What is referred to as the death's head in Night?

In section one of Elie Wiesel's memoir Night, the Germans arrive in the Jewish town of Sighet in Transylvania, expressly to round up the Jewish residents and send them to the concentration camps in Poland and Germany. The German troops who were responsible for gathering the Jews and administering the camps were the SS, or "Schutzstaffel", which is German for "Protective Echelon". They were originally the bodyguards of Hitler and owed their allegiance only to him. The insignia they wore both on their helmets and their shoulders was a silver skull, in German the "totenkopf", called the "death's head." Wiesel writes,

Anguish, German soldiers—with their steel helmets, and their emblem, the death's head.

It was, of course, a fitting emblem for the organization which was responsible for mass atrocities throughout Europe between 1939-1945. In Night, the Jews are in a state of denial about the Germans to the very end, and even the presence of the "death's head" doesn't keep them from thinking all would work out. Wiesel writes,

The Germans were already in the town, the Fascists were already in power, the verdict had already been pronounced, yet the Jews of Sighet continued to smile.

Not long after the appearance of the "death's head", Elie and his family are deported to Auschwitz.