Zobrazeno 1 - 10
of 1 024
pro vyhledávání: '"Papadakis I"'
Context: Extensive, multi-wavelength monitoring campaigns of nearby and higher redshift active galactic nuclei (AGN) have shown that the UV/optical variations are well correlated with time delays which increase with increasing wavelength. Such behavi
Externí odkaz:
http://arxiv.org/abs/2411.09681
Active galactic nuclei (AGNs) are known to be variable across all wavelengths. Significant observational efforts have been invested in the last decade in studying their ultraviolet (UV) and optical variability. Long and densely sampled, multi-wavelen
Externí odkaz:
http://arxiv.org/abs/2409.10417
Autor:
Kumar, Shrabani, Dewangan, G. C., Gandhi, P., Papadakis, I. E., Mithun, N. P. S., Singh, K. P., Bhattacharya, D., Zdziarski, A. A., Stewart, G. C., Bhattacharyya, S., Chandra, S.
We present a multi-wavelength spectral study of NGC 4151 based on five epochs of simultaneous AstroSat observations in the near ultra-violet (NUV) to hard X-ray band ($\sim 0.005-80$ keV) during $2017 - 2018$. We derived the intrinsic accretion disk
Externí odkaz:
http://arxiv.org/abs/2409.04762
Recently, nearby active galactic nuclei (AGN) have been subject to long X-rays/UV/optical monitoring campaigns. These campaigns reveal a strong correlation between the various UV and optical bands, with time lags increasing with wavelength. In a seri
Externí odkaz:
http://arxiv.org/abs/2403.12208
Autor:
Papadakis, I. E., Binas-Valavanis, V.
Publikováno v:
A&A 685, A50 (2024)
We study the X-ray power spectrum of Active Galactic Nuclei (AGN) to investigate whether Seyfert I and II power spectra are similar or not, whether the AGN variability depends on black hole mass and accretion rate, and to compare the AGN power spectr
Externí odkaz:
http://arxiv.org/abs/2402.15373
Autor:
Gliozzi, M., Williams, J. K., Akylas, A., Papadakis, I. E., Shuvo, O. I., Halavatkar, A., Alt, A.
The black hole mass MBH is crucial in constraining the growth of supermassive BHs within their host galaxies. Since direct measurements of MBH with dynamical methods are restricted to a limited number of nearly quiescent nearby galaxies and a small m
Externí odkaz:
http://arxiv.org/abs/2312.14098
We study the connection between the variations in the far ultra-violet (FUV), near ultra-violet (NUV) and X-ray band emission from NGC 4051 using 4-days long AstroSat observations performed during 5-9 June 2016. NGC 4051 showed rapid variability in a
Externí odkaz:
http://arxiv.org/abs/2311.02722
In this paper, we present an updated version of our model (KYNXiltr) which considers thermal reverberation of a standard Novikov-Thorne accretion disc illuminated by an X-ray point-like source. Previously, the model considered only two cases of black
Externí odkaz:
http://arxiv.org/abs/2309.05392
Autor:
Blinov, D., Maharana, S., Bouzelou, F., Casadio, C., Gjerløw, E., Jormanainen, J., Kiehlmann, S., Kypriotakis, J. A., Liodakis, I., Mandarakas, N., Markopoulioti, L., Panopoulou, G. V., Pelgrims, V., Pouliasi, A., Romanopoulos, S., Skalidis, R., Anche, R. M., Angelakis, E., Antoniadis, J., Medhi, B. J., Hovatta, T., Kus, A., Kylafis, N., Mahabal, A., Myserlis, I., Paleologou, E., Papadakis, I., Pavlidou, V., Papamastorakis, I., Pearson, T. J., Potter, S. B., Ramaprakash, A. N., Readhead, A. C. S., Reig, P., Słowikowska, A., Tassis, K., Zensus, J. A.
Publikováno v:
A&A 677, A144 (2023)
Optical polarimeters are typically calibrated using measurements of stars with known and stable polarization parameters. However, there is a lack of such stars available across the sky. Many of the currently available standards are not suitable for m
Externí odkaz:
http://arxiv.org/abs/2307.06151
Autor:
Kumar, Shrabani, Dewangan, G. C., Singh, K. P., Gandhi, P., Papadakis, I. E., Tripathi, P., Mallick, L.
$\require{mediawiki-texvc}$ We study accretion disk emission from eight Seyfert $1 - 1.5$ active galactic nuclei (AGN) using far ultra-violet ($1300-1800$ ${\AA}$) slit-less grating spectra acquired with AstroSat/UVIT. We correct for the Galactic and
Externí odkaz:
http://arxiv.org/abs/2303.11882