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.