Investigating the relation of corona

and disk from a blue AGN sample

Liu, Jieying

Yunnan Astronomical Observatory , CAS

第三届黑洞天体物理前沿问题年度研讨会 (2008),SHAO ，26-28 April,2008

Using the observational data to investigate the

accretion physics in RQ AGN, and constrain on

accretion model. We also compare it with RL AGN in

order to study underlying physics in accretion model.

Motivation

1) disk-corona model in AGN

In luminous AGN and quasars ,their SED indicates coexistence of hot gas and cool gas. The UV/optical emission arises from geometrically thin and optically thick cold disk (Shakura&Sunyeav ,1973,A&A). The soft photons from the disk collide with the hot electrons in corona, emitting in X-ray( Liu,B.F.et al.2002,ApJL).

2) X-ray emission The dependence of X-ray emission on black hole mass

and accretion rate can be different according to different accretion models (Narayan& Yi ,1994;Merloni &Fabian 2002;Merloni et al.2003;Wang,J.M. et al ,2004; Brandon et al.astro-ph/0801.2383v1)

Introduction

RL: 18

RQ: 240

Radio loudness:

Sample

Total: 258 blue AGNs (free of dust extinction, the continuum Slope ≥ 1.5 (f λ∝λ^(-αλ)), λ ranges from 4030-5600

), redshift z≤0.35,including Seyfert 1 galaxies and QSOs, objects covered by FIRST (gives f_20cm value) ,and have f_x(0.1-2.4 keV) （ Dong xiaobo et al. 2008,MRAS,383,581D)

.,/

ZcIvezi

m: I band magnitude; t = -2.5log(F_20cm/3631 Jy)

Ri=log(f_20cm/f_iband)=0.4(m-t)

( et al.2002,AJ,128 )

A

Data analysis

Black hole mass:

Bolometric luminosity :

)A(5100λ

9λbol

L

L

(Vestergaard & Peterson 2006,ApJ,641)

(Kaspi et al 2000,ApJ,533;

Elvis,M. et al 1994,ApJS,95)

Eddingtong ratio: λ=L_bol/L_edd

X-ray luminosity: match with ROSAT bright and faint SRC

Catalogue database

slope-11

slope12

-slopeint

mono EE

slope)1Eff

(

Assuming: slope -ECf

f_x(2keV)

f_x(0.1-2.4 keV) f_x( 2-100 keV)

For X-ray of 0.1-2.4 keV : the slope is different ,the median is 1.73(phton index is 2.73)

For hard X-ray(2-100 keV) :slope = 0.9(Reeves&Turner 2000,MNRAS)

Statistic result

Z < 0.35 ,low redshift

10^6.5 < M_BH < 10^10

The Eddington ratio ranges from 10^-2.5 to1.0,Most of them have strong disk radiation.

Spearman’s rank coefficient

ρ= - 0.171 ， p=0.008

Assuming that the hard X-ray comes from corona , the correlation represents that the corona relative to disk becomes weaker as the Eddington ratio increases. Actually, the X-ray becomes softer as the increase of the accretion （ Lu&Yu ,1999,ApJL).

P is the two-sided significance of its deviation from zero ,less than 0.05 means a significant correlation

ρ= 0.002 P=0.969

There is no correlation between log(L_x/L_bol) and log( M_BH), implying that the accretion physics for AGN is similar in a large range of black hole mass. This could be extrapolated to BHXB.

For RL AGNs, there is no significant correlation between log(L_x/L_bol) and Eddington ratio, it is different from RQ. This may be because the hard X-ray in RL AGNs is affected by jet.

There is also no correlation between log(L_x/L_bol) and the mass of BH.

ρ= - 0.313 ， P=0.206 ρ= 0.281 ， P=0.259

Comparing with X-ray of 0.1-2.4 keV

The correlation is different from the hard X-ray , maybe the disk contributes a significant fraction

on X-ray(0.1-2.4 keV).

ρ= - 0.245 P = 0.0001 ρ= 0.139 P=0.031

1. Both radio-loud and radio-quiet AGNs , logL_x/L_bol

（ hard X-ray) is no correlate with log(M_BH). This

implying that the accretion physics for AGN is similar

in a large range of black hole mass. This could be

extrapolated to BHXB.

2. logL_x/L_bol decreases with the increase of

log(L_bol/L_Edd) for RQ AGNs. It is different with RL

AGNs.

3. Different from the hard X-ray ,the X-ray of 0.1-

2.4 keV may be connected with the disk radiation.

Conclusion and discussion

Thank you ！