2,697 research outputs found

    Optical Spectroscopic Survey of High-latitude WISE-selected Sources

    Get PDF
    We report on the results of an optical spectroscopic survey at high Galactic latitude (|b| ā‰„ 30Ā°) of a sample of WISE-selected targets, grouped by WISE W1 (Ī»_eff = 3.4 Ī¼m) flux, which we use to characterize the sources WISE detected. We observed 762 targets in 10 disjoint fields centered on ultraluminous infrared galaxy candidates using DEIMOS on Keck II. We find 0.30 Ā± 0.02 galaxies arcminā€“2 with a median redshift of z = 0.33 Ā± 0.01 for the sample with W1 ā‰„ 120 Ī¼Jy. The foreground stellar densities in our survey range from 0.23 Ā± 0.07 arcminā€“2 to 1.1 Ā± 0.1 arcminā€“2 for the same sample. We obtained spectra that produced science grade redshifts for ā‰„90% of our targets for sources with W1 flux ā‰„120 Ī¼Jy that also had an i-band flux gsim 18 Ī¼Jy. We used this for targeting very preliminary data reductions available to the team in 2010 August. Our results therefore present a conservative estimate of what is possible to achieve using WISE's Preliminary Data Release for the study of field galaxies

    Morphological Classification of Local Luminous Infrared Galaxies

    Get PDF
    We present an analysis of the morphological classification of 89 luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS) sample using non-parametric coefficients and compare their morphology as a function of wavelength. We rely on images obtained in the optical (B- and I-band) as well as in the infrared (H-band and 5.8Ī¼\mum). Our classification is based on the calculation of GiniGini and the second order of light (M20M_{20}) non-parametric coefficients which we explore as a function of stellar mass (Mā‹†M_\star), infrared luminosity (LIRL_{IR}) and star formation rate (SFR). We investigate the relation between M20M_{20}, the specific SFR (sSFR) and the dust temperature (TdustT_{dust}) in our galaxy sample. We find that M20M_{20} is a better morphological tracer than GiniGini, as it allows to distinguish systems formed by double systems from isolated and post-merger LIRGs. The multi-wavelength analysis allows us to identify a region in the GiniGini-M20M_{20} parameter space where ongoing mergers reside, regardless of the band used to calculate the coefficients. In particular when measured in the H-band, this region can be used to identify ongoing mergers, with a minimal contamination from LIRGs in other stages. We also find that while the sSFR is positively correlated with M20M_{20} when measured in the mid-infrared, i.e. star-bursting galaxies show more compact emission, it is anti-correlated with the B-band based M20M_{20}. We interpret this as the spatial decoupling between obscured and un-obscured star formation, whereby the ultraviolet/optical size of a LIRGs experience an intense dust enshrouded central starburst is larger than in the one in the mid-infrared since the contrast between the nuclear to the extended disk emission is smaller in the mid-infrared. This has important implications for high redshift surveys of dusty sources. [abridged]Comment: ( 18 pages, 12 figures, Accepted for publication in A&A

    The Deep Space Network: A Radio Communications Instrument for Deep Space Exploration

    Get PDF
    The primary purpose of the Deep Space Network (DSN) is to serve as a communications instrument for deep space exploration, providing communications between the spacecraft and the ground facilities. The uplink communications channel provides instructions or commands to the spacecraft. The downlink communications channel provides command verification and spacecraft engineering and science instrument payload data

    Mid-infrared Selection of Active Galactic Nuclei with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-selected Active Galactic Nuclei in COSMOS

