Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-05-06
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
4 pages, 2 color figures, accepted for publication in the Astrophysical Journal Letters
Scientific paper
In this Letter, we present mean optical+NIR color gradient estimates for 5080 early-type galaxies (ETGs) in the grizYJHK wavebands of the Sloan Digital Sky Survey (SDSS) plus UKIRT Infrared Deep Sky Survey (UKIDSS). The color gradient is estimated as the logarithmic slope of the radial color profile in ETGs. With such a large sample size, we study the variation of the mean color gradient as a function of waveband with unprecedented accuracy. We find that (i) color gradients are mainly due, on average, to a metallicity variation of about -0.4dex per decade in galaxy radius; and (ii) a small, but significant, positive age gradient is present, on average, in ETGs, with the inner stellar population being slightly younger, by ~0.1dex per radial decade, than the outer one. Also, we show that the presence of a positive mean age gradient in ETGs, as found in the present study, implies their effective radius to be smaller at high z, consistent with observations.
f.
Rathna. R.
Barbera La
Carvalho de
No associations
LandOfFree
The Origin of Color Gradients in Early-Type Systems and Their Compactness at High-z 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 The Origin of Color Gradients in Early-Type Systems and Their Compactness at High-z, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Origin of Color Gradients in Early-Type Systems and Their Compactness at High-z will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-541771