24 research outputs found

    Exploring the effect of baryons on the radial distribution of satellite galaxies with GAMA and IllustrisTNG

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    We explore the radial distribution of satellite galaxies in groups in the Galaxy and Mass Assembly (GAMA) survey and the IllustrisTNG simulations. Considering groups with masses 12.0≤log10⁡(Mh/h−1M⊙)\u3c14.8 role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3e12.0≤log10(Mh/h−1M⊙)\u3c14.812.0≤log10⁡(Mh/h−1M⊙)\u3c14.8 at z \u3c 0.267, we find a good agreement between GAMA and a sample of TNG300 groups and galaxies designed to match the GAMA selection. Both display a flat profile in the centre of groups, followed by a decline that becomes steeper towards the group edge, and normalized profiles show no dependence on group mass. Using matched satellites from TNG and dark matter-only TNG-Dark runs we investigate the effect of baryons on satellite radial location. At z = 0, we find that the matched subhaloes from the TNG-Dark runs display a much flatter radial profile: namely, satellites selected above a minimum stellar mass exhibit both smaller halocentric distances and longer survival times in the full-physics simulations compared to their dark-matter only analogues. We then divide the TNG satellites into those which possess TNG-Dark counterparts and those which do not, and develop models for the radial positions of each. We find the satellites with TNG-Dark counterparts are displaced towards the halo centre in the full-physics simulations, and this difference has a power-law behaviour with radius. For the ‘orphan’ galaxies without TNG-Dark counterparts, we consider the shape of their radial distribution and provide a model for their motion over time, which can be used to improve the treatment of satellite galaxies in semi-analytic and semi-empirical models of galaxy formation

    Exploring the effect of baryons on the radial distribution of satellite galaxies with GAMA and IllustrisTNG

    Get PDF
    We explore the radial distribution of satellite galaxies in groups in the Galaxy and Mass Assembly (GAMA) survey and the IllustrisTNG simulations. Considering groups with masses 12.0 ≤ log10(M/−1M) < 14.8 at < 0.267, we find a good agreement between GAMA and a sample of TNG300 groups and galaxies designed to match the GAMA selection. Both display a flat profile in the centre of groups, followed by a decline that becomes steeper towards the group edge, and normalised profiles show no dependence on group mass. Using matched satellites from TNG and dark matter-only TNG-Dark runs we investigate the effect of baryons on satellite radial location. At = 0, we find that the matched subhaloes from the TNG-Dark runs display a much flatter radial profile: namely, satellites selected above a minimum stellar mass exhibit both smaller halo-centric distances and longer survival times in the full-physics simulations compared to their dark-matter only analogues. We then divide the TNG satellites into those which possess TNG-Dark counterparts and those which do not, and develop models for the radial positions of each. Wefindthesatellites with TNG-Dark counterparts are displaced towards the halo centre in the full-physics simulations, and this difference has a power-law behaviour with radius. For the ‘orphan’ galaxies without TNG-Dark counterparts, we consider the shape of their radial distribution and provide a model for their motion over time, which can be used to improve the treatment of satellite galaxies in semi-analytic and semi-empirical models of galaxy formation

    Herbert Hoover Elementary / Charleston Complete Corridor Plan

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    Completed as a part of CRP 425 bicycle and pedestrian planning, led by Dr. William Riggs, this planning project assessed the Herbert Hoover Elementary site and Charleston corridor in the City of Palo Alto with an aim to bring a complete streets strategy to the area. The plans recommend improved accessibility for bicycles and pedestrians along Charleston Road including modal separation between bicyclists and pedestians, improved vehicular flows to mitigate vehicular traffic congestion during peak hours and increased innovation in safety features to prevent pedestrian-vehicle conflicts

    Shining the Light on Aging and Isomers Using Photodissociation and Radical Chemistry

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    Biological aging is a complex and nuanced chemical process that proceeds along numerous routes at the molecular level. Spontaneous deamidation of asparagine and isomerization of aspartic acid are among the most prevalent age-related chemical modifications and are associated with a growing list of human diseases. Although both degradation pathways are common throughout the body, they are often unnoticed because the resulting chemical modification is relatively minor and is exceptionally difficult to detect. Structural characterization is further complicated because both deamidation and isomerization produce four isomers of aspartic acid (L-Asp, D-Asp, L-isoAsp, and D-isoAsp). To better understand the aging process, we utilized radical directed dissociation (RDD) in conjunction with mass spectrometry to identify and quantify the products of deamidation and isomerization. We began by outlining intrinsic factors that govern the deamidation rate, and external factors that influence product outcomes to develop models of peptide and protein aging. Subsequent studies revealed the specific structural and functional perturbations associated with the unnatural isomers present in aged proteins. To further expand our isomer detection capabilities, we applied our radical based fragmentation method to the glutamine deamidation, which exhibits several parallels to asparagine deamidation, but has remained largely uncharacterized. Importantly, we demonstrate that radical chemistry generated diagnostic and informative fragment ions for both glutamic acid and isoglutamic acid. We apply this technique in a manner that is amenable to shotgun proteomics and reveal several key differences between the two aging processes. Finally, we tailor our radical based analytical methodology toward the analysis of isomeric glycans. After successfully discriminating a comprehensive family of isomeric glycans with RDD, we demonstrate similar capabilities with 213 nm ultraviolet photodissociation, and outline how such a versatile approach may unify the closely related fields of glycomics and proteomics
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