Transcript Xiao Yang Xia

IR QSOs at low and
high redshift
X.Y.Xia
Tianjin Normal University, China
Collaborators: C.N.Hao, S.Mao, H.Wu & Z.G.Deng
Motivation
• The tight correlation between Mbh and
σof host galaxy
Kommendy&Gebhardt 2001, Merritt & Ferrarese 2001
• The relation of SFR/Mdot vs. Mbh
Heckman & Kauffmann 2004
• IR QSO is ideal laboratory for study such
process-coeval of starburst and BH
growing
Heckman & Kauffman, 2004, based on 23000 SDSS narrow
emission line AGN
Motivation
• The tight correlation between Mbh and
σof host galaxy
Kommendy&Gebhardt 2001, Merritt & Ferrarese 2001
• The relation of SFR/Mdot vs. Mbh
Heckman & Kauffmann 2004
• IR QSO is ideal laboratory for study such
process--coeval of starburst and BH
growing
Transition stage from merger to ellipticals
IR QSOs are in transitionary stage
• Strong FeII emitters
• High Eddington ratio
• Steep x-ray slop
at one extreme end of Eigenvecgtor 1 and they
are young QSOs
• Starburst
Key point
• The starburst and central AGN give main
contributions at different waveband
• By comparing optical and IR QSOs sample,
It is possible to separate the contributions
• Determining SFR and Mdot
IR QSOs at Low redshift
(1) IR QSO sample
Zheng et al. (2002)
(2)
The optically-selected QSO sample
PG QSOs , BG92 (1992), Haas et al. (2003)
(3) NLS1 sample
Wang & Lu (2001)
Sample Selection
• QDOT IRAS galaxy sample (Lawrence et al.
1999)
• 1 Jy ULIRGs sample (Kim & Sanders 1998)
• IRAS-ROSAT cross-identification sample
(Moran et al. 1996)
A sample of 31 IR QSOs (z<0.35)，takes a fraction
of about 25% in local universe. Based on the sample,
statistical results should be representative.
Estimation of physical parameters at low z
M BH
(1) Black hole mass:
RBLRV 2

G
Lbol  9L (5100 A)
(2) Bolometric luminosity:
(3) Accretion rate:
(Kaspi et al. 2000)
Lbol

M
 C2
SFR  6.52M sun yr
(4)
Star formation rate:
(Kaspi et al. 2000)
(Peterson 1997)
1
L60m
1010 Lsun
(Kennicutt 1998; Lawrence et al. 1989; Cardiel et al. 2003)
SFR
M sun yr 1
0.29

 M


 588.8
1 
 M sun yr 
Heckman & Kauffman, 2004, based on 23000 SDSS narrow
emission line galaxies
High-z QSOs
Current available data at radio, UV and Xray show
No any difference between
low-z and high-z QSOs
High-z QSOs
The sample
(1) Optically selected QSOs at redshift about 4
with 1.2mm observation, Omont et al. (2001)
(2) Optically selected QSOs at redshift about 4
with 1.2mm observation, Carilli et al. (2001)
(3) Optically selected QSOs at redshift about 2
with 1.2mm observation, Omont et al. (2003)
T=41K, ß=1.95
Parameters estimates at high z
SFR:
Monochromatic luminosity at 60m
the monochromatic luminosity at 60m from the flux
density at 1.2mm by assuming the rest-frame FIR SED
can be described by
a greybody spectrum with the dust temperature of 41K
and the dust emissivity of 1.95
Priddey & McMahon (2001).
Mdot:
Bolometric luminosity
Vestergaard (2004 )
Lbol  9.74 LB
QSOs
Narrow
emission
Line AGN
Summary
• IR QSOs (at both low and high redshift)
are ideal laboratory for study the starburst
and black hole growing process
extending sample
• The relation of SFR/Mdot with Mbh may
indicate the strong outflow from central
AGN for bright QSOs
Conclusions
(1) The optical emission of both infrared and optically selected QSOs and
NLS1s is mainly from the central AGN, the infrared excess, especially farinfrared excess of IR QSOs should come from starbursts.
(2) Star formation rate and accretion rate onto the central BH in IR QSOs at
low redshift follow Mbulge- MBH relation, i.e., the ratio of the star formation
rate and the accretion rate is about several hundred for IR QSOs, but
decreases with the central black hole mass. This shows that the tight
correlation between the stellar mass and the central black hole mass is
preserved in massive starbursts during violent mergers.
(3) Similar to IR QSOs at low redshift, the optically selected QSOs detected at
mm band at high redshift have far-infrared excess compared to optical
AGNs at low redshift, which should be due to the contribution of starbursts
heating the dust.
(4) The ratio of star formation rate to accretion rate for QSOs at high redshift
is typically smaller than that for IR QSOs at low redshift, which hints the
relatively faster growth of black holes at early epochs.
(4) IR QSOs are accreting and forming stars at the same time.
Therefore, it is an ideal laboratory for us to explore the connection
between black hole accretion and star formation. We find that the
star formation rate and accretion rate in IR QSOs follow the relation:
SFR
M sun yr 1
0.29

 M


 588.8
1 
 M sun yr 
Notice that the derivation of SFR is from the monochromatic
luminosity at 60m due to starbursts, i.e., the contribution from
AGN to L(60 m) has been subtracted by assuming IR QSOs
follow the same regression relation as optical AGNs (the solid line in
Fig. 2c).
Log (Lx/LFIR) vs. Hß blueshift
Discussion
Hß blueshift
Outflows
Hß blueshift
vs.
FeII4570/Hß
High fraction
of strong Fe II
emitters
Outflows
FeII emission
Estimation of physical parameters at low z
(1) Black hole mass:
M BH
RBLRV 2

G
(Kaspi et al. 2000)
(2) Bolometric luminosity:
Lbol  9L (5100 A) (Kaspi et al. 2000)
(3) Accretion rate:
Lbol

M
 C2
(4)
Star formation rate:
SFR  6.52M sun yr
(Peterson 1997)
1
L60m
1010 Lsun
(Kennicutt 1998; Lawrence et al. 1989; Cardiel et al. 2003)
Heckman & Kauffman, 2004, based on 23000 SDSS narrow
emission line galaxies