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4 results on '"NGC 3516"'

1. Long-Term Optical Monitoring of Broad-Line AGNs (LoTerm AGN): Case Study of NGC 3516.

Author

Ilić, Dragana, Popović, Luka Č., Burenkov, Alexander, Shablovinskaya, Elena, Malygin, Eugene, Uklein, Roman, Moiseev, Alexei V., Oparin, Dmitry, Patiño Álvarez, Víctor M., Chavushyan, Vahram, Marziani, Paola, D'Onofrio, Mauro, Floris, Alberto, Kovačević, Andjelka B., Jovičić, Jovana, Miković, Djordje, Rakić, Nemanja, Simić, Saša, Marčeta Mandić, Sladjana, and Ciroi, Stefano

Subjects
*CONSTRAINTS (Physics)
Abstract

Properties of the broad line region (BLR) in active galactic nuclei (AGNs) are commonly used to estimate the mass of the supermassive black hole (SMBH) that powers an AGN. However, the understanding of the physics behind the BLR remains incomplete. The AGNs exhibit strong optical variability, observed in the change of the profiles and fluxes of broad emission lines. Utilizing this variability provides an opportunity to constrain the physics of the BLR, and understand the interplay of the BLR with SMBH and surrounding regions. Here, we present the long-term monitoring campaign of a sample of the known broad-line AGNs (identified as LoTerm AGN). The aim of this study is to show the importance of sustained and dedicated campaigns that continually collect spectroscopic data of the known AGNs over extended timescales, providing unique insight into the origin and structure of the BLR. LoTerm AGN is a collaborative network of seven moderate-size telescopes equipped for spectroscopy. We focus on the recent spectral data of the known changing-look AGN, NGC 3516. Specifically, we examine the broad hydrogen Balmer H α line observed in the period 2020–2023, demonstrating that this AGN remains active with the BLR signatures observed in the spectra. No significant change in the broad line profile of H α line is observed during this recent period. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Long-Term Optical Monitoring of Broad-Line AGNs (LoTerm AGN): Case Study of NGC 3516

Author

Dragana Ilić, Luka Č. Popović, Alexander Burenkov, Elena Shablovinskaya, Eugene Malygin, Roman Uklein, Alexei V. Moiseev, Dmitry Oparin, Víctor M. Patiño Álvarez, Vahram Chavushyan, Paola Marziani, Mauro D’Onofrio, Alberto Floris, Andjelka B. Kovačević, Jovana Jovičić, Djordje Miković, Nemanja Rakić, Saša Simić, Sladjana Marčeta Mandić, Stefano Ciroi, Amelia Vietri, Luca Crepaldi, and Ascensión del Olmo

Subjects
galaxies, active galactic nuclei, emission lines, NGC 3516, Physics, QC1-999
Abstract

Properties of the broad line region (BLR) in active galactic nuclei (AGNs) are commonly used to estimate the mass of the supermassive black hole (SMBH) that powers an AGN. However, the understanding of the physics behind the BLR remains incomplete. The AGNs exhibit strong optical variability, observed in the change of the profiles and fluxes of broad emission lines. Utilizing this variability provides an opportunity to constrain the physics of the BLR, and understand the interplay of the BLR with SMBH and surrounding regions. Here, we present the long-term monitoring campaign of a sample of the known broad-line AGNs (identified as LoTerm AGN). The aim of this study is to show the importance of sustained and dedicated campaigns that continually collect spectroscopic data of the known AGNs over extended timescales, providing unique insight into the origin and structure of the BLR. LoTerm AGN is a collaborative network of seven moderate-size telescopes equipped for spectroscopy. We focus on the recent spectral data of the known changing-look AGN, NGC 3516. Specifically, we examine the broad hydrogen Balmer Hα line observed in the period 2020–2023, demonstrating that this AGN remains active with the BLR signatures observed in the spectra. No significant change in the broad line profile of Hα line is observed during this recent period.

Published
2023
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3. Spectroscopic monitoring of active galactic nuclei. II. The Seyfert-1 galaxy NGC 3516

Author

Wanders, I., van Groningen, E., Alloin, D., Aretxaga, I., Axon, D., de Bruyn, A. G., Clavel, J., Dietrich, M., Goad, M. R., Gondhalekar, P., Horne, K., Jackson, N., Kollatschny, W., Laurikainen, E., Lawrence, A., Masegosa, J., O'Brien, P. T., del Olmo, A., Penston, M. V., Perea, J., Perez, E., Perez-Fournon, I., Perry, J. J., Robinson, A., Rodriguez Espinosa, J. M., Stirpe, G. M., Tadhunter, C., Terlevich, R., Unger, S., Wagner, S. J., Williams, R., Wanders, I., van Groningen, E., Alloin, D., Aretxaga, I., Axon, D., de Bruyn, A. G., Clavel, J., Dietrich, M., Goad, M. R., Gondhalekar, P., Horne, K., Jackson, N., Kollatschny, W., Laurikainen, E., Lawrence, A., Masegosa, J., O'Brien, P. T., del Olmo, A., Penston, M. V., Perea, J., Perez, E., Perez-Fournon, I., Perry, J. J., Robinson, A., Rodriguez Espinosa, J. M., Stirpe, G. M., Tadhunter, C., Terlevich, R., Unger, S., Wagner, S. J., and Williams, R.

Abstract

The authors present the results of a five month spectroscopic monitoring campaign of the Seyfert-1 galaxy NGC 3516. Using a new calibration method and applying a correction for seeing differences during the various observations they can scale the spectra to each other with a much higher accuracy than hitherto achieved. NGC 3516 shows large amplitude variations on a time scale of several weeks. Asymmetric profile variations occur on the same time scale as the continuum variations. The authors show the presence of a varying dip on the blue wing of the Hbeta profile, which is not present on the Halpha profile, and which corresponds to the absorption features previously seen in the UV emission lines of NGC 3516. From cross-correlation analysis they find a time lag of 14plusmn2 days for the Halpha and 7plusmn3 days for the Hbeta emission-line response to continuum variations

Published
1993

4. Seeing and aperture effects on [O III]-based flux calibration of AGN spectra. NGC 3516 : a case study

Author

Wanders, I., Peterson, B. M., Pogge, R. W., DeRobertis, M. M., van Groningen, E., Wanders, I., Peterson, B. M., Pogge, R. W., DeRobertis, M. M., and van Groningen, E.

Abstract

In variability studies of the broad emission lines in the spectra of active galactic nuclei, the narrow emission lines are generally used to flux calibrate spectra taken at different epochs to each other. In objects where the narrow-line region is resolved, seeing affects the ratio of narrow-line flux to broad-line and continuum flux entering the aperture since the broad-line region and the continuum source are unresolved. Thus observing under different seeing conditions introduces artificial correlated variations of the continuum and broad-line fluxes if one assumes the narrow lines to be constant in flux. The authors show that one can correct for this effect by simulating seeing variations using a narrow-band [O III] image, taken in good seeing conditions, of the nearby Seyfert 1 galaxy NGC 3516, in which the narrow-line region is clearly resolved and extends over more than 20". They also show that centring the aperture on the object consistently is very important and miscentring is also a source of artificial variability of the broad-line and continuum fluxes

Published
1992

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