17 research outputs found

    The FLASHES Survey I: Integral Field Spectroscopy of the CGM around 48 z=2.3−3.1z=2.3-3.1 QSOs

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    We present the pilot study component of the Fluorescent Lyman-Alpha Structures in High-z Environments (FLASHES) Survey; the largest integral-field spectroscopy survey to date of the circumgalactic medium at z=2.3−3.1z=2.3-3.1. We observed 48 quasar fields between 2015 and 2018 with the Palomar Cosmic Web Imager (Matuszewski et al. 2010). Extended HI Lyman-α\mathrm{\alpha} emission is discovered around 42/48 of the observed quasars, ranging in projected, flux-weighted radius from 21-71 proper kiloparsecs (pkpc), with 26 nebulae exceeding 100 pkpc100\mathrm{~pkpc} in effective diameter. The circularly averaged surface brightness radial profile peaks at a maximum of 1×10−17 erg s−1 cm−2 arcsec−2\mathrm{1\times 10^{-17}~erg~s^{-1}~cm^{-2}~arcsec^{-2}} (2×10−15 erg s−1 cm−2 arcsec−22\times10^{-15}~\mathrm{erg~s^{-1}~cm^{-2}~arcsec^{-2}} adjusted for cosmological dimming) and luminosities range from 1.9×1043 erg s−11.9\times10^{43}~\mathrm{erg~s^{-1}} to −14.1×1043 erg s−1-14.1\times10^{43}~\mathrm{erg~s^{-1}}. The emission appears to have a highly eccentric morphology and a maximum covering factor of 50%50\% (60%60\% for giant nebulae). On average, the nebular spectra are red-shifted with respect to both the systemic redshift and Lyα\alpha peak of the quasar spectrum. The integrated spectra of the nebulae mostly have single or double-peaked line shapes with global dispersions ranging from 167 km s−1167~\mathrm{km~s^{-1}} to 690 km s−1690~\mathrm{km~s^{-1}}, though the individual (Gaussian) components of lines with complex shapes mostly appear to have dispersions ≀400\leq 400 km s−1\mathrm{km~s^{-1}}, and the flux-weighted velocity centroids of the lines vary by thousands of km s−1 \mathrm{km~s^{-1}} with respect to the systemic QSO redshifts. Finally, the root-mean-square velocities of the nebulae are found to be consistent with gravitational motions expected in dark matter halos of mass Mh≃1012.5M⊙\mathrm{M_h \simeq10^{12.5} M_\odot}. We compare these results to existing surveys at both higher and lower redshift

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    FLASHES Survey. I. Integral Field Spectroscopy of the CGM around 48 z ≃ 2.3–3.1 QSOs

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    We present the pilot study of the Fluorescent Lyman-Alpha Structures in High-z Environments Survey; the largest integral field spectroscopy survey to date of the circumgalactic medium at z = 2.3–3.1. We observed 48 quasar fields with the Palomar Cosmic Web Imager to an average (2σ) limiting surface brightness of 6 × 10⁻Âč⁞ erg s⁻Âč cm⁻ÂČ arcsec⁻ÂČ (in a 1'' aperture and ~20 Å bandwidth). Extended H I Lyα emission is discovered around 37/48 of the observed quasars, ranging in projected radius from 14 to 55 proper kiloparsecs (pkpc), with one nebula exceeding 100 pkpc in effective diameter. The dimming-adjusted circularly averaged surface brightness profile peaks at 1 × 10⁻Âč⁔ erg s⁻Âč cm⁻ÂČ arcsec⁻ÂČ at R⊄ ~ 20 pkpc and integrated luminosities range from 0.4 to 9.4 × 10⁎³ erg s⁻Âč. The emission appears to have an eccentric morphology and an average covering factor of ~30%–40% at small radii. On average, the nebular spectra are redshifted with respect to both the systemic redshift and Lyα peak of the quasar spectrum. The integrated spectra of the nebulae mostly have single- or double-peaked profiles with global dispersions ranging from 143 to 708 km s⁻Âč, though the individual Gaussian components of lines with complex shapes mostly have dispersions ≀400 km s⁻Âč, and the flux-weighted velocity centroids of the lines vary by thousands of km s⁻Âč with respect to the QSO redshifts. Finally, the root-mean-square velocities of the nebulae are found to be consistent with those expected from gravitational motions in dark matter halos of mass Log₁₀(M_h[M⊙]) ≃ 12.2^(+0.7)_(-1.2). We compare these results to existing surveys at higher and lower redshift

