Rebrightening of the changing look Seyfert galaxy NGC 1566
ATel #12314; Dirk Grupe, Rebecca Mikula (Morehead State University), S. Komossa (MPIfR), Kris Stanek (OSU), Katie Auchettl (DARK), Ben Shappee, Anna Payne, James Armstrong (IfA Hawaii), Norbert Schartel, Michael Parker (ESAC), Xinyu Dai (U. Oklahoma)
on 20 Dec 2018; 22:07 UT
Credential Certification: Dirk Grupe (dgrupe007@gmail.com)
Subjects: Optical, Ultra-Violet, X-ray, AGN
We report on new Swift observations of the nearby Seyfert 1.5 galaxy NGC 1566
which indicate a rebrightening of the AGN in X-rays and the UV. NGC 1566 was discovered in a hard X-ray outburst in June 2018 by INTEGRAL (Ducci et al., ATel #11754) and Swift follow-up observation showed dramatic increases in its soft X-ray and UV fluxes as well (Ferrigno et al., ATel #11783; Kuin et al., ATel #11786; Grupe et al., ATel #11903). We continued monitoring NGC 1566 and it faded over the following months, reaching a low point by the end of October. It has steadily become brighter again and in our most recent Swift observation from 2018-December-18 it had an 0.3-10 keV flux (5.77+/-0.15)e-14 W/m^2 which corresponds to a count rate of 1.87+/-0.05 counts/s in the Swift XRT. This is a factor of about 3 higher than in October.
In the UVOT all 6 filters were used and we found the following (corrected/uncorrected for Galactic reddening) Vega magnitudes: V = 13.74/13.74, B = 14.42/14.45, U = 13.52/13.56, UVW1 = 13.65/13.70, UVM2 = 13.65/13.72, UVW2 = 13.84/13.90. All magnitudes were determined with a 3" source extraction radius to avoid significant contribution by starlight and have an uncertainty of 0.05 magnitudes. Since the end of October, NGC 1566 has become brighter by about 0.6 magnitudes in the UV filters.
We would like to thank Brad Cenko for approving our various ToO requests and the Swift team for executing our observations. We continue monitoring this AGN with Swift.
