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The Molecular Gas in QSOs. XiaoYang, Xia Center for Astrophysics Tianjin Normal University Collaborators Y. Gao, Hao, Flaquer, Mao, Leon and Omont. Outline. Motivations The CO observations for IR QSOs by IRAM Comparing with ULIRGs

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the molecular gas in qsos
The Molecular Gas in QSOs

XiaoYang, Xia

Center for Astrophysics

Tianjin Normal University

Collaborators

Y. Gao, Hao, Flaquer, Mao, Leon and Omont

outline
Outline
  • Motivations
  • The CO observations for IR QSOs by IRAM
  • Comparing with ULIRGs
  • Comparing with CO detected

local PG+HE QSOs and high-z QSOs

slide3
The correlation between Black hole mass

and spheroid

  • Is it valid for high-z galaxies?
  • When and how this correlation built up?

Coppin et all. 2008

to answer following questions
To answer following questions
  • Is far-infrared emission of IR QSOs mainly from starburst, instead of central AGN?
  • Do IR QSOs have enough cold molecular gas reservior to sustain star formation?
  • Are IR QSOs in the stage that Msph/Mbh relation is building?
  • Which high-z QSOs are scale-up of IR QSO?
ir qso and ulirgs samples
IR QSO and ULIRGs samples

IR QSOs

Selected from Hao et al. 2005

19 with z<0.18

Observed at 2008 fall (50 hours)

by IRAM 30m and detected 15

Plus 6 archive, IR CO detected IR QSOs are21

ULIRGs 36Solomon et al.1997

slide10
Same Gas

contet

10^9-10^10

Msun

  • Same SFE

(Lfir/Lco’)

  • Similar FWHM
  • Time scale

For SF can last

several10^7 yrs

enough cold gas to sustain star burst

sample of l ow z classical qsos and high z submm luminous qsos co detected
Sample of low-z classical QSOs and high-z submm luminous QSOs (co-detected)

PG & HE QSOs 24

(Hamburg/ESO survey)

Scoville et al. (2003), Evans et al. 2001, 2006 (z<0.1)

Bertram et al. 2008 ( z<0.06)

high-z QSOs 29collected by

Wang et al. 2010

(z=2, 4, 6)

slide12
Tight

correlation

  • Non-linear
  • No gap for

Low and

high-z QSOs

Slop=1.44

slide14
LPAH

vs. Lco’

Slop=1.25

slide15
Star formation gives significant contribution

to far-infrared emission for all QSOs

slide16

Star formation efficency

Lfir/Lco’ ∝LHCN/Lco’(gao&Slomon, 2004)

dence gas fraction

dence gas fraction
Dence gas fraction
  • IR QSO Mrk231 and I Zw I 1kpc gas disk/ring
  • High-z QSOs (APM 08279+5255, Cloverleaf, J1148+5251) observed by high resolution VLA with gas disk less than 1kpc (Riechers et al. 2009, Walter et al. 2009 and Bradford et al. 2009)

However, the cold molecular gas contents are one order of magnitude higher for high-z QSOs,

so the dence gas fraction of high-z QSOs must be higher

slide18

The correlation

between Lbol and Lco’ may implies that both QSO activity and

star formation are dependent on same cold gas reservior

slide19
BH accretion

efficiency

(Lbol/Lco’)for

classical QSOs

and the brightest

high-z QSOs is

much higher than

Those of QSOs

in transition stage

slide20
Histogram of

Lfir/Lbol

(SFR/Mdot)

slide21
IR QSO PG QSOs high-z QSOs

Mdot/SFR 2.7x10^-3 0.8-1.6x10^-2

Local Mbh/Msph=1.4x10^-3 (Raring & Rix, 2004)

BH and spheriod coevally evolve only

for IR QSOs and some relatively faint

high-z QSOs

slide22
After transition stage, the accretion of cold molecular gas to central SMBH is more efficient when the star formation on central kpc scale has not dominated in the energy output

This is consistant with simulation result by Hopkins (2010) that AGN peak is several times 10^7 years delay

the estimation of time scale of co evolution
the estimation of time scale of co-evolution
  • by Mgas/SFR

several times 10^107 years

  • by spatial density
the estimation of time scale of co evolution by spatial density
the estimation of time scale of co-evolution by spatial density
  • fraction of IR QSOs in ULIRGs is about 6% (zheng et al. 2002, Hao et al. 2005)
  • the QSO fraction (broad emission line AGN) in SMGs is about 4% (Chapman et al. 2005)
  • The fraction of CO detected submm luminous QSOs is about 30% (Chapman, 2005), but outlier of QSOs is only 10% (3/28), then high-z QSOs with low Mdot/SFR is 4%

The time scale is few times 10^7 years

slide25

In the transition stage of QSO (10^7 years), the local Mbh/Msph relation

could not be built up

summary
Summary
  • The cold molecular gas content of IR QSOs is as the same as those of ULIRGs (a few times of 10^9- 10^10Msun), there is sufficient fule to sunstain massive star star formation in several 10^7 years
  • There is correlation between Lbol and cold molecular gas content for all QSOs, implying the same cold gas reservoir for QSO and star formation.
  • Only few high-z relatively faint QSOs are like local IR QSOs with high SFR and high accretion rate, during which the spheriod and black hole co-evolve, but the local Mbh/Msphe relation could not be built up during this stage.
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