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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Low Metallicities And Old Ages For Three Ultra-Diffuse Galaxies In The Coma Cluster, Meng Gu, Charlie Conroy, David Law, Pieter Van Dokkum, Renbin Yan, David Wake, Kevin Bundy, Allison Merritt, Roberto Abraham, Jielai Zhang, Matthew Bershady, Dmitry Bizyaev, Jonathan Brinkmann, Niv Drory, Kathleen Grabowski, Karen Masters, Kaike Pan, John Parejko, Anne-Marie Weijmans, Kai Zhang
Low Metallicities And Old Ages For Three Ultra-Diffuse Galaxies In The Coma Cluster, Meng Gu, Charlie Conroy, David Law, Pieter Van Dokkum, Renbin Yan, David Wake, Kevin Bundy, Allison Merritt, Roberto Abraham, Jielai Zhang, Matthew Bershady, Dmitry Bizyaev, Jonathan Brinkmann, Niv Drory, Kathleen Grabowski, Karen Masters, Kaike Pan, John Parejko, Anne-Marie Weijmans, Kai Zhang
Physics and Astronomy Faculty Publications
A large population of ultra-diffuse galaxies (UDGs) was recently discovered in the Coma cluster. Here we present optical spectra of three such UDGs, DF 7, DF 44, and DF 17, which have central surface brightnesses of μg ≈ 24.4–25.1 mag arcsec−2. The spectra were acquired as part of an ancillary program within the SDSS-IV MaNGA Survey. We stacked 19 fibers in the central regions from larger integral field units (IFUs) per source. With over 13.5 hr of on-source integration, we achieved a mean signal-to-noise ratio in the optical of 9.5 Å−1, 7.9 Å−1, …
Recovering Stellar Population Parameters Via Two Full-Spectrum Fitting Algorithms In The Absence Of Model Uncertainties, Junqiang Ge, Renbin Yan, Michele Cappellari, Shude Mao, Hongyu Li, Youjun Lu
Recovering Stellar Population Parameters Via Two Full-Spectrum Fitting Algorithms In The Absence Of Model Uncertainties, Junqiang Ge, Renbin Yan, Michele Cappellari, Shude Mao, Hongyu Li, Youjun Lu
Physics and Astronomy Faculty Publications
Using mock spectra based on Vazdekis/MILES library fitted within the wavelength region 3600–7350 Å, we analyse the bias and scatter on the resulting physical parameters induced by the choice of fitting algorithms and observational uncertainties, but avoid effects of those model uncertainties. We consider two full-spectrum fitting codes: PPXF and STARLIGHT, in fitting for stellar population age, metallicity, mass-to-light ratio, and dust extinction. With PPXF, we find that both the bias μ in the population parameters and the scatter σ in the recovered logarithmic values follows the expected trend μ ∝ σ ∝ 1/(S/N). The bias increases for younger ages …
Sdss-Iv Manga: Star Formation Cessation In Low-Redshift Galaxies. I. Dependence On Stellar Mass And Structural Properties, Enci Wang, Cheng Li, Ting Xiao, Lin Lin, Matthew Bershady, David R. Law, Michael Merrifield, Sebastian F. Sanchez, Rogemar A. Riffel, Rogerio Riffel, Renbin Yan
Sdss-Iv Manga: Star Formation Cessation In Low-Redshift Galaxies. I. Dependence On Stellar Mass And Structural Properties, Enci Wang, Cheng Li, Ting Xiao, Lin Lin, Matthew Bershady, David R. Law, Michael Merrifield, Sebastian F. Sanchez, Rogemar A. Riffel, Rogerio Riffel, Renbin Yan
Physics and Astronomy Faculty Publications
We investigate radial gradients in the recent star formation history (SFH) of 1917 galaxies with 0.01 < z < 0.14 from the Mapping Nearby Galaxies at Apache Point Observatory project. For each galaxy, we obtain two-dimensional maps and radial profiles for three spectroscopically measured parameters that are sensitive to the recent SFH: Dn (4000) (the 4000 Å break), EW(HδA), and EW(Hα) (the equivalent width of the Hδ absorption and the Hα emission line). The majority of the spaxels are consistent with models of a continuously declining star formation rate, indicating that starbursts occur rarely in local galaxies with regular morphologies. We classify the galaxies into three classes: fully star-forming (SF), partly quenched (PQ), and totally quenched (TQ). The galaxies that are less massive than 1010 M⊙ …
Sdss-Iv Manga: The Spatially Resolved Stellar Initial Mass Function In ~400 Early-Type Galaxies, Taniya Parikh, Daniel Thomas, Claudia Maraston, Kyle B. Westfall, Daniel Goddard, Jianhui Lian, Sofia Meneses-Goytia, Amy Jones, Sam Vaughan, Brett H. Andrews, Matthew Bershady, Dmitry Bizyaev, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Niv Drory, Eric Emsellem, David R. Law, Jeffrey A. Newman, Alexandre Roman-Lopes, David Wake, Renbin Yan, Zheng Zheng
Sdss-Iv Manga: The Spatially Resolved Stellar Initial Mass Function In ~400 Early-Type Galaxies, Taniya Parikh, Daniel Thomas, Claudia Maraston, Kyle B. Westfall, Daniel Goddard, Jianhui Lian, Sofia Meneses-Goytia, Amy Jones, Sam Vaughan, Brett H. Andrews, Matthew Bershady, Dmitry Bizyaev, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Niv Drory, Eric Emsellem, David R. Law, Jeffrey A. Newman, Alexandre Roman-Lopes, David Wake, Renbin Yan, Zheng Zheng
Physics and Astronomy Faculty Publications
Mapping Nearby Galaxies at Apache Point Observatory provides the opportunity to make precise spatially resolved measurements of the IMF slope in galaxies owing to its unique combination of spatial resolution, wavelength coverage, and sample size. We derive radial gradients in age, element abundances, and IMF slope analysing optical and near-infrared absorption features from stacked spectra out to the half-light radius of 366 early-type galaxies with masses 9.9–10.8 log M/M⊙. We find flat gradients in age and [α/Fe] ratio, as well as negative gradients in metallicity, consistent with the literature. We further derive significant negative gradients …