Galaxy Zoo: CANDELS barred discs and bar fractions★

• DOI: 10.1093/mnras/stu1817
• Publication Date: 2014-10-31T04:26:52Z
• Authors: B. D. Simmons; Thomas Melvin; Chris Lintott; Karen L. Masters; Kyle W. Willett; William C. Keel; R. J. Smethurst; Edmond Cheung; Robert C. Nichol; Kevin Schawinski; Michael Rutkowski; Jeyhan S. Kartaltepe; Eric F. Bell; Kevin R. V. Casteels; Christopher J. Co...; Omar Almaini; Henry C. Ferguson; Lucy Fortson; William Hartley; Dale Kocevski; Anton M. Koekemoer; Daniel H. McIntosh; Alice Mortlock; Jeffrey A. Newman; Jamie Ownsworth; Steven Bamford; Tomas Dahlen; Sandra M. Faber; Steven L. Finkels...; Adriano Fontana; Audrey Galametz; N. A. Grogin; Ruth Grützbauch; Yicheng Guo; Boris Häußler; Kian J. Jek; Sugata Kaviraj; Ray A. Lucas; Michael Peth; Mara Salvato; Tommy Wiklind; Stijn Wuyts
• Keywords: /dk/atira/pure/core/subjects/cosmology; ST/J500665/1 and ST/K502236/1 and ST/I001204/1; Cosmology and Gravitation; astro-ph.GA; RCUK; FOS: Physical sciences; 530; Astrophysics - Astrophysics of Galaxies; 01 natural sciences; 520; Astrophysics of Galaxies (astro-ph.GA); 0103 physical sciences; evolution, galaxies: general, galaxies: spiral, galaxies: structure [galaxies]; STFC

The formation of bars in disk galaxies is a tracer of the dynamical maturity of the population. Previous studies have found that the incidence of bars in disks decreases from the local Universe to z ~ 1, and by z > 1 simulations predict that bar features in dynamically mature disks should be extremely rare. Here we report the discovery of strong barred structures in massive disk galaxies at z ~ 1.5 in deep rest-frame optical images from CANDELS. From within a sample of 876 disk galaxies identified by visual classification in Galaxy Zoo, we identify 123 barred galaxies. Selecting a sub-sample within the same region of the evolving galaxy luminosity function (brighter than L*), we find that the bar fraction across the redshift range 0.5< z < 2 (f_bar = 10.7 +6.3 -3.5% after correcting for incompleteness) does not significantly evolve. We discuss the implications of this discovery in the context of existing simulations and our current understanding of the way disk galaxies have evolved over the last 11 billion years.<br/>11 pages, 6 figures; accepted for publication in MNRAS<br/>