S18A0134abst
S18A0134
We propose FOCAS spectroscopy of two z∼7 QSO candidates, PSO145+19 and PSO106+25. These QSO candidates were selected by us from PanSTARRs1 based on their red z−y color (z−y>3). Recently we obtained the submillimeter spectra of these sources with ALMA which showed high transition CO(6-5) lines at >4σ significance redshifted to 7.09 and 6.99. We also obtained marginal detection of the second line, CO(7-6), in the spectrum of PSO145+19. The detected CO emission of PSO145+19 and PSO106+25 originates from the star forming regions of their host galaxies. It provides strong constraints on the redshift of these two sources. However, to confirm their quasar nature, it is important to detect quasar lines, the strongest of which is the Lyα line. The goal of our observations with FOCAS is to detect the Lyα lines of PSO145+19 and PSO106+25 at the wavelengths corresponding to their redshifted CO emission. Currently there is only one QSO known at z∼7, ULAS J1120+0641 at z=7.08. If confirmed, PSO145+19 and PSO106+25 will increase the number of known z∼7 QSOs and will be very important for the studies of the early Universe.
This document was translated from LATEX by HEVEA.