Book reviews

Karas, Thomas H.; Brown, Neville; Treverton, Gregory F.

doi:10.1080/00396338708442353

Cited by 11 publications

(13 citation statements)

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“…If the red feature is related to the central illumination of a non-axisymmetric (e.g. spiral) structure on the disc with high emissivity, such as that resulted from density and ionization perturbations or magnetohydrodynamic turbulence considered by Karas et al (2001) and Armitage & Reynolds (2003), respectively, then the line flux modulates as the structure orbits around but can be independent from the illuminating source.…”

Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 99%

“…Note that because a flare is not expected to last much longer than a few dynamical time-scales or be strictly periodic due to its orbital drift as the disc material spirals in (e.g. Karas, Martocchia & Subr 2001), the number of detectable cycles will be limited even in much longer observations. Flares occurring at small radii and/or black holes having small mass could provide shorter characteristic time-scales.…”

Section: N T E R P R E Tat I O N a N D M O D E L L I N Gmentioning

confidence: 99%

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Flux and energy modulation of redshifted iron emission in NGC 3516: implications for the black hole mass

Iwasawa

Miniutti

Fabian

2004

Monthly Notices of the Royal Astronomical Society

113

131

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We report on the tentative detection of the modulation of a transient, redshifted Fe Kα emission feature in the X‐ray spectrum of the Seyfert galaxy NGC 3516. The detection of the spectral feature at 6.1 keV, in addition to a stable 6.4‐keV line, has been reported previously. We find, on reanalysing the XMM–Newton data, that the feature varies systematically in flux at intervals of 25 ks. The peak moves in energy between 5.7 and 6.5 keV. The spectral evolution of the feature agrees with Fe K emission arising from a spot on the accretion disc, illuminated by a corotating flare located at a radius of (7–16) rg, modulated by Doppler and gravitational effects as the flare orbits around the black hole. Combining the orbital time‐scale and the location of the orbiting flare, the mass of the black hole is estimated to be (1–5) × 107 M⊙, which is in good agreement with values obtained from other techniques.

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Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 99%

Section: N T E R P R E Tat I O N a N D M O D E L L I N Gmentioning

confidence: 99%

Flux and energy modulation of redshifted iron emission in NGC 3516: implications for the black hole mass

Iwasawa

Miniutti

Fabian

2004

Monthly Notices of the Royal Astronomical Society

113

131

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“…The most famous DBP emitters are NGC 1097 (Storchi-Bergmann, Baldwin & Wilson 1993;Storchi-Bergmann et al 1995, 1997, Arp 102B (Chen, Halpern & Filippenko 1989;Sulentic et al 1990;Antonucci, Hurt & Agol 1996;Halpern et al 1996;Chen, Halpern & Titarchuk 1997) and 3C390.3 (Gilbert et al 1999;Shapovalova et al 2001) etc. A successful model for DBP emitters is the accretion disc model (circular disc model: , elliptical disc model: Eracleous et al 1995, warped disc model: Bachev 1999Hartnoll & Blackman 2000, circular disc with spiral arm model: Karas, Martocchia & Subr 2001;Hartnoll & Blackman 2002). There are now two samples of DBP emitters; one includes 23 objects which are nearly all, LINERs from radio galaxies (Eracleous & Halpern 1994;Eracleous et al 1995;Eracleous & Halpern 2003), the other includes 112 objects, of which 12 per cent are classified as LINERs (Strateva et al 2003) selected from the Sloan Digital Sky Survey (SDSS) DR2 (York et al 2000).…”

Section: Introductionmentioning

confidence: 99%

The sizes of broad emission line regions and black hole masses of double-peaked broad low-ionization emission line objects

Zhang

Dultzin‐Hacyan

Wang

2007

Monthly Notices of the Royal Astronomical Society

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In this paper, the sizes of the broad emission line regions (BLRs) and black hole (BH) masses of double‐peaked broad low‐ionization emission line emitters (DBP emitters) are compared using different methods: virial BH masses versus BH masses from stellar velocity dispersions, the size of BLRs from the continuum luminosity versus the size of BLRs from the accretion disc model. First, the virial BH masses of DBP emitters estimated by the continuum luminosity and linewidth of broad Hβ are about six times (a much larger value, if including another DBP emitters, of which the stellar velocity dispersions are traced by the linewidths of narrow emission lines) larger than the BH masses estimated from the relation MBH–σ which is a more accurate relation to estimate BH masses. Second, the sizes of the BLRs of DBP emitters estimated by the empirical relation of RBLR–L5100 Å are about three times (a much larger value, if including another DBP emitters, of which the stellar velocity dispersions are traced by the linewidths of narrow emission lines) larger than the mean flux‐weighted sizes of BLRs of DBP emitters estimated by the accretion disc model. The higher electron density of BLRs of DBP emitters would be the main reason which leads to smaller size of BLRs than the predicted value from the continuum luminosity.

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“…Observations and theoretical interpretations of wide X-ray lines (particularly the iron K α line) in AGNs are actively discussed in a number of papers (Yaqoob et al 1996;Wanders et al 1997;Sulentic et al 1998a,b;Paul et al 1998;Bianchi & Matt 2002;Turner et al 2002;Levenson et al 2002). The results of numerical simulations in the framework of different physical assumptions on the origin of the wide emissive iron K α line in the nuclei of Seyfert galaxies are presented in the following papers: Paul et al (1998) ;Bromley, Chen & Miller (1997); Pariev & Bromley (1998a) ;Pariev & Bromley (1998b); Cui, Zhang & Chen (1998) ;Bromley, Miller & Pariev (1998); Pariev et al (2001); Ma (2000); Ma (2002); Karas, Martocchia & Subr (2001). The results of Fe K α line observations and their possible interpretation are summarized by Fabian (2001).…”

mentioning

confidence: 99%

Magnetic fields in active galactic nuclei and microquasars

Кардашев¹,

Lukash²,

Repin³

2003

Monthly Notices of the Royal Astronomical Society

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Observations of active galactic nuclei and microquasars by ASCA, RXTE, Chandra and XMM–Newton indicate the existence of wide X‐ray emission lines of heavy ionized elements in their spectra. The emission can arise in the inner parts of accretion discs where the effects of general relativity must be counted; moreover, such effects can dominate. We describe a procedure to estimate an upper limit of the magnetic fields in the regions where X‐ray photons are emitted. We simulate typical profiles of the iron Kα line in the presence of a magnetic field and compare them with observational data. As an illustration, we find H < 1010–1011 Gs for Seyfert galaxy MCG–6‐30‐15. Using the perspective facilities of measurement devices (e.g. Constellation‐X mission) a better resolution of the blue peak structure of the iron Kα line will allow us to find the value of the magnetic fields if the latter are high enough.

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Book reviews

Cited by 11 publications

References 0 publications

Flux and energy modulation of redshifted iron emission in NGC 3516: implications for the black hole mass

Flux and energy modulation of redshifted iron emission in NGC 3516: implications for the black hole mass

The sizes of broad emission line regions and black hole masses of double-peaked broad low-ionization emission line objects

Magnetic fields in active galactic nuclei and microquasars

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