1. Studies of QSO host galaxies
The 10th East Asian Meeting on Astronomy
Studies of QSO host galaxies
Yiping Wang
National Astronomical Observatories of China

2. Outline Briefly review the BH growth and the host galaxy formation
2) Discuss the limit of the current study on QSO host properties
3) Look forward to 2020s

3. Motivation Where comes the fuel to feed BH?
How to power the central engine?
z=7.1, most distant known qso,
Constellation: Virgo : Redshift:
Type: Blazar, Sy1, Radio source ; Mv: ~ -26
Notable features: optically-brightest quasar;
first spectrum of a quasar
Host galaxy: a giant elliptical galaxy
1964 discovery, 2003 ACS image， SDSS 120,000多个类星体
Discovered by UKIDSS; Reported in June, 2011

4. Motivation

5. Local scaling relation for inactive galaxies and AGNs:
z<0.2 QSOs, Seyferts
Kormendy & Richstone 1995
McLure & Dunlop 2001

6. merger
Jahnke & Maccio 2011
Wang & Biermann
1998, 2000

7. Interplay between merging, SF and BH growth
These studies all implied that :
the broad distribution of the scaling relation could be due to different velocity dispersion of the accreting gas supplied by different formation mechanism, and the scaling relation in bright QSOs is probably a limiting case of black hole evolution by merger enhanced accretion close to Eddington limit (Wang & Biermann 1998, Wang et al. 2000).
only luminous quasars are preferentially triggered by major mergers, as well as showing that the black hole grows substantially only in a late stage of the merger and after the peak of star formation (Hopkins & Hernquist and Hopkins et al ).
the creation of the scaling relations can be fully explained by the hierarchical assembly of BH and stellar mass through galaxy merging from an initially uncorrelated distribution of BH and stellar masses in the early universe, provided some physics for the absolute normalization (Jahnke & Maccio 2011).
To understand the interplay between merging, and SF in the process of BH growth or accretion, we need to look at the host properties in detail.
Interplay between merging, SF and BH growth

8. Local evidence The I Zw 1 System J-band image (ISAAC+VLT)
2. Palomar Green QSO with
a spiral host
3. Possily minor merger
4. Possibly transition stage
5. Narrow-line Seyfert I, probably
young stage of nuclear activity
(Mathur et al. 2000)
6. Black hole mass, small BH,
QSO in formation?
Foreground star
Local template objects
Scharwachter et al. 2003;
Courtesy: Julia Scharwacher’s ppt
@20 April 2007-Huatulco

9. “Antennae”-like merger?
Local evidence
1. z=0.367
2. radio source
3. Mv ~ -25
4. first solid identification of a quasar host galaxy
5. possibly two interacting galaxy centers,
as a major merger
“Antennae”-like merger?
Courtesy: Julia Scharwacher’s April 2007-Huatulco
~ 1” to the NE of the QSO nucleus,
possibly two merging nuclei?
Stockton & Ridgway 1991

10. Merger-driven Evolutionary sequence from ULIGs to QSO
Sanders et al. 1998
Signs of two galaxy centers, as a major meger
ACS’s coronagraph reveals a spiral plume
wound around the QSO, a red dust lane, a blue arc and clump in the path of the jet blasted from the QSO.
Signs of SF enhanced by tidal interaction, possibly a minor meger
What activity in host galaxy would feed the BH

11. Challenges from high-z monsters
Walter et al.2004;
Peng et al. 2006;
McLure et al. 2006;
Riechers et al/ 2008;
Merloni et al. 2010;
Wang et al. 2010,2012
Courtesy: Rosa Valiante’s presentation

12. How to grow quickly a monster in the early universe?
---- by super-Eddington
accretion?
---- by merging of BHs?
---- born as giant babies?
Problem, or challenge comes because of those monsters at high-z, and local outliers.

13. Local outliers and labs
In the outer envelop of M87
Seth et al. Nat.Vol.513,2014

14. Scaling relation over cosmic time
= M_bh / M*
To see co-evolution or not of the scaling relation by pushing it to high-z; Fig.11
The circles are the lensed hosts and the triangles are the directly imaged hosts from
Ridgway et al 2001 and Kukula et al Points with a vertical line may represent
the low limits.
Peng et al. 2006

15. MNRAS 429, 2, 2013 Sample design: 17 ~L* quasar at z~1 and z~2
(-24 =< Mv <= -25, RLQ & RQQ (~ fifty-fifty)
Filter selection: rest-frame U&V, avoiding strong galaxy emission lines
Results: 1) rest-frame U-V colors of host galaxies are systematically
bluer than those of comparably massive galaxies at same z
2) mean SFR decreases by a factor of two from z~2 to z~1;
mean SFR for RLQ are about three times of that for RQQ
3) morphology: all bulge-dominated host galaxies
Why should we study host properties in detail? Unavoidable if we want to understand the BH growth?, SF in the host galaxy would be an important engine to tune the accretion and BH growth.

17. Passive RLQ RQQ M*=10^12M_sun M*=10^11M_sun 0.02% 0.04%
0.01%
0.02%
RLQ
0.04%
Fig.3, and Fig.5 of Floyd et al. 2013
0.08%
RQQ
0.16%
0.32%
M*=10^11M_sun
0.64%
1.28%
2.56%
5.12% SF

18. Host galaxies of high-z QSOs, MBH-Mbulge relation at z~3
Schramm et al. 2013

20. IRCS+AO observation of UM402 at z~3
A faint tidal tail?
5” x 5”, AO corrected FWHM~0.”2
AO corrected FWHM~0.”13
UM402
1) 2”.4 north of the QSO sightline. The candidate is indicated in the image. 2) impact parameter of ~ 19.6 kpc, if at z~ ) apparent K-magnitude m=21.91+/-0.26, as well as a red color J-K~1.6
Wang et al. 2013, 2015
2”.4 north of the QSO sightline. The candidate is indicated in the image.
2) impact parameter of ~ 19.6 kpc, if at z~2.53.
3) apparent K-magnitude m=21.91+/-0.26, as well as a red color R-K>3.3
2”.4 north of the QSO sightline. The candidate is indicated in the image.
2) impact parameter of ~ 19.6 kpc, if at z~2.53.
3) apparent K-magnitude m=21.91+/-0.26, as well as a red color R-K>3.3

21. WFC3/F140W archive images : 2 orients x 2 dithers / single orbit
Pixel scale 0.13”
Total exposure: s

22. 2) impact parameter of ~ 19.6 kpc, if at z~2.53.
UM402
2”.4 north of the QSO sightline. The candidate is indicated in the image.
2) impact parameter of ~ 19.6 kpc, if at z~2.53.
3) apparent K-magnitude m=21.91+/-0.26, as well as a red color R-K>3.3
2”.4 north of the QSO sightline. The candidate is indicated in the image.
2) impact parameter of ~ 19.6 kpc, if at z~2.53.
3) apparent K-magnitude m=21.91+/-0.26, as well as a red color R-K>3.3

23. AJ152,38L,2016

24. Simulated images of z~2 QSOs with MICADO@E-ELT in Ks band, assuming a
0.6” seeing, and a very compact and faint host galaxies of Re~0.3”, m(k)~ 23
For those z~2 QSOs whose host galaxies are 3-4 magnitudes fainter than the nucleus, it’s possible to determine their host galaxy luminosity with an accuracy better than 10-15%.

25. Thank you very much !