||DO CIRCUMNUCLEAR DENSE GAS DISKS DRIVE MASS ACCRETION ONTO SUPERMASSIVE BLACK HOLES
Izumi, Takuma ,
Kawakatu, NozomuKohno, Kotaro
The Astrophysical Journal Online Edition
2016-08-10 , IOP Publishing
We present a positive correlation between the mass of dense molecular gas (Mdense) of ~ 100 pc scale circumnuclear disks (CNDs) and the black hole mass accretion rate (M_ BH) in total 10 Seyfert galaxies, based on data compiled from the literature and an archive (median aperture θmed = 220 pc). A typical Mdense of CNDs is 107-8 M⊙, estimated from the luminosity of the dense gas tracer, the HCN(1 -0) emission line. Because dense molecular gas is the site of star formation, this correlation is virtually equivalent to the one between nuclear star formation rate and M_ BH revealed previously. Moreover, the Mdense -M_ BH correlation was tighter for CND-scale gas than for the gas on kpc or larger scales. This indicates that CNDs likely play an important role in fueling black holes, whereas >kpc scale gas does not. To demonstrate a possible approach for studying the CND-scale accretion process with the Atacama Large Millimeter/submillimeter Array (ALMA), we used a mass accretion model where angular momentum loss due to supernova explosions is vital. Based on the model prediction, we suggest that only the partial fraction of the mass accreted from the CND (M_ acc) is consumed as M_ BH. However, M_ acc agrees well with the total nuclear mass flow rate (i.e., M_ BH + outflow rate). Although these results are still tentative with large uncertainties, they support the view that star formation in CNDs can drive mass accretion onto supermassive black holes in Seyfert galaxies.
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UTokyo Research "Dense molecular gas disks drive the growth of supermassive black holes" URI: http://www.u-tokyo.ac.jp/en/utokyo-research/research-news/dense-molecular-gas-disks-drive-the-growth-of-supermassive-black-holes.html