科研之友
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摘要
We present ALMA detections of the [C (Pi)] 158 mu m emission line and the underlying far-infrared (FIR) continuum of three quasars at 6.6 < z < 6.9 selected from the VIKING survey. The [C (Pi)] line fluxes range between 1.6 and 3.4 Jy km s(-1) ([C (Pi)] luminosities similar to(1.9-3.9) x 10(9) L-circle dot). We measure continuum flux densities of 0.56-3.29 mJy around 158 mu m (rest frame), with implied FIR luminosities of (0.6-7.5) x 10(12) Le and dust masses M-d = (0.7-24) x 10(8) M-circle dot. In one quasar we derive a dust temperature of 30(-9)(+12) K from the continuum slope, below the canonical value of 47 K. Assuming that the [C (Pi)] and continuum emission are powered by star formation, we find star formation rates from 100 to 1600 M-circle dot yr(-1) based on local scaling relations. The L[C (Pi)]/L-FIR ratios in the quasar hosts span a wide range from (0.3-4.6) x 10(-3), including one quasar with a ratio that is consistent with local star-forming galaxies. We find that the strength of the L-[C Pi] and 158 mu m continuum emission in z greater than or similar to 6 quasar hosts correlates with the quasar's bolometric luminosity. In one quasar, the [C (Pi)] line is significantly redshifted by similar to 1700 km s(-1) with respect to the Mg II broad emission line. Comparing to values in the literature, we find that, on average, the Mg II is blueshifted by 480 km s(-1) (with a standard deviation of 630 km s(-1)) with respect to the host galaxy redshift, i.e., one of our quasars is an extreme outlier. Through modeling we can rule out a flat rotation curve for our brightest [C (Pi)] emitter. Finally, we find that the ratio of black hole mass to host galaxy (dynamical) mass is higher by a factor of 3-4 (with significant scatter) than local relations.
- 出版日期2016-1-1
