论文标题
产生MGII吸收的类星体顶部星系的性质
Nature of the Galaxies On Top Of Quasars producing MgII absorption
论文作者
论文摘要
小分离处的类星 - 加拉克斯对是星系中磁盘 - 哈洛界面中气流的重要探针。我们研究了198个MGII吸收剂的宿主星系，价格为$ 0.39 \ le z_ {abs} \ le1.05 $，显示了SDSS Spectra中可检测到的nebular发射线。 We report measurements of impact parameter (5.9$\le D[kpc]\le$16.9) and absolute B-band magnitude ($-18.7\le {\rm M_B}\le -22.3$ mag) of host galaxies of 74 of these absorbers using multi-band images from the DESI Legacy Imaging Survey, more than doubling the number of known host galaxies with $ d \ le17 $ kpc。这使我们能够量化MGII休息等效宽度（$ W_ {2796} $）和D之间的关系，最佳拟合参数为$ W_ {2796}（D = 0）= 3.44 \ pm 0.20 $ 0.20 $ 0.20 $ angstrom和指数级的比例长度为21.6 $^{+2.41 $^{+2.41} {+2.41} = $ 1.97}我们发现$ M_B $和D之间有很大的反相关，以及$ M_B $和$ W_ {2796} $，与产生更强的MGII吸收的明亮星系一致。我们使用堆叠的图像来检测完整样品中星系的平均排放。使用这些图像和堆叠的光谱，我们得出平均恒星质量（$ 9.4 \ le log（m _*/m _ \ odot）\ 9.8 $），星形组（$ 2.3 \ le {\ rm sfr} [m_ \ odot yr^{ - 1}] （12+log（o/h）$ \ sim $ 8.3）和电离参数（log〜q [cm s $^{ - 1} $] $ \ sim $ 7.7）。与文献中研究的MGII吸收器相比，发现的平均$ m _*$比较少。推断出的平均SFR和金属性与主序列和已知恒星质量金属关系中的预期一致。该样品的高空间分辨率随访和该样品的成像观察对于探测靠近高$ z $星系的星形区域的气流。
Quasar-galaxy pairs at small separations are important probes of gas flows in the disk-halo interface in galaxies. We study host galaxies of 198 MgII absorbers at $0.39\le z_{abs}\le1.05$ that show detectable nebular emission lines in the SDSS spectra. We report measurements of impact parameter (5.9$\le D[kpc]\le$16.9) and absolute B-band magnitude ($-18.7\le {\rm M_B}\le -22.3$ mag) of host galaxies of 74 of these absorbers using multi-band images from the DESI Legacy Imaging Survey, more than doubling the number of known host galaxies with $D\le17$ kpc. This has allowed us to quantify the relationship between MgII rest equivalent width($W_{2796}$) and D, with best-fit parameters of $W_{2796}(D=0) = 3.44\pm 0.20$ Angstrom and an exponential scale length of 21.6$^{+2.41}_{-1.97}$ $kpc$. We find a significant anti-correlation between $M_B$ and D, and $M_B$ and $W_{2796}$, consistent with the brighter galaxies producing stronger MgII absorption. We use stacked images to detect average emissions from galaxies in the full sample. Using these images and stacked spectra, we derive the mean stellar mass ($9.4\le log(M_*/M_\odot) \le 9.8$), star formation rate ($2.3\le{\rm SFR}[M_\odot yr^{-1}] \le 4.5$), age (2.5$-$4 Gyr), metallicity (12+log(O/H)$\sim$8.3) and ionization parameter (log~q[cm s$^{-1}$]$\sim$ 7.7) for these galaxies. The average $M_*$ found is less compared to those of MgII absorbers studied in the literature. The average SFR and metallicity inferred are consistent with that expected in the main sequence and the known stellar mass-metallicity relation, respectively. High spatial resolution follow-up spectroscopic and imaging observations of this sample are imperative for probing gas flows close to the star-forming regions of high-$z$ galaxies.
