) in this broadband mode is generally not more effective than SDI in the individual J, H, or K bands. In the future, the data processing framework and analysis developed in this paper will be important to consider for additional SCExAO/CHARIS broadband observations and other ExAO instruments which plan to implement a similar integral field spectrograph broadband mode.Natural Sciences and Engineering Council of Canada through the Postgraduate Scholarships-Doctoral discovery grant; Technologies for Exo-Planetary Science Collaborative Research and Training Experience programs; JSPS [23340051, 26220704, 23103002]; Astrobiology Center of the National Institutes of Natural Sciences, Japan; Mt. Cuba Foundation; directors contingency fund at Subaru Telescope; MEXT of the Japanese government [23103002]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Spatiotemporal expression and transcriptional perturbations by long noncoding RNAs in the mouse brain

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    Long noncoding RNAs (lncRNAs) have been implicated in numerous cellular processes including brain development. However, the in vivo expression dynamics and molecular pathways regulated by these loci are not well understood. Here, we leveraged a cohort of 13 lncRNA-null mutant mouse models to investigate the spatiotemporal expression of lncRNAs in the developing and adult brain and the transcriptome alterations resulting from the loss of these lncRNA loci. We show that several lncRNAs are differentially expressed both in time and space, with some presenting highly restricted expression in only selected brain regions. We further demonstrate altered regulation of genes for a large variety of cellular pathways and processes upon deletion of the lncRNA loci. Finally, we found that 4 of the 13 lncRNAs significantly affect the expression of several neighboring protein-coding genes in a cis-like manner. By providing insight into the endogenous expression patterns and the transcriptional perturbations caused by deletion of the lncRNA locus in the developing and postnatal mammalian brain, these data provide a resource to facilitate future examination of the specific functional relevance of these genes in neural development, brain function, and disease.National Science Foundation (U.S.) (Postdoctoral Research Fellowship in Biology DBI-0905973

    Scientific Design of a High Contrast Integral Field Spectrograph for the Subaru Telescope

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    Ground-based telescopes equipped with adaptive-optics (AO) systems and specialized science cameras are now capable of directly detecting extrasolar planets. We present the expected scientific capabilities of CHARIS, the Coronagraphic High Angular Resolution Imaging Spectrograph, which is being built for the Subaru 8.2 m telescope of the National Astronomical Observatory of Japan. CHARIS will be implemented behind the new extreme adaptive optics system at Subaru, SCExAO, and the existing 188-actuator system AO188. CHARIS will offer three observing modes over near-infrared wavelengths from 0.9 to 2.4 microns (the y-, J-, H-, and K-bands), including a low-spectral-resolution mode covering this entire wavelength range and a high-resolution mode within a single band. With these capabilities, CHARIS will offer exceptional sensitivity for discovering giant exoplanets, and will enable detailed characterization of their atmospheres. CHARIS, the only planned high-contrast integral field spectrograph on an 8m-class telescope in the Northern Hemisphere, will complement the similar instruments such as Project 1640 at Palomar, and GPI and SPHERE in Chile.Comment: 10 pages, 7 figures, SPIE Astronomical Telescopes and Instrumentation 201

    JWST/NIRCam Coronagraphy of the Young Planet-hosting Debris Disk AU Microscopii

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    High-contrast imaging of debris disk systems permits us to assess the composition and size distribution of circumstellar dust, to probe recent dynamical histories, and to directly detect and characterize embedded exoplanets. Observations of these systems in the infrared beyond 2--3 μ\mum promise access to both extremely favorable planet contrasts and numerous scattered-light spectral features -- but have typically been inhibited by the brightness of the sky at these wavelengths. We present coronagraphy of the AU Microscopii (AU Mic) system using JWST's Near Infrared Camera (NIRCam) in two filters spanning 3--5 μ\mum. These data provide the first images of the system's famous debris disk at these wavelengths and permit additional constraints on its properties and morphology. Conducting a deep search for companions in these data, we do not identify any compelling candidates. However, with sensitivity sufficient to recover planets as small as ∼0.1\sim 0.1 Jupiter masses beyond ∼2′′\sim 2^{\prime\prime} (∼20\sim 20 au) with 5σ5\sigma confidence, these data place significant constraints on any massive companions that might still remain at large separations and provide additional context for the compact, multi-planet system orbiting very close-in. The observations presented here highlight NIRCam's unique capabilities for probing similar disks in this largely unexplored wavelength range, and provide the deepest direct imaging constraints on wide-orbit giant planets in this very well studied benchmark system.Comment: 27 pages, 14 figure

    Generation tourism: towards a common identity

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    The purpose of this article is to highlight the implications of the indiscipline of tourism academia for a new generation of tourism academics. Generation Tourism is characterised by scholars with a multi-disciplinary education associated with a broad field of study and commonly considered to lack the advantages of a discipline-focused education with its strong theoretical and methodological foundations. The problem this article addresses relates to how new generations of scholars and their views on knowledge creation achieve ascendancy in ways that move on from existing paradigms and earlier cohorts of scholars. Our main argument is that Generation Tourism scholars would benefit from a more clearly developed and common academic identity. To begin the critical conversation around the identity of Generation Tourism we outline five possible points of departure. These points are: (1) learning from historical developments in parent disciplines; (2) spearheading inter-disciplinary scholarship; (3) working towards theoretical developments; (4) embracing mediating methodologies and (5) forming tourism nodes and networks. Recognising these as starting points rather than final statements, we hope that the conversation about Generation Tourism identity will continue in other forums

