标题： PRIMUS: 密近星系对中的增强恒星形成速率 显示英文标题

标题： PRIMUS: Enhanced Specific Star Formation Rates In Close Galaxy Pairs

摘要： 星系之间的潮汐相互作用可以触发恒星形成，这有助于宇宙的总体恒星形成率密度，并可能是蓝、正在形成恒星的星系随着时间转变为红、休眠星系的因素之一。 我们研究了来自光谱多目标巡天（PRIMUS）的孤立近距星系对中的潮汐触发恒星形成，这是一个低色散棱镜红移巡天，已在9.1平方度范围内测量了约12万可靠星系红移，直到z ≈ 1。 我们选择了一组红移在0.25 < z < 0.75之间、在投影分离300 h^-1 kpc内没有其他物体且dz/(1+z) = 0.01的孤立星系对样本，并将其与孤立星系对照样本进行比较，以测试它们的FUV-r和NUV-r框架下相对比值作为相对特定SFR的代理是否存在系统性差异。 我们发现，r_p < 50 h^-1 kpc的星系对中的星系在FUV-r中比对照星系平均更蓝，差值为-0.134 ± 0.045个亮度等级，在NUV-r中为-0.075 ± 0.038个亮度等级，分别对应于SSFR约15-20%的增加。 这表明由于潮汐相互作用导致SSFR增强。 我们还发现，对于r_p < 30 h^-1 kpc的子集星系对，这种相对增强更大，其中FUV-r中的平均颜色偏移为-0.193 ± 0.065个亮度等级，NUV-r中为-0.159 ± 0.048个亮度等级，分别对应于SSFR约25-30%的增加。 我们在样本红移范围内测试了潮汐触发恒星形成的增强随红移的变化情况，并发现在0.25 < z < 0.5到0.5 < z < 0.75之间存在SSFR增强减弱的边缘证据。 这表明由潮汐相互作用在低密度环境中触发的增强恒星形成的变化不是这一红移范围内全球恒星形成率密度下降的原因。 显示英文摘要

摘要： Tidal interactions between galaxies can trigger star formation, which contributes to the global star formation rate 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 ~120,000 robust galaxy redshifts over 9.1 deg^2 out to z ~ 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 dz/(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 SFR. 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 magnitudes in FUV-r and -0.075 +/- 0.038 magnitudes in NUV-r, corresponding to a ~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 colors offsets are -0.193 +/- 0.065 magnitudes in FUV-r and -0.159 +/- 0.048 magnitudes in NUV-r, corresponding to a ~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 star formation rate density across this redshift range.