STELLAR POPULATIONS OF ULTRALUMINOUS INFRARED GALAXIES

Journal Article · Tue May 10 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/2/72· OSTI ID:21576890

Hou, L G; Han, J L ^[1]; Kong, M Z ^[2]; Xuebing, Wu ^[3]

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1. National Astronomical Observatories, Chinese Academy of Sciences, Jia-20 DaTun Road, Chaoyang District, Beijing 100012 (China)
2. Department of Physics, Hebei Normal University, Shijiazhuang 050016 (China)
3. Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)

Ultraluminous infrared galaxies (ULIRGs) are classified into several types depending on the dominance of starburst or active galactic nucleus (AGN) components. We conducted a stellar population analysis for a sample of 160 ULIRGs to study the evolution of ULIRGs. We found that the dominance of intermediate-age and old stellar populations increases along the sequence of H II-like ULIRGs, Seyfert-H II composite ULIRGs, and Seyfert 2 ULIRGs. Consequently, the typical mean stellar age and stellar mass increase along the sequence. Comparing the gas mass estimated from the CO measurements to the stellar mass estimated from the optical spectra, we found that the gas fraction is anti-correlated with stellar mass. Even so, the total masses of H II-like ULIRGs with small stellar masses and a large fraction of gas are not comparable to the small masses of Seyfert 2 ULIRGs. This indicates that H II-like ULIRGs with small stellar masses have no evolutionary connections with massive Seyfert 2 ULIRGs. Only massive ULIRGs may follow the evolution sequence toward AGNs, and massive H II-like ULIRGs are probably in an earlier stage of the sequence.

• OSTI ID: 21576890
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 732; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
MASS
OXIDES
OXYGEN COMPOUNDS
STARS