Discovery of the NLS1 Mkn 335 in the lowest UV flux state ever.

ATel #11815; Dirk Grupe (Morehead State University), S. Komossa (MPIfR), & Luigi Gallo (St. Mary's University),
on 4 Jul 2018; 18:23 UT
Credential Certification: Dirk Grupe (dgrupe007@gmail.com)

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We report on the discovery of the highly variable Narrow-Line Seyfert 1 galaxy Mkn 335 (RA-2000=00h06m19.5s, Dec-2000=+20d12m11s) in its lowest ultra-violet flux state ever seen, since the beginning of our Swift monitoring. We have started monitoring Mkn 335 with Swift in May 2007 (Grupe et al. 2007, 2012) when it was caught in a very low X-ray flux state, and we have followed it ever since. In our most recent Swift observation on 2018-July-02, 10:00 (UT), we found it in the UVOT W2 filter at 14.15+/-0.04 mag which corresponds to an uncorrected flux of (2.25+/-0.09)e-14 W m^-2 (Galactic reddening E(B-V) = 0.035 in the direction of Mkn 335, resulting in 13.86 mag and 2.9e-14 W m^-2). This is even about 20% lower than the previous deep UV low state in December 2015 (Grupe et al. 2015, Atel #8477; Gallo et al. 2018, MNRAS 478, 2557). The X-ray flux also remains very low, with (1.7+/-0.2)e-15 W m^-2 in the 0.3-10 keV band.