Gustavo Dudamel starts a new era as music director of the New York Philharmonic in September, and he wants it to feel bold and modern. The orchestra announced a three-part opening to launch his first season in New York after 17 seasons with the Los Angeles Philharmonic. Dudamel begins at Radio City Music Hall on Sept. 10. He then leads a 9/11 anniversary concert at the World Trade Center site. His first Geffen Hall subscription program includes John Adams’ “On the Transmigration of Souls,” plus new music and Prokofiev. Dudamel will conduct a European tour one month into his tenure.