Obscuration and Evolution in Luminous Quasars
Abstract
It is now clear that as many as half of luminous quasars are hidden behind obscuring gas and dust, thanks to recent mid-IR and X-ray observations with WISE, NuSTAR and other observatories. Detailed studies of these sources have revealed some surprises: (1) Many quasars are so heavily obscured, with heavily Compton-thick gas columns, that they are not detectable even in deep X-ray observations, and (2) The stronger clustering of obscured quasars compared to unobscured sources implies that obscuration is likely connected to a discrete phase (for example a galaxy merger) in the evolution of the central black hole. I will give a brief overview of these results, and highlight how they challenge our picture about the nature and evolution of powerful growing black holes. This work was supported in part by NSF grant numbers 1554584 and 1813702, by NASA grant numbers NNX15AP24G and NNX16AN48G, and Chandra GO award GO7-18130X.
- Publication:
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American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23512503H