Face-on galaxies NGC 524 and NGC 6340: chemically decoupled nuclei and inclined circumnuclear disks

Central regions of the early-type disk galaxies NGC 524 and NGC 6340 have been investigated with the Multi-Pupil Field Spectrograph at the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. I confirm the existence of chemically distinct stellar nuclei in these galaxies which have been claimed earlier. The metallicity differences which are found between the nuclei and the bulges, 0.5 - 1.0 kpc from the centers, reach 0.5 - 0.6 dex. Both nuclei are magnesium overabundant, but the bulges have different magnesium-to-iron ratios: it is solar in NGC 6340 and the same as the nuclear one in NGC 524. The kinematical and morphological analyses reveal the existence of inclined central disks in these galaxies. In NGC 524 the central disk consists of stars, dust, and ionized gas; its extension may be as large as up to R=3 kpc, and it is inclined by more than 20 deg to the global galactic plane. In NGC 6340 only a gaseous polar disk with the radius less than 500 pc is detected.