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Observations of Molecular Outflows in Quasars. Anna Boehle March 2 nd , 2012. Background. merger driven galaxy evolution: gas rich mergers -> starbursts and AGN activity star-formation is quenched as gas is expelled transition from blue to red what drives this negative feedback?
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Observations of Molecular Outflows in Quasars Anna Boehle March 2nd, 2012
Background • merger driven galaxy evolution: • gas rich mergers -> starbursts and AGN activity • star-formation is quenched as gas is expelled • transition from blue to red • what drives this negative feedback? • quasar (radiation pressure) • starburst (radiation pressure or winds from SNe)
Previous Observations • Outflows seen in ionized gas • this is a small fraction of the total gas in the galaxy • molecular gas must be outflowing in order to quench star-formation • Feruglio et al 2010 and Sturm et al 2011: observational evidence of molecular outflows
Feruglio et al 2010 • observe CO(1-0) emission line • Plateau di Bure Interferometer (PdBI) • target: Mrk 231, nearest quasar object • wider bandwidth (1 GHz) than previous CO observations!
Observed CO Emission Lines Fit Components: Broad, Narrow, Total Feruglio et al 2010
Spatial Maps Red Wing 500 km/s -> 800 km/s Blue Wing -500 km/s -> -700 km/s Feruglio et al 2010
Sturm et al 2011 • observe FIR spectra with PACS spectrometer on Herschel • primary line used: OH 79 μm doublet • targets shown here: • 5 ULIRGS with range of SFR and AGN contribution (including Mrk 231) • one starburst template (NGC 253)
OH 79 μm Doublet Sturm et al 2011
From Outflow Velocities to Mass Outflow Rates • mass outflow rate for molecular gas: • main assumptions going into model: • conversion from observed line (CO/OH) to H2 • outflow geometry Rupke et al 20
What drives molecular outflows? vmax of outflow versus AGN Luminosity vmax of outflow versus Star Formation Rate Sturm et al 2011
What drives molecular outflows? Gas depletion time versus AGN luminosity Ṁ/SFR versus SFR Sturm et al 2011