Multiwavelength Observations of Short-Timescale Variability in NGC 4151. II. Optical Observations

Kaspi, S.; Maoz, Dan; Netzer, H.; Peterson, B. M.; Alexander, Tal; Barth, Aaron J.; Bertram, R.; Cheng, F. H.; Chuvaev, K. K.; Edelson, R.; Filippenko, AV; Hemar, Shirley; Ho, L. C.; Kovo, O.; Matheson, T.; Pogge, R. W.; Qian, BC; Smith, S.; Wagner, R. M.; Wu, H. R.; Xue, SJ; Zou, ZL

doi:10.1086/177870

Cited by 103 publications

(141 citation statements)

References 20 publications

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“…To address such situation, we proposed a hybrid method to detect unknown weak periodic signals in the AGN light curves, which is a modification of the recently proposed timing methods used Hα Dietrich et al 1998Shapovalova et al 2010Sergeev et al 2011Dietrich et al 2012Afanasiev et al 2015 50000 51000 52000 53000 54000 55000 56000 JD -2400000 in geophysics (Pering et al 2014) and acoustics research (Yang & Tse 2005 Kaspi et al 1996Shapovalova et al 2010Bon et al 2012 47000 48000 49000 50000 51000 52000 53000 54000 JD -2400000 for investigation of transient or unstable periodic phenomena), and Spearman correlation technique that accounts for non-linearity and variable amplitude of the wavelet coefficients.…”

Section: Methodsmentioning

confidence: 99%

“…Due to complexity of this object, it might be useful to search for periodicity information hidden in the other wavebands, i. e. the continuum 1370 Å, Lyα and CIV lines collected by IUE satellite from 1978-1992(Wamsteker et al 1997) and from 1994December to 1996March (O' Brien et al 1998 (iv) For NGC 4151, Fig. 3, the light curves include observations from Kaspi et al (1996Kaspi et al ( , covering period over two months in 1993, from Shapovalova et al (2010bShapovalova et al ( , covering period 1996Shapovalova et al ( -2006, and finally we added two observations presented in Bon et al (2012Bon et al ( , one from 1986Bon et al ( , and other from 1989; (v) Up to now, for E1821+643 the only information available are fluxes obtained from its the first long term monitoring campaign conducted by Shapovalova et al (2016) …”

Section: The Light Curvesmentioning

confidence: 99%

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Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

Kovačević

Pérez-Hernández

Shapovalova

et al. 2018

Monthly Notices of the Royal Astronomical Society

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A new combined data of 5 well known type 1 AGN are probed with a novel hybrid method in a search for oscillatory behavior. Additional analysis of artificial light curves obtained from the coupled oscillatory models gives confirmation for detected periods that could have physical background. We find periodic variations in the long-term light curves of 3C 390.3, NGC 4151, NGC 5548 and E1821+643, with correlation coefficients larger than 0.6. We show that oscillatory patterns of two binary black hole candidates NGC 5548 and E1821+643 corresponds to qualitatively different dynamical regimes of chaos and stability, respectively. We demonstrate that absence of oscillatory patterns in Arp 102B could be due to a weak coupling between oscillatory mechanisms. This is the first good evidence that 3C 390.3 and Arp 102B, categorized as double-peaked Balmer line objects, have qualitative different dynamics. Our analysis shows a novelty in the oscillatory dynamical patterns of the light curves of these type 1 AGN.

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Section: Methodsmentioning

confidence: 99%

Section: The Light Curvesmentioning

confidence: 99%

Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

Kovačević

Pérez-Hernández

Shapovalova

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…Peterson 1993;Netzer & Peterson 1997 for a review; Marshall et al 1997;Nandra et al 1998;Edelson et al 2000). Thus, over the last decade, several large space-based and ground-based monitoring programs have been undertaken for nearby AGN, such as NGC 5548 (Clavel et al 1991;Peterson et al 1991Peterson et al , 1992Peterson et al , 1994Peterson et al , 1999Maoz et al 1993;Dietrich et al 1993;Korista et al 1995;Chiang et al 2000), NGC 3783 Stirpe et al 1994;Alloin et al 1995), NGC 4151 Kaspi et al 1996;Warwick et al 1996;Edelson et al 1996), Fairall 9 (Rodríguez-Pascual et al 1997Santos-Lleó et al 1997), 3C 390.3 (Leighly et al 1997;Dietrich et al 1998;O'Brien et al 1998), and NGC 7469 (Wanders et al 1997;Collier et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…However short term monitoring campaigns had been undertaken for NGC 4151 (Xanthopoulos & DeRobertis 1991;Crenshaw et al 1996;Kaspi et al 1996;Warwick et al 1996;Edelson et al 1996) and for a small sample of AGN (e.g. NGC 5548, NGC 4151, 3C 390.3, Arp102B, Mkn 6;Eracleous & Halpern 1993).…”

