Hi Damiana, and welcome to comparative-religion.com!
There are two main usuages of the term Aryan:
1/ The most common reference is to an ideology that Caucasian whites are the supreme triumphant expression of humanity on the planet. Really, this is quite a bastard mix of sources all forced together, referencing a small number of often extremist German/Austrian writers. There are no specific texts associated with this, excepting perhaps "Mein Kamf" by Adolf Hitler, which is simply a diatribe against Jews as much as anything.
2/ The second use of the term "Aryan" is much more interesting - this referes to the nomads of the Iranian Plateau, who are believed to have descended into the Indus Valley around 1500BC (I think) and conquered the fluorishing Harappa civilisation there.
This is especially interesting from a comparative point of view, not least because the Aryans very much defined the Hindu Pantheon, though likely some original Harappan forms survived tucked into the pantheon that later literature recorded.
The Aryans had a specific interest in fire - more to the point, fire worship - and in the Vedas prime respect and worship is given to fire deities such as Agni and Indra.
It's also interesting to see that fire workship remains in Iran - and consequently evolved into the first (long-lived) monotheisic religion, being Zoroastrianism.