DO CIRCUMNUCLEAR DENSE GAS DISKS DRIVE MASS ACCRETION ONTO SUPERMASSIVE BLACK HOLES?

作者：Izumi Takuma; Kawakatu Nozomu; Kohno Kotaro

来源：Astrophysical Journal, 2016, 827(1): 81.

DOI：10.3847/0004-637X/827/1/81

• galaxies: active
• galaxies: evolution
• galaxies: Seyfert
• ISM: molecules

We present a positive correlation between the mass of dense molecular gas (M-dense) of similar to 100 pc scale circumnuclear disks (CNDs) and the black hole mass accretion rate ((M) over dot(BH)) in a. total of 10 Seyfert galaxies, based on data compiled from the literature and an archive (median aperture theta(med) = 220 pc). A typical M-dense of CNDs is 10(7)-(8) M-circle dot, 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 the nuclear star-formation rate and (M)over dot(BH) revealed previously. Moreover, the M-dense-(M) over dot(BH) correlation was tighter for CND-scale gas than for the gas on kiloparsec or larger scales. This indicates that CNDs likely play an important role in fueling black holes, whereas greater than kiloparesec scale gas does not. To demonstrate a possible approach for studying the CND-scale accretion process with the Atacama Large Millimeter/ submillimeter Array, 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)over dot(acc)) is consumed as (M)over dot(BH). However, (M)over dot(acc) agrees well with the total nuclear mass flow rate (i.e., (M)over dot(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.

• 出版日期2016-8-10