"This is our synagogue."
Translation:Це наша синагога.
The usage of copula "є" in the modern standard Ukrainian is characteristic for the scientific, business, or journalistic style. In the spoken language copula "є" is not used, except for some special cases, for example, if the same word is used as subject and predicate: "Життя є життя." (p. 44)
To me the sentence does not look like one of those styles, so using "є" here sounds unnatural. Although, it may be used in some dialects.