Multiwavelength Monitoring of the Narrow‐Line Seyfert 1 Galaxy Arakelian 564. III. Optical Observations and the Optical–UV–X‐Ray Connection
| Autor: | M. H. Lannon, C. J. Taylor, W. Brinkmann, Bradley M. Peterson, P. Romano, T. L. Jewell, S. G. Sergeev, V. I. Pronik, C. M. Gaskell, Shai Kaspi, K. A. Crowley, H. Netzer, Zheng Zheng, S. Collier, Paul Martini, G. M. Stirpe, M. E. Hiller, K. S. Rumstay, I. Papamastorakis, E. Detsis, Mario Gliozzi, I. E. Papadakis, B. W. Peterson, R. W. Pogge, Philip Uttley, Hitoshi Negoro, Marianne Vestergaard, K. von Braun, S. Mathur, Alexei V. Filippenko, Ohad Shemmer, E. S. Klimek, Wei Li, R. Bertram, Richard R. Treffers, T. J. Turner, Robert Wagner, T. A. George, E. A. Sergeeva |
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| Rok vydání: | 2001 |
| Předmět: |
Physics
010308 nuclear & particles physics Astrophysics (astro-ph) X-ray FOS: Physical sciences Astronomy and Astrophysics Astrophysics Light curve 01 natural sciences Monitoring program Galaxy Wavelength Space and Planetary Science 0103 physical sciences Optical emission spectroscopy 010303 astronomy & astrophysics |
| Zdroj: | The Astrophysical Journal. 561:162-170 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1086/323236 |
| Popis: | We present the results of a two-year long optical monitoring program of the narrow-line Seyfert 1 galaxy Akn 564. The majority of this monitoring project was also covered by X-ray observations (RXTE) and for a period of ~50 days, we observed the galaxy in UV (HST) and X-rays (RXTE & ASCA) simultaneously with the ground-based observations. Rapid and large-amplitude variations seen in the X-ray band, on a daily and hourly time-scale, were not detected at optical and UV wavelengths, which in turn exhibited much lower variability either on short (one day) or long (several months) time-scales. The only significant optical variations can be described as two 2--4 day events with ~10% flux variations. We detect no significant optical line variations and thus cannot infer a reverberation size for the broad-line region. Similarly, the large X-ray variations seem to vanish when the light curve is smoothed over a period of 30 days. The UV continuum follows the X-rays with a lag of ~0.4 days, and the optical band lags the UV band by ~2 days. No significant correlation was found between the entire X-ray dataset and the optical band. Focusing on a 20-day interval around the strongest optical event we detect a significant X-ray--optical correlation with similar events seen in the UV and X-rays. Our data are consistent with reprocessing models on the grounds of the energy emitted in this single event. However, several large X-ray flares produced no corresponding optical emission. 10 pages, 6 figures included, LaTeX emulateapj5.sty, accepted for publication in The Astrophysical Journal |
| Databáze: | OpenAIRE |
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