As you do, heat immediately spreads from your hand throughout the rest of your body. You no longer feel the ice-cold air of the stone chamber; it's like you are standing before a warm hearthfire.
The runes on the sword are similar to those on the map you took from Fyespon, and the general style of the sword's decorations reminds you of that mural in another room of this complex.
Here is a better look at the runes on the sword: