view Abstract Citations (78) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optical Variation of the Nuclei of Three Compact Galaxies Together with New Photometric Data for Seyfert Galaxies Sandage, Allan Abstract Optical variations of the N-type galaxies 3C 109, 3C 390.3, and I Zw 1727+50 have been found, which, together with 3C 371, bring the known number of optically variable nuclei to four. New photometry of radio and non-radio N-type galaxies continues to show a clear separation of quasi-stellar sources and compact galaxies in the U - B, B - V diagram. Variation of optical or radio intensity can no longer be used as an argument against the cosmological interpretation of redshifts because the optically variable galaxies, and the radio-variable Seyfert nuclei, NGC 1275 (Per A) and 3C 120, all follow the Hubble expansion law. Publication: The Astrophysical Journal Pub Date: December 1967 DOI: 10.1086/180120 Bibcode: 1967ApJ...150L.177S full text sources ADS | data products NED (14)