The sizes and kinematic structure of absorption systems towards the lensed quasar APM08279+5255
The sizes and kinematic structure of absorption systems towards the lensed quasar APM08279+5255
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透镜类星体 APM08279 5255 吸收系统的尺寸和运动结构
DOI：
10.1051/0004-6361:20034003
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发表时间：
2003
影响因子：
6.5
通讯作者：
R. Srianand
中科院分区：
文献类型：
--
作者：
S. Ellison;R. Ibata;M. Pettini;G. Lewis;B. Aracil;P. Petitjean;R. Srianand
利用哈勃空间望远镜（HST）上的空间望远镜成像光谱仪（STIS）获得了z em = 3.911的类星体APM 08279 + 5255的空间分辨光谱。我们研究视线等效宽度（EW）的差异和速度剪切的高，低电离吸收（包括阻尼莱曼α [DLA]系统中确定的空间分辨地基光谱）在三条视线。一个特别丰富的光谱和三个视线的组合，使我们能够研究27个干预吸收系统的红移范围1.1 80%）超过千秒差距尺度。强（EW> 0.3A）Mg Ⅱ系统的最小半径大于1.4h-170kpc。对于弱Mg Ⅱ吸收体（EW <0.3 A），最大似然分析表明，均匀球形几何体的最可几相干尺度为2.0 h-1 70 kpc，95%置信限在1.5~4.4 h-1 70 kpc之间。因此，弱镁II吸收剂可能代表一个独特的人口较小的星系相比，我们知道，强镁II系统与发光星系的晕延伸超过几十千秒差距。或者，弱星系可能位于较大星系的外部，那里的填充因子可能较低。通过互相关谱沿着不同的视线，我们推断剪切速度通常小于20公里s-1的高和低电离吸收。最后，对于可以自信地转换为柱密度的弱吸收系统，我们发现在三条视线上的常数N（C IV）/N（Si IV）。同样，在z abs = 2.974DLA中的[Al/Fe]比值与太阳相对丰度在1.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
We have obtained spatially resolved spectra of the z em = 3.911 triply imaged QSO APM08279+5255 using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). We study the line of sight equivalent width (EW) differences and velocity shear of high and low ionization absorbers (including a damped Lyman alpha [DLA] system identified in a spatially unresolved ground based spectrum) in the three lines of sight. The combination of a particularly rich spectrum and three sight-lines allow us to study 27 intervening absorption systems over a redshift range 1.1 80%) over kpc scales. A minimum radius for strong (EW > 0.3 A) Mg II systems of >1.4 h -1 70 kpc is inferred from absorption coincidences in all lines of sight. For weak Mg II absorbers (EW < 0.3 A), a maximum likelihood analysis indicates a most probable coherence scale of 2.0 h -1 70 kpc for a uniform spherical geometry, with 95% confidence limits ranging between 1.5 and 4.4 h -1 70 kpc. The weak Mg II absorbers may therefore represent a distinct population of smaller galaxies compared with the strong Mg II systems which we know to be associated with luminous galaxies whose halos extend over tens of kpc. Alternatively, the weak systems may reside in the outer parts of larger galaxies, where their filling factor may be lower. By cross-correlating spectra along different lines of sight, we infer shear velocities of typically less than 20 km s -1 for both high and low ionization absorbers. Finally, for systems with weak absorption that can be confidently converted to column densities, we find constant N(C IV)/N(Si IV) across the three lines of sight. Similarly, the [Al/Fe] ratios in the z abs = 2.974 DLA are consistent with solar relative abundances over a transverse distance of ∼0.35 h -1 70 kpc.