    SUBARU Near-Infrared Imaging Polarimetry of Misaligned Disks Around The SR24 Hierarchical Triple System

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    The SR24 multi-star system hosts both circumprimary and circumsecondary disks, which are strongly misaligned from each other. The circumsecondary disk is circumbinary in nature. Interestingly, both disks are interacting, and they possibly rotate in opposite directions. To investigate the nature of this unique twin disk system, we present 0.''1 resolution near-infrared polarized intensity images of the circumstellar structures around SR24, obtained with HiCIAO mounted on the Subaru 8.2 m telescope. Both the circumprimary disk and the circumsecondary disk are resolved and have elongated features. While the position angle of the major axis and radius of the NIR polarization disk around SR24S are 55∘^{\circ} and 137 au, respectively, those around SR24N are 110∘^{\circ} and 34 au, respectively. With regard to overall morphology, the circumprimary disk around SR24S shows strong asymmetry, whereas the circumsecondary disk around SR24N shows relatively strong symmetry. Our NIR observations confirm the previous claim that the circumprimary and circumsecondary disks are misaligned from each other. Both the circumprimary and circumsecondary disks show similar structures in 12^{12}CO observations in terms of its size and elongation direction. This consistency is because both NIR and 12^{12}CO are tracing surface layers of the flared disks. As the radius of the polarization disk around SR24N is roughly consistent with the size of the outer Roche lobe, it is natural to interpret the polarization disk around SR24N as a circumbinary disk surrounding the SR24Nb-Nc system.Comment: 14 pages, 5 figures, accepted for publication in A

    Harvesting Memory, Preserving Home: A Cookbook of the Painted Turtle Farm/Cosechando Memoria, Preservando el Hogar: Un Libro de Cocina de la Granja de la Tortuga Pintada

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    About this Project In the fall of 2018, 14 of the families and 32 students from two first-year seminars, Crossing Borders: Immigration, Identity, and Development and Immigrant Stories, worked together to create this cookbook. Families submitted their favorite dishes and then invited students to their homes to demonstrate the preparation. As they cooked and ate together, students recorded the steps to make the recipe and listened as connections between food, memory, family, migration, traditions, and religion emerged. Harvesting Memory, Preserving Home: A Cookbook of the Painted Turtle Farm is the product of this undertaking. In it, we offer the collection of recipes as well as a short story from each family, bring meaning to the food we eat, the places life brings us, and the memories we share. Sobre este Projecto En el otoño de 2018, 12 de las familias y 32 estudiantes de dos clases, Cruzando Fronteras: Immigración, Identidad, y Desarrollo y Las Historias Immigrantes trabajaron juntos para cear este libro de cocina. Las familias escogieron platos con una importancia o una memoria especial para preparar en sus casas con los estudiantes. Durante el proceso de concinar y comer juntos, los estudiantes anotaron los pasos para preparar la receta. Ellos escucharon las conexiones entre la comida, la memoria, la familia, la migración, las tradiciones, y la religión. Cosechando Memoria, Preservando el Hogar: Un Libro de Cocina de la Granja de la Tortuga Pintada es el fruto de este proyecto. Ofrecemos la collección de recetas además de una historia breve de cada familia, para dar significado a los alimentos que comemos, los lugares donde la vida nos trae, y las memorias que nos compartimos

    Publication Trends of Pediatric and Adult Randomized Controlled Trials in General Medical Journals, 2005–2018: A Citation Analysis

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    Policy has been developed to promote the conduct of high-quality pediatric randomized controlled trials (RCTs). Whether these strategies have influenced publication trends in high-impact journals is unknown. We aim to evaluate characteristics, citation patterns, and publication trends of pediatric RCTs published in general medical journals (GMJs) compared with adult RCTs over a 13-year period. Studies were identified using Medline, and impact metrics were collected from Web of Science and Scopus. All RCTs published from 2005–2018 in 7 GMJs with the highest impact factors were identified for analysis. A random sample of matched pediatric and adult RCTs were assessed for publication characteristics, academic and non-academic citation. Citations were counted from publication until June 2019. Among 4146 RCTs, 2794 (67.3%) enrolled adults, 591 (14.2%) enrolled children, and 761 RCTs (18.3%) enrolled adult and pediatric patients. Adult RCTs published in GMJs grew by 5.1 publications per year (95% CI: 3.3–6.9), while the number of pediatric RCTs did not show significant change (−0.4 RCTs/year, 95% CI: −1.4–0.6). Adult RCTs were cited more than pediatric RCTs (median(IQR): 29.9 (68.5–462.8) citations/year vs. 13.2 (6.8–24.9) citations/year; p < 0.001); however, social media attention was similar (median(IQR) Altmetric Attention Score: 37 (13.75–133.8) vs. 26 (6.2–107.5); p = 0.25). Despite policies which may facilitate conduct of pediatric RCTs, the publishing gap in high-impact GMJs is widening
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