7143
where " a " is the radius of the circular aperture , " k " is equal to 2π / λ and J is a Bessel function .
 person: Bessel
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Bessel