A study of the light variation of distant quasars by near-infrared imaging II

DOI
  • Sekine Shota
    Department of Physics, School of Advanced Science and Engineering, Faculty of Scinece and Engineering, Waseda University
  • Inoue Akio
    Department of Physics, School of Advanced Science and Engineering, Faculty of Scinece and Engineering, Waseda University Waseda Research Institute for Science and Engineering, Faculty of Science and Engineering, Waseda University
  • Saito Tomoki
    Nishi-Harima Astronomical Observatory, Center for Astronomy, the University of Hyogo
  • Yamanaka Satoshi
    NIT Toba Collage
  • Fujimoto Seiji
    Department of Astronomy, the University of Texas at Austin
  • Motohara Kentaro
    Advanced Technology Center, National Astronomical Observatory of Japan Department of Astronomy, Faculty of Science, the University of Tokyo
  • Konishi Masahiro
    Institute of Astronomy, Faculty of Science, the University of Tokyo
  • Takahashi Hidenori
    Kiso Observatory, Institute of Astronomy, Faculty of Science, the University of Tokyo
  • Koyama Shuhei
    Institute of Astronomy, Faculty of Science, the University of Tokyo
  • Kushibiki Kosuke
    Department of Astronomy, Faculty of Science, the University of Tokyo
  • Yoshii Yuzuru
    Institute of Astronomy, Faculty of Science, the University of Tokyo Steward Observatory, the University of Arizona
  • Miyata Takashi
    Institute of Astronomy, Faculty of Science, the University of Tokyo

Bibliographic Information

Other Title
  • 近赤外線撮像観測による遠方クェーサーの変光調査II

Abstract

In the early universe, the formation process of supermassive blackholes in quasars is still in debate. Our group focuses on the light variation of quasars and discuss this problem. We continuously observe high-z quasars in J, H, and Ks bands with Nayuta/NIC since 2019. Here we report 2022 data for three quasars, PSO338+29 (redshift z = 6.66), ULAS J1120+0641 (redshift z = 7.09) and ULAS J1342+0928 (redshift z = 7.54). We also report J, Ks bands magnitude of ULAS J1342+0928 observed with Subaru/SWIMS in 2022. PSO338+29 shows a ∼ 2 σ level light variation in the J band. ULAS J1342+0928 shows a sign of ∼ 102 days periodic variation in the J band. At redshift z ∼ 7, the C IV emission line comes into the J band. Hence, we discuss the relation between periodic motion of BLR (Broad Line Region) to this variability period. The orbital period of BLR is ∼ 104 days. We conclude that the BLR motion is not responsible to this periodic variability. It is important to reduce the magnitude uncertainty for the variability research. We have examined the magnitude uncertainties when adopting different numbers of dithering points and ubercalibration. However, any significant reduction of the uncertainties was not observed.

Journal

  • Stars and Galaxies

    Stars and Galaxies 5 (0), 9-, 2022

    Center for Astronomy, University of Hyogo

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