Bar strength and star formation activity in late-type barred galaxies

Galactic bars are important drivers of galactic evolution, and yet how they impact the interstellar medium and correspondingly star formation, remains unclear. We present simulation results for two barred galaxies with different formation mechanisms, bars formed in isolation or via a tidal interaction, to consider the spatially and temporally varying trends of star formation. We focus on the early (< 1Gyr) epoch of bar formation so that the interaction is clearly identifiable...

This is the first paper of a series aimed to understand the formation and evolution of bars in early-type spirals and their influence in the evolution of the galaxy. Optical long-slit spectra along the major axis of the bar of a sample of 20 galaxies are analyzed. Line-strength indices in the bar region are measured to derive stellar mean-age and metallicity distributions along the bars using stellar population models. We find three different types of bars according to their ...

Bars inhabit the majority of local-Universe disk galaxies and may be important drivers of galaxy evolution through the redistribution of gas and angular momentum within disks. We investigate the star formation and gas properties of bars in galaxies spanning a wide range of masses, environments, and star formation rates using the MaNGA galaxy survey. Using a robustly-defined sample of 684 barred galaxies, we find that fractional (or scaled) bar length correlates with the host'...

We present the first results of a pilot study aimed at understanding the influence of bars on the evolution of galaxy discs through the study of their stellar content. We examine here the kinematics, star formation history, mass-weighted, luminosity-weighted, and single stellar population (SSP) equivalent ages and metallicities for four galaxies ranging from lenticulars to late-type spirals. The data employed extends to 2-3 disc scalelengths, with S/N(A)>50. Several technique...

I review both well established and more recent findings on the properties of bars, and their host galaxies, stemming from photometric and spectroscopic observations, and discuss how these findings can be understood in terms of a global picture of the formation and evolution of bars, keeping a connection with theoretical developments. In particular, I show the results of a detailed structural analysis of ~ 300 barred galaxies in the Sloan Digital Sky Survey, providing physical...

We performed a series of 29 gasdynamical simulations of disc galaxies, barred and unbarred, with various stellar masses, to study the impact of the bar on star formation history. Unbarred galaxies evolve very smoothly, with a star formation rate (SFR) that varies by at most a factor of three over a period of 2 Gyr. The evolution of barred galaxies is much more irregular, especially at high stellar masses. In these galaxies, the bar drives a substantial amount of gas toward th...

Simulations and observations of galactic bars suggest they do not commonly evolve into bulges, although it is possible that the earliest bars formed bulges long ago, when galaxies were smaller, denser, and had more gas. The most highly evolved of today's bars may become lenses over a Hubble time. Most galaxies in the early Universe are extremely clumpy, with 10^8-10^9 Msun blue clumps that resemble in color and magnitude the isolated field objects nearby. The presence of blue...

In this paper, we use the Galaxy Zoo 2 dataset to study the behavior of bars in disk galaxies as a function of specific star formation rate (SSFR), and bulge prominence. Our sample consists of 13,295 disk galaxies, with an overall (strong) bar fraction of $23.6\pm 0.4\%$, of which 1,154 barred galaxies also have bar length measurements. These samples are the largest ever used to study the role of bars in galaxy evolution. We find that the likelihood of a galaxy hosting a bar ...

Having once thought that we understood how some galaxies were barred and had difficulty accounting for the absence of bars in others, it now seems that we have the opposite problem. Most real galaxies have centres dense enough to inhibit bar formation, even if they have massive discs. This is also true for barred galaxies, which therefore could not have acquired their bars as a result of a self-excited, global instability. There is a hint from the morphology of galaxies in th...

Stellar bars are a common feature in massive disc galaxies. On a theoretical ground, the response of gas to a bar is generally thought to cause nuclear starbursts and, possibly, AGN activity once the perturbed gas reaches the central super-massive black hole. By means of high resolution numerical simulations we detail the purely dynamical effects that a forming bar exerts on the gas of an isolated disc galaxy. The galaxy is initially unstable to the formation of non-axisymmet...