Section: Introductionmentioning

confidence: 99%

A spectroscopic and photometric study of short-timescale variability in NGC 5548

Dietrich

Bender

Bergmann

et al. 2001

A&A

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Abstract.Results of a ground-based optical monitoring campaign on NGC 5548 in June 1998 are presented. The broad-band fluxes (U , B, V ), and the spectrophotometric optical continuum flux F λ (5100Å) monotonically decreased in flux while the broad-band R and I fluxes and the integrated emission-line fluxes of Hα and Hβ remained constant to within 5%. On June 22, a short continuum flare was detected in the broad band fluxes. It had an amplitude of about ∼18% and it lasted only ≈90 min. The broad band fluxes and the optical continuum F λ (5100Å) appear to vary simultaneously with the EUV variations. No reliable delay was detected for the broad optical emission lines in response to the EUVE variations. Narrow Hβ emission features predicted as a signature of an accretion disk were not detected during this campaign. However, there is marginal evidence for a faint feature at λ 4962Å with F W HM 6Å redshifted by ∆v 1100 km s −1 with respect to Hβnarrow.

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“…(Paper V) Optical (Ground-based) Stirpe et al (1994) (Paper VI) NGC4151 UV (IUE) Crenshaw et al (1996) Optical (Ground-based) Kaspi et al (1996) X-ray (ROSAT/ASCA) & γ-Ray (CGRO) Warwick et al (1996) Edelson et al The individual UV and optical continuum variability characteristics of the AGN monitored by AGN Watch are discussed in detail in the publications listed in Table 1. The principal results are:…”

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confidence: 99%

AGN Watch continuum monitoring of radio-quiet and radio-loud AGN

O’Brien

Leighly

1998

Advances in Space Research

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The International AGN Watch has monitored a number of radio-quiet and radio-loud Active Galactic Nuclei -the most luminous objects in the universe. We present a review of the main observational results from the continuum monitoring campaigns, concentrating on those which aim to quantify the simultaneous ultraviolet to X-ray variability characteristics. These data provide strong constraints on the proposed continuum emission mechanisms. The AGN Watch campaigns have made extensive use of a wide variety of both ground-and space-based multi-waveband observational facilities, and we stress that long-term simultaneous access to the entire electromagnetic spectrum is essential if further progress is to be made. THE INTERNATIONAL AGN WATCHIn the late 1980's an informal consortium of about 100 astronomers was formed to obtain large, high-quality multi-waveband data for investigation of the continuum and emission-line variability characteristics of Active Galactic Nuclei (AGN). The consortium was formed in response to the realization that small groups were unlikely to obtain large amounts of observing time, and would face great practical difficulty in both coordinating observations over many months and rapidly reducing data from numerous ground-based and orbiting observatories. The AGN Watch exists to obtain such data and rapidly place them in the public domain. Smaller collaborations, drawn from both inside and outside AGN Watch, can then use these data to place firm constraints on the seemingly evergrowing list of proposed AGN models. Here we summarize the continuum monitoring campaigns. The emission-line monitoring is presented elsewhere (e.g. Peterson, these proceedings). CONTINUUM MONITORING OF SEYFERT 1 GALAXIESThe AGN watch has conducted campaigns on 7 AGN to date. The object names, wavebands covered and publications in which the original data can be found are given in Table 1. The initial campaigns concentrated on UV (1150-3200Å) and optical monitoring using IUE and numerous ground-based telescopes. More recently the campaigns have been expanded to the EUV, X-ray and γ-ray wavebands to investigate the photoionizing continuum in detail, and to the IR to investigate the properties of hot dust and the putative dense molecular torus around the nucleus.

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Multiwavelength Observations of Short-Timescale Variability in NGC 4151. II. Optical Observations

Cited by 103 publications

References 20 publications

Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

A spectroscopic and photometric study of short-timescale variability in NGC 5548

AGN Watch continuum monitoring of radio-quiet and radio-loud AGN

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