We report linearly polarized continuum emission properties of Sgr A* at
∼492 GHz, based on the Atacama Large Millimeter Array (ALMA) observations.
We used the observations of the likely unpolarized continuum emission of Titan,
and the observations of C\textsc{i} line emission, to gauge the degree of
spurious polarization. The Stokes I flux of 3.6±0.72 Jy during our run is
consistent with extrapolations from the previous, lower frequency observations.
We found that the continuum emission of Sgr A* at ∼492 GHz shows large
amplitude differences between the XX and the YY correlations. The observed
intensity ratio between the XX and YY correlations as a function of parallactic
angle may be explained by a constant polarization position angle of
∼158∘±3∘. The fitted polarization percentage of Sgr
A* during our observational period is 14\%±1.2\%. The calibrator quasar
J1744-3116 we observed at the same night can be fitted to Stokes I = 252 mJy,
with 7.9\%±0.9\% polarization in position angle P.A. =
4.1∘±4.2∘. The observed polarization percentage and
polarization position angle in the present work appear consistent with those
expected from longer wavelength observations in the period of 1999-2005. In
particular, the polarization position angle at 492 GHz, expected from the
previously fitted 167∘±7∘ intrinsic polarization position
angle and (-5.6±0.7)×105 rotation measure, is 155−8+9,
which is consistent with our new measurement of polarization position angle
within 1σ. The polarization percentage and the polarization position
angle may be varying over the period of our ALMA 12m Array observations, which
demands further investigation with future polarization observations.Comment: 10 pages, 6 figures, 1st referee report received and revise