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arXiv 2201.07257astro-ph.GAastro-ph.CO
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MUSE eXtremely深场:z~2.9-4.4静止标架紫外选择星系周围Lyα晕的单个探测

The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z~2.9-4.4

Haruka Kusakabe, Anne Verhamme, Jeremy Blaizot, Thibault Garel, Lutz Wisotzki, Floriane Leclercq, Roland Bacon, Joop Schaye, Sofia G. Gallego, Josephine Kerutt,… 展开作者

Haruka Kusakabe, Anne Verhamme, Jeremy Blaizot, Thibault Garel, Lutz Wisotzki, Floriane Leclercq, Roland Bacon, Joop Schaye, Sofia G. Gallego, Josephine Kerutt, Jorryt Matthee, Michael Maseda, Themiya Nanayakkara, Roser Pello, Johan Richard, Laurence Tresse, Tanya Urrutia, Eloise Vitte

摘要:

氢Ly $α$晕(LAH)通常被用作环星系介质(CGM)高红移的示踪剂。在这项工作中,我们的目标是探索存在的Ly $α$晕周围的个别UV选择的星系,而不是周围的Ly $α$发射器(LAEs),在高红移。我们的样品是连续选择的,F775 W <=27.5,由于最深(100至140小时)的现有甚大望远镜(VLT)/多单元光谱探测器(MUSE)数据与自适应光学,光谱红移被分配或约束的所有来源。最后的样本包括21个星系,这些星系都是在红移范围z=2.9-4.4和UV星等范围-20<=M1500<=-18内选择的纯F775 W星等,从而避免了对LAE的任何偏见。我们测试了银河系的Ly $α$发射是否比MUSE PSF卷积连续分量更显着扩展。我们发现了17个LAH和4个非LAH。我们报告的第一个人检测到的扩展赖氨酸$α$发射周围的非LAEs。因此,Ly $α$晕圈分数高达$81.0^{+10.3}_{-11.2}$ %,这接近于文献中z=3-6的LAE的分数。这意味着紫外线选择的星系通常在其CGM中有大量的氢。我们推导出了我们的LAHs的平均表面亮度(SB)的轮廓与宇宙调光校正,发现赖氨酸$α$发射扩展到5.4弧秒(~40物理千秒差距,在中点红移z=3.6)以上的典型的1 $σ$ SB限制。对于M1500 ≤-18等、z~3.7的星系,在Ly $α$中探测到的周围气体的入射率dn/dz估计为$0.76^{+0.09}_{-0.09}$。假设Ly $α$发射和吸收出现在相同的气体中,这表明,基于丰度匹配,LAH追踪与阻尼Ly $α$系统(DLAs)和子DLAs相同的气体。

英文摘要:

Hydrogen Ly$α$ haloes (LAHs) are commonly used as a tracer of the circumgalactic medium (CGM) at high redshifts. In this work, we aim to explore the existence of Ly$α$ haloes around individual UV-selected galaxies, rather than around Ly$α$ emitters (LAEs), at high redshifts. Our sample was continuum-selected with F775W<=27.5, and spectroscopic redshifts were assigned or constrained for all the sources thanks to the deepest (100- to 140-hour) existing Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) data with adaptive optics. The final sample includes 21 galaxies that are purely F775W-magnitude selected within the redshift range z=2.9-4.4 and within a UV magnitude range -20<=M1500<= -18, thus avoiding any bias toward LAEs. We tested whether galaxy's Ly$α$ emission is significantly more extended than the MUSE PSF-convolved continuum component. We find 17 LAHs and four non-LAHs. We report the first individual detections of extended Ly$α$ emission around non-LAEs. The Ly$α$ halo fraction is thus as high as $81.0^{+10.3}_{-11.2}$%, which is close to that for LAEs at z=3-6 in the literature. This implies that UV-selected galaxies generally have a large amount of hydrogen in their CGM. We derived the mean surface brightness (SB) profile for our LAHs with cosmic dimming corrections and find that Ly$α$ emission extends to 5.4 arcsec (~40 physical kpc at the midpoint redshift z=3.6) above the typical 1$σ$ SB limit. The incidence rate of surrounding gas detected in Ly$α$ per one-dimensional line of sight per unit redshift, dn/dz, is estimated to be $0.76^{+0.09}_{-0.09}$ for galaxies with M1500<= -18 mag at z~3.7. Assuming that Ly$α$ emission and absorption arise in the same gas, this suggests, based on abundance matching, that LAHs trace the same gas as damped Ly$α$ systems (DLAs) and sub-DLAs.

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