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Authors: O.Gonzalez-Martin, S. Vaughan Speaker: Xuechen Zheng 2014.5.13
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Introduction Sample and Data Data Analysis Results Discussion
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1 、 PSD: BH-XRB vs. AGN Similarities: power law, bend frequency BH-XRB: ‘state’– PSD shape QPOs problem 2 、 Main purpose: AGN PSD properties
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From XMM-Newton public archives until Feb. 2009: Z <0.4 Observation duration T >40 ksec Classification, redshift, mass, bolometric luminosity: literature Sample: 209 observations and 104 distinct AGN(61 Type-1, 21 Type-2, 15 NLSy1, 7 BLLACs)
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Example.
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2-10 kev luminosity fitting using absorbed power-law model Required only reasonable estimates LLAGN luminosity agree with other literature Type- 1 Seyferts, QSOs, NLSy1: high discrepancies soft-excess long-term variability
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For a given PSD model P( ν ; θ ), likelihood function: I: observed P: model Confidence intervals:
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A. Simple power law: B. Bending power law:
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LRT: Likelihood ratio test Not well calibrated Accurate calibration: computation expensive
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1 、 Largest outlier vs. Chi-squared distribution for periodogram Candidate: p<0.01 2 、 Similar test to smoothing periodogram (top-hat filter) QPOs broader than frequency resolution p-value not correctly calibrated, crude but efficient
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75 out of 104 AGN show variability No variability: 12 of 14 LINERs, 2 of 11 Type-2 Seyferts, 12 of 54 Type-1 Seyferts, 2 of 3 QSOs, 1 of 7 BLLACs
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Low number of bins in the PSD above Poisson noise some sources unable to constrained parameters Model B: 17 vs. Papadakis et al.(2010): bump or QPOs? 16 Type-1, 1 S2
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QPOs: only one candidate Slope: Model A ---- α =2.01±0.01(T) 2.06±0.01(S) 1.77±0.01(H) K-S test distributions statistically indistinguishable Model B ---- α =3.08±0.04(T) 3.03±0.01(S) 3.15±0.08(H)
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Mean value: log(v_b) = -3.47 ± 0.10
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Papadakis(2004): A= ν ×F( ν ) roughly constant at bend frequency
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Leakage bias: reduce sensitivity to bends and QPOs model A α ≈ 2: possibly be affected ‘End matching’(Fougere 1985) reduce leakage bias remove linear trend: first and last point equal model A indices higher than before but lower than high frequency index in bend PSDs
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1 、 72% of the sample show variability, most LINERs do not vary 2 、 17 sources (16 Type-1 Seyferts) model B; others model A 3 、 slope discrepancy between model A and B 4 、 only one QPO (hard to detect)
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Equation 1: A = 1.09 ±0.21 C = -1.70 ±0.29 SSE :11.14 for 19 dof Equation 2: A = 1.34 ±0.36 B = -0.24 ±0.28 C = -1.88 ±0.36 SSE: 10.69 for 18 dof
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Cygnus X-1: test relation on BH-XRB vs. McHardy et al.(2006): Weak dependence of T_b on L Use smaller mass dependence recover( B = -0.70 ±0.30) Maybe due to uncertainties
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McHardy et al.(2006): correlation between T and optical line widths(V) Lines: H β, Pa β Correlation coefficient: r = 0.692 D = 2.9 ±0.7 E = -10.2±2.3 SSE: 13.47 for 19 dof
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Model B high frequency slope steep: May be similar to BH-XRB‘soft’states XMM-Newton and RXTE Selection effect Majority of sample show no bend: Massive object have lower v_b Leakage bias selection effect Bends: M_bh, L expected T_b 17 source bends within frequency range(13 detected)
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