NOAO > Observing Info > Approved Programs > 2013B-0475
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NOAO > Observing Info > Approved Programs > 2013B-0475 |
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PI: Susan Ridgway, NOAO, ser@noao.edu
Address: PO Box 26732, 950 North Cherry Avenue, Tucson, AZ 85726-6732, USA
CoI: Mark Lacy, NRAO Headquarters
CoI: Tanya Urrutia, AIP/Potsdam
CoI: Andreea Petric, Caltech
Title: Flamingos 2 Spectroscopy of Obscured and Unobscured Quasars
Abstract:
We will use Flamingos-2 to obtain spectra of luminous AGN and quasars
selected in the mid-infrared. Mid-infrared selection is much less biased with
respect to obscuration than optical and X-ray techniques, and hence allows
for finding obscured (Type-2) quasars as well as Type-1 quasars. Our survey
so far has been very successful and has provided an unique opportunity to
construct luminosity functions for both Type-1 and Type-2 quasars selected in
the same way and covering similar redshifts and luminosities. We have
quantifed the change in the obscured fraction with luminosity and redshift
for the first time, and find interesting indications that at high redshift
the obscured fraction rises, consistent with models for the joint formation
of the galaxy and black hole populations. Our samples are, however, still
quite incomplete at low fluxes (and therefore lower luminosities at a given
redshift), particularly in the southern hemisphere. Near-infrared
spectroscopy, such as that we have previously obtained with NIRI at Gemini N,
offers us the best possibility of bringing these southern samples to a
reasonable completeness level, and will greatly increase the number of high z
quasars in our sample. This will allow us to better judge our tantalizing
initial results on the redshift evolution of the obscured fraction. In
addition, these southern targets can be followed up with ALMA and GEMS/GSAOI
to study the morphologies and star-formation properties of the hosts,
allowing further exploration of the relationship between the formation of
massive bulges and supermassive blackholes in the early universe.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2013B-0475 |
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