期刊
ASTROPHYSICAL JOURNAL
卷 728, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/728/2/119
关键词
galaxies: interactions
资金
- NSF [AST-0607701, 0908246, 0908442, 0908354]
- NASA [08-ADP08-0019, NAS 5-26555]
- Space Telescope Science Institute [HF-01217]
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [0908246] Funding Source: National Science Foundation
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [0908442] Funding Source: National Science Foundation
Tidal interactions between galaxies can trigger star formation, which contributes to the global star formation rate (SFR) density of the universe and could be a factor in the transformation of blue, star-forming galaxies to red, quiescent galaxies over cosmic time. We investigate tidally triggered star formation in isolated close galaxy pairs drawn from the Prism Multi-Object Survey (PRIMUS), a low-dispersion prism redshift survey that has measured similar to 120,000 robust galaxy redshifts over 9.1 deg(2) out to z similar to 1. We select a sample of galaxies in isolated galaxy pairs at redshifts 0.25 <= z <= 0.75, with no other objects within a projected separation of 300 h(-1) kpc and Delta z/(1 + z) = 0.01, and compare them to a control sample of isolated galaxies to test for systematic differences in their rest-frame FUV - r and NUV - r colors as a proxy for relative specific star formation rates (SSFRs). We find that galaxies in r(p) <= 50 h(-1) kpc pairs have bluer dust-corrected UV - r colors on average than the control galaxies by -0.134 +/- 0.045 mag in FUV - r and -0.075 +/- 0.038 mag in NUV - r, corresponding to an similar to 15%-20% increase in SSFR. This indicates an enhancement in SSFR due to tidal interactions. We also find that this relative enhancement is greater for a subset of r(p) <= 30 h(-1) kpc pair galaxies, for which the average color offsets are -0.193 +/- 0.065 mag in FUV - r and -0.159 +/- 0.048 mag in NUV - r, corresponding to an similar to 25%-30% increase in SSFR. We test for evolution in the enhancement of tidally triggered star formation with redshift across our sample redshift range and find marginal evidence for a decrease in SSFR enhancement from 0.25 <= z <= 0.5 to 0.5 <= z <= 0.75. This indicates that a change in enhanced star formation triggered by tidal interactions in low-density environments is not a contributor to the decline in the global SFR density across this redshift range.
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