부산대학교 도서관

The physical conditions of the circumgalactic medium are investigated by means of intervening absorption-line systems in the spectrum of background quasi-stellar objects (QSOs) out to the epoch of cosmic reionization1–4. A correlation between the ionization state of the absorbing gas and the nature of the nearby galaxies has been suggested by the sources detected in either Lyα or [C ii] 158 μm near to, respectively, highly ionized and neutral absorbers5,6. This is also probably linked to the global changes in the incidence of absorption systems of different types and the process of cosmic reionization7–12. Here we report the detection of two [C ii]-emitting galaxies at redshift z ≈ 5.7 that are associated with a complex, high-ionization C iv absorption system. These objects are part of an overdensity of galaxies and have compact sizes (