Properties of Barred Galaxies in SDSSastrokias.kias.re.kr/sdssksg09/Data/0210/2.4... · Properties...
Transcript of Properties of Barred Galaxies in SDSSastrokias.kias.re.kr/sdssksg09/Data/0210/2.4... · Properties...
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2009. 2. 10 – 12
SDSS KSG winter workshop
Gwang-Ho Lee, Changbom Park, & Yun-Young Choi
Properties of Barred Galaxies in SDSS
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Introduction
• Understanding the role that environment plays in the
process of galaxy formation and evolution is one of
the most important problems in recent astrophysics.
• Bar structures are believed to be important with
regard to the evolution of late-type galaxies. But, it
remains an open question.
• Our goal is to understand how the properties of
galaxies, like as environment factors, affect the
formation of the bar.
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Data Set & Visual Classification
1. Start with D2 sample of 15,414 galaxies drawn from DR4+
with Mr < -19.5, and redshift 0.025 < z < 0.05485
→ 1,267 barred galaxies → bar fraction 8.2%
2. Find 8,689 late-type galaxies (S/Irr) using automated method
(Park & Choi, 2005) and additional visual classification
→ 968 barred galaxies → bar fraction 11.1%
3. Excluding highly inclined (b/a < 0.6) systems,
5,156 Late-type galaxies remain.
→ 792 barred galaxies → bar fraction 15.4%
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Dependence of The Bar fraction
1. Physical ParametersNo Dependence
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Dependence of The Bar Fraction
2. Local Galaxy Number Density
No Dependence?
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Dependence of The Bar Fraction
2. Local Galaxy Number Density
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Dependence of The Bar Fraction
3. The Nearest Neighbor Galaxy
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Conclusion
• The bar fraction of late-type depends strongly on color of the galaxies. The bar fraction is higher in redder galaxies.
• When color and luminosity are fixed, local galaxy number density seems to affect the bar fraction.
• We also find that the bar fraction depends on environment attributed to the distance of nearest neighbor and also on neighbor’ morphology.
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Thanks !!