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The Fundamental Plane Relationship of Astrophysical Black Holes. Ran Wang Supervisor: Xuebing Wu Peking University. Topics. Introduction – the black hole fundamental plane (FP) The sample Selection Properties Results – the FP relation and correlation tests Discussion Summary.
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The Fundamental Plane Relationship of Astrophysical Black Holes Ran Wang Supervisor: Xuebing Wu Peking University
Topics • Introduction – the black hole fundamental plane (FP) • The sample • Selection • Properties • Results – the FP relation and correlation tests • Discussion • Summary
Introduction • Dominant energy producing mechanism in black hole systems – accretion. • For observation, strong X-ray emission and sometimes accompanied by a relativistic jet. • Such kind of systems exist at different scales from black hole X-ray binaries (XRBs) to active galactic nuclei (AGNs).
Analogy between Stellar-mass BH and Supermassive BH systems: Common physics: BH, accretion disk, jet, ...
Introduction – the black hole FP • The non-linear relationship between X-ray emission, core radio emission, and black hole mass, also called black hole fundamental plane (FP), was discovered and studied(eg. Merloni et al. 2003; Heinz & Sunyaev et al. 2003; Falcke et al. 2004). • Merloni et al. (2003) studied a sample of XRBs and AGNs and fitted a FP relation among 5GHz radio luminosity (LR), X-ray 2-10keV luminosity (Lx), and black hole mass (MBH).
Introduction – the black hole FP Merloni et al. (2003)
Introduction • The reliability of the FP in Merloni et al. (2003) was challenged. • Non-uniform sample • Distance – distance effect: (Bregman 2005; Merloni et al. 2006) • Have LX/LEDD in a large range – 10-6 to 1 • Various methods in the black hole mass estimation. • We test the black hole FP relationship with a uniform broad-line AGN sample in this work
The sample • A RASS-SDSS-FIRST cross identified sample based on the X-ray-emitting SDSS AGN catalog in Anderson et al. (2003) • 964 broad permitted line AGNs (FWHM > 1000km s-1) that have 0.1-2.4 X-ray data from RASS. • 132 sources are detected by the FIRST survey at 1.4GHz and a 3σ sensitivity of 0.45mJy(White et al. 1997). • We use Hβλ4861Å and Mg II λ2798Å lines to determine the BH mass, thus excluded sources with low SNR optical spectra. • We also excluded 4 sources that have only C IV lines (z>2) in the SDSS spectra to reduce the scatter in BH mass estimation. • Finally, 115 sources are selected and divided into radio loud (76) and radio quiet (39) subsamples .
Black hole mass estimates • Virial law (Kaspi et al. 2000) • R-LHβrelation (Wu et al. 2004) • McLure -Jarvis (2002) relation
The sample • The advantage of this sample • X-ray: 0.1-2.4keV from ROSAT All-Sky Survey (RASS). • Optical spectra from the SDSS survey. • Radio: 1.4GHz from the FIRST survey. • X-ray to Eddington luminosity ratios distribute from 10-3.5 to 1. • Redshift: 0<z<2 • Minimize the scatters introduced by observations and calculations.
Results – Correlation tests • We test the intrinsic correlation between MBH, and LX/Lr. • The partial Kendall τtest indicates the BH mass is correlated to the X-ray and radio luminosities (Pnull < 0.05). • But this correlation disappears in the radio quiet sub-sample when scaling the luminosities with Eddington luminosity (Pnull~0.6). • Distance effect in Lr-LX correlation. • The partial Kendall τtest suggests the LX-Lr correlation still exists when excluding the effect introduced by distance. • We can also see the correlation in a flux plot.
Discussion – the black hole FP • Theoretically, the FP relationship reflect the common physics of a disc-jet system around the central black hole. • The slopes of the FP should be different with different X-ray emission mechanism (Yuan & Cui 2005): • Dominated by accretion flow • Dominated by jet • Jet emission may dominate the X-ray when the accretion rate drop to certain critical value and give a slope > 1(Heinz 2004). Yuan & Cui 2005
Heinz (2004, MNRAS) Scaling relations for scale-invariant cooled jets (both Lr & Lx are from jets): lg F - r -x lg For canonical synchrotron spectrum of p=2,αr=0.5,αx=1 Consistent with our results for radio-loud AGNs!
Discussion • Beaming effect is most likely to be responsible for the steeper slope in radio loud sources. • Doppler beaming can increase the jet intrinsic power by a factor of δ2+α. • The differences between observed radio luminosity and that derived from the radio quiet FP relation increase with radio loudness. • Thus the observed radio-loud FP is unreliable unless the beaming effect can be removed. • The difficulty is that the beaming factor is hard to measure directly.
Discussion • Radio-quiet FP: • We compared our radio-quiet FP relationship with different physical models. • Accretion disc models listed in Merloni et al. (2003) • The multicolor thermal emission from the inner part of a standard thin disk. • Radiation cooling jet. • Our result can be marginally matched when: • The X-ray luminosity has a nonlinear dependence on accretion rate with a power-law index ~2 – the radiatively inefficient accretion flow. • However, our sample have higher X-ray to Eddington luminosity ratios than that expected from the radiatively inefficient accretion flow models. • The soft X-ray emission in AGNs is complex and may be contributed by different mechanisms.
Summary • We studied the black hole FP relationship with a uniform sample of broad line AGN. • Our found the FP relationship have a weak dependence on the black hole mass. • The FP relationships are different for radio loud and radio quiet AGNs. • The FP relationship for radio loud AGNs is likely to be affected by the Doppler beaming. • The radio-quiet FP relationship is possibly consistent with the theoretical prediction from the accretion-flow-dominated X-ray model. • More theoretical and observational studies are needed.
The end Thanks
Results • On the log Lr-log LX plot, We do not see the clear trend that tracks of different mass bins are parallel to each other. • We can not see this trend on the logLr /LEdd -log LX/LEdd plot either.
Results • However, when we plotted the sources in different radio loudness bins, we see the parallel tracks. • The X-ray and radio luminosities are correlated in each radio loudness bin
Discussion • The black hole FP relationships • We obtained different FP relationships from that in Merloni et al. (2003) • We use 0.1-2.4keV X-ray emission instead of 2-10keV. • We use 1.4GHz rest frame radio luminosity instead of 5GHz. • These differences will only change the constant term if the emission can be described as power laws with a typical spectral index in each band for all sources. • Otherwise, the slope items may be affected.