The Evolution of Binary Stars

Markowitz, Wm.

doi:10.1086/143359

Cited by 8 publications

(16 citation statements)

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“…However, we think it is rather remarkable that the present results are consistent with the hypothesis of a linear relation between break time‐scale and M BH in Seyferts and quasars. This result becomes even more remarkable if we also consider the similarity in the PSD shape and the linear mass–time‐scale relation between Seyfert and Galactic X‐ray black hole binaries suggested by Edelson & Nandra (1999), Uttley et al (2002) and Markowitz et al (2003). The similarity of the PSD shape implies that the same variability mechanism operates in accreting systems with an enormous black hole mass range (10–10 8 M⊙).…”

Section: Discussionsupporting

confidence: 59%

“…3 as the thick solid line. Its slope is much flatter than the typical value inferred by Lawrence & Papadakis (1993) from the analysis of EXOSAT data of a Seyfert 1 galaxies, or of single power‐law fits to RXTE PSDs or Seyferts (Uttley et al 2002; Markowitz et al 2003).…”

Section: The 2–10 Kev Flux Variabilitymentioning

confidence: 72%

“…It is interesting to compare the ratio of the break time‐scales and black hole mass between PG 0804+761 and the Seyfert galaxies studied by Markowitz et al (2003). These authors find that the 2– 10 keV PSD of three Seyfert 1 galaxies, namely NGC 3783, 3516 and 4151, shows a steepening from a −1 to a −2 slope at 4 × 10 −6 , 2 × 10 −6 and 1.3 × 10 −6 Hz, respectively.…”

Section: Discussionmentioning

confidence: 98%

“…Long‐term RXTE observations have recently revealed the presence of similar frequency breaks in the PSDs of a few Seyfert galaxies as well (Edelson & Nandra 1999; Pounds et al 2001; Uttley et al 2002; Markowitz et al 2003). Both the excellent agreement of the PG 0804+761 σ 2 rms / L X measurement with the σ 2 rms versus L X relationship defined for Seyfert galaxies and the similarity between the shape of its overall PSD with the power spectra of other Seyfert galaxies support the idea that that the same variability process operates in both Seyfert galaxies and quasars.…”

Section: Discussionmentioning

confidence: 99%

“…Further progress in the study of the longer‐term X‐ray variability has been afforded by RXTE which has shown a flattening of the PSD at lower frequencies (Edelson & Nandra 1999; Pounds et al 2001; Uttley, M c Hardy & Papadakis 2002; Markowitz et al 2003). The results so far suggest that the AGN power spectra are similar (both in shape and fractional rms amplitude) to those of Galactic black hole X‐ray binaries, like Cyg X–1, except that characteristic time‐scales are ‘shifted’ to much lower frequencies.…”

Section: Introductionmentioning

confidence: 99%

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The long time-scale X-ray variability of the radio-quiet quasar PG 0804+761

Papadakis

Reig

Nandra

2003

Monthly Notices RAS

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We present the results from a study of the timing properties and the energy spectrum of the radio‐quiet quasar PG 0804+761, based on monitoring RXTE/PCA observations that lasted for a year. This is a systematic study of the X‐ray variations on time‐scales of weeks/months of the most luminous radio‐quiet quasar studied so far. We detect significant variations in the 2–10 keV band of an average amplitude of ∼15 per cent. The excess variance of the light curve is smaller than that of Seyfert galaxies, entirely consistent with the relationship between variability amplitude and luminosity defined from the Seyfert data alone. The power spectrum of the RXTE light curve follows a power‐like form of slope ∼−1. However, when we extend the power spectrum estimation at higher frequencies using archival ASCA data, we find strong evidence for an intrinsic steepening to a slope of ∼−2 at around ∼1 × 10−6 Hz. This ‘break frequency’ corresponds to a time‐scale of ∼10 d. The time‐average energy spectrum is well fitted by a Γ∼ 2 power‐law model. We also find evidence for an iron line at ∼6.4 keV (rest frame) with EW ∼ 110 eV, similar to what is observed in Seyfert galaxies. The flux variations are not associated with any spectral variation. This is the only major difference that we find when we compare the variability properties of PG 0804+761 with those of Seyfert galaxies. Our results support the hypothesis that the same X‐ray emission and variability mechanism operates in both Seyfert galaxies and quasars.

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