We present a study of large-scale bars in the local Universe , based on a large sample of \sim 3692 galaxies , with -18.5 \leq M _ { g } < -22.0 mag and redshift 0.01 \leq z < 0.03 , drawn from the Sloan Digitized Sky Survey .
While most studies of bars in the local Universe have been based on relatively small samples that are dominated by bright galaxies of early to intermediate Hubble types with prominent bulges , the present sample is \sim 10 times larger , covers a larger volume , and includes many galaxies that are disk-dominated and of late Hubble types .
Both color cuts and Sérsic cuts yield a similar sample of \sim 2000 disk galaxies .
We characterize bars and disks by ellipse-fitting r -band images and applying quantitative criteria .
After excluding highly inclined ( > 60 ^ { \circ } ) systems , we find the following results .
( 1 ) The optical r -band fraction ( f _ { opt - r } ) of barred galaxies , when averaged over the whole sample , is \sim 48 \% - 52 \% .
The bars have diameters d of 2 to 24 kpc , with most ( \sim 72 \% ) having d \sim 2 to 6 kpc .
( 2 ) When galaxies are separated according to half light radius ( r _ { e } ) , or normalized r _ { e } / R _ { 24 } , which is a measure of the bulge-to-disk ( B / D ) ratio , a remarkable result is seen : f _ { opt - r } rises sharply , from \sim 40 % in galaxies that have small r _ { e } / R _ { 24 } and visually appear to host prominent bulges , to \sim 70 % for galaxies that have large r _ { e } / R _ { 24 } and appear disk-dominated .
Visual classification , performed for \sim 900 galaxies , confirms our result that disk-dominated galaxies with no bulge or a very low B / D display a significantly higher optical bar fraction ( > 70 % vs 40 % ) than galaxies with prominent bulges .
It also shows that barred galaxies host a larger fraction ( 31 % vs 5 % ) of quasi-bulgeless disk-dominated galaxies than do unbarred galaxies .
( 3 ) f _ { opt - r } rises for galaxies with bluer colors ( by \sim 30 \% ) and lower masses ( by \sim 15 \% - 20 \% ) .
( 4 ) The significant rise in the optical bar fraction toward late-type galaxies is discussed in terms of their higher gas mass fraction , higher dark matter fraction , and lower bulge-to-disk ratio .
( 5 ) While hierarchical \Lambda CDM models of galaxy evolution models fail to produce galaxies without classical bulges , our study finds that \sim 20 \% of disk galaxies appear to be “ quasi-bulgeless ” .
( 6 ) Our study of bars at z \sim 0 in the optical r -band provides the z \sim 0 comparison point for HST ACS surveys ( e.g. , GEMS , GOODS , COSMOS ) that measure the rest-frame optical bar fraction in bright galaxies out to z \sim 1 .
After applying the same cutoffs in magnitude , bar ellipticity ( e _ { bar } \geq 0.4 ) , and bar size ( a _ { bar } \geq 1.5 kpc ) , which are applied in z \sim 0.2 - 1.0 studies in order to trace strong bars with adequate spatial resolution in bright disks , we obtain an optical r -band bar fraction of 34 \% .
This is comparable to the value reported at z \sim 0.2 - 1.0 , implying that the optical fraction of strong bars does not suffer a dramatic order of magnitude decline in bright galaxies out to z \sim 1 .