On the spiral structure of M31 galaxy in U-light

As a result of processing of three plates obtained with 52'' Schmidt-telescope in the Tautenburg observatory a digital image of M31 galaxy in U-light with a resolution ∼ 30'' was obtained. The regions of high brightness corresponding to complexes of young high-luminosity stars become apparent by means of the median filtering method. The spiral structure of M31 galaxy is distorted, two-armed and of a trailing type. It can be traced up to ∼ 1 kps distance from the centre. In addition to the spiral arms designations of Arp, arms with numbers 1 and 0 are inserted into consideration. The sequences of high brightness regions in the central part resemble a multi-armed spiral structure. In the central part a bar-like formation with ∼ 6 kps extension and ∼ 70 deg position angle was found. the position of the spiral arms 0-7 on the big axis are in good agreement with each of the laws r=5.03 exp (0.218φ-0.0034φ2) and r=3.59+1.03φ+0.192φ2. The arms 0-4 and 4-6 also correspond to the logarithmic spirals with pitch angles of 9 deg.8 and 7 deg.4, but for the arms 3-7 the line spiral is suitable. The positions of the spiral arms on the big axis and on the northwest small semi-axis show that the inclination angle of M31 plane is 12 deg.9 ±0 deg.2