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The Massive Hosts of Radio Galaxies Across Cosmic Time

Nick Seymour·Daniel Stern·Carlos De Breuck·Joel Vernet·Alessandro Rettura·Mark Dickinson·Arjun Dey·Peter Eisenhardt·Robert Fosbury·Mark Lacy·Pat McCarthy·George Miley·Brigitte Rocca-Volmerange·Huub Rottgering·S. Adam Stanford·Harry Teplitz·Wil van Breugel·Andrew Zirm
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Abstract

We present the results of a comprehensive Spitzer survey of 69 radio galaxies across 1 60% for ~75% the high redshift radio galaxies. As expected from unified models of AGN, the stellar fraction of the rest-frame H-band luminosity has no correlation with redshift, radio luminosity, or rest-frame mid-IR (5um) luminosity. Additionally, while the stellar H-band luminosity does not vary with stellar fraction, the total H-band luminosity anti-correlates with the stellar fraction as would be expected if the underlying hosts of these radio galaxies comprise a homogeneous population. The resultant stellar luminosities imply stellar masses of 10^{11-11.5}Msun even at the highest redshifts. Powerful radio galaxies tend to lie in a similar region of mid-IR color-color space as unobscured AGN, despite the stellar contribution to their mid-IR SEDs at shorter-wavelengths. The mid-IR luminosities alone classify most HzRGs as LIRGs or ULIRGs with even higher total-IR luminosities. As expected, these exceptionally high mid-IR luminosities are consistent with an obscured, highly-accreting AGN. We find a weak correlation of stellar mass with radio luminosity.

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Nick Seymour, Daniel Stern, Carlos De Breuck, Joel Vernet, Alessandro Rettura, Mark Dickinson, Arjun Dey, Peter Eisenhardt, Robert Fosbury, Mark Lacy, Pat McCarthy, George Miley, Brigitte Rocca-Volmerange, Huub Rottgering, S. Adam Stanford, Harry Teplitz, Wil van Breugel, Andrew Zirm. 2007-03-09. The Massive Hosts of Radio Galaxies Across Cosmic Time. https://doi.org/10.1086/517887

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