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arXiv · 1312.6572

Decoupled gas kinematics in isolated early-type disc galaxies

Ivan Katkov·Olga Sil'chenko·Victor Afanasiev
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Abstract

We have studied a sample of completely isolated galaxies by means of long-slit spectroscopy at the 6-m telescope. We have found that 7 of 12 (58 +/- 14 %) galaxies have revealed a presence of large-scale ionized-gas component which angular momentum is mostly differ from stellar one: 5 of 7 (71 +/- 17 %) show a visible counterrottation. The diagnostic diagram demonstrates a wide range of gas excitation mechanism. We have estimated the gas oxygen abundance in the cases where excitation mechanism by young stars dominates and have found that ionized gas has a subsolar metallicity. We concluded that cold-gas accretion from primordial cosmological filaments is unlikely for these objects, while external accretion from dwarf gas-rich satellites is more suitable.

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Ivan Katkov, Olga Sil'chenko, Victor Afanasiev. 2013-12-23. Decoupled gas kinematics in isolated early-type disc galaxies. https://arxiv.org/abs/1312.6572

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