%0 Generic %1 dekel2013contraction %A Dekel, Avishai %A Burkert, Andreas %D 2013 %K cold galaxy quenching stream %T Wet Disc Contraction to Galactic Blue Nuggets and Quenching to Red Nuggets %U http://arxiv.org/abs/1310.1074 %X We study the origin of high-z, compact, quenched spheroids (red nuggets) through the dissipative shrinkage of gas-rich disc galaxies into compact star-forming systems (blue nuggets). The discs, intensely fed by cold streams, undergo violent disc instability (VDI) that drives gas into the centre (in parallel with mergers). The inflow is dissipative when the timescale for inflow is shorter than the timescale for star formation. This implies a threshold of ~0.28 in the cold-to-total mass ratio within the disc radius. For the typical cold-to-baryonic mass ratio ~0.5 at z=2, this threshold can be traced back to a maximum spin parameter of ~0.05. It implies that about half the star-forming galaxies contract to blue nuggets, while the rest form extended stellar discs. Blue nuggets are expected to be much less abundant at low redshifts when the gas fraction is lower. The star-forming galaxies at high z are expected to show a corresponding bimodality in stellar surface density about a critical value ~10^9 Msun/kpc^2, slightly increasing with mass. The blue nuggets quench to red nuggets by complementary mechanisms associated with the bulge and the halo. Bulge quenching can include starbursts, stellar and AGN feedback, and morphological quenching of instability. It can be the trigger for fast quenching acting mostly at high z. Halo quenching is due to the development of a hot medium once the halo grows above a critical mass of ~10^12 Msun. It serves for a slow, maintenance mode of quenching, dominating at low z. These predictions are confirmed in hydro-cosmological simulations and are qualitatively consistent with observations at z=0-3.

@misc{dekel2013contraction, abstract = {We study the origin of high-z, compact, quenched spheroids (red nuggets) through the dissipative shrinkage of gas-rich disc galaxies into compact star-forming systems (blue nuggets). The discs, intensely fed by cold streams, undergo violent disc instability (VDI) that drives gas into the centre (in parallel with mergers). The inflow is dissipative when the timescale for inflow is shorter than the timescale for star formation. This implies a threshold of ~0.28 in the cold-to-total mass ratio within the disc radius. For the typical cold-to-baryonic mass ratio ~0.5 at z=2, this threshold can be traced back to a maximum spin parameter of ~0.05. It implies that about half the star-forming galaxies contract to blue nuggets, while the rest form extended stellar discs. Blue nuggets are expected to be much less abundant at low redshifts when the gas fraction is lower. The star-forming galaxies at high z are expected to show a corresponding bimodality in stellar surface density about a critical value ~10^9 Msun/kpc^2, slightly increasing with mass. The blue nuggets quench to red nuggets by complementary mechanisms associated with the bulge and the halo. Bulge quenching can include starbursts, stellar and AGN feedback, and morphological quenching of instability. It can be the trigger for fast quenching acting mostly at high z. Halo quenching is due to the development of a hot medium once the halo grows above a critical mass of ~10^{12} Msun. It serves for a slow, maintenance mode of quenching, dominating at low z. These predictions are confirmed in hydro-cosmological simulations and are qualitatively consistent with observations at z=0-3.}, added-at = {2013-10-05T20:10:02.000+0200}, author = {Dekel, Avishai and Burkert, Andreas}, biburl = {https://www.bibsonomy.org/bibtex/2af35a9650c5fd3a2f2ebc62d7ab317a6/miki}, description = {[1310.1074] Wet Disc Contraction to Galactic Blue Nuggets and Quenching to Red Nuggets}, interhash = {4ba04eca918a429dc326dcbab1549272}, intrahash = {af35a9650c5fd3a2f2ebc62d7ab317a6}, keywords = {cold galaxy quenching stream}, note = {cite arxiv:1310.1074Comment: 11 pages, 1 figure}, timestamp = {2013-10-05T20:10:02.000+0200}, title = {Wet Disc Contraction to Galactic Blue Nuggets and Quenching to Red Nuggets}, url = {http://arxiv.org/abs/1310.1074}, year = 2013 }