Which South Indian poet and composer has a school of music where Sooryakantam  is called Chāyāvati ?
Suryakantam Suryakantam or Sooryakantam (pronounced sūryakāntam) is a rāgam in Carnatic music (musical scale of South Indian classical music). It is the 17th "melakarta" rāgam (parent scale) in the 72 "melakarta" rāgam system of Carnatic music. It is called Chāyāvati in Muthuswami Dikshitar school of Carnatic music.
Pavanadūta Pavanadūta (पवनदूत) or "Wind Messenger" was composed by Dhoyin or Dhoyī, a poet at the court of the Sena king Lakshmana who ruled Gauda, in what is now Bengal, during the latter part of the twelfth century CE. His Pavanadūta is probably the earliest surviving example of the many messenger poems which were written in imitation of the "Meghadūta" or Cloud Messenger by Kālidāsa. It tells the story of Kuvalayavatī, a gandharva maiden from the south who falls in love with King Laksmana when she sees him during his victory tour of the world. She asks the south wind to take her message to the king at his court.