%0 Generic %1 russell2019driving %A Russell, H. R. %A McNamara, B. R. %A Fabian, A. C. %A Nulsen, P. E. J. %A Combes, F. %A Edge, A. C. %A Madar, M. %A Olivares, V. %A Salome, P. %A Vantyghem, A. N. %D 2019 %K cluster filaments %T Driving massive molecular gas flows in central cluster galaxies with AGN feedback %U http://arxiv.org/abs/1902.09227 %X We present an analysis of new and archival ALMA observations of molecular gas in twelve central cluster galaxies. We examine emerging trends in molecular filament morphology and their velocities to understand their origins. Molecular gas masses in cluster centrals range between $10^9-11$M$_ødot$, far more than most gas-rich galaxies. ALMA images reveal a distribution of morphologies from filamentary to disk-dominated structures. Circumnuclear disks on kpc scales are rare. In most systems, half to nearly all of the molecular gas lies in filamentary structures with masses of a few $\times10^8-10$M$_ødot$ that extend several to several tens of kpc into the galaxy. In nearly all cases the molecular gas velocities lie far below stellar velocity dispersions, indicating youth, transience or both. Filament bulk velocities lie far below the galaxy's escape and free-fall speeds indicating they are bound and being decelerated, a remarkable and poorly understood property. Most extended molecular filaments surround or lie beneath radio bubbles inflated by the central AGN. Smooth velocity gradients found along the filaments are consistent with gas flowing along streamlines surrounding the rising radio bubbles. Evidence suggests most of the molecular clouds formed from low entropy X-ray gas that cooled and became thermally unstable when lifted out of the galaxy by the buoyant bubbles. This behaviour is consistent with molecular clouds forming when the ratio of the atmospheric cooling time to its infall time to return to the galaxy approaches or falls below unity. Inflow and outflow are inferred. Current outflows will stall and fall back to the galaxy in a circulating flow. The distribution in morphologies from filament to disk-dominated sources therefore implies slowly evolving molecular structures driven by the episodic activity of the AGN.

@misc{russell2019driving, abstract = {We present an analysis of new and archival ALMA observations of molecular gas in twelve central cluster galaxies. We examine emerging trends in molecular filament morphology and their velocities to understand their origins. Molecular gas masses in cluster centrals range between $10^{9-11}$M$_{\odot}$, far more than most gas-rich galaxies. ALMA images reveal a distribution of morphologies from filamentary to disk-dominated structures. Circumnuclear disks on kpc scales are rare. In most systems, half to nearly all of the molecular gas lies in filamentary structures with masses of a few $\times10^{8-10}$M$_{\odot}$ that extend several to several tens of kpc into the galaxy. In nearly all cases the molecular gas velocities lie far below stellar velocity dispersions, indicating youth, transience or both. Filament bulk velocities lie far below the galaxy's escape and free-fall speeds indicating they are bound and being decelerated, a remarkable and poorly understood property. Most extended molecular filaments surround or lie beneath radio bubbles inflated by the central AGN. Smooth velocity gradients found along the filaments are consistent with gas flowing along streamlines surrounding the rising radio bubbles. Evidence suggests most of the molecular clouds formed from low entropy X-ray gas that cooled and became thermally unstable when lifted out of the galaxy by the buoyant bubbles. This behaviour is consistent with molecular clouds forming when the ratio of the atmospheric cooling time to its infall time to return to the galaxy approaches or falls below unity. Inflow and outflow are inferred. Current outflows will stall and fall back to the galaxy in a circulating flow. The distribution in morphologies from filament to disk-dominated sources therefore implies slowly evolving molecular structures driven by the episodic activity of the AGN.}, added-at = {2019-02-26T15:39:15.000+0100}, author = {Russell, H. R. and McNamara, B. R. and Fabian, A. C. and Nulsen, P. E. J. and Combes, F. and Edge, A. C. and Madar, M. and Olivares, V. and Salome, P. and Vantyghem, A. N.}, biburl = {https://www.bibsonomy.org/bibtex/2c16a8162564092fb4784c38dc58d329a/heh15}, description = {Driving massive molecular gas flows in central cluster galaxies with AGN feedback}, interhash = {13db033201318f3a5a3a17170b4d7045}, intrahash = {c16a8162564092fb4784c38dc58d329a}, keywords = {cluster filaments}, note = {cite arxiv:1902.09227Comment: 28 pages, 33 figures, 5 tables, submitted to MNRAS}, timestamp = {2019-02-26T15:39:15.000+0100}, title = {Driving massive molecular gas flows in central cluster galaxies with AGN feedback}, url = {http://arxiv.org/abs/1902.09227}, year = 2019 }