Triggered Star Formation in Galaxy Pairs at z=0.08-0.38
| Autor: | Ian P. Dell'Antonio, Michael J. Kurtz, Deborah Freedman Woods, Eduard Westra, Daniel G. Fabricant, Margaret J. Geller |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Physics
education.field_of_study Cosmology and Nongalactic Astrophysics (astro-ph.CO) Stellar population Star formation Population FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Redshift survey Galaxy Redshift Stars Space and Planetary Science Astrophysics::Solar and Stellar Astrophysics Emission spectrum Astrophysics::Earth and Planetary Astrophysics education Astrophysics::Galaxy Astrophysics Astrophysics - Cosmology and Nongalactic Astrophysics |
| Popis: | We measure the strength, frequency, and timescale of tidally triggered star formation at redshift z=0.08-0.38 in a spectroscopically complete sample of galaxy pairs drawn from the magnitude-limited redshift survey of 9,825 Smithsonian Hectospec Lensing Survey (SHELS) galaxies with R1/5) pair galaxies with $M_R < -20.8 in the redshift range z=0.08-0.31. The size and completeness of the spectroscopic survey allows us to focus on regions of low local density. The spectrophotometric calibration enables the use of the 4000 Ang break (D_n4000), the H\alpha specific star formation rate (SSFR_{H\alpha}), and population models to characterize the galaxies. We show that D_n4000 is a useful population classification tool; it closely tracks the identification of emission line galaxies. The sample of major pair galaxies in regions of low local density with low D_n4000 demonstrates the expected anti-correlation between pair-wise projected separation and a set of star formation indicators explored in previous studies. We measure the frequency of triggered star formation by comparing the SSFR_{H\alpha} in the volume-limited sample in regions of low local density: 32 +/-7% of the major pair galaxies have SSFR_{H\alpha} at least double the median rate of the unpaired field galaxies. Comparison of stellar population models for pair and for unpaired field galaxies implies a timescale for triggered star formation of ~300-400 Myr. Comment: 25 pages, 15 figures. Accepted to AJ |
| Databáze: | OpenAIRE |
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