Galaxy group at z=0.3 associated with the damped Lyman α system towards quasar Q1127–145
Galaxy group at z=0.3 associated with the damped Lyman α system towards quasar Q1127–145
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z=0.3 处的星系群，与朝向类星体 Q1127–145 的阻尼莱曼 α 系统相关
DOI：
10.1111/j.1365-2966.2010.16667.x
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发表时间：
2010
影响因子：
4.8
通讯作者：
Nmsu
中科院分区：
文献类型：
--
作者：
G. Kacprzak;M. Murphy;C. Technology;Nmsu
我们对mF814W620.3 (LB> 0: 15L ？在类星体Q1127-145 （zem = 1:18）的100 ~ 100万范围内（z = 0: 3）。VLT/UVES类星体光谱包含三个zabs<0.33 Mgii的吸收系统。我们获得了8个新的星系红移，加上之前已知的4个，并在可能的情况下计算了星系恒星形成率（SFRs）和金属丰度。一个强Mgii系统（Wr(2796) = 1:8 A），是一个已知的阻尼ly吸收体（DLA），有三个先前确定的星系；我们发现了另外两个与这个系统有关的星系。这五个星系组成了一个具有不同性质的星系群，例如亮度范围为0.046 LB6 0.063 l ？B，冲击参数范围为17 6 D 6 241 kpc，速度弥散为115 km s−1。DLA星系群的红移跨越了DLA本身金属吸收线的350 km s−1速度扩展。两个最亮的星系群的SFRs小于Myr - 1，不应该有强风。我们有足够的光谱信息来直接比较五群星系中的三个（发射线）金属丰度w与DLA（吸收）金属丰度：DLA金属丰度为太阳的1/10，大大低于三个星系的金属丰度范围在不到1/2到太阳之间。HST/WFPC-2成像显示了三个最亮星系群的扰动多形态，潮汐尾延伸25kpc。我们倾向于认为DLA的吸收来自于群体环境中的潮汐碎片。另一个吸收体表现出弱的Mgii吸收（Wr(2796) = 0.03 A），并且有一个先前确定的星系处于类似的红移。我们已经确定了与这个系统有关的第二个星系。在HST/WFPC-2的图像中，这两个星系都有太阳的金属丰度和未扰动的形态。一个星系的SFR远低于强外流的预期。最后，我们还确定了5个没有相关Mgii吸收的大型星系的撞击参数（Wr(2796)）。Q1127-145光谱中的5:7 mA， 3°)。
We performed a spectroscopic galaxy survey, complete to mF814W620.3 (LB> 0: 15L ? B at z = 0: 3), within 100� 100 00 of the quasar Q1127-145 (zem = 1: 18). The VLT/UVES quasar spectrum contains three zabs<0.33 Mgii absorption systems. We obtained eight new galaxy redshifts, adding to the four previously known, and galaxy star formation rates (SFRs) and metallicities were computed where possible. A strong Mgii system (Wr(2796) = 1: 8 A), which is a known damped Lyabsorber (DLA), had three previously identified galaxies; w e found two additional galaxies associated with this system. These five galaxies form a group with diverse properties, such as a luminosity range of 0: 046 LB6 0: 63L ? B , an impact parameter range of 17 6 D 6 241 kpc and velocity dispersion of�= 115 km s −1 . The DLA group galaxy redshifts span beyond the 350 km s −1 velocity spread of the metallic absorption lines of the DLA itself. The two brightest group galaxies have SFRs offew Myr −1 and should not have strong winds. We have suffi cient spectroscopic information to directly compare three of the five group galaxies' (emission-line) metallicities w ith the DLA (absorption) metallicity: the DLA metallicity is 1/10th solar, substantially lower than the three galaxies' wh ich range between less than 1/2 solar to solar metallicity. HST/WFPC-2 imaging shows perturbed mor- phologies for the three brightest group galaxies, with tida l tails extending� 25 kpc. We favor a scenario where the DLA absorption originates from tidal debris in the group environment. Another absorber exhibits weak Mgii absorption (Wr(2796) = 0: 03 A) and had a previ- ously identified galaxy at a similar redshift. We have identi fied a second galaxy associated with this system. Both galaxies have solar metallicities an d unperturbed morphologies in the HST/WFPC-2 image. The SFR of one galaxy is much lower than expected for strong out- flows. Finally, we have also identified five galaxies at large i mpact parameters with no asso- ciated Mgii absorption (Wr(2796). 5: 7 mA, 3� ) in the spectrum of Q1127-145.