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arXiv 2109.06206astro-ph.GA
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亚千秒差距尺度透镜$z \sim 1$星系的径向轮廓

Radial profiles of lensed $z \sim 1$ galaxies on sub-kiloparsec scales

David Nagy, Miroslava Dessauges-Zavadsky, Johan Richard, Daniel Schaerer, Françoise Combes, Matteo Messa, John Chisholm

摘要:

我们研究了MACS J1206.2-0847中的宇宙蛇弧和Abell 0521(A521)中的宇宙蛇弧的空间分辨物理性质。这是两个强透镜星系,红移分别为$z=1.036$和$z=1.044$。我们使用了哈勃太空望远镜(HST)和阿塔卡马大型毫米/亚毫米阵列(ALMA)的观测结果。前者提供恒星形成率(SFR)和恒星质量($M_\star$),后者提供H $_2$分子气体质量($M_{\mathrm{mol}}$)。HST和ALMA观测具有相似的$0.15^{\prime \prime}-0.2^{\prime \prime}$角分辨率,在强引力透镜的帮助下,使我们能够分别在这两个星系中达到$\sim 30\,\mathrm{pc}$和$\sim 100\,\mathrm{pc}$的空间分辨率。这些分辨率接近观测附近星系的分辨率。我们研究了这些高红移星系的SFR、$M_\star$和$M_{\mathrm{mol}}$表面密度的径向分布,并将相应的指数尺度长度与本星系的指数尺度长度进行了比较。我们发现宇宙蛇的标度长度约为$0.5\,\mathrm{kpc}-1.5\,\mathrm{kpc}$,而A521的标度长度要大3到10倍。这是一个显着的差异,知道这两个星系具有可比的综合性质。然而,这些高红移标度长度与覆盖广泛分布的本地星系相当。我们的高红移径向配置文件的特殊性是$M_{\mathrm{mol}}$表面密度配置文件($ΣM_{\mathrm{mol}}$)的归一化,这是偏移高达20倍的$z=0$对应的配置文件。SFR表面密度分布也偏移了与$ΣM_{\mathrm{mol}}$相同的因子,正如Kennicutt-Schmidt定律所预期的那样。

英文摘要:

We study the spatially resolved physical properties of the Cosmic Snake arc in MACS J1206.2-0847 and the arc in Abell 0521 (A521). These are two strongly lensed galaxies at redshifts $z=1.036$ and $z=1.044$. We used observations of the Hubble Space Telescope (HST) and the Atacama Large Millimeter/submillimeter Array (ALMA). The former gives access to the star formation rate (SFR) and stellar mass ($M_\star$), and the latter to the H$_2$ molecular gas mass ($M_{\mathrm{mol}}$). HST and ALMA observations have similar angular resolutions of $0.15^{\prime \prime}-0.2^{\prime \prime}$, which with the help of strong gravitational lensing enable us to reach spatial resolutions down to $\sim 30\,\mathrm{pc}$ and $\sim 100\,\mathrm{pc}$ in these two galaxies, respectively. These resolutions are close to the resolution of observations of nearby galaxies. We study the radial profiles of SFR, $M_\star$, and $M_{\mathrm{mol}}$ surface densities of these high-redshift galaxies and compare the corresponding exponential scale lengths with those of local galaxies. We find that the scale lengths in the Cosmic Snake are about $0.5\,\mathrm{kpc}-1.5\,\mathrm{kpc}$, and they are 3 to 10 times larger in A521. This is a significant difference knowing that the two galaxies have comparable integrated properties. These high-redshift scale lengths are nevertheless comparable to those of local galaxies, which cover a wide distribution. The particularity of our high-redshift radial profiles is the normalisation of the $M_{\mathrm{mol}}$ surface density profiles ($ΣM_{\mathrm{mol}}$), which are offset by up to a factor of 20 with respect to the profiles of $z=0$ counterparts. The SFR surface density profiles are also offset by the same factor as $ΣM_{\mathrm{mol}}$, as expected from the Kennicutt-Schmidt law.

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