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(Cold) dust and gas in high-z AGNs: a prelude to Herschel and ALMA Roberto Maiolino Osservatorio Astronomico di Roma
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The “cold” side of AGNs Molecular transitions (gas mass, dynamics...) Far-IR fine structure lines (PDR, HII, star formation, dynamics...) Thermal dust emission (star formation, dust mass,...) Cleaner view of the host galaxy (unaffected/little affected by AGN light) than at other wavelengths...
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Two modes of star formation “starburst” high efficiency merger-interaction driven “secular” low efficiency disk instabilities (smooth gas inflow) Daddi+10 Genzel+10 In what mode does black hole accretion occur? Higher gas fraction at high-z Does this play a role into BH accretion and obscuration at high-z? Tacconi+10 gas fraction local QSOs high-z slope=1.3
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Shao+10 Herschel: a tight connection between BH accretion and galaxy formation only seen in the luminous QSO regime (merging?) Low luminosity AGN hosts mostly undergoing secular evolution Walter+09 1.5 kpc z=6.4 L AGN ~L Edd SFR ~ 1000 M o yr -1 kpc -2 (Eddington limited SF) gas ~ 10 10 M o kpc -2 (~GMC cores) M BH /M bul L(SF) [erg/s] L(AGN) [erg/s]
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CO velocity fields: AGN host galaxy dynamics at high z High z QSO hosts Low z galaxies M BH -M * Relation out to z>6 M * ~ M dyn -M gas CO Velocity (deprojected) Riechers+09 Wang+10 Lamastra+10 CO map (Einstein ring z~4.8) from CO rotation curve... yes, the molecular gas rotates... and traces the dynamical mass... really true?
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If molecular gas in QSO hosts rotates and is dynamically settled... where’s the feedback?!... the bulk of the gas (~molecular) in the host galaxy seems unaffected by the presence of a QSO. Mrk231 the closest QSO However past CO observations plagued by narrow bandwidth -200 +200 0 Mrk231 re-observed with IRAM broad bandwidth Feruglio+10 Velocity (km/s) Downes & Solomon 1998 Broad wings
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Massive molecular outflow in Mrk231 extended over ~1 kpc Inferred outflow rate ~ 2000 M /yr ! Will expel the available molecular gas (hence stop star formation) in less than 10 7 yrs Same outflow component observed by Herschel through OH and H 2 O absorption Fisher+10
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Herschel+ALMA powerful tools to probe dynamics and feedback in high-z AGN hosts! But are molecular tracers really the best ones in typical galaxies at high-z? “Low metallicity” (Z~0.3 Zsun) galaxy observed by Herschel [CII]/CO ~ 50000 !!! Far-IR fine structure lines (especially PDR tracers) more promising Cormier+10 [CII] CO
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star forming galaxies ULIRGs Far-IR fine structure lines in high-z AGN hosts. Not only kinematics, but also galaxy physics. Iono+06 Walter+09 Maiolino+05,09 Ivison+10 z>4 QSOs AGN in z~2 SMG AGN in z~2 SMG local ULIRGs local SB and SF galaxies n=10 6 n=10 4 n=10 2 G 0 =10 2 G 0 =10 4 L CO(1-0) /L bol L [CII] /L bol [CII] @ z=4.4
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Also NLR far-IR tracers at high-z, but not clear-cut in identifying AGNs Sturm+10 Ferkinhoff+10 However, the mm/submm spectral range host other powerful tracers of (obscured) AGNs...
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X-ray Dominated Regions (XDR’s) Photo Dissociated Regions (PDR’s) UV X-ray X-rays penetrate deep into the molecular cloud and keep the temperature high Maloney+96, Lepp & Dalgarno 96, Meijerink+05,07
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Van den Werf+10 Herschel-SPIRE XDR Powerful tool to identify totally obscured and embedded AGNs
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Weiss etal 2005/7 non - linear (slope 1.7) QSOs SMGs The high CO excitation observed in high-z QSOs is probably associated with XDR
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X-ray Dominated Regions (XDR’s) Photo Dissociated Regions (PDR’s) UV X-ray X-rays penetrate deep into the molecular cloud and keep the temperature high high-T favors chemical reactions ( e.g. formation of HCN) Maloney+96, Lepp & Dalgarno 96, Meijerink+05,07
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XDR-enhanced species can identify the presence of hidden/elusive AGNs HCO+(1-0) Starbursts and Composite Sy’s Pure Sy’s HCN / HCO+ HCN / CO Khono+08 Krips+09
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With ALMA the identification of XDR will be feasible not only in all local (obscured) AGNs, but also at high redshift HCN HCO+ CO CCH Example of QSO at z=6.4 Not only ~ S/N on CO line ( detailed dynamical studies, see discussion later on), but also several other molecular lines -> astrochemistry -> XDR tracers IRAM 14 hours Bertoldi+03
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