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Date and Time of the Query: 2019-05-20 T02:13:51 PDT
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For refcode 2013ApJ...776...64G:
Retrieve 33 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
2013ApJ...776...64G The Stellar Halos of Massive Elliptical Galaxies. II. Detailed Abundance Ratios at Large Radius Greene, Jenny E.; Murphy, Jeremy D.; Graves, Genevieve J.; Gunn, James E.; Raskutti, Sudhir; Comerford, Julia M.; Gebhardt, Karl Abstract. We study the radial dependence in stellar populations of 33 nearby early-type galaxies with central stellar velocity dispersions sigma_*_ >~ 150 km s^-1^. We measure stellar population properties in composite spectra, and use ratios of these composites to highlight the largest spectral changes as a function of radius. Based on stellar population modeling, the typical star at 2R_e_ is old (~10 Gyr), relatively metal-poor ([Fe/H] ~ -0.5), and {alpha}-enhanced ([Mg/Fe] ~ 0.3). The stars were made rapidly at z ~ 1.5-2 in shallow potential wells. Declining radial gradients in [C/Fe], which follow [Fe/H], also arise from rapid star formation timescales due to declining carbon yields from low-metallicity massive stars. In contrast, [N/Fe] remains high at large radius. Stars at large radius have different abundance ratio patterns from stars in the center of any present-day galaxy, but are similar to average Milky Way thick disk stars. Our observations are thus consistent with a picture in which the stellar outskirts are built up through minor mergers with disky galaxies whose star formation is truncated early (z ~ 1.5-2). Key words: galaxies: abundances, galaxies: elliptical and lenticular, cD, galaxies: evolution
Retrieve 33 NED objects in this reference.
Please click here for ADS abstract

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