Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-25T16:14:35.434Z Has data issue: false hasContentIssue false
  • English
  • Français

Stellar population gradients in GASS

Published online by Cambridge University Press:  17 July 2013

Jonas Johansson ,
Guinevere Kauffmann  and
Sean Moran
Jonas Johansson
Affiliation:
Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany
Guinevere Kauffmann
Affiliation:
Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany
Sean Moran
Affiliation:
Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We study relationships between the stellar populations and interstellar medium in massive galaxies using the Galex Arecibo SDSS Survey (GASS). The sample consists of HI-observations (~1000 galaxies) and complementary H2-observations (330 galaxies) and long-slit spectroscopy (230 galaxies). Luminosity-weighted stellar population ages, metallicitites and element abundance ratios, are derived by fitting stellar population models of absorption line indices. We find that the ages correlate more strongly with molecular gas fraction (MH2/M*) than with neutral Hydrogen fraction (MHI/M*). This result strengthens the theory that H2 is a better tracer of star-formation than HI. The sample is dominated by negative metallicity-gradients and flat Mg/Fe-gradients. Galaxies with high MH2/M*-ratios show in general flat or weakly negative age-gradients. For low MH2/M*-ratios the age-gradients are overall negative. These results are in agreement with the inside-out galaxy formation scenario. For galaxies with high r90/r50-ratios, a sub-population show positive age-gradients indicating additional formation channels. Furthermore, for galaxies with high MH2/M*-ratios more massive systems have older stellar populations in their centers, suggesting downsizing within the inside-out formation scenario.

Keywords

galaxies: evolution – galaxies: elliptical and lenticularcD – galaxies: spiral – galaxies: stellar content
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S295: The intriguing life of massive galaxies , August 2012 , pp. 304 - 307
Copyright
Copyright © International Astronomical Union 2013 

References

Cappellari, M. & Emsellem, E., 2004, PASP, 116, 138Google Scholar
Dekel, A. & Birnboim, Y., 2006, MNRAS, 368, 2Google Scholar
Johansson, J., Thomas, D., & Maraston, C., 2012, MNRAS, 421, 1908Google Scholar
Kauffmann, G., et al., 2006, MNRAS, 367, 1394Google Scholar
La Barbera, , et al., 2012, MNRAS, 426, 2300Google Scholar
Marmol-Queralto, E., Trujillo, I., Villar, V., Barro, G., & Perez-Gonzalez, P., 2013, MNRAS, 429, 792Google Scholar
Moran, S., et al., 2012, ApJ, 745, 66CrossRefGoogle Scholar
Catinella, B., 2010, MNRAS, 403, 683CrossRefGoogle Scholar
Saintonge, A., Kauffmann, G., Wang, J., et al. 2011, MNRAS, 415, 61Google Scholar
Sarzi, M., et al., 2006, MNRAS, 366, 1151CrossRefGoogle Scholar
Szomoru, D., Franx, M., & van Dokkum, P., 2012, ApJ, 749, 121Google Scholar
Thomas, D., Maraston, C., & Johansson, J., 2011, MNRAS, 412, 2183CrossRefGoogle Scholar
Trager, S. C., Worthey, G., Faber, S. M., Burstein, D., & Gonzalez, J. J., 1998, ApJS, 116, 1Google Scholar
Trujillo, I., et al., 2007, MNRAS, 382, 109Google Scholar
van Dokkum, P. G., et al., 2010, ApJ, 709, 1018CrossRefGoogle Scholar
Worthey, G. & Ottaviani, D. L., 1997, ApJS, 111, 377Google Scholar
Wuyts, S., 2012, ApJ, 753, 114CrossRefGoogle Scholar