Abstract We report the discovery of a bright ($g = 14.5$$mag (AB),$$K = 11.9$$mag (Vega)) quasar at redshift$$z=0.83$$— the optically brightest (unbeamed) quasar at$$z>0.4$$. SMSS J114447.77-430859.3, at a Galactic latitude of$$b=+18.1^{\circ}$$, was identified by its optical colours from the SkyMapper Southern Survey (SMSS) during a search for symbiotic binary stars. Optical and near-infrared spectroscopy reveals broad Mgii, H$$\unicode{x03B2}$$, H$$\unicode{x03B1}$$, and Pa$$\unicode{x03B2}$$emission lines, from which we measure a black hole mass of$$\log_{10}\! (M_{\mathrm{BH}}/\mathrm{M}_{\odot}) = 9.4 \pm 0.5$$. With its high luminosity,$$L_{\mathrm{bol}} = (4.7\pm1.0)\times10^{47}\,\mathrm{erg\,s}^{-1}$$or$$M_{i}(z=2) = -29.74$$mag (AB), we estimate an Eddington ratio of$$\approx1.4$$. As the most luminous quasar known over the last$${\sim}$$9 Gyr of cosmic history, having a luminosity$$8\times$greater than 3C 273, the source offers a range of potential follow-up opportunities.
Onken, Christopher A., et al. "Discovery of the most luminous quasar of the last 9 Gyr." Publications of the Astronomical Society of Australia, vol. 39, Jan. 2022. https://doi.org/10.1017/pasa.2022.36
Onken, Christopher A., Lai, Wolf, Christian, Lucy, Adrian B., Hon, Wei Jeat, Tisserand, Patrick, Sokoloski, Jennifer L., Luna, Gerardo J. M., Manick, Rajeev, Fan, Xiaohui, & Bian (2022). Discovery of the most luminous quasar of the last 9 Gyr. Publications of the Astronomical Society of Australia, 39. https://doi.org/10.1017/pasa.2022.36
Onken, Christopher A., Lai, Wolf, Christian, et al., "Discovery of the most luminous quasar of the last 9 Gyr," Publications of the Astronomical Society of Australia 39 (2022), https://doi.org/10.1017/pasa.2022.36
@article{osti_1981807,
author = {Onken, Christopher A. and Lai and Wolf, Christian and Lucy, Adrian B. and Hon, Wei Jeat and Tisserand, Patrick and Sokoloski, Jennifer L. and Luna, Gerardo J. M. and Manick, Rajeev and Fan, Xiaohui and others},
title = {Discovery of the most luminous quasar of the last 9 Gyr},
annote = {Abstract We report the discovery of a bright ($g = 14.5$mag (AB),$K = 11.9$mag (Vega)) quasar at redshift$z=0.83$— the optically brightest (unbeamed) quasar at$z>0.4$. SMSS J114447.77-430859.3, at a Galactic latitude of$b=+18.1^{\circ}$, was identified by its optical colours from the SkyMapper Southern Survey (SMSS) during a search for symbiotic binary stars. Optical and near-infrared spectroscopy reveals broad Mgii, H$\unicode{x03B2}$, H$\unicode{x03B1}$, and Pa$\unicode{x03B2}$emission lines, from which we measure a black hole mass of$\log_{10}\! (M_{\mathrm{BH}}/\mathrm{M}_{\odot}) = 9.4 \pm 0.5$. With its high luminosity,$L_{\mathrm{bol}} = (4.7\pm1.0)\times10^{47}\,\mathrm{erg\,s}^{-1}$or$M_{i}(z=2) = -29.74$mag (AB), we estimate an Eddington ratio of$\approx1.4$. As the most luminous quasar known over the last${\sim}$9 Gyr of cosmic history, having a luminosity$8\times$greater than 3C 273, the source offers a range of potential follow-up opportunities.},
doi = {10.1017/pasa.2022.36},
url = {https://www.osti.gov/biblio/1981807},
journal = {Publications of the Astronomical Society of Australia},
issn = {ISSN 1323-3580},
volume = {39},
place = {United States},
publisher = {CSIRO},
year = {2022},
month = {01}}