Sodium excess objects. I. SDSS-DR7 Virtual Observatory Resource

Authors
  1. Jeong H.
  2. Yi S.K.
  3. Kyeong J.
  4. Sarzi M.
  5. Sung E.-C.
  6. Oh K.
  7. Published by
    CDS
Abstract

Several studies have reported the presence of sodium excess objects having neutral atomic absorption lines at 5895{AA} (Na.D) and 8190{AA} that are deeper than expected based on stellar population models that match the stellar continuum. The origin of these lines is therefore hotly debated. van Dokkum & Conroy (2010Natur.468..940V) proposed that low-mass stars (<~0.3M_{sun}_) are more prevalent in massive early-type galaxies, which may lead to a strong Na I 8190 line strength. It is necessary to test this prediction, however, against other prominent optical line indices such as Na.D, Mg b, and Fe 5270, which can be measured with a significantly higher signal-to-noise ratio than Na I 8190. We identified a new sample of roughly 1000 Na.D excess objects (NEOs; ~8% of galaxies in the sample) based on Na.D line strength in the redshift range 0.00<=z<=0.08 from the Sloan Digital Sky Survey (SDSS) DR7 through detailed analysis of galaxy spectra. We explore the properties of these new objects here. The novelty of this work is that the galaxies were carefully identified through direct visual inspection of SDSS images, and we systematically compared the properties of NEOs and those of a control sample of galaxies with normal Na.D line strengths. We note that the majority of galaxies with high velocity dispersions ({sigma}_e_>250km/s) show Na.D excesses.

Keywords
  1. chemical-abundances
  2. galaxies
  3. spectroscopy
  4. visible-astronomy
  5. sloan-photometry
  6. galaxy-classification-systems
  7. redshifted
Bibliographic source Bibcode
2013ApJS..208....7J
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/208/7
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJS/208/7
Document Object Identifer DOI
doi:10.26093/cds/vizier.22080007

Access

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http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/208/7
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http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/208/7/table5?

History

2013-10-28T08:54:41Z
Resource record created
2013-10-28T08:54:41Z
Created
2013-11-12T20:46:20Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr