SDSS-IV MaNGA: properties of galaxies with kinematically decoupled stellar and gaseous components

Abstract

We study the properties of 66 galaxies with kinematically misaligned gas and stars from MaNGA survey. The fraction of kinematically misaligned galaxies varies with galaxy physical parameters, i.e. M * , SFR and sSFR. According to their sSFR, we further classify these 66 galaxies into three categories, 10 star-forming, 26 "Green Valley" and 30 quiescent ones. The properties of different types of kinematically misaligned galaxies are different in that the star-forming ones have positive gradient in D n 4000 and higher gas-phase metallicity, while the green valley/quiescent ones have negative D n 4000 gradients and lower gas-phase metallicity on average. There is evidence that all types of the kinematically misaligned galaxies tend to live in more isolated environment. Based on all these observational results, we propose a scenario for the formation of star forming galaxies with kinematically misaligned gas and stars − the progenitor accretes misaligned gas from a gas-rich dwarf or cosmic web, the cancellation of angular momentum from gas-gas collisions between the pre-existing gas and the accreted gas largely accelerates gas inflow, leading to fast centrally-concentrated star-formation. The higher metallicity is due to enrichment from this star formation. For the kinematically misaligned green valley and quiescent galaxies, they might be formed through gas-poor progenitors accreting kinematically misaligned gas from satellites which are smaller in mass.

The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

“…The central regions of blue counter-rotators show younger stellar populations and more intense star formation than in their outer parts. Jin et al (2016) have further studied the properties of 66 galaxies with kinematically misaligned gas and stars. They find that the star-forming misaligned galaxies have positive gradients in D n 4000 and higher gas-phase metallicity, while the green valley/quiescent ones have negative D n 4000 gradients and lower gas-phase metallicity on average.…”

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

“…Several examples have been found using IFS data; (e.g. Emsellem et al 2004;Krajnović et al 2011;Barrera-Ballesteros et al 2014Allen et al 2015;Jin et al 2016). Our approximation to this problem is to further constrain a-posteriori the PA ph by using as a prior knowledge of the PA kn (which is discussed in the next section).…”

SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

“…We visually examine the low-l out , high-ò outliers and show a possible candidate for a double-σ galaxy in Appendix A, although our ability to distinguish such features is limited by spatial resolution (see also a first sample of counterrotating gas disks picked out from MaNGA; Jin et al 2016). Otherwise, there are no obvious differences between these galaxies and those with low l out but correspondingly low ò.…”