High-redshift quasars in the PanSTARRS1 survey data
Ekaterina Koptelova1*, Tomotsugu Goto1
1Institute of Astronomy, National Tsing Hua University, Hsinchu, Taiwan
* presenting author:Ekaterina Koptelova, email:ekaterina@phys.nthu.edu.tw
High-redshift QSOs are highly important objects in various scientific aspects. For example, their spectra reveal the onset of reionization of the intergalactic medium (Gunn-Peterson trough). At high-redshifts (z > 6.5), Layman alpha emission of QSOs moves out of the z band into the redder y band. Therefore, to find a QSO at 6.5 < z < 8, a large survey in both optical z band and near-infrared y band is necessary. The Pan-STARRS1 survey provides a large enough area coverage (30000 deg2) in the z and y bands to find about 100 new high-redshift QSOs, the first sample to overcome cosmic variance at 6.5 < z < 7. We have carefully selected faint i- and z-band dropout objects and rejected contamination from brown dwarf stars. In this work we present our selection criteria and best candidates proposed for the long-slit follow-up spectroscopy with the FOCAS spectrograph on Subaru telescope. Acknowledgement: The projects is supported by the Ministry of Science and Technology of Taiwan and National Tsing Hua University (Contract No. 103VSR-56).

Keywords: cosmology, high-redshift quasars (QSOs), wide field surveys