Color Gradients and the Secular Evolutionary Scenario in Late-Type Spiral Galaxies

Details Color Gradients and the Secular Evolutionary Scenario in Late-Type Spiral Galaxies Color Gradients and the Secular Evolutionary Scenario in Late-Type Spiral Galaxies

Oct 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999mst..........2g&link_type=abstract

University of Sao Paulo M.Sc. thesis; supervisor: Dr. S. dos Anjos

Astronomy and Astrophysics

Astrophysics

Scientific paper

We have done a statistical study of the behaviour of the broadband color profiles (UBV) for 257 Sbc galaxies, barred and unbarred, collecting data obtained through photoelectric aperture photometry, available in the literature (Longo & de Vaucouleurs 1983,1985). We have determined (B-V) and (U-B) color gradients for the total sample of galaxies, as well as (B-V) and (U-B) color indices of bulges and disks separately, using robust statistical methods. Applying a bi-dimensional decomposition technique to model the brightness profiles of bulges and disks in images from the Digitised Sky Survey (DSS), we obtained characteristic structural parameters for 39 galaxies. The acquisition of images for 14 galaxies in the Laboratorio Nacional de Astrofisica (Astrophysics National Laboratory) allowed us to do a comparative photometric study, and verify the validity of the results obtained in this work. Among the main results obtained, we point out: (i) - 65% of the galaxies have negative color gradients (reddish inward), 25% have zero gradients, and 10% show positive gradients; (ii) - galaxies that show zero color gradients tend to be barred; (iii) - the color indices along the galaxies with zero color gradients are similar to the color indices of the disks of the galaxies with negative color gradients; (iv) - we confirm the correlation between the color indices of bulges and disks, already found by other authors; (v) - the absence of correlation between color and metallicity gradients suggests that the excess of barred galaxies with zero or positive color gradients reflects a difference in the behaviour of the mean age of the stellar population along barred and unbarred galaxies; (vi) - galaxies with zero or positive color gradients show a slight tendency of having larger bulges, with a greater central concentration of light; and (vii) - we confirm the correlation between the scale lenghts of bulges and disks, already found by other authors. These results are compatible and favourable to the secular evolutionary scenario, in which stellar bars induce radial mass fluxes to the central regions of galaxies, not only turning homogeneous the stellar populations along the galaxies, producing disks and bulges with similar color indices, but also contributing to the formation and/or building of galactic bulges.

Affiliated with

Also associated with

No associations

Rating

Color Gradients and the Secular Evolutionary Scenario in Late-Type Spiral Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Color Gradients and the Secular Evolutionary Scenario in Late-Type Spiral Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color Gradients and the Secular Evolutionary Scenario in Late-Type Spiral Galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1830391