标题： 旋转黑洞周围冷暗物质晕的偏振图像 显示英文标题

标题： Polarized image of a rotating black hole surrounded by a cold dark matter halo

摘要： 我们研究了围绕旋转黑洞的赤道发射环的偏振图像，该黑洞被冷暗物质（CDM）晕包围。 结果表明，CDM晕的密度对黑洞偏振图像的影响与晕的特征半径具有类似的效果。 CDM晕对偏振图像的影响取决于磁场构型、流体速度和观测倾角。 随着CDM晕参数的增加，当磁场位于赤道平面时，观测到的偏振强度会减少，但在磁场垂直于赤道平面的情况下，观测到的偏振强度随CDM晕的变化还取决于环中发射点的位置。 电矢量位置角（EVPA）随CDM晕的变化变得更加复杂。 我们的结果还表明，CDM晕对偏振图像的影响通常较小，这与暗物质晕对黑洞阴影的影响一致。 这些结果有助于进一步从黑洞图像中理解暗物质。 显示英文摘要

摘要： We have studied the polarized image of an equatorial emitting ring around a rotating black hole surrounded by a cold dark matter (CDM) halo. Results show that the CDM halo density has the similar effects of the halo's characteristic radius on the polarized image for the black hole. The effects of the CDM halo on the polarized image depend on the magnetic field configuration, the fluid velocity and the observed inclination. With the increase of the CDM halo parameters, the observed polarization intensity decreases when the magnetic field lies in equatorial plane, but in the case where the magnetic field is perpendicular to the equatorial plane, the change of the observed polarization intensity with CDM halo also depends on the position of the emitting point in the ring. The change of the electric vector position angle (EVPA) with the CDM halo becomes more complicated. Our results also show that the influence of the CDM halo on the polarized image is generally small, which are consistent with the effects of dark matter halo on black hole shadows. These results could help to further understand dark matter from black hole images.