view Abstract Citations (116) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Southern galaxies. VII. The remarkable lenticular barred galaxy NGC 1291. de Vaucouleurs, G. Abstract The lenticular barred galaxy NOC 1291 is the largest example of revised type (R) SB(s)0/a at the transition stage between late lenticulars and early spirals. The central lens (12 x 10 kpc) is surrounded by a large, semidetached outer ring (21 x 19 kpc) from which emerge two faint spiral arms showing incipient resolution at 20.5.In the nuclear region at the center of the primary bar (10 x 2.5 kpc), a secondary bar (1.8 x 0.2 kpc) and secondary nucleus (0.5 x 0.4 kpc) have been detected, repeating the primary lens-bar-nucleus pattern on a smaller scale approximating the ratio of the Jeans lengths. Other examples suggest that this repetitive pattern may be typical. Detailed surface photometry from long- and photographs with the Mount Stromlo 75-cm reflector and the McDonald 205-cm reflector is presented (isophotes, luminosity profiles, and photometric parameters). The total apparent magnitude m(B) = 9.37 (photoelectrically calibrated) and maximum dimensions 20' x 18' (at the detection threshold u 28.2 mag 5-2 - 0.3 Q0 ) correspond to MT(B) = -20.63 and = 52 kpc, with (B - V)r = 0.92, (U - B)r = 0.47, if rn - M = 30.0 and A = 8.9 Mpc (estimated from brightest stars and redshifr). The average surface brightness in the "dark" zone between the lens and the ring is about = 24.5 mag 2 10 at an average radius r 8 kpc from the center; the average maximum brightness in the ring is only slightly greater, about 24.0 mag s The effective equivalent radius of the isophote enclosing half the total flux is r* = 1;54 = 4.0 kpc, the same as for M31, and indicating a giant system. The spheroidal component obeying the r114 law dominates the light distribution within the lens and contributes 57 percent of the total luminosity; if it is valid up to r = 0, the true central brightness may be as high as uB(0) = 13.46 mag 2 = 2.2 x i0 . The flat component contributing to the lens and dominant in the ring does not obey the simple exponential distribution previously found in the disks of late-type spirals. The nuclear spectrum observed in the blue region at medium resolution (Mount Stromlo) and in the red region at low resolution with an image-tube spectrograph (McDonald) is a typical K-type, approximating G5 at H and K and KO III at Hy with weak 3727 emission and no H . The mean heliocentric radial velocity from three optical and one radio observations is V = + 830 km s . The total mass, neutral hydrogen mass, and massluminosity ratio estimated from corrected values of the 21-cm line parameters given by Lewis and from an optical upper limit to the velocity dispersion ( <200 km s1) are 931T 1 x 10119)lo, with 9flH/ 0.025 and 93tj B 4. These values are about normal for type 50/a (t = 0). The frequency of outer ring structures around the main bodies of galaxies of different types is discussed in an Appendix; such structures are observed only around lenticulars and spirals earlier than Sc with a sharp maximum at 80/a. Subject headings: galactic structure galaxies, individual galaxies, photometry of Publication: The Astrophysical Journal Supplement Series Pub Date: June 1975 DOI: 10.1086/190341 Bibcode: 1975ApJS...29..193D Keywords: Astronomical Photometry; Galactic Nuclei; Galactic Structure; Stellar Luminosity; Calibrating; Color; Galactic Evolution; Graphs (Charts); Isophotes; Morphological Indexes; Spiral Galaxies; Stellar Spectra; Tables (Data); Astronomy full text sources ADS | data products SIMBAD (4) NED (2) Related Materials (7) Part 1: 1961ApJ...133..405D Part 2: 1962ApJ...136..107D Part 3: 1963ApJ...137..720D Part 4: 1963ApJ...138..934D Part 5: 1964ApJ...139..899D Part 6: 1964ApJ...140..399D Part 7: 1973ApJ...181...31D