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T. Urrutia (UC Davis / LLNL), M. Lacy (Spitzer Science Center), R. Becker, M. Gregg (UC Davis / LLNL), D. Helfand (Columbia University), R. White (Space Telescope Science Institute)
We present Hubble/ACS observations of 13 dust-reddened Type 1 quasars to study the properties of their host galaxies. The quasars have a mean reddening of E(B-V) = 0.8 and lie at moderate redshifts (0.4 < z < 1.0). Images were taken in I and g' band during one or two Hubble orbits. After correcting for absorption the absolute magnitudes of the quasars lie around MV = -27. We are just probing the tip of the luminosity iceberg and there must be many more obscured quasars at these redshifts.
The images show extensive merger activity such as tidal tails and various compact halos even before subtracting the quasar contribution. The red quasar phenomenon is likely to be an evolutionary effect. The young quasar is obscured while the dust of the merging galaxies is still settling in. None of the quasars fit a perfect elliptical profile after subtracting the PSF as all of them show many irregularities. The host galaxies also seem to be having bluer colors that typical galaxies, although there is a large scatter in the data. This would argue for recent star-formation most likely triggered my the merger, in concordance with models arguing the emergence of AGN from dusty Starburst galaxies.
This work was partly performed under the auspices of the US Department of Energy, National Nuclear Security Administration by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.