English

SDSS-IV MaNGA: Bar pattern speed estimates with the Tremaine-Weinberg method and their error sources

Astrophysics of Galaxies 2020-01-08 v1

Abstract

Estimating the bar pattern speed (\Om{}) is one of the main challenges faced in understanding the role of stellar bars in galaxy dynamical evolution. This work aims to characterise different uncertainty sources affecting the Tremaine Weinberg (TW)-method to study the correlation between bar and galaxies physical parameters. We use a sample of 15 MaNGA SDSS-IV galaxies and 3 CALIFA galaxies from \cite{Aguerri2015}. We studied the errors related with (i) galaxy centre determination, (ii) disc position angle (PA) emphasising the difficulties triggered by outer non-axisymmetric structures besides the bar, (iii) the slits length and (iv) the spatial resolution. In average, the PA uncertainties range 15%\sim 15 \%, the slit length 9%\sim 9 \% and the centring error 5%\sim 5 \%. Reducing the spatial resolution increases the sensitivity to the PA error. Through Monte Carlo simulations, we estimate the probability distribution of the \R{} bar speed parameter. The present sample is composed of 7 slow, 4 fast and 7 ultrafast bars, with no trend with morphological types. Although uncertainties and low sample numbers may mask potential correlations between physical properties, we present a discussion of them: We observe an anti-correlation of \Om{} with the bar length and the stellar mass, suggesting that massive galaxies tend to host longer and slower bars. We also observe a correlation of the molecular gas fraction with \R{}, and a weak anti-correlation with \Om{}, suggesting that bars rotate slower in gaseous discs. Confirmation of such trends awaits future studies.

Keywords

Cite

@article{arxiv.1911.00090,
  title  = {SDSS-IV MaNGA: Bar pattern speed estimates with the Tremaine-Weinberg method and their error sources},
  author = {L. Garma-Oehmichen and M. Cano-Díaz and H. Hernández-Toledo and E. Aquino-Ortíz and O. Valenzuela and J. A. L. Aguerri and S. F. Sánchez and M. Merrifield},
  journal= {arXiv preprint arXiv:1911.00090},
  year   = {2020}
}

Comments

17 pages, 11 figures, accepted for publication in MNRAS