Time Delay Measurement of Mg ii Line in CTS C30.10 with SALT

Olejak, Aleksandra; Rałowski, Mateusz; Kozłowski, S.; Aldama, Mary Loli Martinez; Pych, W.; Hryniewicz, Krzysztof; Pietrzyński, G.; Figaredo, Catalina Sobrino; Haas, Martín; Šredzińska, Justyna; Krupa, Magdalena; Kurcz, Agnieszka; Udalski, A.; Górski, Marek; Karas, V.; Panda, Swayamtrupta; Śniegowska, Marzena; Naddaf, Mohammad-Hassan; Bilicki, Maciej; Sarna, M. J.

doi:10.3847/1538-4357/ab2913

Cited by 58 publications

(93 citation statements)

References 59 publications

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“…In the SWIFT/UVOT grism monitoring of NGC 5548, Cackett et al (2015) showed that the Mg II emission line is not strongly correlated with the continuum variability, and there is no significant lag between the two. However, more recent studies of CTS C30.10 (radio quiet quasar) and 3C 454.3 (blazar) Czerny et al (2019) and Nalewajko et al (2019) show that there are time delays of 562 +116 −68 and ∼600 days, respectively, between the continuum variations and the response of the Mg II emission line. León-Tavares et al (2013) and Isler et al (2013) reported the statistically significant flare-like event in the Mg II emission line in the blazar 3C 454.3.…”

Section: Mg II and Fe Ii Variabilitymentioning

confidence: 98%

Flare-like Variability of the Mg ii λ2798 Å Emission Line and UV Fe ii Band in the Blazar CTA 102

Chavushyan

Patiño-Álvarez

Amaya-Almazán

et al. 2020

ApJ

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We report on the detection of a statistically significant flare-like event in the Mg II λ 2798Å emission line and the UV Fe II band of CTA 102 during the outburst of autumn 2017. The ratio between the maximum and minimum of λ3000Å continuum flux for the observation period (2010 − 2017) is 179±15. Respectively, the max/min ratios 8.1±10.5 and 34.0±45.5 confirmed the variability of the Mg II emission line and of the Fe II band. The highest levels of emission lines fluxes recorded coincide with a superluminal jet component traversing through a stationary component located at ∼0.1 mas from the 43 GHz core. Additionally, comparing the Mg II line profile in the minimum of activity against the one in the maximum, we found that the latter is broader and blue-shifted. As a result of these findings, we can conclude that the non-thermal continuum emission produced by material in the jet moving at relativistic speeds is related to the broad emission line fluctuations. In consequence, these fluctuations are also linked to the presence of broad-line region (BLR) clouds located at ∼25 pc from the central engine, outside from the inner parsec, where the canonical BLR is located. Our results suggest that during strong activity in CTA 102, the source of non-thermal emission and broadline clouds outside the inner parsec introduces uncertainties in the estimates of black hole (BH) mass. Therefore, it is important to estimate the BH mass, using single-epoch or reverberation mapping techniques, only with spectra where the continuum luminosity is dominated by the accretion disk.

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Section: Mg II and Fe Ii Variabilitymentioning

confidence: 98%

Flare-like Variability of the Mg ii λ2798 Å Emission Line and UV Fe ii Band in the Blazar CTA 102

Chavushyan

Patiño-Álvarez

Amaya-Almazán

et al. 2020

ApJ

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“…We see that the majority of the sources follow radius-luminosity relation within uncertainties, with CTS252 being an outlier, which could be the hint of the trend of a smaller time-delay for higher Eddington-ratio sources as was already studied for Hβ measurements (Du et al, 2018;Martínez-Aldama et al, 2019a Figure 5. The radius-luminosity relation for MgII broad line using the sources as listed in Table 3 in Czerny et al (2019) and the new measurement of CTS C30.10 (orange star). The red dashed line stands for the standard Bentz relation R Hβ − L 5100 (Bentz et al, 2013), derived for 3000Å using the bolometric corrections from Netzer (2019): log(R BLR /1lt-day) = 1.391 + 0.533 log (L 3000 /10 44 erg s −1 ).…”

Section: Radius-luminosity Relation For Mgiimentioning

confidence: 99%

Current and Future Applications of Reverberation-Mapped Quasars in Cosmology

Panda

Martínez-Aldama

2019

Front. Astron. Space Sci.

