Hot Disks and Delayed Bar Formation
Abstract
We present observational evidence for the inhibition of bar formation in dispersion-dominated (dynamically hot) galaxies by studying the relationship between galactic structure and host galaxy kinematics in a sample of 257 galaxies between 0.1 < z ≤ 0.84 from the All-Wavelength Extended Groth Strip International Survey and the Deep Extragalactic Evolutionary Probe 2 survey. We find that bars are preferentially found in galaxies that are massive and dynamically cold (rotation-dominated) and on the stellar Tully-Fisher relationship, as is the case for barred spirals in the local universe. The data provide at least one explanation for the steep (×3) decline in the overall bar fraction from z = 0 to z = 0.84 in L* and brighter disks seen in previous studies. The decline in the bar fraction at high redshift is almost exclusively in the lower mass (10 < log M_*(M_☉) < 11), later-type, and bluer galaxies. A proposed explanation for this "downsizing" of the bar formation/stellar structure formation is that the lower mass galaxies may not form bars because they could be dynamically hotter than more massive systems from the increased turbulence of accreting gas, elevated star formation, and/or increased interaction/merger rate at higher redshifts. The evidence presented here provides observational support for this hypothesis. However, the data also show that not every disk galaxy that is massive and cold has a stellar bar, suggesting that mass and dynamic coldness of a disk are necessary but not sufficient conditions for bar formation—a secondary process, perhaps the interaction history between the dark matter halo and the baryonic matter, may play an important role in bar formation.
Additional Information
© 2012 American Astronomical Society. Received 2012 July 30; accepted 2012 August 30; published 2012 October 9. We thank the referee for the careful reading and suggestions that improved the paper. We are also grateful to the DEEP2 team for graciously sharing their data for this analysis. We thank Richard Ellis, Rick Fisher, Sarah Miller, and Preethi Nair for insightful discussions that helped improve this paper. K.S. acknowledges support from the National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. E.A. acknowledges financial support to the DAGAL network from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/ under REA grant agreement number PITN-GA-2011-289313. We wish to extend thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged guests. Facilities: HST, Keck:II (DEIMOS)Attached Files
Published - 0004-637X_758_2_136.pdf
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Additional details
- Eprint ID
- 35881
- Resolver ID
- CaltechAUTHORS:20121207-132951057
- National Radio Astronomy Observatory
- PITN-GA-2011-289313
- Marie Curie Fellowship
- Created
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2012-12-10Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field