Morphologies of local Lyman break galaxy analogs II: A Comparison with galaxies at z=2-4 in ACS and WFC3 images of the Hubble Ultra Deep Field - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: Lyman break galaxies LBGs display a range in structures fromsingle-compact to clumpy-extended that is different from typical localstar-forming galaxies. Recently, we have introduced a sample of rare, nearbyz<0.3 starbursts that appear to be good analogs of LBGs. These -Lyman BreakAnalogs- LBAs provide an excellent training set for understanding starburstsat different redshifts. We present an application of this by comparing therest-frame UV-optical morphologies of 30 LBAs with those of sBzK galaxies atz~2, and LBGs at z~3-4 in the HUDF. The UV-optical colors and sizes of LBAs andLBGs are very similar, while the BzK galaxies are somewhat redder and larger.There is significant overlap between the morphologies G, C, A and M 20 of thelocal and high-z samples, although the latter are somewhat less concentratedand clumpier. We find that in the majority of LBAs the starbursts appear to betriggered by interactions-mergers. When the images of the LBAs are degraded tothe same sensitivity and resolution as the images of LBGs and BzK galaxies,these relatively faint asymmetric features are no longer detectable. Thiseffect is particularly severe in the rest-frame UV. It has been suggested thathigh-z galaxies experience intense bursts unlike anything seen locally,possibly due to cold flows and instabilities. In part, this is based on thefact that the majority ~70% of LBGs do not show morphological signatures ofmergers. Our results suggest that this evidence is insufficient, since a largefraction of such signatures would likely have been missed in currentobservations of z>2 galaxies. This leaves open the possibility that clumpyaccretion and mergers remain important in driving the evolution of thesestarbursts, together with rapid gas accretion through other means.



Autor: R.A. Overzier, T.M. Heckman, D. Schiminovich, A. Basu-Zych, T. Goncalves, D.C. Martin, R.M. Rich

Fuente: https://arxiv.org/







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