Is there a UV/X-ray connection in IRAS 13224−3809?

Buisson, D. J. K.; Lohfink, A.; Alston, W. N.; Cackett, Edward M.; Chiang, Chia-Ying; Dauser, Robert C.; Marco, Barbara De; Fabian, A. C.; Gallo, Luigi; García, Javier A.; Jiang, Jiachen; Kara, Erin; Middleton, Matthew; Miniutti, G.; Parker, M. L.; Pinto, C.; Uttley, P.; Walton, D. J.; Wilkins, D. R.

doi:10.1093/mnras/sty008

Cited by 35 publications

(37 citation statements)

References 78 publications

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“…In the case of NGC 5548, the X-ray emission has been found to lead the optical emission on timescales of 1 year (Uttley et al 2003), but it has been noted recently that the X-ray and UV/optical emissions correlate poorly on shorter timescales, which again require extra reprocessing mechanisms to explain such results (Edelson et al 2015;Gardner & Done 2017;Starkey et al 2017). Others, however, have found no correlation between the X-ray and UV emission, attributing this to light bending of a centrally compact X-ray source near to the black hole, X-ray flux in our line of sight not being correlated with the X-ray emission that is reprocessed in the disk, and/or other mechanisms driving the observed UV variability (Robertson et al 2015;Buisson et al 2018).…”

Section: Introductionmentioning

confidence: 65%

X-Ray and UV Monitoring of the Seyfert 1.5 Galaxy Markarian 817

Morales

Miller

Cackett

et al. 2019

ApJ

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We report the results of long-term simultaneous X-ray and UV monitoring of the nearby (z = 0.03145) Seyfert 1.5 galaxy Mrk 817 using the Neil Gehrels Swift Observatory XRT and UVOT. Prior work has revealed that the X-ray flux from Mrk 817 has increased by a factor of 40 over the last 40 years, whereas the UV emission has changed by a factor of 2.3. The X-ray emission of Mrk 817 now compares to some of the brightest Seyferts, but it has been poorly studied in comparison. We find that the X-ray (0.3-10.0 keV) and the UVM2 (roughly 2000-2500Å) fluxes have fractional variability amplitudes of 0.35 and 0.18, respectively, over the entire monitoring period (

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Section: Introductionmentioning

confidence: 65%

X-Ray and UV Monitoring of the Seyfert 1.5 Galaxy Markarian 817

Morales

Miller

Cackett

et al. 2019

ApJ

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“…Its X-ray spectrum shows a soft continuum with strong relativistic reflection and soft excess (Ponti et al 2010;Fabian et al 2013;Chiang et al 2015;Jiang et al 2018). The relationship between the variable X-ray and UV emission was explored in (Buisson et al 2018). The UV was found to have a low fractional variability amplitude (∼ 2 % on timescales ∼ < 10 −5 Hz) and no significant correlation was found between the X-ray and UV emission, which is typical of high accretion-rate Seyferts (e.g.…”

mentioning

confidence: 99%

The remarkable X-ray variability of IRAS 13224–3809 – I. The variability process

Alston

Fabian

Buisson

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present a detailed X-ray timing analysis of the highly variable NLS1 galaxy, IRAS 13224-3809. The source was recently monitored for 1.5 Ms with XMM-Newton which, combined with 500 ks archival data, makes this the best studied NLS1 galaxy in X-rays to date. We apply standard time-and Fourier-domain techniques in order to understand the underlying variability process. The source flux is not distributed lognormally, as expected for all types of accreting sources. The first non-linear rms-flux relation for any accreting source in any waveband is found, with rms ∝ flux 2/3 . The light curves exhibit significant strong non-stationarity, in addition to that caused by the rms-flux relation, and are fractionally more variable at lower source flux. The power spectrum is estimated down to ∼ 10 −7 Hz and consists of multiple peaked components: a lowfrequency break at ∼ 10 −5 Hz, with slope α < 1 down to low frequencies; an additional component breaking at ∼ 10 −3 Hz. Using the high-frequency break we estimate the black hole mass M BH = [0.5 − 2] × 10 6 M , and mass accretion rate in Eddington units, m Edd ∼ > 1. The broadband PSD and accretion rate make IRAS 13224-3809 a likely analogue of Very-high/Intermediate state black hole X-ray binaries. The non-stationarity is manifest in the PSD with the normalisation of the peaked components increasing with decreasing source flux, as well as the low-frequency peak moving to higher frequencies. We also detect a narrow coherent feature in the soft band PSD at 7×10 −4 Hz, modelled with a Lorentzian the feature has Q ∼ 8 and an rms ∼ 3 %. We discuss the implication of these results for accretion of matter onto black holes.

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“…For NLS1s the correlation between X-ray and UV variability is weak or nonexistent for some objects (see e.g. [23]).…”

Section: Monitoring Of the Typical CL Object Ngc 2617mentioning

confidence: 99%

Changing-look Narrow-Line Seyfert 1s?

Malanchev¹,

Gaskell²

2018

Proceedings of Revisiting Narrow-Line Seyfert 1 Galaxies and Their Place in the Universe — PoS(NLS1-2018)

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Two major challenges to unification schemes for active galactic nuclei (AGN) are the existence of Narrow-Line Seyfert 1s (NLS1s) and the existence of changing-look (CL) AGNs. AGNs can drastically change their spectral appearance in the optical (changing their Seyfert type) and/or in the X-ray region. We illustrate the CL phenomenon with our multi-wavelength monitoring of NGC 2617 and discuss its properties compared with NLS1s. There are few examples of CL NLS1s and the changes are mostly only in the X-ray region. It has been proposed that some of these could be cases of a tidal-disruption events (TDE) or supernova events. If BLRs have a flat geometry and NLS1s are seen face-on then we have to see CL cases only if the orientation of the BLR changes as a result of a TDE or a close encounter of a star without a TDE. If NLS1s include both high Eddington accretion rate and low-inclination AGNs then a significant fraction of NLS1s could be obscured and would not be identified as NLS1s. CL cases might happen more in such objects if dust sublimation occurs following a strong increase in the optical luminosity.Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe -NLS1 Padova

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Is there a UV/X-ray connection in IRAS 13224−3809?

Cited by 35 publications

References 78 publications

X-Ray and UV Monitoring of the Seyfert 1.5 Galaxy Markarian 817

X-Ray and UV Monitoring of the Seyfert 1.5 Galaxy Markarian 817

The remarkable X-ray variability of IRAS 13224–3809 – I. The variability process

Changing-look Narrow-Line Seyfert 1s?

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