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| Paper: |
Molecular Gas Reservoir in low-z Powerful Radio Galaxies |
| Volume: |
290, Active Galactic Nuclei: from Central Engine to Host Galaxy |
| Page: |
529 |
| Authors: |
Lim, J.; Leon, S.; Combes, F.; Dinh-v-Trung |
| Abstract: |
Classical double-lobed radio galaxies are hosted almost exclusively by elliptical galaxies that otherwise resemble normal elliptical galaxies in both their global stellar distribution and kinematics. Given that normal elliptical galaxies usually contain undetectable quantities of neutral gas, what fuels the AGN in powerful elliptical radio galaxies? Here, we present results of a search for molecular gas in radio galaxies at z < 0.031 selected from the revised 3C catalog, comprising the most powerful radio galaxies in the Local Universe. We detected 4 of the 22 galaxies observed, with molecular gas masses ranging from about 107 - 109 Msun; the remaining galaxies were not detected at a typical upper limit of about 108 Msun. We argue that this molecular gas most likely originates from the cannibalism of secondary gas-rich galaxies by the parent elliptical galaxy, rather than the merger of two gas-rich galaxies that spawned a remnant elliptical galaxy. All the galaxies detected possess central dust disks or lanes, and exhibit very broad double-horned line profiles characteristic of a rapidly-rotating disk with an inner depression. We suggest that this molecular-gas disk comprises the gas reservoir for fueling the central supermassive black hole. Finally, we present preliminary results of a follow-up survey to better understand the mass distribution of molecular gas in powerful radio galaxies. The results thus far show that an increasing number of radio galaxies become detectable in molecular gas at lower mass limits, suggesting a broad (at least 3 orders of magnitude) distribution of molecular gas masses in powerful radio galaxies. |
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