%0 Generic %1 Bournaud2011 %A Bournaud, Frederic %A Juneau, Stephanie %A Floc'h, Emeric Le %A Mullaney, James %A Daddi, Emanuele %A Dekel, Avishai %A Duc, Pierre-Alain %A Elbaz, David %A Salmi, Fadia %A Dickinson, Mark %D 2011 %K accretion blackhole clumps galaxy %T An Observed Link between Active Galactic Nuclei and Violent Disk Instabilities in High-Redshift Galaxies %U http://arxiv.org/abs/1111.0987 %X We provide evidence for a correlation between the presence of giant clumps and the occurrence of active galactic nuclei (AGN) in disk galaxies. Giant clumps of 10^8-9 Msun are expected to arise from violent gravitational instability in galaxies fed by rapid gas accretion, and it has been proposed that this instability could feed supermassive black holes (BH). We use the Mass-Excitation and Blue AGN diagrams to compare a sample of 14 clumpy, unstable disks and a sample of 13 smoother, stable disks. The majority of clumpy disks in our sample have a high probability (>50%) of containing AGN. Their Oiii5007 emission line is strongly excited, inconsistent with low-metallicity star formation, instead indicating Seyfert 2-type activity. Stable disks rarely have such properties. Stacking ultra sensitive Chandra observations (4Ms) reveals an X-ray excess in clumpy galaxies, which cannot be solely due to star formation and confirms the presence of AGN much more frequently than in stable disks. These AGN are probably substantially absorbed but not necessarily Compton thick. The clumpy galaxies in our intermediate-redshift sample have global properties typical of gas-rich disk galaxies rather than mergers, which suggests that our findings also apply to the physically-similar and numerous unstable disks at z~2. In this context, the instability-driven BH feeding, with low average BH accretion rates (10^-3 to 10^-2 Msun/yr) and AGN luminosities (intrinsic Lx~10^42 erg.s^-1 with possible bursts), could build up a large fraction of today's BH masses over a couple of Gyr. Hence, violent instabilities at high redshift (giant clumps) are a much more efficient driver of BH growth than the weak instabilities in nearby spirals (bars). The observed evolution of violent instabilities with redshift could explain the simultaneous downsizing of star formation and black hole growth.

@misc{Bournaud2011, abstract = { We provide evidence for a correlation between the presence of giant clumps and the occurrence of active galactic nuclei (AGN) in disk galaxies. Giant clumps of 10^8-9 Msun are expected to arise from violent gravitational instability in galaxies fed by rapid gas accretion, and it has been proposed that this instability could feed supermassive black holes (BH). We use the Mass-Excitation and Blue AGN diagrams to compare a sample of 14 clumpy, unstable disks and a sample of 13 smoother, stable disks. The majority of clumpy disks in our sample have a high probability (>50%) of containing AGN. Their [Oiii]5007 emission line is strongly excited, inconsistent with low-metallicity star formation, instead indicating Seyfert 2-type activity. Stable disks rarely have such properties. Stacking ultra sensitive Chandra observations (4Ms) reveals an X-ray excess in clumpy galaxies, which cannot be solely due to star formation and confirms the presence of AGN much more frequently than in stable disks. These AGN are probably substantially absorbed but not necessarily Compton thick. The clumpy galaxies in our intermediate-redshift sample have global properties typical of gas-rich disk galaxies rather than mergers, which suggests that our findings also apply to the physically-similar and numerous unstable disks at z~2. In this context, the instability-driven BH feeding, with low average BH accretion rates (10^-3 to 10^-2 Msun/yr) and AGN luminosities (intrinsic Lx~10^42 erg.s^-1 with possible bursts), could build up a large fraction of today's BH masses over a couple of Gyr. Hence, violent instabilities at high redshift (giant clumps) are a much more efficient driver of BH growth than the weak instabilities in nearby spirals (bars). The observed evolution of violent instabilities with redshift could explain the simultaneous downsizing of star formation and black hole growth. }, added-at = {2011-11-07T19:17:06.000+0100}, author = {Bournaud, Frederic and Juneau, Stephanie and Floc'h, Emeric Le and Mullaney, James and Daddi, Emanuele and Dekel, Avishai and Duc, Pierre-Alain and Elbaz, David and Salmi, Fadia and Dickinson, Mark}, biburl = {https://www.bibsonomy.org/bibtex/27b227f7eebddbf6a00420868ad3d7fca/miki}, description = {[1111.0987] An Observed Link between Active Galactic Nuclei and Violent Disk Instabilities in High-Redshift Galaxies}, interhash = {7fc12cc2d011e3470efad8054bbc522e}, intrahash = {7b227f7eebddbf6a00420868ad3d7fca}, keywords = {accretion blackhole clumps galaxy}, note = {cite arxiv:1111.0987 Comment: ApJ submitted}, timestamp = {2011-11-07T19:17:06.000+0100}, title = {An Observed Link between Active Galactic Nuclei and Violent Disk Instabilities in High-Redshift Galaxies}, url = {http://arxiv.org/abs/1111.0987}, year = 2011 }