Star formation properties in barred galaxies (SFB). I. Ultraviolet to infrared imaging and spectroscopic studies of NGC7479

Abstract

Large-scale bars and minor mergers are important drivers for the secular evolution of galaxies. Based on ground-based optical images and spectra as well as ultraviolet data from the Galaxy Evolution Explorer and infrared data from the Spitzer Space Telescope, we present a multi-wavelength study of star formation properties in the barred galaxy NGC7479, which also has obvious features of a minor merger. Using various tracers of star formation, we find that under the effects of both a stellar bar and a minor merger, star formation activity mainly takes place along the galactic bar and arms, while the star formation rate changes from the bar to the disk. With the help of spectral synthesis, we find that strong star formation took place in the bar region about 100Myr ago, and the stellar bar might have been 10Gyr old. By comparing our results with the secular evolutionary scenario from Jogee etal., we suggest that NGC7479 is possibly in a transitional stage of secular evolution at present, and it may eventually become an earlier type galaxy or a luminous infrared galaxy. We also note that the probable minor merger event happened recently in NGC7479, and we find two candidates for minor merger remnants. © 2011. The American Astronomical Society. All rights reserved..