Browsing by Subject "digital"
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Item Continuum Observations At 350 Microns Of High-Redshift Molecular Emission Line Galaxies(2009-12) Wu, Jingwen Wu; Vanden Bout, Paul A.; Evans, Neal J.; Dunham, Michael M.; Wu, Jingwen Wu; Evans, Neal J.; Dunham, Michael M.We report observations of 15 high-redshift (z = 1-5) galaxies at 350 mu m using the Caltech Submillimeter Observatory and Submillimeter High Angular Resolution Camera II array detector. Emission was detected from eight galaxies, for which far-infrared luminosities, star formation rates (SFRs), total dust masses, and minimum source size estimates are derived. These galaxies have SFRs and star formation efficiencies comparable to other high-redshift molecular emission line galaxies. The results are used to test the idea that star formation in these galaxies occurs in a large number of basic units, the units being similar to star-forming clumps in the Milky Way. The luminosity of these extreme galaxies can be reproduced in a simple model with (0.9-30) x10(6) dense clumps, each with a luminosity of 5 x 10(5) L(circle dot), the mean value for such clumps in the Milky Way. Radiative transfer models of such clumps can provide reasonable matches to the overall spectral energy distributions (SEDs) of the galaxies. They indicate that the individual clumps are quite opaque in the far-infrared. Luminosity-to-mass ratios vary over two orders of magnitude, correlating strongly with the dust temperature derived from simple fits to the SED. The gas masses derived from the dust modeling are in remarkable agreement with those from CO luminosities, suggesting that the assumptions going into both calculations are reasonable.Item Dusty Disks Around Central Stars Of Planetary Nebulae(2014-06) Clayton, Geoffrey C.; De Marco, Orsola; Nordhaus, Jason; Green, Joel; Rauch, Thomas; Werner, Klaus; Chu, You-Hua; Green, Joel D.Only a few percent of cool, old white dwarfs (WDs) have infrared excesses interpreted as originating in small hot disks due to the infall and destruction of single asteroids that come within the star's Roche limit. Infrared excesses at 24 mu m were also found to derive from the immediate vicinity of younger, hot WDs, most of which are still central stars of planetary nebulae (CSPNe). The incidence of CSPNe with this excess is 18%. The Helix CSPN, with a 24 mu m excess, has been suggested to have a disk formed from collisions of Kuiper belt-like objects (KBOs). In this paper, we have analyzed an additional sample of CSPNe to look for similar infrared excesses. These CSPNe are all members of the PG 1159 class and were chosen because their immediate progenitors are known to often have dusty environments consistent with large dusty disks. We find that, overall, PG 1159 stars do not present such disks more often than other CSPNe, although the statistics (five objects) are poor. We then consider the entire sample of CSPNe with infrared excesses and compare it to the infrared properties of old WDs, as well as cooler post-asymptotic giant branch (AGB) stars. We conclude with the suggestion that the infrared properties of CSPNe more plausibly derive from AGB-formed disks rather than disks formed via the collision of KBOs, although the latter scenario cannot be ruled out. Finally, there seems to be an association between CSPNe with a 24 mu m excess and confirmed or possible binarity of the central star.Item Media Education, Media Literacy and Digital Competence(2012-03) Gutierrez, Alfonso; Tyner, Kathleen; Tyner, KathleenThis article addresses some possible relationship between education and media in contemporary society and explores the role that formal education should play in both the integration of media in the curriculum and the digital literacy skills necessary for the 21st century. The authors discuss here different theories and approaches that have dominated international media studies, media education and media literacy in recent decades. Confusion and misunderstandings in terminology for contemporary literacy in a complex, global and intercultural environment are explored and the authors present some inclusive categories for 21st century literacy such as media literacy, digital, multimodal, critical and functional. Interpretations of media literacy and digital competencies are discussed with particular emphasis on the current European regulatory framework. The authors warn that reductionist interpretations that focus on applied technical competencies with devices, hardware and software have the potential to severely limit media literacy education. Instead, the authors stress critical approaches as central to media literacy. In addition to technical competency, the authors highlight the need to include a broader and deeper analysis of the social uses, attitudes, and values associated with new media tools, texts and practices.Item the SDSS-III APOGEE Spectral Line List for H-Band Spectroscopy(2015-12) Shetrone, Matthew; Bizyaev, D.; Lawler, James E.; Prieto, Carlos Allende; Johnson, J. A.; Smith, V. V.; Cunha, K.; Holtzman, J.; Perez, A. E. G.; Meszaros, S.; Sobeck, J.; Zamora, O.; Garcia-Hernandez, D. A.; Souto, D.; Chojnowski, D.; Koesterke, L.; Majewski, S.; Zasowski, G.; Shetrone, MatthewWe present the H-band spectral line lists adopted by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). The APOGEE line lists comprise astrophysical, theoretical, and laboratory sources from the literature, as well as newly evaluated astrophysical oscillator strengths and damping parameters. We discuss the construction of the APOGEE line list, which is one of the critical inputs for the APOGEE Stellar Parameters and Chemical Abundances Pipeline, and present three different versions that have been used at various stages of the project. The methodology for the newly calculated astrophysical line lists is reviewed. The largest of these three line lists contains 134,457 molecular and atomic transitions. In addition to the format adopted to store the data, the line lists are available in MOOG, Synspec, and Turbospectrum formats. The limitations of the line lists along with guidance for its use on different spectral types are discussed. We also present a list of H-band spectral features that are either poorly represented or completely missing in our line list. This list is based on the average of a large number of spectral fit residuals for APOGEE observations spanning a wide range of stellar parameters.