You should notice that `HBrO_3` represents an oxyacid since it contains hydrogen and an oxyanion. Identifying the oxyanion yields that `BrO_3^-` is the bromate ion.
You need to name the acid starting with the name of oxyanion, hence, since its name contains brom, then the root is brom, `Br` , and since the name of oxyanion ends in -ate, you need to put the suffix -ic. At the end, you need to put the word that specifies the nature of compound, hence, you need to put acid.
Hence, the given oxyacid `HBrO_3` is called bromic acid.