Redshift 6.4 host galaxies of 108 solar mass black holes: Low star formation rate and dynamical mass

  1. Get@NRC: Redshift 6.4 host galaxies of 108 solar mass black holes: Low star formation rate and dynamical mass (Opens in a new window)
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Journal titleThe Astrophysical Journal
Article number13
AbstractWe present Atacama Large Millimeter Array observations of rest-frame far-infrared continuum and [C II] line emission in two z = 6.4 quasars with black hole masses of 108 M ⊙. CFHQS J0210-0456 is detected in the continuum with a 1.2 mm flux of 120 ± 35 μJy, whereas CFHQS J2329-0301 is undetected at a similar noise level. J2329-0301 has a star formation rate limit of <40 M ⊙ yr-1, considerably below the typical value at all redshifts for this bolometric luminosity. Through comparison with hydro simulations, we speculate that this quasar is observed at a relatively rare phase where quasar feedback has effectively shut down star formation in the host galaxy. [C II] emission is also detected only in J0210-0456. The ratio of [C II] to far-infrared luminosity is similar to that of low-redshift galaxies of comparable luminosity, suggesting that the previous finding of an offset in the relationships between this ratio and far-infrared luminosity at low and high redshifts may be partially due to a selection effect due to the limited sensitivity of previous continuum data. The [C II] line of J0210-0456 is relatively narrow (FWHM = 189 ± 18 km s-1), indicating a dynamical mass substantially lower than expected from the local black hole-velocity dispersion correlation. The [C II] line is marginally resolved at 0.″7 resolution with the blue and red wings spatially offset by 0.″5 (3 kpc) and a smooth velocity gradient of 100 km s-1 across a scale of 6 kpc, possibly due to the rotation of a galaxy-wide disk. These observations are consistent with the idea that stellar mass growth lags black hole accretion for quasars at this epoch with respect to more recent times. © 2013. The American Astronomical Society. All rights reserved.
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AffiliationNational Research Council Canada (NRC-CNRC); NRC Herzberg Institute of Astrophysics (HIA-IHA)
Peer reviewedYes
NPARC number21269882
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Record identifier72a45b48-b76d-42c9-afa5-df95e3d0894d
Record created2013-12-13
Record modified2016-07-18
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