So is Abrasax the name of this Angel of the Jews?Abrasax is not the name of the Yahweh Angel of the Jews according to Basilides. Abrasax is the astral lord who rules the celestial spheres. He is distinct from the Yahweh Angel who is the ruler of the lowest of the heavens (365th heaven) that is visible from earth. Abrasax probably originated in the magical traditions of Egypt and the Hermetic practioners. He is found named on many gems and in the Greek Magical Papyri.
Incidentally, Abrasax sounds like Carlos Santana's 1970 album, but the 's' and the 'x' or reversed. And I can't remember where I heard it, but someone told me it was the name of a fallen angel (or demon). Would you know anything about this, Dr. D.
His name was created to equal 365. In Greek numerology each letter is associated with a number. When the letters of his name are added up, they equal 365. Thus he is the god responsible for the astral sphere. He would be the one most powerful in controlling your fate. So appeasing him (and using his Name) would be very important and give you some sense of control.
His name is spelled variously: Abrasax and Abraxas. Thus Santana's album. Abrasax is no fallen Jewish angel, although he is a "demon" in the sense that he is a capricious very powerful power in the skies who controls your fate, ruling the entire universe. The fallen angel you are thinking of is likely Azazel.