Martin, Peter, and Philip Kennedy

My gr. gr. grandfather, Martin Kennedy, was most likely from the area around Ahascragh.  I don't know much about his life in Ireland before he left.   He was born about 1818 and died in 1890.  According to his naturalization records (1846), he arrived in America in 1843.  He married Ellen Rafferty in 1848 (she was the daughter of Thomas Rafferty and Catherine Shanley).   He definitely had a brother named Peter Kennedy born about 1830) who also wound up in Baltimore, who I think married Mary Cecelia Dignan, adopted her sister's son, and was the proprietor of a saloon/restaurant.   A Bridget Kennedy, born 1790, was living with Martin in 1860 and I suspect that she was his mother (although the census record does not specify the relationship).  Since Martin named his first born child Peter, I believe his father may have been named Peter Kennedy.  I believe that Mary Kennedy, born about 1820 and married to Michael Naughton was his sister.   Philip Kennedy born about 1825 and Patrick Kennedy born 1824 may also be brothers (or cousins), since they also emigrated to Baltimore and were associated through baptisms with Martin and his brother Peter.   I've been trying to confirm the origin of Martin and trying to understand why he left prior to the famine.   His naturalization sponsors were Andrew Heavey (and Bridget Kennedy) and this Andrew was from the parish of Kilclooney in Ballinasloe, so there may be connection there as well.  I want to learn more about Martin (his origin, his parents, his siblings) and why he apparently left Ireland before the famine.  Any genealogic information on these various families would be so greatly appreciated!