why are picard groups called picard groups

Question

I am looking for an origin of the picard groups. Unfortunately I cann't find a reference where this is mentionned. Does anybody know where the name comes from?

Answer 1

Here is a (translated) quote from G. Castelnuovo, "Sur les intègrales de différentielles totales appartenant à une surface irrégulaière", Comptes rendus hebdomadaires des séances de l'Acadeémie des sciences, Paris. 140, 23 Jan 1905. pp. 220-222:

out of respect for Picard's profound research on surfaces admitting a group of birational automorphisms, [he] proposes calling the variety $P$ (and [a certain] group $G_d$) the Picard variety (and Picard group) associated to the surface $X$.

I have found this in Kleiman's "The Picard scheme", which contains some further historical remarks.

Answer 2

According to wikipedia "The name is in honor of Émile Picard's theories, in particular of divisors on algebraic surfaces." I would assume one of the references on the page probably contains what you want.