Interstellar polarization at high galactic latitudes from distant stars - VI. Extended polarization map and connection with the local spiral structure

We present new interstellar polarization measurements for 116 stars at high galactic latitudes. Our data show that Markkanen's cloud - the main polarization structure seen in the North Galactic Pole area (b >75degrees) extends further towards lower latitudes. Especially, we have found a new dust formation in the area 35degrees < l<45degrees, 57degrees < b<63degrees. Interstellar polarization in this part of the sky peaks at 0.7%, which gives a lower limit to the extinction A(V) > 0.(m)23. Polarization vectors in this cloud are very well aligned along the direction of l = 50degrees. On the IRAS 100 micron map this dust structure shows up as a bright emission area. We discuss the new polarization map extending from circumpolar to lower latitudes and point out features which suggest that Markkanen's cloud may be a part of the dust lane in the inner edge of the local spiral or spur.