arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0812.0427astro-ph
收藏

富星系团的IR光度函数

The IR Luminosity Functions of Rich Clusters

Lei Bai, George H. Rieke, Marcia J. Rieke, Daniel Christlein, Ann I. Zabludoff

摘要:

我们提出了星系团A3266的MIPS观测。在24微米处已经探测到大约100个光谱簇成员。A3266的红外光度函数与后发座星系团的红外光度函数非常相似,直到探测极限L_IR~10^43 ergs/s,这表明对于M~10^15 M_sun的局部富星系团,亮端红外LF是一种普遍形式。A3266-后发座复合红外LF的亮端形状与近场星系的亮端形状没有显著差异,但两个星系团中红外亮星系(SFR > 0.2M_sun/yr)所占的比例随团心半径的增加而增加。蓝星系比例向高密度核心的减少只是部分趋势;中等SFR(0.2 < SFR < 1 M_sun/yr)的红星系比例也随着星系密度的增加而减少。这些结果表明,对于红外亮星系,附近的富星系团与场的区别在于较低的恒星形成星系比例,而不是L*_IR的变化。与两个z~0.8星系团MS 1054和RX J 0152的合成IR LF相比,Coma和A3266的合成IR LF显示出强烈的演化,其中L*_IR \propto(1+z)^{3.2+/-0.7},Phi*_IR \propto(1+z)^{1.7+/-1.0}。这种L*_IR演化与在野外中的演化没有区别,并且Phi*_IR演化更强,但仍然与在野外中的演化一致。在非常不同的集群和领域环境中的亮端红外LF的演化的相似性表明,这种演化是由在两种环境中工作的机制驱动的,或者集群不断地从领域补充其恒星形成星系,产生类似于领域的红外LF的演化。在0.5R_200范围内的星团的质量归一化积分恒星形成率(SFR)也随着红移而强烈演化,如(1+z)^[5.3]。

英文摘要:

We present MIPS observations of the cluster A3266. About 100 spectroscopic cluster members have been detected at 24 micron. The IR luminosity function in A3266 is very similar to that in the Coma cluster down to the detection limit L_IR~10^43 ergs/s, suggesting a universal form of the bright end IR LF for local rich clusters with M~10^15 M_sun. The shape of the bright end of the A3266-Coma composite IR LF is not significantly different from that of nearby field galaxies, but the fraction of IR-bright galaxies (SFR > 0.2M_sun/yr) in both clusters increases with cluster-centric radius. The decrease of the blue galaxy fraction toward the high density cores only accounts for part of the trend; the fraction of red galaxies with moderate SFRs (0.2 < SFR < 1 M_sun/yr) also decreases with increasing galaxy density. These results suggest that for the IR bright galaxies, nearby rich clusters are distinguished from the field by a lower star-forming galaxy fraction, but not by a change in L*_IR. The composite IR LF of Coma and A3266 shows strong evolution when compared with the composite IR LF of two z~0.8 clusters, MS 1054 and RX J0152, with L*_IR \propto (1+z)^{3.2+/-0.7},Phi*_IR \propto (1+z)^{1.7+/-1.0}. This L*_IR evolution is indistinguishable from that in the field, and the Phi*_IR evolution is stronger, but still consistent with that in the field. The similarity of the evolution of bright-end IR LF in very different cluster and field environments suggests either this evolution is driven by the mechanism that works in both environments, or clusters continually replenish their star-forming galaxies from the field, yielding an evolution in the IR LF that is similar to the field. The mass-normalized integrated star formation rates (SFRs) of clusters within 0.5R_200 also evolve strongly with redshift, as (1+z)^5.3.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