The mass relations between
supermassive Black Holes and their
host galaxies at 1<z<2 with HST-WFC3
Xuheng Ding
UCLA
collaborator: John Silverman, Tommaso Treu
@Galaxy Evolution Workshop 2019

Outline• Motivation• The supermassive BH and host galaxy correlation• The challenge of tracing to higher redshift• Methodology• Sample selection• AGN image decomposition• Infer of the host stellar mass

• Results

Outline• Motivation• The supermassive BH and host galaxy correlation• The challenge of tracing to higher redshift• Methodology• Sample selection• AGN image decomposition• Inference of the host stellar mass

• Results

The BH and host galaxy relation
Almost every galactic nuclei harbor a supermassive black hole (BH),
whose mass is well known to be correlated with the host properties(including: luminosity, stellar mass, stellar velocity dispersion).

The BH and host galaxy relation
Currently, the physical mechanism that can produce such atight relationship is unknown, due to the daunting range ofscales between the scale of the host galaxy (∼ 10 kpc) andcenter BH dynamical sphere (∼ pc).
~100 arcsec across
50 μ arcsec across～106

Center SMBH
Messier 87, credit HST.

credit Event Horizon Telescope.

Possible origins
1. Physical coupling? (e.g. AGNfeedback? fixed feeding rate?)

Centaurus A,credit HST + VLA.

2. Merger of Galaxies?

Jahnke & Maccio 2011

Trace the correlation to higher redshift
One key to this study is tracing their correlation to higher redshift.
However, direct dynamical determinations of MBH are not feasible
at distance universe. The only approach so far is to inferred MBH
from the AGN emission line using virial method.

2MBH ≃ f RBLRV g

Trace the correlation to higher redshift
The main challenge is to determine the host properties.

•AGNs are very bright.

•Cosmological surface
brightness dimming as (1+z)4.

bright quasar 3C 273
z = 0.158
credit HSTInfer host galaxy properties using 2D decomposition

Park et al. 2015

However, most of these studies are limited within z<1.

DeGraf et al. 2015

The simulations predict a strong evolution with SMBHs more massive
by 0.5 dex at z~1.4 as compared to z=0.

Outline• Motivation• The supermassive BH and host galaxy correlation• The challenge of tracing to higher redshift• Methodology• Sample selection• AGN image decomposition• Inference of the host stellar mass

• Results

Study the correlations up to z>1 using HST/WFC3
We selected 32 broad-line AGNs uniformly within 1.2<z<1.7 from acatalog provided by the X-ray coverage of COSMOS, (E)-CDFS-S, andSXDS fields.
The HST filter WFC3/F125w and WFC3/F140W are adopted, for samples
at z~1.2–1.44 and z~1.44–1.7, respectively.
The benefits by our selection:•AGNs fall below the knee of the black hole mass function.

•BH masses measured using Balmer lines (i.e., Hα) toremove systematics with Mgii, Civ. (by Schulze et al. 2018).

•Imaging the host galaxy above the 4000 A break andbelow the broad Hα line (6563 A).

•

X-ray selected AGN have higher host-to-total flux.

•

The multi-band information (HST/ACS images and groundbased photometry).

AGN imaging data
We obtain six separate exposures ~400s/frame. (i.e.
~2400s in total) and use astrodrizzle software to co-add
the image with an output pixel scale of 0."0642.

CID543

Decompose the AGN 2D image

Assumptions:••

Host galaxy as a convolved
Sersic profile

Fitting ingredients:•AGN imaging data•

Noise level map•

PSF

Bright nuclei as scaled PSF

Build up PSF libraryBuild up PSF libraryBuild up PSF library
The sample includes 20 systems by WFC3/F140W and 12 WFC3/F125W. In total, I collect 78 PSFs for F140W and 36 PSFs for F125W.
We carry out the AGN decomposition using each PSF, one by one, inthe library. We ranking the performance of each PSF based on thegoodness (i.e. Chisq), to infer the host properties by weighting theresults from the top ranked PSFs.

Weight the inference using top ranked PSF
I adopt the imaging modeling tool LENSTRONOMY to perform thedecomposition of the host and nuclear light.

Distribution of fitted the Sersic parameters

Decompose the AGN at ACS band
21/32 systems in COSMOS field have ACS/F814W images.
Following the same approach, I derived the host flux in ACS
band using the build up the PSFs library in ACS.

Adopt stellar template

I find that the 1 Gyrs galaxy template is very consistent for the colors between
WFC3 and ACS. We thus adopt this stellar template to derive the rest-frame Rband luminosity (LR) and the stellar mass (M*).

Outline• Motivation• The BH and host galaxy correlation• The importance to trace to higher redshift and its challenge• Methodology• Sample selection• AGN decomposition• Inference of the host stellar mass

• Results

Combining with MBH to infer the relation
We combining the inference of the host properties can study
their relation with their BH mass.

The evolution of MBH-M*

Extension the with HSC at redshift desert

HSCG band

R bandI bandZ band

Y bandThanks!