Discovery of the Most Ultra-Luminous QSO Using GAIA, SkyMapper, and WISE
Abstract
We report the discovery of the ultra-luminous quasi-stellar object SMSS J215728.21-360215.1 with magnitude z = 16.9 and W4 = 7.42 at redshift 4.75. Given absolute magnitudes of M145, AB = -29.3, M300, AB = -30.12, and logLbol/Lbol, ⊙ = 14.84, it is the quasi-stellar object with the highest unlensed UV-optical luminosity currently known in the Universe. It was found by combining proper-motion data from Gaia DR2 with photometry from SkyMapper DR1 and the Wide-field Infrared Survey Explorer. In the GAIA database, it is an isolated single source and thus unlikely to be strongly gravitationally lensed. It is also unlikely to be a beamed source as it is not discovered in the radio domain by either NRAO-VLA Sky Survey or Sydney University Molonglo Southern Survey. It is classed as a weak-emission-line quasi-stellar object and possesses broad absorption line features. A lightcurve from ATLAS spanning the time from 2015 October to 2017 December shows little sign of variability.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- June 2018
- DOI:
- 10.1017/pasa.2018.22
- arXiv:
- arXiv:1805.04317
- Bibcode:
- 2018PASA...35...24W
- Keywords:
-
- galaxies: active;
- galaxies: high-redshift;
- quasars: general;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 6 pages, 4 figures, accepted for publication in PASA