The Cosmic Ultraviolet Baryon Survey (CUBS) – I. Overview and the diverse environments of Lyman limit systems at z < 1
Monthly Notices of the Royal Astronomical Society(2020)
摘要
We present initial results from the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS is designed to map diffuse baryonic structures at redshift z ≲ 1 using absorption-line spectroscopy of 15 UV-bright QSOs with matching deep galaxy survey data. CUBS QSOs are selected based on their NUV brightness to avoid biases against the presence of intervening Lyman limit systems (LLSs) at z
abs
< 1. We report five new LLSs of
$\log \, N({\mathrm{ H} \,{\small I}})/{{\rm cm^{-2}}}\gtrsim 17.2$
over a total redshift survey path-length of
$\Delta \, z_{\mathrm{ LL}}=9.3$
, and a number density of
$n(z)=0.43_{-0.18}^{+0.26}$
. Considering all absorbers with
$\log \, N({{\mathrm{ H} \,{\small I}}})/{{\rm cm^{-2}}}\gt 16.5$
leads to
$n(z)=1.08_{-0.25}^{+0.31}$
at z
abs
< 1. All LLSs exhibit a multicomponent structure and associated metal transitions from multiple ionization states such as C ii, C iii, Mg ii, Si ii, Si iii, and O vi absorption. Differential chemical enrichment levels as well as ionization states are directly observed across individual components in three LLSs. We present deep galaxy survey data obtained using the VLT-MUSE integral field spectrograph and the Magellan Telescopes, reaching sensitivities necessary for detecting galaxies fainter than
$0.1\, L_*$
at d ≲ 300 physical kpc (pkpc) in all five fields. A diverse range of galaxy properties is seen around these LLSs, from a low-mass dwarf galaxy pair, a co-rotating gaseous halo/disc, a star-forming galaxy, a massive quiescent galaxy, to a galaxy group. The closest galaxies have projected distances ranging from d = 15 to 72 pkpc and intrinsic luminosities from
${\approx} 0.01\, L_*$
to
${\approx} 3\, L_*$
. Our study shows that LLSs originate in a variety of galaxy environments and trace gaseous structures with a broad range of metallicities.
更多查看译文
关键词
surveys,galaxies: evolution,galaxies: haloes,quasars: absorption lines
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要