The stellar mass content of distant galaxy groups
The stellar mass content of distant galaxy groups
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遥远星系群的恒星质量含量
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发表时间：
2006
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通讯作者：
Ociw
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作者：
M. Balogh;D. Wilman;Robert D E Henderson;R. Bower;D. Gilbank;R. Whitaker;S. Morris;G. Hau;J. Mulchaey;A. Oemler;R. G. C. U. O. Waterloo;Mpe;Garching;D. University;U. Toronto;Ociw
我们从威廉·赫歇尔望远镜和斯皮策望远镜红外阵列相机 (IRAC) 数据档案中获得了 58 个星系团的近红外 (NIR) 成像，红移范围为 0.1 < z < 0.6。这些组是从 CNOC2 红移巡天中选出的，并带有来自巴德望远镜（麦哲伦）的附加光谱。我们的小组样本在统计上完整，K vega = 17.7 (INGRID) 和 [3.6 um] AB = 19.9 (IRAC)。根据这些数据，我们为速度色散、高达 800 km s -1 和红移的组构建 NIR 光度函数。将每组的近红外光度总量与根据速度色散估计的动态质量进行比较，以计算质光比 M 200 /LK。我们发现这些群体中的 M 200 /LK 值与其 z = 0 时的统计后代的值非常一致，没有证据表明进化超出了被动进化群体的预期。 M 200 /LK 随群体质量呈趋势，从 a < 250km S -1 群体的 M 200 /LK ≈ 10 增加到 425 km s -1 < a < 800km s -1 群体的 M 200 /LK ≈ 100。如果我们根据弱透镜测量来估计总质量，这种趋势较弱，但仍然存在。就恒星质量而言，最小星团中恒星质量占≥2%，最大质量星团中恒星质量占≤1%。我们还使用 NIR 数据来考虑 0.1 < z < 0.6 的星系群和场星系的恒星种群和恒星质量之间的相关性。我们发现，与相同恒星质量和相同红移的场星系相比，显示出强[On]发射的星系群较少。我们得出的结论是，这些群体中的大部分恒星质量在 z ∼ 0.4 时就已经就位，迄今为止几乎没有环境驱动的演化。
We have obtained near-infrared (NIR) imaging of 58 galaxy groups, in the redshift range 0.1 < z < 0.6, from the William Herschel Telescope and from the Spitzer telescope Infrared Array Camera (IRAC) data archive. The groups are selected from the CNOC2 redshift survey, with additional spectroscopy from the Baade telescope (Magellan). Our group samples are statistically complete to K vega = 17.7 (INGRID) and [3.6 um] AB = 19.9 (IRAC). From these data we construct NIR luminosity functions, for groups in bins of velocity dispersion, up to 800 km s -1 , and redshift. The total amount of NIR luminosity per group is compared with the dynamical mass, estimated from the velocity dispersion, to compute the mass-to-light ratio, M 200 /LK. We find that the M 200 /LK values in these groups are in good agreement with those of their statistical descendants at z = 0, with no evidence for evolution beyond that expected for a passively evolving population. There is a trend of M 200 /LK with group mass, which increases from M 200 /LK ≈ 10 for groups with a < 250km S -1 to M 200 /LK ≈ 100 for 425 km s -1 < a < 800km s -1 . This trend is weaker, but still present, if we estimate the total mass from weak lensing measurements. In terms of stellar mass, stars make up ≥2 per cent of the mass in the smallest groups, and ≤1 per cent in the most massive groups. We also use the NIR data to consider the correlations between stellar populations and stellar masses, for group and field galaxies at 0.1 < z < 0.6. We find that fewer group galaxies show strong [On] emission, compared with field galaxies of the same stellar mass and at the same redshift. We conclude that most of the stellar mass in these groups was already in place by z ∼ 0.4, with little environment-driven evolution to the present day.