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Reverberation mapping technique (RM) is an important milestone that has elevated our understanding of Active Galactic Nuclei (AGN) demographics, giving information about the kinematics and the structure of the Broad Line Region (BLR). It is based on the time-delay response between the continuum and the emission line. The time delay is directly related to the size of the BLR which in turn is related to the continuum luminosity of the source, producing the well-known Radius-Luminosity (RL) relation. The majority of the sources with RM data, have been monitored for their Hβ emission line in low redshift sources (z < 0.1), while there are some attempts using the Mg II line for higher redshift ranges. In this work, we present a recent Mg II monitoring for the quasar CTS C30.10 (z = 0.90) observed with the 10-meter Southern African Large Telescope (SALT), for which the RL scaling based on Mg II holds within measurement and time-delay uncertainties. One of the most important advantages of reverberation mapping technique is the independent determination to the distant source, and considering the large range of redshifts and luminosities found in AGNs their use in cosmological studies is promising. However, recently it has been found that highly accreting sources show the time delays shorter than expected from the RL relation. We have proposed a correction for this effect using a sample of 117 Hβ reverberating-mapped AGN with 0.02 < z < 0.9, which recovers the low scatter along with the relation. We are able to determine the cosmological constants, Ω m and Ω Λ . Despite the applied correction, the scatter is still large for being effective for cosmological applications. In the near future, Large Synoptic Survey Telescope (LSST) 1 will cover over 10 million quasars in six photometric bands during its 10-year run. We present the first step in modelling of light curves for Hβ and Mg II and discuss the quasar selection in the context of photometric reverberation mapping with LSST. With the onset of the LSST era, we expect a huge rise in the overall quasar counts and redshift range covered (z 7.0), which will provide a better constraint of AGN properties with cosmological purposes.

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“…The MgII emission‐line light curve is constructed based on a long‐slit spectroscopy using the SALT telescope in a service mode, using the slit width of 2″; for further details, please read Modzelewska et al () and Czerny et al (). The MgII line information was extracted from the quasar spectra in the wavelength range between 2700 and 2900 Å by fitting different spectral components to the spectra, namely, the power–law component corresponding to the accretion disc emission, FeII‐line pseudocontinuum, and the two kinematic components of MgII line (redshifted and blueshifted Lorentzians), each of which furthermore consists of a doublet at 2,796.35 and 2,803.53 Å, with a doublet ratio of 1.6.…”

Section: Observational Datamentioning

confidence: 99%

“…We show this using the example of a bright quasar CTS C30.10 at z = 0.9, for which the AGN continuum and MgII line‐emission light curves were obtained. The detailed observational analysis was shown in Modzelewska et al () and Czerny et al (). Here, we provide an overview of the time lag determination methods, which provide statistically robust results even for sparse and heterogeneous time series of more distant sources.…”

Section: Introductionmentioning

confidence: 99%

Reverberation mapping of distant quasars: Time lag determination using different methods

2019

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By applying different statistically robust methods, we analyze the time lag between the continuum and ionized line-emission (Mg II line) light curves for the distant bright quasar CTS C30.10 (redshift z∼0.9). The data were obtained by the 10-meter South African Large Telescope (SALT) telescope in South Africa. In detail, we demonstrate the application of several methods using the interpolated cross-correlation function (ICCF), discrete correlation function (DCF), z-transformed discrete correlation function (zDCF), von Neumann estimator, and the JAVELIN code package. In particular, we discuss the uncertainties of these methods. In conclusion, we find that the quasar lies on the broad-line region (BLR) size-monochromatic luminosity power-law scaling, BLR ∝ 1∕2 5100 , which was already confirmed for low-redshift sources. In case, the BLR size-luminosity relation holds for other distant sources, quasars could be used to probe cosmological models as "standard candles" complementary to supernovae Ia.

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Time Delay Measurement of Mg ii Line in CTS C30.10 with SALT

Cited by 58 publications

References 59 publications

Flare-like Variability of the Mg ii λ2798 Å Emission Line and UV Fe ii Band in the Blazar CTA 102

Flare-like Variability of the Mg ii λ2798 Å Emission Line and UV Fe ii Band in the Blazar CTA 102

Current and Future Applications of Reverberation-Mapped Quasars in Cosmology

Reverberation mapping of distant quasars: Time lag determination using different methods

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