a notable name in something
luminary - notable
If somebody is highly notable or respected for their skill at doing something or their expertise with regards to a particular subject, then they can be called a ‘luminary’. This word originally referred to a celestial body emitting light, so a good way to remember how to use it is to think of people who might figuratively emit light and offer knowledge and insight. Often applied in its plural form.
Our class were delighted to receive a talk from that doctor as she is quite a luminary in the medical profession.
Luminaries of stage and screen gathered in New York for the glitzy awards show last night.
A number of luminaries in the field were brought together to try and affect a solution to the ongoing crisis.