Bibcode
Holmes, L.; Spekkens, K.; Sánchez, S. F.; Walcher, C. J.; García-Benito, R.; Mast, D.; Cortijo-Ferrero, C.; Kalinova, V.; Marino, R. A.; Mendez-Abreu, J.; Barrera-Ballesteros, J. K.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 451, Issue 4, p.4397-4411
Advertised on:
8
2015
Citations
33
Refereed citations
32
Description
We carry out a direct search for bar-like non-circular flows in
intermediate-inclination, gas-rich disc galaxies with a range of
morphological types and photometric bar classifications from the first
data release (DR1) of the Calar Alto Legacy Integral Field Spectroscopy
Area (CALIFA) survey. We use the DISKFIT algorithm to apply rotation
only and bisymmetric flow models to H α velocity fields for 49/100
CALIFA DR1 systems that meet our selection criteria. We find
satisfactory fits for a final sample of 37 systems. DISKFIT is sensitive
to the radial or tangential components of a bar-like flow with
amplitudes greater than 15 km s-1 across at least two
independent radial bins in the fit, or ˜2.25 kpc at the
characteristic final sample distance of ˜75 Mpc. The velocity
fields of 25/37 {(67.6^{+6.6}_{-8.5} per cent)} galaxies are best
characterized by pure rotation, although only 17/25
{(68.0^{+7.7}_{-10.4} per cent)} of them have sufficient H α
emission near the galaxy centre to afford a search for non-circular
flows. We detect non-circular flows in the remaining 12/37
{(32.4^{+8.5}_{-6.6} per cent)} galaxies. We conclude that the
non-circular flows detected in 11/12 {(91.7^{+2.8}_{-14.9} per cent)}
systems stem from bars. Galaxies with intermediate (AB) bars are largely
undetected, and our detection thresholds therefore represent upper
limits to the amplitude of the non-circular flows therein. We find 2/23
{(8.7^{+9.6}_{-2.9} per cent)} galaxies that show non-circular motions
consistent with a bar-like flow, yet no photometric bar is evident. This
suggests that in ˜10 per cent of galaxies either the existence of
a bar may be missed completely in photometry or other processes may
drive bar-like flows and thus secular galaxy evolution.