Photometric reverberation mapping of 3C 120

Núñez, F. Pozo; Ramolla, M.; Westhues, C.; Bruckmann, C.; Haas, Martín; Chini, R.; Steenbrugge, K. C.; Murphy, M.

doi:10.1051/0004-6361/201219107

Cited by 50 publications

(66 citation statements)

References 37 publications

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“…The proposed technique of microlensing-aided reverberation mapping aims at taking advantage of this effect to measure the time lag between the continuum and broad line variations. Our method is not conceptually very different from photometric reverberation mapping (Haas et al 2011;Chelouche & Daniel 2012;Chelouche & Zucker 2013;Pozo Nuñez et al 2012;Edri et al 2012;Zu et al 2014;Bachev et al 2014). In that case, multi-band photometry is used to disentangle the flux of the continuum and of the BLR, while our technique can already be applied to singleband data.…”

Section: Introductionmentioning

confidence: 99%

Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping

Sluse¹,

Tewes²

2014

A&A

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Owing to the advent of large area photometric surveys, the possibility to use broad band photometric data, instead of spectra, to measure the size of the broad line region of active galactic nuclei, has raised a large interest. We describe here a new method using time-delay lensed quasars where one or several images are affected by microlensing due to stars in the lensing galaxy. Because microlensing decreases (or increases) the flux of the continuum compared to the broad line region, it changes the contrast between these two emission components. We show that this effect can be used to effectively disentangle the intrinsic variability of those two regions, offering the opportunity to perform reverberation mapping based on single band photometric data. Based on simulated light curves generated using a damped random walk model of quasar variability, we show that measurement of the size of the broad line region can be achieved using this method, provided one spectrum has been obtained independently during the monitoring. This method is complementary to photometric reverberation mapping and could also be extended to multi-band data. Because the effect described above produces a variability pattern in difference light curves between pairs of lensed images which is correlated with the time-lagged continuum variability, it can potentially produce systematic errors in measurement of time delays between pairs of lensed images. Simple simulations indicate that time-delay measurement techniques which use a sufficiently flexible model for the extrinsic variability are not affected by this effect and produce accurate time delays.

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Section: Introductionmentioning

confidence: 99%

Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping

Sluse¹,

Tewes²

2014

A&A

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“…We combined the RoBoTT telescope data (Pozo Nuñez et al 2012) with new data from the BEST II (Kabath et al 2009). …”

Section: Observations and Data Reductionmentioning

confidence: 99%

The stability of the optical flux variation gradient for 3C 120

Ramolla

Núñez

Westhues

et al. 2015

A&A

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New B-and V-band monitoring in 2014-2015 reveals that the Seyfert 1 Galaxy, 3C 120, has brightened by a magnitude of 1.4, compared to our campaign that took place in 2009-2010. This allowed us to check for the debated luminosity and time-dependent color variations claimed for SDSS quasars. For our 3C 120 data, we find that the B/V flux ratio of the variable component in the bright epoch is indistinguishable from the faint one. We do not find any color variability on different timescales ranging from about 1 to 1800 days. We suggest that the luminosity and time-dependent color variability is an artifact caused by analyzing the data in magnitudes instead of fluxes. The flux variation gradients of both epochs yield consistent estimates of the host galaxy contribution to our 7. 5 aperture. These results confirm that the optical flux variation gradient method works well for Seyfert galaxies.

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“…Because the narrow-band collects both the emission line flux and the underlying continuum, the challenge is to extract the pure emission line light curve. In the dedicated case study of 3C 120, Pozo Nuñez et al (2012) demonstrated that PRM reaches an accuracy similar to spectroscopic RM (Grier et al 2012).…”

Section: Introductionmentioning

confidence: 95%

“…An advantage is that it does not require high spatial resolution imaging and can be applied directly to the monitoring data. Recently, FVG has been tested on PRM data (Haas et al 2011;Pozo Nuñez et al 2012). These tests show that by using a well defined range for the host galaxy slope (Sakata et al 2010) it is possible to separate the AGN contribution at the time of the monitoring campaigns.…”

Section: Introductionmentioning

confidence: 99%

Size and disk-like shape of the broad-line region of ESO 399-IG20

Núñez

Westhues

Ramolla

et al. 2013

A&A

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We present photometric reverberation mapping of the narrow-line Seyfert 1 galaxy ESO 399-IG20 performed with the robotic 15 cm telescope VYSOS-6 at the Cerro Armazones Observatory. Through the combination of broad-and narrow-band filters we determine the size of the broad-line emitting region (BLR) by measuring the time delay between the variability of the continuum and the Hα emission line. We use the flux variation gradient method to separate the host galaxy contribution from that of the active galactic nucleus (AGN), and to calculate the 5100 Å luminosity L AGN of the AGN. Both measurements permit us to derive the position of ESO 399-IG20 in the BLR size -AGN luminosity R BLR ∝ L 0.5 AGN diagram. We infer the basic geometry of the BLR through modeling of the light curves. The pronounced sharp variability patterns in both the continuum and the emission line light curves allow us to reject a spherical BLR geometry. The light curves are best fitted by a disk-like BLR seen nearly face-on with an inclination angle of 6 • ± 3 • and with an extension from 16 to 20 light days.

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Photometric reverberation mapping of 3C 120

Cited by 50 publications

References 37 publications

Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping

Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping

The stability of the optical flux variation gradient for 3C 120

Size and disk-like shape of the broad-line region of ESO 399-IG20

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