Studying the long-time variability of the Seyfert 2 galaxy NGC 4388 with INTEGRAL and Swift

Fedorova, E.; Beckmann, V.; Neronov, A.; Soldi, S.

doi:10.1111/j.1365-2966.2011.19335.x

Cited by 21 publications

(20 citation statements)

References 43 publications

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“…On the other hand, the effect the decreasing dependence of FeK EW of the luminosity has been claimed (Bianchi et al 2007;Dadina 2008;Page et al 2004, Ricci 2013, Gimenez-Garcia et al, 2015 for the Seyfert1s in the range of 2 10 keV . Recently, Baldwin effect has been reported for Seyfert2s using the Suzaku data (Fukuzawa et al 2011) and both for Suzaku and XMM-Newton data (Ricci et al 2014b and references therein).…”

Section: 4the X-ray Baldwin Effectmentioning

confidence: 99%

“…This model predicts the low values of the exponential cutoff of the primary emission of an RL AGN (below 100 keV) and high values or absence of it in an RQ AGN spectrum. However, there are some objects that seem to contradict this paradigm , Fedorova et al 2011, Soldi et al 2005. That is why it is interesting to analyse the dependence of the high-energy exponential cut-off from the RL/RQ characteristics of the AGNs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

X-ray spectral parameters for a sample of 95 active galactic nuclei

Vasylenko

Жданов

Fedorova

2015

Astrophys Space Sci

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Section: 4the X-ray Baldwin Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

X-ray spectral parameters for a sample of 95 active galactic nuclei

Vasylenko

Жданов

Fedorova

2015

Astrophys Space Sci

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“…For instance, the most probable reasons of the great percentage of peculiar RL object can be in fact "fake" caused by the X-ray contamination from the jet. However, in the same time we note, especially for RQ objects, that the percentage of peculiar objects can be a bit higher due to uncorrelated variability in different ranges of energies [15]: a part of objects with a variable spectral shape like NGC 4388 or NGC 4945 [7,14], can be missed in an investigation like that of the present paper.…”

mentioning

confidence: 50%

“…One of the consequences of this model is that the innermost part of AD in RL AGN is disrupted and smeared away by powerful centrifugally-driven jet outflows, leading to the low values of the exponential cutoff in the spectrum of the primary emission (below 100 keV), whereas the high values or absence of the high-energy cut-off are prescribed to RQ AGN spectrum. However, some objects were found which seem to contradict this paradigm [6][7][8][9]. That is why it is interesting to compare the high-energy exponential cut-off with the RL/RQ characteristics of AGNs.…”

mentioning

confidence: 99%

Peculiar AGNs from the INTEGRAL and RXTE data

Fedorova¹,

Vasylenko²,

Жданов³

2017

BTSNUA

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However, for a long time in past there were no detected the positive correlations between the characteristics of sunspots cycle (Wolf number or the total area of spots) and polar magnetic flux (which characterized the value of poloidal field B P ) at the end of the cycle. In the terms of dynamo theory it was supposedly evidenced of the absence of functional dependence poloidal fields B P at the end of cycles on the toroidal field B T in maximum of cycles. As it turned out later, this was due to the fact that the surface α-effect of Babcock-Leighton (which defined by tilt angles of the bipolar magnetic fields, turbulent diffusion and meridional circulation, and causes the regeneration of the poloidal field) is characterized by random fluctuations in time and space. The situation, however, changed drastically after the introducing of the parameter of magnetic strength spots of cycle, which is a product of the area of spots cycle and tilt angles of the bipolar magnetic groups. By combining assimilation of the area of spots, the distance between the weighted canters of opposite magnetic polarity and the tilt angles, the functional dependence of polar magnetic flux (which is an indicator of poloidal field B P ) on the assimilated parameter magnetic strength of sunspots (which describes the relative intensity of the toroidal field B T ) was restored. Within the framework of the αΩ-dynamo this indicates that the surface α-effect of Babcock-Leighton leads to the generation of the poloidal magnetic field at the end of the current cycle, and assimilated parameter of magnetic strength spots of cycle is an integral component for future forecasts of solar activity based on the dynamo models. УДК PECULIAR AGNS FROM THE INTEGRAL AND RXTE DATAWe analysed how the active galactic nucleus (AGN) X-ray primary continuum depends on AGN activity in radio, using the data of RXTE Spectral & Timing Database (Rossi X-ray Timing Explorer) and INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory). Our aim is to test the relation between spectral shapes of these AGNs and the prediction of the "spinparadigm" model of the AGN "central engine". We have found that for the major part of radio-quiet (RQ) AGNs the value of highenergy exponential cut-off in primary spectrum appears to be significantly higher than 100 keV and thus follows the "spinparadigm" predictions. In the same time, near 25 % of radio-loud (RL) AGNs demonstrate the high-energy cut-off at the energies above 150 keV, contradicting the "spin paradigm". We have composed a sample of "peculiar" 69 RQ and 10 RL AGNs that seem to contradict to the "spin paradigm" for further individual studies of these objects.Key words: galaxies: Seyfert -X-rays: galaxies: active -galaxies Introduction. One of the most prominent physical differences between AGNs of various classes can be related with jet activity and RL/RQ dichotomy. There are several schemes explaining physical (non-geometrical) differences in the AGN structure, and one of the most well-known of them is often referred to as the ...

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“…On the other hand, NGC 4151 presents no changes in the slope of the underlying continuum for different X-ray fluxes but a significant variation of the temperature of the Comptonising plasma is observed [14]. For other objects, a clear variability pattern has not been recognized yet and equivalent flux levels can present significantly different spectral slopes (NGC 4388 [17], NGC 7172 [18]) or different cut-off energies (this work and IC 4329A [19]). …”

Section: Discussionmentioning

confidence: 97%

Compton processes in the bright AGN MCG +8-11-11

Soldi¹,

Beckmann²,

Gehrels³

et al. 2011

Proceedings of 8th INTEGRAL Workshop “The Restless Gamma-Ray Universe” — PoS(INTEGRAL 2010)

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We present preliminary results on the hard X-ray emission properties of the Seyfert 1.5 galaxy MCG +8−11−11, as observed by INTEGRAL and SWIFT. All the INTEGRAL IBIS/ISGRI data available up to October 2009 have been analysed together with two SWIFT/XRT snapshot observations performed in August and October 2009, quasi-simultaneously to INTEGRAL pointed observations of MCG +8−11−11. No correlation is observed between the hard Xray flux and the spectral slope, while the position of the high-energy cut-off is found to have varied during the INTEGRAL observations. This points to a change in the temperature of the Comptonising medium from a minimum value of kT e = 30 − 50 keV to values larger than 100-150 keV. There is no significant detection of Compton reflection, with a 3σ upper limit of R < 0.2, and no line has been detected at 112 keV, as previously claimed from HEAT observations (F 112 keV < 2.4 × 10 −4 ph cm −2 s −1 ). The variability behaviour of MCG +8−11−11 is found to be similar to that shown by IC 4329A, with different temperatures of the electron plasma for similar flux levels of the source, while other bright Seyfert galaxies present different variability patterns at hard X-rays, with spectral changes correlated to flux variations (e.g. NGC 4151).

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Studying the long-time variability of the Seyfert 2 galaxy NGC 4388 with INTEGRAL and Swift

Cited by 21 publications

References 43 publications

X-ray spectral parameters for a sample of 95 active galactic nuclei

X-ray spectral parameters for a sample of 95 active galactic nuclei

Peculiar AGNs from the INTEGRAL and RXTE data

Compton processes in the bright AGN MCG +8-11-11

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