1611.05039
The structural and size evolution of star-forming galaxies over the last 11 Gyrs
Paulino-Afonso, et al
Present new results on the evolution of the rest-frame blue/UV sizes and Sersic indices of Halpha-selected SF galaxies over the last 11 Gyrs. Investigate how the perceived evolution can be affected by a range of biases and systematics such as cosmo dimming and resolution effects. Use GALFIT and an artificial redshifting technique, which includes the luminosity evolution of Halpha-selected galaxies, to quantify the change on the measured structural parameters with redshift. Find typical sizes of 2 to 3 kpc and Sersic indices of n~1.2, close to pure exponential disks all the way from z=2.23 to z=0.4. At z=0 find typical sizes of 4-5 kpc. The results show that, when using GALFIT, Cosmo dimming has a negligible impact on the derived effective radius for galaxies with <10 kpc, but find a ~20% bias on the estimate of the median Sersic indices, rendering galaxies more disk-like. SF galaxies have grown on average by a factor of 2-3 in the last 11 Yrs with r_e~(1+z)^-0.75. By exploring the evolution of the stellar mass-size relation, find evidence for a stronger size evolution of the most massive SF galaxies since z~2, as they grow faster towards z~0 when compared to the lower stellar mass counterparts. As the rest-frame blue/UV are being traced, we are likely witnessing the growth of disks where SF is ongoing in galaxies while their profiles remain close to exponential disks, n<1.5, across the same period.
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