On the X-ray origin in On the X-ray origin in Quiescent Black Hole X-ray Quiescent Black Hole X-ray

BinariesBinaries

Hui Zhang (Hui Zhang ( 张惠张惠 ))Shanghai Astronomical Observatory, Chinese Academy of SciencesShanghai Astronomical Observatory, Chinese Academy of Sciences

Collaborators: Feng Yuan Collaborators: Feng Yuan (SHAO)(SHAO) Wei Cui Wei Cui (Purdue University)(Purdue University) Gabor Pszota Gabor Pszota (Purdue University)(Purdue University)

OutlineOutline1.1. Introduction:Introduction: (a)observation of Black hole X-ray binary(a)observation of Black hole X-ray binary (b) theoretical model: Coupled accretion-Jet(b) theoretical model: Coupled accretion-Jet2. Prediction of Yuan & Cui for quiescent state2. Prediction of Yuan & Cui for quiescent state3.X-ray Observation results of three 3.X-ray Observation results of three sources in quiescent statesources in quiescent state4.Our modeling results4.Our modeling results

What is black hole X-ray binary?What is black hole X-ray binary?

More than 40 black hole X-ray binaries and their candidates have been found in our Galaxy.

They are in the quiescent state in most of their life.

When the accretion rate increases, some instability mechanism happen, then outburst occurs, going through various states

Models for various Spectral statesModels for various Spectral states

Esin et al. 1997, ApJ

Spectral states in black hole binariesSpectral states in black hole binariesQuiescent State:Quiescent State: - Large transient radius; - very low luminosity, Lx~1030.5-1033.5 erg/s ;

- power law spectrum photon index =1.5~2.1; - Jet is thought to be exist

Hard State:Hard State: - power law spectrum >80% (2-20keV)

- power law spectrum photon index =1.4~2.1 - strong varibility (QPO) - strong radio emission (Jet exist)

SPL/Very High State/Intermediate State :SPL/Very High State/Intermediate State : - power law spectrum photon index >2.4 - power law component>20% (2-20keV)and QPO - power law component>50% (2-20keV) and no QPO - radio flare at HSVHS

High Soft State (Thermal Dominant State):High Soft State (Thermal Dominant State): - disk component>75%(2-20keV) - no QPO or QPO is toot weak to be detected - very weak radio emission and no Jet exist - power law spectrum photon index =2.1~4.8

Done, C. 2007, A&ARv

Coupled Accretion-Jet ModelsCoupled Accretion-Jet Models

SSD: Opt/UVADAF: X-ray, Opt/UV

Jet: Radio, infrared

Coupled Accretion-Jet ModelsCoupled Accretion-Jet Models

Standard thin disk (SSD):Standard thin disk (SSD): -geometrical thin, optical thick - T r-3/4 -multicolor black body spectrum

Advection Dominated Accretion Flow (ADAF):Advection Dominated Accretion Flow (ADAF): -geometrical thick, optical thin -Compton scattering, synchrotron, bremsstrahlung -strong advection, low emission efficiency -double high temperature plasma

Jet model:Jet model: -internal shock -power law distribution of electron -synchrotron emission dominated

ADAF-Jet Models for hard stateADAF-Jet Models for hard state

Yuan, Cui & Narayan, 2005, ApJ

Success in hard state of XTE J1118+480!

SSD

ADAF

Jet

Radio/X-ray correlationRadio/X-ray correlation

Gallo et al. 2003, MNRAS, 344

LR~LX0.7

Yuan & Cui 2005 predictionYuan & Cui 2005 prediction

1. When the accretion rate decreases, the correlation between the radio and X-ray still exist, but when the luminosity lower than a certain critical value, the correlation will change and become more steeper than before. Because Lacc,x M2, LJet,x M . So most of the X-ray comes from Jet in quiescent state.

2. Because jet radiation dominates below this critical luminosity, the spectrum of X-ray is a power law.

The change of the radio—X-ray correlation from hard to quiescent states

The critical luminosity :

Yuan & Cui 2005,ApJ

Lcrit~(10-5~10-6)LEdd

Recent new study Recent new study result:result:

Yuan & Cui 2005 also predicted:

Recently, Wrobel, Terashima & Ho 2008 studied two quiesent LLAGN in NGC 4621 and NGC 4697, they found the observed radio luminosity is within a factor of 3 of the predicted value (based on Lx~10-9 LEdd and the relation above).

XMM/Newton Observation XMM/Newton Observation of Quiescent Sourcesof Quiescent Sources

We observed two black hole X-ray binaries XTE J1550-564XTE J1550-564 and GRO J1655-40GRO J1655-40 for long time by XMM-Newton. We also analysed V404 CygV404 Cyg from archival data.

Jet SSD

ADAF

ADAF

Modeling results Modeling results (GRO J1655-40)(GRO J1655-40)

Jet

SSD

ADAF

ADAF

Modeling results Modeling results (V404Cyg)(V404Cyg)

Jet

SSD

ADAF

ADAF

Modeling results Modeling results (XTE J1550-564)(XTE J1550-564)

ConclusionConclusion

In quiescent black hole X-ray binaries, In quiescent black hole X-ray binaries, the X-ray emission originates from the X-ray emission originates from JetJet ! !

Jet model can fit all the X-ray spectrum of these three sources, but for XTE J1550-564, It can also be modeled by ADAF .

Because the spectrum of ADAF is curved at low accretion rate, however, the spectrum of Jet is power-law.