New UV and X-ray Spectra of NGC 5548 during its Long-Lived Obscuration Event

We obtained coordinated UV and X-ray spectra of the Seyfert 1 galaxy NGC 5548 in January 2016, two and a half years after it was discovered to be in an unusual obscured state by Kaastra et al. High column density ($> 10^{22}~\rm cm^{-2}$), low-ionization gas strongly suppressed the soft X-ray continuum and produced broad ($1800~\rm km~s^{-1}$), blue-shifted ($v_{out} = -500~\rm km~s^{-1}$) UV absorption troughs associated with all UV permitted transitions including C II, C III, Si II, Si III, Si IV, C IV, N V, and Ly$\alpha$. The strength of the obscuration varied on timescales from a day to weeks, and it persisted from 2013 throughout the 2014 reverberation mapping campaign on NGC 5548 using HST. In 2016, our new observations show that NGC 5548 was still obscured. Our new spectra with HST/COS use 9 orbits with grating settings G130M/1096, G130M/1327, and G160M/1600 to cover 950 Å to 1800 \AA. We obtained 70 ks simultaneously with the XMM-Newton RGS. The spectra show continued soft X-ray absorption along with broad, fast, UV absorption associated with O VI and Ly$\beta$ and all other ions previously seen.