Bars in early- and late-type discs in COSMOS

Cameron, E. ; Carollo, C. M. ; Oesch, P. ; Aller, M. C. ; Bschorr, T. ; Cerulo, P. ; Aussel, H. ; Capak, P. ; Le Floc'h, E. ; Ilbert, O. ; Kneib, J.-P ; Koekemoer, A. ; Leauthaud, A. ; Lilly, S. J. ; Massey, R. ; McCracken, H. J. ; Rhodes, J. ; Salvato, M. ; Sanders, D. B. ; Scoville, N. ; Sheth, K. ; Taniguchi, Y. ; Thompson, D.

In: Monthly Notices of the Royal Astronomical Society, 2010, vol. 409, no. 1, p. 346-354

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    Summary
    We investigate the (large-scale) bar fraction in a mass-complete sample of M > 1010.5 M⊙ disc galaxies at 0.2 < z < 0.6 in the Cosmological Evolution Survey (COSMOS) field. The fraction of barred discs strongly depends on mass, disc morphology and specific star formation rate (SSFR). At intermediate stellar mass (1010.5 < M < 1011 M⊙) the bar fraction in early-type discs is much higher, at all redshifts, by a factor of ∼2, than that in late-type discs. This trend is reversed at higher stellar mass (M > 1011 M⊙), where the fraction of bars in early-type discs becomes significantly lower, at all redshifts, than that in late-type discs. The bar fractions for galaxies with low and high SSFRs closely follow those of the morphologically selected early- and late-type populations, respectively. This indicates a close correspondence between morphology and SSFR in disc galaxies at these earlier epochs. Interestingly, the total bar fraction in 1010.5 < M < 1011 M⊙ discs is built up by a factor of ∼2 over the redshift interval explored, while for M > 1011 M⊙ discs it remains roughly constant. This indicates that, already by z∼ 0.6, spectral and morphological transformations in the most massive disc galaxies have largely converged to the familiar Hubble sequence that we observe in the local Universe, while for intermediate-mass discs this convergence is ongoing until at least z∼ 0.2. Moreover, these results highlight the importance of employing mass-limited samples for quantifying the evolution of barred galaxies. Finally, the evolution of the barred galaxy populations investigated does not depend on the large-scale environmental density (at least, on the scales which can be probed with the available photometric redshifts)