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The Changing Look AGN NGC 2617 is in the deepest low stateстатья
- Авторы: Oknyansky V.L., Tsygankov S.S., Dodin A.S., Tatarnikov A.M., Metlov V.G., Burlak M.A., Ikonnikova N.P., Belinski A.A., Shatsky N.I., Chelouche D., Figaredo C.Sobrino, Kaspi S., Brotherton M., Pu D.
- Журнал: The Astronomer’s Telegram
- Номер: ATel #16324
- Год издания: 2023
- Аннотация: We report on recent observations of the Changing Look (CL) AGN NGC2617 obtained by the Neil Gehrels Swift Observatory and with ground-based telescopes (at WIRO, CMO, Wise and some others). The object was observed to undergo a dramatic change from a largely obscured Seyfert 1.8 to an unobscured Seyfert 1 from 2003 to 2013 (Shappee et al. 2013, ATel #5010, Shappee et al. 2014). We started monitoring NGC 2617 in 2016 to see if the object was in the Sy1 state yet (see details here Oknyansky et al. 2016, ATel #9015, #9030, #9050; Oknyansky et al. 2017, MNRAS, 467, 1496; Oknyansky et al. 2017, arXiv/1711.02631; Oknyansky et al. 2023, MNRAS, 525, 2571). In December 2017, the X-ray flux was shortly in its lowest minimum since monitoring began (in 1990) with X-ray flux being (2.71+/-0.55) E-12 erg/s/cm^2, UVW1=15.16+/-0.03, B=15.60+/-0.03 (Swift), but broad Hbeta emission was seen prominent. Later we observed several minima and maxima, but the object was mostly in a low activity and brightness state during the past several years (see Oknyansky et al., 2023). From the beginning of the present observing season in September 2023, the object was mostly in the state of very low continuum flux in all wavelengths as well as of low intensity of broad emission lines. In October 2023 the broad emission Hbeta was hardly seen and we found the object changing look (CL) to Sy1.9 type, more than 10 years after the first CL to Sy1 discovered by Shappee et al. (2014) in 2013. On November 1 (2023) we found a deeper minimum than was registered in December 2017 with an X-ray flux of (1.32+/-0.18) E-12 erg/s/cm^2 and a very soft X-ray spectrum with Photon index of 1.86+/-0.20. This deepest minimum is in agreement with a very low flux at UV/optical wavelengths (Swift/UVOT and our optical ground based photometry).
- Добавил в систему: Окнянский Виктор Львович