    The Keck Cosmic Web Imager Integral Field Spectrograph

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    We report on the design and performance of the Keck Cosmic Web Imager (KCWI), a general purpose optical integral field spectrograph that has been installed at the Nasmyth port of the 10 m Keck II telescope on Maunakea, Hawaii. The novel design provides blue-optimized seeing-limited imaging from 350–560 nm with configurable spectral resolution from 1000–20,000 in a field of view up to 20'' × 33''. Selectable volume phase holographic (VPH) gratings and high-performance dielectric, multilayer silver, and enhanced-aluminum coatings provide end-to-end peak efficiency in excess of 45% while accommodating the future addition of a red channel that will extend wavelength coverage to 1 micron. KCWI takes full advantage of the excellent seeing and dark sky above Maunakea with an available nod-and-shuffle observing mode. The instrument is optimized for observations of faint, diffuse objects such as the intergalactic medium or cosmic web. In this paper, a detailed description of the instrument design is provided with measured performance results from the laboratory test program and 10 nights of on-sky commissioning during the spring of 2017. The KCWI team is lead by Caltech and JPL (project management, design, and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (observatory interfaces)

    Strategies for identifying stable lentil cultivars (Lens culinaris Medik) for combating hidden hunger, malnourishment, and climate variability

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    Iron and zinc malnutrition is a global humanitarian concern that mostly affects newborns, children, and women in low- and middle-income countries where plant-based diets are regularly consumed. This kind of malnutrition has the potential to result in a number of immediate and long-term implications, including stunted growth, an elevated risk of infectious diseases, and poor development, all of which may ultimately cause children to not develop to the fullest extent possible. A determination of the contributions from genotype, environment, and genotype by environment interactions is necessary for the production of nutrient-dense lentil varieties that offer greater availability of iron and zinc with a high level of trait stability. Understanding the genotype and environmental parameters that affect G x E (Genotype x Environment) interactions is essential for plant breeding. We used GGE(Genotype, Genotype x Environment interactions) and AMMI (Additive Main effects and Multiplicative Interaction) models to study genetic stability and GE(Genotype x Environment interactions) for grain Fe, Zn, Al, and anti-nutritional factors like phytic acid content in sixteen commercially produced lentil cultivars over several different six geographical locations across India. Significant genetic variability was evident in the Fe and Zn levels of different genotypes of lentils. The amounts of grain iron, zinc, and phytic acid varied from 114.10 to 49.90 mg/kg, 74.62 to 21.90 mg/kg, and 0.76 to 2.84 g/100g (dw) respectively. The environment and GE (Genotype x Environment interactions) had an impact on the concentration of grain Fe, Zn, and phytic acid (PA). Heritability estimations ranged from low to high (53.18% to 99.48%). The study indicated strong correlation between the contents of Fe and Zn, a strategy for simultaneously increasing Fe and Zn in lentils may be recommended. In addition, our research revealed that the stable and ideal lentil varieties L4076 (Pusa Shivalik) for Fe concentration and L4717 (Pusa Ageti) for Zn content, which have lower phytic acid contents, will not only play an essential role as stable donors in the lentil bio-fortification but will also enable the expansion of the growing area of bio-fortified crops for the security of health and nutrition

    The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey

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    The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T_eff<5000 K and in metallicity estimates for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SDSS-III Sloan Extension for Galactic Understanding and Exploration-2 (SEGUE-2). The astrometry error introduced in the DR8 imaging catalogs has been corrected in the DR9 data products. The next data release for SDSS-III will be in Summer 2013, which will present the first data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) along with another year of data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at http://www.sdss3.org/dr
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