Night-to-night variation in the optical emission lines in the nuclear spectrum of the Seyfert galaxy NGC 3227

Abstract

Fifty-three spectrograms in the optical region (3700–7300 A)with a spectral resolution of about 8 A have been obtained for the Seyfert nucleus of the galaxy NGC 3227 with the 6 m telescope on 12–15 January 1977 while the nucleus was in the historically important epoch of its extreme maximum brightness. The width of the slit was 1″, and the length of the box during the spectral measurements was 1.5″. The data obtained by us and those compiled from literature showed that profiles of the Balmer lines Hα, Hβ and Hγ are different, demonstrating that the gas emitting these lines is highly self-absorbed. The profiles of the Balmer lines contain various components that kept their positions (radial velocities) over 10 years. The components can reflect long-lived flows or jets in the broad-line region (BLR). A blue bump at a radial velocity of −5000 km s−1 in the Hγ profile was revealed. Variations in the intensities of the revealed components and broad wings of the emission lines Hβ and Hγ profiles were detected o...