2mass-allsky

The Black Hole Masses and Star Formation Rates of z>1 Dust Obscured Galaxies: Results from Keck OSIRIS Integral Field Spectroscopy

April 2011 • 2011AJ....141..141M

Authors • Melbourne, J. • Peng, Chien Y. • Soifer, B. T. • Urrutia, Tanya • Desai, Vandana • Armus, L. • Bussmann, R. S. • Dey, Arjun • Matthews, K.

Abstract • We have obtained high spatial resolution Keck OSIRIS integral field spectroscopy of four z ~ 1.5 ultra-luminous infrared galaxies that exhibit broad Hα emission lines indicative of strong active galactic nucleus (AGN) activity. The observations were made with the Keck laser guide star adaptive optics system giving a spatial resolution of 0farcs1 or <1 kpc at these redshifts. These high spatial resolution observations help to spatially separate the extended narrow-line regions—possibly powered by star formation—from the nuclear regions, which may be powered by both star formation and AGN activity. There is no evidence for extended, rotating gas disks in these four galaxies. Assuming dust correction factors as high as A(Hα) = 4.8 mag, the observations suggest lower limits on the black hole masses of (1-9) × 108 M sun and star formation rates <100 M sun yr-1. The black hole masses and star formation rates of the sample galaxies appear low in comparison to other high-z galaxies with similar host luminosities. We explore possible explanations for these observations, including host galaxy fading, black hole growth, and the shut down of star formation.

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IPAC Authors
(alphabetical)

Lee_armus

Lee Armus

Senior Scientist


Vandana Desai

Senior Scientist