The high-Eddington NLS1 Ark 564 has the coolest corona

Understand

Ark 564 is an archetypal Narrow line Seyfert 1 that has been well observed in soft X-rays from 0.3-10 keV, revealing a steep spectrum, strong soft excess, iron K emission line and dramatic variability on the order of hours.

• Because of its very steep spectrum, observations of the source above 10 keV have been sparse.
• We report here on the first NuSTAR observation of Ark 564.
• The source was observed for 200 ks with NuSTAR, 50 ks of which were concurrent with Suzaku observations.