The disciples of Vaiśampāyana became authorities in the Atharva Veda. They were known as the Carakas because they executed strict vows to free their guru from his sin of killing a brāhmaṇa.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
वैशम्पायनशिष्या वै चरकाध्वर्यवोऽभवन् । यच्चेरुर्ब्रह्महत्यांहः क्षपणं स्वगुरोर्व्रतम्
vaiśampāyanaśiṣyā vai carakādhvaryavo'bhavan | yaccerurbrahmahatyāṃhaḥ kṣapaṇaṃ svagurorvratam
SB 12.6.61