Outflows in sodium excess objects

Jongwon Park, Hyunjin Jeong, Sukyoung Yi

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Van Dokkum and Conroy revisited the unexpectedly strong Na i lines at 8200 found in some giant elliptical galaxies and interpreted them as evidence for an unusually bottom-heavy initial mass function. Jeong et al. later found a large population of galaxies showing equally extraordinary Na D doublet absorption lines at 5900 (Na D excess objects: NEOs) and showed that their origins can be different for different types of galaxies. While a Na D excess seems to be related to the interstellar medium (ISM) in late-type galaxies, smooth-looking early-type NEOs show little or no dust extinction and hence no compelling signs of ISM contributions. To further test this finding, we measured the Doppler components in the Na D lines. We hypothesized that the ISM would have a better (albeit not definite) chance of showing a blueshift Doppler departure from the bulk of the stellar population due to outflow caused by either star formation or AGN activities. Many of the late-type NEOs clearly show blueshift in their Na D lines, which is consistent with the former interpretation that the Na D excess found in them is related to gas outflow caused by star formation. On the contrary, smooth-looking early-type NEOs do not show any notable Doppler components, which is also consistent with the interpretation of Jeong et al. that the Na D excess in early-type NEOs is likely not related to ISM activities but is purely stellar in origin.

Original languageEnglish
Article number91
JournalAstrophysical Journal
Volume809
Issue number1
DOIs
Publication statusPublished - 2015 Aug 10

Fingerprint

near Earth objects
outflow
sodium
D lines
galaxies
extinction
star formation
dust
gas
elliptical galaxies
gases
test

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Park, Jongwon ; Jeong, Hyunjin ; Yi, Sukyoung. / Outflows in sodium excess objects. In: Astrophysical Journal. 2015 ; Vol. 809, No. 1.
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Outflows in sodium excess objects. / Park, Jongwon; Jeong, Hyunjin; Yi, Sukyoung.

In: Astrophysical Journal, Vol. 809, No. 1, 91, 10.08.2015.

Research output: Contribution to journalArticle

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