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ADAF and jets in LLAGNs. 参考文献: Advection-dominated accretion, jets and spectral energy distribution of LINERs by Rodrigo S.Nemmen Revisting the foundamental plane of Black hole activity at extremely low luminositie by Feng Yuan

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adaf and jets in llagns
ADAF and jets in LLAGNs

参考文献:Advection-dominated accretion, jets and spectral

energy distribution of LINERs by Rodrigo S.Nemmen

Revisting the foundamental plane of Black hole

activity at extremely low luminositie by Feng Yuan



  • Some concepts about the LLAGNs
  • Data set and models for the continuum emission
  • Results and conclusions of part one
  • Introduction of foundamental plane of black hole activity
  • The “fundamental plane” of BH activity at extremly low luminosity
  • Modeling results for individual objetcts
  • Summary and discussion
some concepts about the llagn
Some concepts about the LLAGN
  • Most AGN in the present-day universe have low luminosities, being thus called low-luminosity AGNs (LLAGNs)
  • The bulk of the LLAGN population (about 2/3) are low-ionization nuclear emission-line regions (LINERs)
  • The observational properties of LINERs-and LLAGNs in general-are quite different from those of more luminous AGNs
  • ADAFs are very hot, geometrically thick, optically thin flows which are typified by low radiative efficiencies and occur at low accretion rates
  • Supermassive black holes are thought to spend >95% of their lifes in the ADAF state
data set and models for the continuum emission
Data set and Models for the continuum emission
  • Consists of 24 SEDs of LINERs which include radio (VLA), near-IR-optical-UV (HST) and X-ray (Chandra) data with high spatial resolution
  • In this model, the accretion/ejection flow consists of three components
  • ADAF: synchrotron emission, bremsstrahlung, and inverse Compton scattering
  • The truncated thin disk spectrum is simply thermal
  • The jet: sychrotron emission
  • Spectral fits for two LINERs for sake of bravity

Model parameters

for M84, the parameters in the left panel

here,δ controls the amount of energy dissipated via turbulence that is directly deposited on electrons

the parameters in the right panel


Model parameters

for Sombrero galaxy, “ADAF dominated X-ray” model

“jet-dominated X-rays” model


From modeling of the LINER SEDs, constrain important parameters that characterize their central engines:

  • The typical accretion rate available at the outskirts of the acceretion flow is
  • Typical jet mass-loss rates are in the range

(3) The jet power

(4) Given the bolometric luminosities, we have

 Draw a link between the supermassive black holes in LINERs and the quiescent beast in our galaxy, Sgr A*

conclusions of part one
Conclusions of part one
  • Successfully model the SEDs of 24 LINERs in the context of a coupled ADAF-jet scenario
  • Differents parts for different emission
  • Obtain estimates of fundamental parameters of the central engines of LLAGNs
introduction of fudamental plane of bh activity
Introduction of fudamental plane of BH activity
  • Merloni et al. find a so-called fundamental plane of black hole activity, which is a correlation between the black hole mass and radio and X-ray luminosities:
  • YC05 predict that the X-ray emission of the system should originate from jets rather than ADAFs when the X-ray luminosity in the 2-10 kev band is lower than a critical value:
  • YC05 predict that below Lx,crit the correlation should correspondingly steepen in to the following form:

The validity of the prediction of YC05 can be checked in two ways

The first is by modeling the X-ray spectra

The second is to look at the radio-X-ray correlation

the fundamental plane of bh activity at extremely low luminosity
The “fundamental plane” of BH activity at extremely low luminosity
  • 22 sources meet the criterion: Lx<Lx,crit

The left plot :

The right plot :

modeling results for individual objects
Modeling results for individual objects
  • The ADAF-jet model: refer to Yuan et al. (2005) for more detail
  • Fit the radio and X-ray spectra of 16 sources using the ADAF-jet model
  • Among these sources, seven are dominated by ADAFs and nine by jets
  • Regarding the origin of the X-ray emission, all but three of these 16 sources are consistent with the prediction of YC05
summary and discussion of part two
Summary and discussion of part two
  • Fender et al. (2003) and YC05 both emphasize the importance of the jet when the system is very dim
  • Explain the X-ray nuclei spectrum difference between FR I and FR II radio galaxies
  • We need to be cautious when we conclude that one source is not consistent with the YC05 prediction
  • Current investigations indicate that the YC05 prediction holds for most sources, including AGNs and black hole X-ray binaries