    Get PDF
    The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 ā€“ W2 ā‰„ 0.8 (i.e., [3.4]ā€“[4.6] ā‰„0.8, Vega), which identifies 61.9 Ā± 5.4 active galactic nucleus (AGN) candidates per deg^2 to a depth of W2 ~ 15.0. This implies a much larger census of luminous AGNs than found by typical wide-area surveys, attributable to the fact that mid-infrared selection identifies both unobscured (type 1) and obscured (type 2) AGNs. Optical and soft X-ray surveys alone are highly biased toward only unobscured AGNs, while this simple WISE selection likely identifies even heavily obscured, Compton-thick AGNs. Using deep, public data in the COSMOS field, we explore the properties of WISE-selected AGN candidates. At the mid-infrared depth considered, 160 Ī¼Jy at 4.6 Ī¼m, this simple criterion identifies 78% of Spitzer mid-infrared AGN candidates according to the criteria of Stern et al. and the reliability is 95%. We explore the demographics, multiwavelength properties and redshift distribution of WISE-selected AGN candidates in the COSMOS field

    Measuring surface-area-to-volume ratios in soft porous materials using laser-polarized xenon interphase exchange NMR

    Full text link
    We demonstrate a minimally invasive nuclear magnetic resonance (NMR) technique that enables determination of the surface-area-to-volume ratio (S/V) of soft porous materials from measurements of the diffusive exchange of laser-polarized 129Xe between gas in the pore space and 129Xe dissolved in the solid phase. We apply this NMR technique to porous polymer samples and find approximate agreement with destructive stereological measurements of S/V obtained with optical confocal microscopy. Potential applications of laser-polarized xenon interphase exchange NMR include measurements of in vivo lung function in humans and characterization of gas chromatography columns.Comment: 14 pages of text, 4 figure

    ā€˜Donā€™t just travelā€™: thinking poetically on the way to professional knowledge

    Get PDF
    This paper describes how the medium of ā€˜found poetryā€™ is incorporated into a doctoral programme for nurses, educators and allied health and social care professionals at the start of their various doctoral journeys. It advocates a narrative practice approach to issues of researcher identity and reflexivity. ā€˜Findingā€™ the poems begins with the creation of collages as representational anchors for students to talk about themselves, their professional practice, their hopes and expectations of the doctoral experience, and their research ideas. (Re)presenting their transcribed talk as poetry involves culling and playing with words, phrases and segments, making changes in spacing, lines and rhythm to arrive at an evocative distillation (Butler-Kisber, 2002). This process enables each person to bring stories and/or fragments of experience into critical engagement with others. Poetic thinking functions pedagogically, helping students find a critical voice to enliven and hone their reflexive writing in relation to their doctoral experience and their research positioning. Arts-based methods of inquiry are an ongoing topic of interest in research communities. Found poetry is a useful starting point to explore creative means by which research participants can recount their stories, and equally, by which researchers can witness and disseminate what they have to tell.self funde

    Academic medical center clinical research professional workforce: Part 2 - issues in staff onboarding and professional development

    Get PDF
    Background: Defining key barriers to the development of a well-trained clinical research professional (CRP) workforce is an essential first step in identifying solutions for successful CRP onboarding, training, and competency development, which will enhance quality across the clinical and translational research enterprise. This study aimed to summarize barriers and best practices at academic medical centers related to effective CRP onboarding, training, professional development, identify challenges with the assessment of and mentoring for CRP competency growth, and describe opportunities to improve training and professionalization for the CRP career pathway. Materials/Methods: Qualitative data from a series of Un-Meeting breakout sessions and open-text survey questions were analyzed to explore the complex issues involved when developing high-quality onboarding and continuing education opportunities for CRPs at academic medical centers. Results: Results suggest there are several barriers to training the CRP workforce, including balancing foundational onboarding with role-based training, managing logistical challenges and institutional contexts, identifying/enlisting institutional champions, assessing competency, and providing high-quality mentorship. Several of these themes are interrelated. Two universal threads present throughout all themes are the need for effective communication and the need to improve professionalization of the CRP career pathway. Conclusion: Few institutions have solved all the issues related to training a competent and adaptable CRP workforce, although some have addressed one or more. We applied a socio-technical lens to illustrate our findings and the need for NCATS-funded academic medical centers to work collaboratively within and across institutions to overcome training barriers and support a vital, well-qualified workforce and present several exemplars from the field to help attain this goal
    • ā€¦
    corecore